A Beginner’s Guide to Water Management — Bacteria

A Beginner’s Guide toWater Management — Bacteria

Information Circular 106

Florida LAKEWATCHUF/IFAS

Department of Fisheries and Aquatic Sciences Gainesville, Florida

February 20031st Edition

Reviewed June 2020

This publication was produced by:

Florida LAKEWATCH © 2003UF/IFASDepartment of Fisheries and Aquatic Sciences7922 NW 71st StreetGainesville, FL 32653-3071Phone: (352) 392-4817Toll-Free Citizen Hotline: 1-800-LAKEWATCH (525-3928)

E-mail: [email protected]

Web Address: http://lakewatch.ifas.ufl.edu/

Copies of this document are available for download from the Florida LAKEWATCH website:

http://lakewatch.ifas.ufl.edu/LWcirc.html

As always, we welcome your questions and comments.

A Beginner’s Guide toWater Management — Bacteria

Information Circular 106

Florida LAKEWATCHUF/IFAS

Department of Fisheries and Aquatic Sciences Gainesville, Florida

February 20031st Edition

Reviewed June 2020

This publication was produced by:

Florida LAKEWATCH © 2003University of Florida / Institute of Food and Agricultural Sciences Department of Fisheries and Aquatic Sciences

7922 NW 71st Street

Gainesville, FL 32653-3071

Phone: (352) 392-4817

Toll-Free Citizen Hotline: 1-800-LAKEWATCH (525-3928)

E-mail: [email protected]

Web Address: http://lakewatch.ifas.ufl.edu/

Copies of this document are available for download

from the Florida LAKEWATCH website:

http://lakewatch.ifas.ufl.edu/LWcirc.html

A Beginner’s Guide to Water Management – The ABCs (Circular 101)This 44-page publication provides a basic introduction to the terminology and concepts used intoday’s water management arena, in a user-friendly glossary format.

A Beginner’s Guide to Water Management – Nutrients (Circular 102)A basic introduction to the presence of phosphorus and nitrogen—two nutrients commonly associatedwith algal growth and other forms of biological productivity in lakes. Limiting nutrients are alsodiscussed, along with conceptual and mathematical tools that can be used to achieve a variety ofwater management goals. The booklet is 36 pages in length.

A Beginner’s Guide to Water Management – Water Clarity (Circular 103)Anyone interested in the subject of water clarity can benefit from reading this 36-page circular.Topics include techniques for measuring water clarity, the factors that affect it, as well as adiscussion of the techniques needed and/or used for managing it.

A Beginner’s Guide to Water Management – Lake Morphometry (Circular 104)Knowledge of the size and shape of a lake basin (i.e., lake morphometry) can tell us a great dealabout how a lake system functions. It can also help us appreciate lakes for what they are and managethem with more realistic expectations. This 36-page booklet is recommended for anyone interestedin learning more about the terminology and techniques currently being used to study lake morphometryin Florida.

A Beginner’s Guide to Water Management – Symbols, Abbreviations & Conversion Factors(Circular 105)This 44-page booklet provides the symbols, abbreviations and conversion factors necessary tocommunicate with water management professionals and scientists in the U.S. and internationally.Included are explanations for expressing, interpreting and/or translating chemical compounds andvarious units of measure.

Copies of any of these publications can be obtained by contacting

the Florida LAKEWATCH office at 1-800-LAKEWATCH (1-800-525-3928).

They can also be downloaded for free from the Florida LAKEWATCH web site at:

http://lakewatch.ifas.ufl.edu/LWcirc.html

or from the

UF/IFAS Electronic Document Information System (EDIS):

http://edis.ifas.ufl.edu

In addition to reading this circular, we encourage youto read the five publications that precede it:

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After years of working with FloridaLAKEWATCH volunteers and discussinglake management issues with them, we’ve

come to the conclusion that bacterial contamina-tion is one of the major concerns, if not thebiggest, among citizens who live on or use ourstate waters. Such concerns are certainly under-standable; for centuries, waterborne diseases haveravaged human populations worldwide and, insome countries, continue even today. Fortunately,within the United States and Florida, advanceshave been made in the treatment of human wastethat have greatly reduced incidences of diseasefrom contaminated water.

So why are people still worried?It may have something to do with the

swimming beach closures that occur everysummer due to high bacteria counts, as well asperiodic reports of bacterial contamination indrinking water supplies. As sporadic as theseincidences may be, it is evidence that even withmodern technology and the improvements madein wastewater treatment, problems do occur.(As usual, it’s the rare problems that we remember,rather than the many successes.)

These occasional problems seem tounderscore a general apprehension amongsome Floridians that changes in land use andunprecedented population growth could becontributing to an increase in the contaminationof our local waters. When one considers thatthe state’s population has increased by morethan 115% in the past thirty years (i.e., since the1970s), with even more growth expectedduring the 21st century, it’s no surprise thatpeople are beginning to wonder about theeffects that such growth may be having on ourlakes, rivers and coastline.

The widespread development of permanenthomes and businesses, many of them built on ornear lakes, has been accompanied by a dramatic

increase in the number of septic tanks and/ormunicipal sewage treatment plants. With therecord pace at which many of these systemswere installed, concerns are re-emergingamongst citizens and some scientists.

Are these concerns warranted?As Professor Dan Canfield1 likes to say,

“Yes, no, and maybe.” No individual or agencycan guarantee with absolute certainty that recreat-ing in a given waterbody is completely withoutrisk. While this may be an unsettling thought tomany individuals, it is important to rememberthat in most monitored waters, there is a very,very low risk of becoming ill. When you driveyour car a few miles to the grocery store and backhome, you are exposing yourself to a muchgreater health risk than one would normallyexperience while recreating in Florida’s waters.

What should one do if bacterialcontamination is suspected?

The first thing to do is to stay well informedand this circular provides a good place to start.(See the outline provided at the end of the intro-duction for an overview of the topics covered.)

Secondly, if you or a group of homeownerssuspect recurring contamination and you havethe financial capability to pay for testing by aprivate laboratory, we recommend that you doso, as many public health agencies are limited inwhat they can do. If these agencies do test forbacteria, it usually involves only one or twoindicator tests. Then, due to lack of funding andpersonnel, their only option is often restricted tosimply ordering the site closed until re-testingindicates the water is again safe for use.

This is unfortunate, especially if there is a

1 Dr. Canfield is director of Florida LAKEWATCH, a citizen-based volunteer water monitoring program at the University ofFlorida’s Department of Fisheries and Aquatic Sciences.

Introduction

chronic problem that needs to be identified andeliminated.

Whether you hire a laboratory or decide tocollect water samples and do the testing yourself,we strongly suggest that you refer to the Part 7of this booklet for an easy, relatively inexpensiveapproach to guide you through the process. Evenif you have the financial resources to pay for morecomplicated testing methods (also described inthis circular), we think our Four Step approach is agood way to begin and may save further expense inthe long run.

Unless there is a catastrophic failure of amajor sewage collection line or septic system,finding a leak is not always easy or cheap. Insome instances, contamination can be the resultof outdated or improperly installed septic tanksand at other times, miles of leaky sewer linesmay be the culprit. Or it could be from an entirelydifferent point of origin; sometimes, bacterialcontamination is the result of naturally occurringanimal waste from birds and other wildlife livingnearby. “False alarms” are also common.

That’s why good detective work is requiredfrom both professionals and the general public.Everyone must recognize that, even if the source

of the problem may seem obvious at first, it’simportant to remain objective and not jump toconclusions before doing one’s homework.

The bottom line?Correcting the problem should be the most

important management objective once the publichas been warned about possible contamination!The solution to this problem should not belimited to simply foregoing the use of thewaterbody, but being aware and committed totracking down the source.

Lastly, remember that prudence shouldalways be the watchword when it comes to humanhealth. If you have been swimming in a lake,river or coastal waters and become ill, go seeyour doctor and be sure to tell her/him that youhave been in contact with recreational waters.You’ll probably find out that your illness is notrelated to a waterborne disease, but if it is, mostillnesses can be treated quickly and effectively.

Should you have any questions or concernsregarding bacterial contamination in your lake,please call Florida LAKEWATCH:

1-800-LAKEWATCH (1-800-525-3928).

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Included in this circular:Part 1 A Brief Lesson On Bacteria 1

Bacteria in Lakes, 1 Why the Concern? 1 Viruses and Protozoa in Water, 2

Sidebar: Amoebas in Lakes, 3

Part 2 Sources of Bacterial Contamination 5

Human Waste, 5 Domestic Animal Waste, 5 Naturally Occurring Contamination from Wildlife, 6

Sidebar: A Taxonomic Headache, 7

Part 3 The Wastewater Treatment Debate: 9Septic Tanks vs. Wastewater Treatment Plants

Septic Tanks, 9Wastewater Treatment Plants, 11

Sidebar: Septic Systems for Dogs, 13

Part 4 Indicators Used to Detect 15Bacterial Contamination inRecreational Waters

Enterobacteriaceae, 16Total coliforms, 18 Fecal coliforms, 19 Escherichia coli (E. coli), 20

Sidebar: Pseudomonas aeruginosa, 21 Enterococcus, 22

Sidebar: Other Indicators, 23

Part 5 Laboratory Methods for Counting 25Indicator Organisms

Membrane Filtration, 25 Most Probable Number, 25 Plate Counts, 26 Presence/Absence, 26

Sidebar: Which Laboratory Method DoesLAKEWATCH Use? 27

Part 6 Criteria for Assessing Coliform 29Contamination in Florida Waters

Part 7 A Four Step Process for Identifying 31and Locating Bacterial Contamination

The Good News Step 1 Collect Samples from Multiple Sites, 32 Step 2 Identify Sites with Elevated Fecal

Coliform Counts, 32 Step 3 Test for E. coli and Look for FalsePositives, 33

Step 4 Re-sample Sites with Elevated Fecal Coliform Counts, 34Sidebar: Locations to Consider When TrackingPossible Sources of Contamination, 35

Suppliers, 37Selected References, 38

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When we think about bacteria, many ofus often think of pathogenic (disease-causing) organisms that are notorious

for causing illnesses in humans such as cholera,tuberculosis, typhoid fever, etc. While admittedly,these diseases can be quite serious, it is importantto recognize that the bacteria responsible for suchillnesses represent a relatively small fraction of thethousands of “species” that are known to exist.

It also helps to keep things in perspectiveby acknowledging that bacteria have been aroundfor a very long time. In fact, fossil remains tell usthat one group of bacteria, known as Cyanobacteria,was among the first life forms to have beenestablished on earth more than three billion yearsago. Some scientists even theorize that theseorganisms helped to create the earth’s uniquelife-giving atmosphere by producing so muchoxygen, via photosynthesis, that eventually theatmosphere became habitable for other creatures.

Bacteria can be found in virtually everyenvironment you can think of including air, soil,and water. Some strains have even been found involcanic vents and deep inside arctic ice flows—environments once thought to be barren of anylife. However, bacteria are also found muchcloser to home. Did you know that a singleteaspoon of topsoil is thought to contain morethan a billion bacteria and one square centimeterof human skin holds an average of 100,000bacteria cells!

Bacteria in LakesBacteria are a natural component of life in

all aquatic systems including freshwater lakes,

rivers, streams and oceans, where they serve as“decomposers,” helping to break down deadplant and animal tissue and continually releasingnutrients back into the water. For example,Cyanobacteria play a critical role in the photosyn-thetic production that occurs within manyaquatic ecosystems,2 while other bacteria arecrucial to important chemical processes in watersuch as nitrogen fixation and denitrification.3

Why the Concern?Like most things in life, it only takes a few

troublemakers to spoil the fun. In this case,health officials are mostly concerned about asmall number of bacteria strains that are enteric(i.e., of or related to the intestines of warm-blooded animals, including humans), as well asopportunistic viruses and protozoa that can causeillness in people, particularly those with weakenedimmune systems.

Bacterial contamination generally refers toinstances in which human or animal wastes arefound in concentrations greater than the receivingwaters can handle (i.e., when the volume ofwater is not enough to dilute waste products toan acceptable level). In such instances, humans

2 Because cyanobacteria are aquatic and capable ofmaking their own food via photosynthesis, they aresometimes called blue-green algae.

3 Some bacteria are known to convert gaseous nitrogeninto nitrates or nitrites. The resulting products are releasedinto the water, making it possible for some plants to capturethese nutrients. This process is known as nitrogen fixation.When bacteria metabolize nitrates and turn them intonitrogen gas or nitrous oxide, it is known as denitrification.

Part 1A Brief Lesson on Bacteria

These standards tend to be conservative andexperience has shown that they are effective inpreventing human health problems nearly all ofthe time. However, even if risk levels may bedeemed acceptable, meeting the standard doesnot completely eliminate the possibility ofbecoming sick. Along those same lines, justbecause a bacterium enters a waterbody, it doesn’tnecessarily mean the risk of contracting a diseaseis increased. It simply means that there is thepotential for a problem.

Viruses and Protozoa in WaterBacteria are not the only microbial concern

related to water usage. Pathogenic viruses andprotozoa such as amoebas may also be present

2

drinking from, swimming in, or eating shellfishfrom a contaminated waterbody, run a greaterrisk of being exposed to harmful bacteria orpathogenic viruses that may also be present.

Because it is impossible to eliminate all harm-ful bacteria from aquatic environments, U.S.government health agencies have set standards foracceptable levels allowed in public waters.

See Part 6 on page 29 for more on the criteria usedto assess coliform contamination of Florida waters.

and can be even more difficult to detect. Forexample, an infectious dose for a virus is farlower than that of bacteria—by at least one orderof magnitude (i.e., 1/10th of the concentration).This means that detecting a virus in a waterbodyis akin to finding a microscopic-sized needle in ahaystack. Adding to the challenge is the fact thatsome enteric viruses can remain infective forseveral months in both sediments and water andtend to be somewhat resistant to disinfectants.

Testing for protozoa can also be tricky asthey are present in relatively low concentrations,even in polluted waters, and the number of organ-isms can change quickly over time. Currentmethods for detection are not well standardized,so there has been a lack of consistency when itcomes to setting water safety standards for theseorganisms. Because of the difficulties and theexpense associated with this type of monitoring,most efforts have been limited to work beingconducted by researchers, as opposed to publichealth agencies. However, if epidemiologicalevidence indicates that sampling is needed, somepublic health organizations are equipped to doextensive and detailed sampling.

If you have questions regarding viruses orprotozoa, contact your public health department.

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Every summer, questionssurface about an aquatic

amoeba (Naegleria fowleri)with a bad reputation. Thisorganism is part of the largerprotozoa group mentioned onpage 2. Over the past 30 years,there have been 34 deathsrecorded in the United Statesdue to exposure to this nastylittle organism. Fifteen of thedeaths occurred in Florida. Fortunately, the chances ofcoming in contact withNaegleria, or contracting theresulting illness (PrimaryAmoebic Meningoencephalitis—PAM, for short) are quite slim.In Florida, health officialsestimate that there is only one case for every 2.5million hours that people spend in freshwater. Drown-ing and boating accidents pose a much greater threatto our state’s water enthusiasts. With that said, thereare a few precautions swimmers can take to decreasetheir chances of exposure even more. The first thing you should know is that, with the

exception of Antarctica, this amoeba is believed toexist in virtually every lake and river around theworld. It is also found in spas, hot tubs, thermallyenriched waters and poorly chlorinated swimmingpools. So, if you’re thinking of simply avoiding theseaquatic environments, you might get a little lonely.

So, How Does One Avoid the Amoeba? The best way to prevent exposure to Naegleria is toavoid stirring up bottom sediments, as this is where theamoeba lives and feeds on bottom sediments composedof fallen leaves and dead plants. Once sediments aremixed into the water column, the amoeba could beforced up the nose of a swimmer who jumps or fallsinto the water. This increases the chance for it toenter into an ear or nasal passage where it canfollow the olfactory nerve and gain entry into thebrain, where it has been known to cause problems.

It’s important to note thatswimmers who have contractedPAM usually got it after rootingaround the lake bottom, inheavy silt where the amoebalives. Therefore, keepingone’s face away from thebottom of a lake, river, canal,etc. and keeping swimmersfrom jumping off a dock intoshallow water—or any otherscenario that would result inthe disruption of bottomsediments—will significantlyreduce the risk of exposure toNaegleria. Young children areat the highest risk of exposureas they tend to engage insuch activities.

Everyone can be further protected by wearing earplugs and a nose clip (or a dive mask that covers thenose) when swimming. Remember, exposure tobottom sediments is the single MOST importantfactor that increases chances for infection.

During most of the year, concentrations ofNaegleria are rarely high enough to cause publichealth problems. However, as water temperaturesrise during the summer (82-86 degrees Farenheit), itprovides a more accommodating environment for theamoeba to feed and multiply. So, if possible, avoidswimming in warm shallow waters during this time.

DiagnosisEarly diagnosis is the best bet for survival. In the

two known cases where patients survived infectionfrom Naegleria, the family doctor recognized thesymptoms immediately and was quick to react withappropriate antibiotics. Persons who complain ofsevere headaches, rigidity of the neck, impairedsense of smell and taste, nausea, vomiting and/or ahigh fever, and who have been swimming in a lakeshould be taken to a doctor. If the treatment is goingto be effective, it needs to be administered quickly.

Note: You cannot get PAM by eating fish from a lake.

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Amoebas in Lakes

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There are numerous potential sources ofbacterial contamination in Florida lakes—and other lakes, for that matter. In a

booklet such as this, it’s impractical to list everyone of them. However, they can be grouped intothree general categories: human waste, domesticanimal waste, and naturally occurring contamina-tion from wildlife. Of course, contamination canalso result from a combination of sources.

Human WasteThe disposal of untreated human waste into

the nearest waterbody was once a commonpractice throughout the world, including theUnited States. Even as recently as the mid-20thcentury, it was common practice for U.S. citiesand towns to discharge untreated human wasteinto rivers, streams, lakes, or oceans. For years,dilution was considered to be the “solution topollution.” This practice is no longer condonedand now, there are legal requirements for thetreatment of human wastes.

In less developed countries, some communitiescontinue to discharge both human and animalwastes into local waters. This is not always aproblem if the amount of waste is small relativeto the volume of the receiving water. In someinstances, wastes are used as fertilizers forterrestrial crops and/or even as fish food foraquaculture crops.

In developed countries where more finan-cial resources are available, large municipalwastewater treatment plants are used to treat largevolumes of human waste. These types of treatmentplants are extremely effective at removing

disease-causing bacteria from wastewaterdischarges (often greater than 99.9% of thetime). However, there is still a risk that a pathogenor virus could be released in the water dischargedfrom the treatment plant.

In rural and suburban areas of Florida, septictanks are the most common treatment systemused for human waste. However, despite theirprevalent use, septic tanks are often malignedwhen issues of nutrient enrichment and bacterialcontamination are discussed among lake users.This is unfortunate because, while there iscertainly evidence that septic tanks can addnutrients and bacteria to lakes, the contribution isusually not as great as many people think.

See Part 3 The Wastewater Treatment Debateon page 9.

Domestic Animal WasteThe improper disposal of human waste is not

the only possible source of bacterial contamination.Domesticated animals are warm-blooded andtheir wastes can, at times, harbor pathogens knownto adversely affect humans. So, unmanaged storm-water runoff from sites with high concentrationsof domesticated animals such as animal feedlots,cattle and pig grow-out operations, etc. can alsobe potential sources for bacterial contamination.Given the high visibility of these facilities, andthe odors they tend to emit, it’s natural for arearesidents to point to these areas first whenbacterial contamination issues arise. However,such operations are not always to blame andbacterial testing must be conducted before anyconclusions are made.

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Part 2Sources of Bacterial Contamination

Naturally Occurring Contaminationfrom Wildlife

When issues of bacterial contaminationoccur at a lake, the focus almost immediatelyturns to sources such as septic tanks, runoff fromlivestock holding pens, or leaky sewer lines.While these should always be considered, itshould also be remembered that there are natu-rally occurring sources of bacteria. For example,large concentrations of wildlife such as deer orbirds represent a significant potential source for

bacterial contamination of awaterbody.

A case in point is thebacterial contaminationproblem that occurred atLake Fairview in Orlando,Florida. It was originallythought that the contamina-tion was due to leaky septictanks. This resulted indiscussions concerning theneed for a municipal watertreatment plant. However,after an extensive bacterialstudy, it was determined that

the source of contamination could be traced tobird droppings from large numbers of seagullsthat were using the lake. Apparently, the seagullswere feeding at a nearby landfill during the dayand then congregating at Lake Fairview to roosteach evening.

An observant biologist happened to noticethat when the seagulls were absent, there was nocontamination. In this instance, it’s evident thateliminating septic tanks would not have solvedthe bacterial contamination problem as it wasessentially a natural phenomenon that wasdifficult to control. It is also a good lesson forthose who may balk at the expense of additionalbacterial sampling for a lake or waterbody. In thecase of Lake Fairview, the cost of the extrasampling paled in comparison to the cost of anew wastewater treatment plant and expensesassociated with long-term maintenance of theplant and its sewage collection pipes.

Domesticated animals living on openrangeland or pastureland, such as cattle orhorses, can also contribute to high bacteriacounts in lakes and waterbodies. Often thecontamination is related to the animals enteringthe water for drinking or cooling purposes, andthen defecating directly into the water. This canbe corrected relatively easily by fencing theanimals away from the water.

However, the animals will then need to beprovided drinking and cooling water, which canbe expensive. In thesesituations, the problem, andresulting tensions amongneighbors, can sometimes beresolved more quickly if theeffected community is willingto assist the landowner(s) inobtaining financing that willhelp correct the problem.

Perhaps the mostpervasive problem associatedwith domesticated animals isthe runoff that follows heavyrains. This is often referredto as “non-point source”runoff. However, it must be remembered that thissource of contamination is not solely limited toagricultural lands. In urban areas, contaminatedstormwater runoff is believed to originate fromanimal waste generated by pets, particularly inparks where people bring their pets to exercise.

This type of non-point source runoff isdifficult to control. In some areas, attempts arebeing made to reduce the problem by preventingthe direct flow of stormwater into a waterbody.Swales (a shallow depression in the landscape),man-made wetlands, and stormwater retentionponds are a few of the methods that have beenwidely used in recent years. However, becauseuse of such techniques is not always possible, thesafest approach is to avoid recreational activitiesin your neighborhood lake for two to three daysfollowing exceptionally heavy rainfall. While itmay not eliminate the possibility of contractingan illness, it can reduce the probability.

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If bacterial contamination is

suspected, bacterial testing

is a good first step to try and

locate the source(s).

See Part 7 on pages 31-35

for a step-by-step approach

to determining if bacterial

contamination has occurred

in a waterbody.

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One of the problems related to the study of bacteria is the difficulty in isolating and

describing the thousands of organisms that exist. It’s hard enough to locate and

identify insects, birds and mammals; imagine working with microscopic

organisms, many of which have a half-life* of one hour!

So how does one differentiate between different typesof bacteria?

Classification by shape and/or structure is one way.Fortunately for us, bacteria are essentially limitedto three basic shapes:

Rod or stick-shaped bacteria are referred to as bacilli (pronounced buh-sill-eye);

Sphere shaped bacteria are classified as cocci (pronounced cox-eye); and

Spiral shaped bacteria are classified as borrelia (pronounced boar-el-eeya).

Some live as individual cells while others tend togroup into pairs, chains, squares or other configurations.

The composition of a bacteria’s cellular wall is also animportant defining characteristic: Gram positive bacteriahave multi-layered cell walls, while gram negative bacteriatend to have much thinner cell walls.

Adding to the challenge

Recent advances in microbial research are presenting anotherdilemma. Thanks to new information gained from DNA and RNAsequencing, many bacteria are being renamed and/or re-classified.As a result, many old lengthy complicated names are being changedto new lengthy complicated names. This can be quite confusing, as manyof these outdated references are still in use.

If you should find that the science has indeed gotten ahead of this publication, pleasedon’t hesitate to let us know! And remember, your questions and comments are alwayswelcome. Call Florida LAKEWATCH at 1-800-LAKEWATCH (1-800-525-3928).

* Half-life – the time required for half of the atoms of a substance/organism to disintegrate.

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There can be no doubt that advances inwastewater treatment over the last 50years have contributed greatly to the

reduction in waterborne illnesses. With this greatsuccess, one might wonder why we’re nottreating all human waste with advanced treat-ment processes and why opposition to upgradingexisting wastewater plants always seems toemerge during public discussion. The followingis a brief overview of the on-going debate,including some of the advantages and disadvan-tages associated with each system.

Septic TanksThe septic tank is the most common waste-

water treatment system in many rural and suburbanareas of Florida. Yet despite its prevalent use, itis often maligned among lake communities whenissues of nutrient enrichment (eutrophication)and bacterial contamination are discussed.

Certainly, there is evidence that septic tankscan add nutrients and bacteria to lakes, but thecontribution of these materials to local waters isusually not as great as many people think.Properly functioning septic tanks generallycontribute only small amounts of nutrients, if atall. In fact, some long-term lake studies havesuggested that septic tanks may have only alimited impact on nutrient levels in most lakes.The same seems to be true regarding the issue ofbacterial contamination, but each situation mustbe examined carefully.

Failed septic systems are primarily associatedwith effluent leakage to the soil’s surface fromthe drainfield and are usually detectable by

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Part 3The Wastewater Treatment Debate:Septic Tanks vs. Wastewater Treatment Plants

A septic system is a self-contained,

underground wastewater treatment system

that uses natural processes to treat and

dispose of wastewater. These systems are

also referred to as onsite or decentralized

wastewater systems.

Septic systems are simple in design, consist-

ing of two main components—a watertight

tank and a drainfield.

The tank is usually made of concrete or

fiberglass, with an inlet and outlet pipe.

Wastewater from the home or building flows to

the inlet pipe and septic tank through a sewer

pipe. Once inside the tank, the wastewater

eventually separates, forming three layers.

Solids that are lighter than water, such as

greases and oils, float to the top while solids

heavier than water settle to the bottom, leaving

a middle layer of partially clarified wastewater.

Naturally occurring bacteria that live in the

wastewater continually work to break down the

solids. Any sludge that cannot be broken down

is retained in the tank until the tank is pumped.

The middle layer of clarified liquid flows from

the tank via the outlet pipe to the drainfield,

which usually consists of a series of pipes

placed in trenches lined with gravel or course

sand. The drainfield treats the wastewater by

allowing it to slowly trickle from the pipes into

the gravel and down through the soil, which

serves as a biological filter.

smell. As a general rule, if youcan smell waste, there is most

likely a problem that needs to beaddressed quickly. If there isleakage, it tends to be near

the ends of the drainage field orsometimes it’s due to the lack of

soil over the drainage area. In these situations,wastewater is subject to being washed to a nearbylake via surface water runoff. Fortunately, thistype of problem can be easily fixed by importingmore soil and covering the area.

In other instances, leakage is due to thedrainage field becoming clogged over time. Thiscan be remedied by providing a new field or expand-ing the existing field. Homeowners often balk atthis solution because it is expensive, but healthconcerns should override any monetary concerns.

There may also be times when solid wastewill need to be pumped from the septic tankitself. This is usually dependent on the amount ofwastewater generated, based on the number ofpeople using the system and the amount of waterused. Kitchen garbage disposals, for example, areinfamous for increasing the amount of solids in aseptic tank, making it more difficult for bacteriato do their job of breaking down the waste.

In the 21st century, homeowners now have achoice between below-ground septic tank systemsor above-ground systems. While the below-groundtype may seem risky for lakefront communities,there are systems that are specially designed forwaterfront property. The tanks are setback consid-erably from the lake shoreline to minimize thepossibility of untreated waste or nutrients enteringthe lake as seepage or runoff. If maintainedproperly, they can provide reliable cost-effectivewastewater treatment for years.

Above-ground septic tanks are becomingpopular in low-lying areas where soils remainwet for prolonged periods of time. When workingproperly, they are considered to be quite effectiveat treating wastewater. Some people believethese new elevated above-ground septic systemsare better than the in-ground versions. This is adangerous assumption as improperly constructed

elevated drainage field mounds have been knownto leak through the sides. For that matter, well-constructed elevated drainage fields have hadleakage problems. Therefore, even the newersystems should be carefully examined for potentialproblems.

Admittedly, there is no perfect septic disposalsystem and there probably never will be. How-ever, the failure of one septic system shouldnot be used to condemn this method of wastetreatment. Expensive municipal wastewatertreatment plants have problems of their own.

See pages 11-12 for more informationon municipal wastewater treatment plants.

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In 1997, the US EPA reported that “adequatelymanaged decentralized wastewater systems

(i.e., septic tanks) are a cost-effective and long-term option for meeting public health and waterquality goals, particularly in less denselypopulated areas.” The agency also recognizedthat poor septic tank management is a majorpart of the problems and/or criticisms associ-ated with these systems. As a result, in 1998the EPA was challenged to produce a set ofvoluntary national management standards forcitizens to follow. These guidelines are availablein the EPA publication entitled Onsite Waste-water Treatment Systems Manual (EPA625R 00008). Free copies can be ordered bycalling 800-490-9198. For more information,check out the EPA website:

http://www.epa.gov/owmitnet/mtb/decent/summary.htm

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Wastewater Treatment PlantsPerhaps the strongest argument in favor of

wastewater treatment plants is their effective-ness. Today’s advanced treatment processes areabout 99.9% effective in removing pathogensfrom wastewater. However, their effectivenessduring normal operation should not always bethe primary focus of concern. There are otherissues that should also be considered.

One major concern for Floridians should bethe potential for complete disruption of servicesduring natural disasters, such as hurricanes.During these periods, the public is asked to avoidcontaminated water and be patient until servicesare restored. Depending on the problem, this cansometimes take weeks. (Parents should beespecially vigilant to keep children from playingor swimming in potentially contaminated waterfollowing such storm events.)

Another point of contention relates to thefinancial burden that wastewater treatment plants

can have on a community; they are expensive tobuild and to operate. And while governmentgrants are often available for the construction ofthe plants, the cost of properly maintainingthese systems for the long haul is borne by thecommunity. This means that any communitycontemplating the construction of a wastewatertreatment system must be prepared to expendsignificant amounts of money on maintenancefor both the treatment plant and its collectionsystem. If long-term expenses are overlooked,problems often become apparent years after theconstruction of a wastewater treatment plantwhen bacterial contamination is discovered in anearby lake or in the groundwater.

After many meetings and expensive upgradesare made to the main treatment facility, somecommunities are surprised to find that the sourceof contamination still may not have been eliminated.Instead, the problem could very well be withinthe collection system—miles and miles of sewer

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pipes that, when deteriorated, can begin to releasesmall amounts of untreated waste. When thishappens, additional capital will be needed to payfor the upgrade or repairs.

There is another aspect concerning theconstruction of new wastewater treatment plantsthat many people don’t think about. While citizensmay be anxious to modernize their community’ssewage treatment facilities, they may not realizethat by building a new system or expanding anexisting one, they might also be opening the doorto the dramatic development of an area, includ-ing an increase in the local population. If septicsystems are suspected sources of bacterialcontamination, one might first assess the cost ofimproving those systems before jumping on thewastewater treatment plant bandwagon.

As with septic systems, municipal wastewatersystems also have a limited life expectancy andmust be maintained and repaired constantly toretain their effectiveness and integrity. It has

even been speculated that aging wastewatercollection systems (sewer pipes, etc.) representthe greatest threat of fecal contamination tolakes—even more than septic tanks.

Sometimes extensive monitoring is necessaryto determine if waste is leaking into a local water-body or the groundwater supply. Fortunately,there are several methods that have been developedin recent years that make this task a little easier.

Lastly, it’s important to remember that nohuman invention is foolproof. All wastewatertreatment plants can experience failures in treat-ment processes. When severe failures do occur,wastewater plant operators must release untreatedwastes to the nearest waterbody because theycannot treat the waste or they risk damage to asection of the treatment plant. This doesn’t occuroften, but it will most likely occur at some timeduring a plant’s history.

See Part 7 on pages 31-35 for more on identifyingsuspected sources of contamination.

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Wastewater treatment plants are centrallylocated facilities, usually built and operated by cityor county municipalities and are primarily designedto do one thing: Remove harmful pollutants fromdomestic and industrial liquid waste so that it is safeto return to the environment. This is accomplishedby pumping wastewater from private homes orbusinesses through many miles of sewer pipes towaste treatment plants. It is then pumped through aseries of treatment processes to remove unwantedmaterials and chemicals. The removal of harmful materials, includingmicro-organisms, is accomplished with strictlyregulated control processes and specializedequipment such as control pumps, valves, etc. Once the wastewater is treated, it is returned tostreams, rivers, and oceans, or re-used as “graywater” to irrigate landscaping. Industrial facilitiessending waste to municipal treatment plants mustmeet certain minimum standards to ensure thatwastes have been adequately pretreated and willnot damage municipal treatment facilities. Wastefrom private homes is currently not regulated.Jo

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rdSeptic Systems for Dogs (What Will They Think of Next?)

With the increasing popularity of dog parks around the nation, concern about surface runoff

from doggie waste has also cropped up. Some park planners are thinking ahead by

incorporating waste treatment systems into their plans. Underground septic tanks located at the

parks are used to prevent seepage into low-lying areas or possibly into nearby streams or lakes.

Pet owners are asked to collect pet waste and deposit it into clean-up stations located throughout

the park; the waste is ultimately disposed of via the septic system. According to estimates, septic

tanks only need to be pumped out once a year or on an as-needed basis. The system costs

about $700, and is reimbursed from annual fees paid by park users.

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Detecting pathogenic bacteria and virusesin water can be a challenging endeavor.Even with today’s advances in microbiol-

ogy, it is extremely difficult and expensive toisolate specific organisms. Some species arerarely found in large enough numbers for detection,while others are nearly impossible to cultivate ina laboratory as they require just the right combina-tion of environmental conditions to grow.

So, instead of trying to identify elusivepathogens in a water sample, nearly all monitoringprograms test for the presence of non-pathogenicbacteria that are far more numerous and easier todetect. This approach is based on the theory thatif certain non-harmful indicator organisms arepresent in a water sample, then harmful bacteriaor viruses may also be present. The concept wasintroduced in 1892 and continues to be the basisfor most water quality standards today.

For many years, public health agencies havelargely relied upon the presence of two coliformbacteria groups, total coliforms and fecalcoliforms, as indicators of bacterial contamina-tion in water. As you can see in Figure 4-1 onpage 16, coliforms are classified as two sub-groups of the Enterobacteriaceae family(pronounced Enter-o-bac-teer-ee-a-see-ay). Theirclassification within this family means that, asidefrom their genetic similarities, coliform bacteriashare several common traits that make themuseful indicator organisms, including:

Many of these organisms are known to exist inthe intestines and feces of warm-blooded animals,including humans, and therefore serve as fairly

reliable indicators that fecal waste may be present;

They tend to live longer and are found ingreater numbers than pathogens, making themeasier to detect in a laboratory sample;

They are generally non-pathogenic and there-fore less risky to deal with when collectingsamples and analyzing in a laboratory; and

Laboratory methods used for detecting andcounting these organisms are relatively simpleand inexpensive.

Continue reading the rest of this section tolearn more about the Enterobacteriaceae family,total coliforms, and fecal coliforms. Learn whythey may or may not be appropriate indicatorsfor specific bacterial contamination concerns.Also, learn about other bacteria groups, includ-ing the Enterococcus family, that are beingconsidered for use as indicator organisms.

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Part 4Indicators Used to Detect BacterialContamination in Recreational Waters

The indicator organisms discussed in this

circular are primarily used for the detection of

bacteria in “non-potable” waters — waters

intended for swimming or bathing. While several

of the same organisms may be used for monitor-

ing potable (drinking) water or even wastewater,

there may be some variation, more than we have

room for in this publication. For more information

about monitoring criteria and techniques used for

detecting bacteria in drinking water or waste-

water, please refer to the Selected References

section in the back of this publication.

As scientific names go, the wordEnterobacteriaceae is a definite tongue-twister. However, it’s really not as hard

to decipher as one might think. One helpful hintis the prefix entero which tells us that thesebacteria are enteric—of or relating to the intestines.Also, its lengthy name is certainly appropriate asthis family represents an expansive group oforganisms that includes nearly a dozen separategenus groups and more than 40 “species.”

See Figure 4-1 for a general idea of the hierarchyof the Enterobacteriaceae family.

Fortunately for us, there are only a fewgroups within this family that we need to knowfor bacterial monitoring purposes:

The larger total coliform group includesmany different species and strains of coliformbacteria, originating from a variety of sources(i.e., fecal and non-fecal) including both plantsand animals.

The fecal coliform group includes bacteriathat usually originate from fecal matter (i.e.,animal or human waste).

Escherichia coli (E. coli)5 is just one of themany types of bacteria within the fecal coliformgroup. This “species” has recently surfaced as aparticularly useful indicator organism.

For years, most public health agencieslargely depended on the first two groups, totaland fecal coliforms, as indicators for detectingpotential bacterial contamination. Why?

Ease of testing is one reason. Because thesegroups include a broad spectrum of closelyrelated organisms, scientists were able to developa fairly simple testing method for estimating thenumber of coliform bacteria colonies in a volume

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of water. The tests are commonly referred to astotal coliform counts and fecal coliform counts.

Traditionally, health officials using thesecounts have assumed that if high numbers ofcoliforms are detected in a water sample, thenrecent fecal contamination is present and repre-sents a health threat. (Remember the theory: ifindicator organisms are present in a water sample,disease-causing bacteria or viruses may also bepresent.)

Years ago, when many U.S. cities and townswere discharging untreated waste into publicwaters, this assumption was most likely correct.

5 The strains of E. coli discussed in this circular are notthe same as those associated with cases of severe foodpoisoning.

Enterobacteriaceae

Figure 4-1

Bacteria within the Enterobacteriaceaefamily belong to at least four genera4:Escherichia, Citrobacter, Klebsiella, andEnterobacter. Within these groups, there aremany different “species” and/or strains—fartoo many to list here.

4 The term genera is plural for genus. A genus iscomprised of one or more species and is one of theprimary ranking categories used for classifying livingorganisms within the animal kingdom. An organism’sgenus name helps to rank it within the larger familygroup, but is still one level above its “species” name.

E.coli

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However, now that the vast majority ofmunicipalities have wastewater treatmentplants—effectively eliminating most major healththreats—total and fecal coliform counts are nolonger considered to be as useful. (i.e., They are notconsidered “sensitive” enough for detectingsmall amounts of bacteria.) In fact, the U.S.Environmental Protection Agency (U.S. EPA)and many state health agencies are now recom-mending that total and fecal coliform tests bephased out and replaced with E. coli tests.

For the time being however, it’s importantto remember that fecal and total coliform countsremain the legal standard for Florida waters.These standards continue to be used for severalreasons:

(1) They are the least expensive tests to perform;

(2) They are commonly used as water safetycriteria in many state legal standards;

(3) They can provide valuable clues on what isreally going on in the lake or waterbody.

As you will learn from reading the rest ofthis section, there are a few drawbacks related tothe use of total and fecal coliform counts. However,they still provide a good screening mechanism tobegin with if bacterial contamination is suspectedin a waterbody. If one does find high total andfecal coliform counts, steps can then be made toinvestigate further, perhaps using other indicatororganisms and tests.

If you are deciding whether to do the testingyourself or hire a private laboratory, equipmentrequirements will undoubtedly be a major factor.Many testing methods require the use of an incuba-tor, an autoclave (for sterilizing) and membranefiltration devices—all of which involve a largeinitial investment. However, once the equipmentis obtained, routine testing is fairly inexpensive,especially if water samples are collected byvolunteers.

The good news is there are several compa-nies working to develop reliable bacteria detec-tion methods that involve less equipment and areeasier to use. So stay tuned.

Jennifer Donze, with Florida LAKEWATCH, places

bacteria samples into an incubator where they will

“bake” for 24 hours. After incubation, samples are

observed and bacteria colonies counted. LAKE-

WATCH has been monitoring bacteria for survey

purposes, on a limited number of lakes, since the

year 2000. Total coliform counts, fecal coliform counts

and E. coli counts have been the bacteria testing

methods of choice for the survey.

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For years, many state governments,including Florida, have come to rely ontotal and fecal coliform counts for thedetection of bacterial contamination.Many have enacted legislation estab-lishing numerical bacteria standards orguidelines for determining if a water-body is “safe” for recreational activities.See page 29 for the current Floridastandards, but also remember towatch for changes that may occurin the near future.

Total Coliforms

The term total coliformsrefers to a numerical count

of the total number of coliformbacteria that exist in a measuredamount of water (i.e., from a sample).This count generally includes both fecal andnon-fecal coliforms and an expansive assemblageof closely related organisms within the Entero-bacteriaceae family.

See Figure 4-1.

For years, total coliform counts have beenconsidered tried-and-true indicators of bacterialcontamination, mainly because they includefecal coliforms, which tend to be more prevalentand longer-lasting than the elusive pathogensthat sometimes co-exist in fecal waste.

Also, their ability to carry out lactosefermentation at fairly low temperatures (95-97degrees F) makes it relatively easy and inexpen-sive to process samples in a laboratory: Samplesare incubated to “trigger” a fermentation process,which causes coliform bacteria to grow. Oncegrowth has occurred, colonies can be counted.For those with a limited budget, a samplingmethod that can be achieved without expensive

high-tech incubators is certainly preferred.As an indicator, total coliform counts are

most effective at red-flagging contamination indrinking water. World Health Organizationguide-lines for drinking water allows a maximumof 0-2 organisms per 100 mL as acceptable forpiped water supplies and a maximum of 10 per100 mL for unpiped water supplies. It also statesthat “frequent occurrences of high coliform countssignify the need for an alternative water source orsanitary protection of the current source.” 6

When using total coliform counts as anindicator of contamination in recreational waters,remember that even though coliforms are foundin fecal waste, there are other bacteria within thesame group that naturally occur in aquatic plantsand soils. Because of this, high total coliformcounts cannot always be considered an indicatorof fecal contamination. It’s also the reason whytotal coliform counts are no longer considered asuseful for determining the safety of recreationalswimming or the consumption of shellfish.

Does this mean that total coliform counts shouldno longer be used as indicators?

Not necessarily. While high total coliformcounts may not always be an indication of fecalcontamination in a waterbody, they may still bean indication of a potential health risk. Forexample, high total coliforms may sometimesindicate the presence of plant material and anassociated bacteria known as Pseudomonasaeruginosa. This bacteria is considered to benon-fecal in origin and, therefore, unlikely topose any severe health threats. However, it isknown to be a major cause of ear infections inhumans and is also associated with skin rashes.

So, even if a lake shows no sign of fecalcontamination, a high total coliform count couldindicate a potential risk for swimmers, waterskiers, or others that come in contact with thewater for a prolonged period of time.

See page 21 for more on Pseudomonas aeruginosa.

6 Hach Company. 2000. The Use of Indicator Organismsto Assess Public Water Safety. Technical InformationSeries – Booklet No. 13.

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As illustrated in Figure 4-1,fecal coliforms are a sub-

set of total coliforms. They arealso the group of bacteria that,from a human health perspective,people are most concerned about because theyindicate the presence of fecal matter in awaterbody.

When comparing the effectiveness of totalcoliform counts versus fecal coliform counts, itcould be said that fecal coliform counts areconsidered to be a more reliable indicator ofpossible contamination within a waterbody.Use of this test has long been based on twoassumptions:

(1) Fecal coliforms originate only from warm-blooded animals; and

(2) Fecal coliforms do not survive for an extendedperiod of time in water and are, therefore, fairlyreliable indicators of recent contamination.

When dealing with large-scale humancontamination from untreated wastes or aninoperative wastewater plant, these assumptionsare typically true. However, they’ve also becomedogma among many public health workers, evenwhen studies have shown otherwise. For instance,several studies now show that fecal coliformcounts sometimes include bacteria that are notnecessarily fecal in origin. An example is thefree-living strain of the Klebsiella bacteria that isoften present in soils.

The presence of such organisms in a fecalcoliform count can result in false positive read-ings. In other words, the test results will suggestfecal contamination, when there is none. Studieshave also definitively shown that fecal coliformscan survive and even multiply in the naturalenvironment, therefore their presence does notnecessarily indicate contamination from anoutside source.

Perhaps the strongest criticism related to

Fecal Coliformsfecal coliform counts is the fact that these countsdo not seem to correlate with the incidences ofgastrointestinal illness experienced or reportedby individuals using recreational waters.

Does this mean that fecal coliforms should nolonger be used as indicators?

Again, not necessarily. Many public healthagencies continue to use fecal coliform counts asindicator bacteria. Legal standards are onereason; a large number of states, includingFlorida, still rely on long-standing fecal coliformcriteria to set the legal limits for water qualityand safety. In many instances new standards orcriteria have yet to be developed for several ofthe newer indicator organisms, including E. coli.

So, even if new indicator organisms areadded to the testing regimen, fecal coliform testsstill have to be used to meet the existing legalstandards. Also, some groups have decided tocontinue fecal coliform counts in their testingregimen so that current data can be directlycompared with historical data, which usuallyconsists of fecal coliform measurements.

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there seems to be a correlation between the pres-ence of E. coli and swimming-related illnesses.

Note: Admittedly, this can be somewhat confusing;even though the indicator strain of E. coli isconsidered to be harmless, it can sometimes beaccompanied by the toxic strain (O157:H7) andother organisms that can cause illness.

Does this mean that E. coli bacteria shouldalways be used as indicator organisms?

Not necessarily. The methods used fordetecting E. coli do have a few drawbacks:

Some methods involve two incubation steps,making it more time-consuming and expensivethan total and fecal coliform counts.

When counting colonies of E. coli bacteria ina laboratory sample, there are times when othernaturally occurring bacteria, belonging to thegroup Klebsiella, may be present and inadvertentlycounted along with the E. coli.9 This can result infalse positives. There is also the chance that E. colicounts may be elevated due to the presence ofbird feces.

When any of these scenarios occur, additionalsteps are required to definitively demonstrate thatthe vast majority of detected coliforms are, infact, E. coli. Even with these drawbacks, the EPAis now recommending that public health agenciesregularly use the E. coli test when monitoring forbacteria contamination.

Escherichia coli (E. coli) bacteria represent a sub-

group within the fecal coliformgroup. (See Figure 4-1.) Amazingly,even within this smaller E. colibacteria group, there are hundreds, perhapsthousands, of different strains. Although moststrains are harmless and live in the intestines ofhealthy humans and animals, there are a fewknown to cause problems. For example, many ofus have heard rather alarming reports about E. coliO157:H7, a strain associated with an estimated73,000 cases of food-borne illness each year.7

This deadly organism is different from the E. coliused as an indicator for water quality.

Use of the “harmless” E. coli strain as anindicator organism has advantages over fecalcoliform counts:

(1) It occurs only in the feces of warm-bloodedmammals and is therefore a good indicator of thepresence of fecal waste in water;8

(2) EPA studies have shown that, in fresh water,

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7 From the Center for Disease Control: The combinationof letters and numbers in the name of the E. coli bacteriumrefers to the specific markers found on its surface anddistinguishes it from other types of E. coli. Other knownsources of infection from E-coli O157:H7 include theconsumption of sprouts, lettuce, salami, unpasteurizedmilk and juice, and swimming in or drinking sewage-contaminated water.

8 Similar to the total and fecal coliform indicator approach,E. coli testing is based on the assumption that if E. colibacteria are found in a waterbody, there is the chancethat pathogenic bacteria or viruses may also be present.

9 Klebsiella pneumoniae is a naturally occurring free-living soil bacterium that can also be found in the humangut shortly after birth. There is no evidence to suggestthat this species has caused healthy individuals toexperience illness due to exposure.

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While researching testing methods, you may run

across the phrase “EPA Approved.” It is importantto note that just because a testing method is EPA approved,it does not necessarily mean that it is adopted by your

local public health organization. If your purpose is todetermine if a sample meets state legal water safetystandards, you need to check with your local health

organization before deciding which method to use.

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In addition to the indicator organisms mentioned in this section, a bacteriaknown as Pseudomonas aeruginosa (abbreviated P. aeruginosa often shows

up incidentally in total coliform counts, even though it is not a coliform.

This bacterium can be found almost everywhere in nature and in some man-made environments, including the garden hose in your back yard. In lakes,P. aeruginosa is often found as a naturally occurring bacteria within aquaticplant communities and in the surrounding soils.

According to an informational bulletin published by the Hach Company,10

a standard laboratory method has tentatively been accepted for P. aeruginosatesting. While it is not considered to be a particularly useful indicator of fecalcontamination (i.e., it is rarely found in the feces of healthy humans andseldom isolated from animal feces), it can be useful for monitoring bathingbeaches. This is because P. aeruginosa has been known to be a major causeof skin rashes and ear infections in swimmers and bathers.

10 Hach Company. 2000. The Use of Indicator Organisms to Assess Public Water Safety. TechnicalInformation Series – Booklet No. 13. Page 26.

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As we enter the 21st century, an entirelydifferent group of bacteria, belonging to the

Enterococcus family are now being consideredas indicator organisms (plural: Enterococci,pronounced enter-o-cox-eye).

Previously known as group D streptococcus,Enterococcus bacteria represent an entirelydifferent strain of bacteria from the Enterobacte-riaceae family. Because of their hardy nature,these bacteria occur naturally in almost everyenvironment including soil, plants, water, andalso within the gastrointestinal tract of manyanimals and birds. They have even been found invarious food products such as cheese, raw andpasteurized milk, frozen seafood, frozen fruits,fruit juices, and vegetables.

Prior to 1984, Enterococci bacteria weregrouped within the fecal Streptococcus genusand were often referred to as “fecal streps” bybacteriologists. However, with recent advancesin genetics, microbiologists have found thatcertain bacteria within the fecal Streptococcusgroup were genetically unique enough to classifythem as a separate genus.11 As a result, approxi-mately 17 different bacteria have been identifiedwithin this new Enterococcus group.12

Enterococci as bacterial indicatorsRecently, many professionals have come to

consider the Enterococcus bacteria group as oneof the preferred indicators of fecal contaminationfrom warm-blooded animals. This is true for atleast two reasons:

(1) In marine environments, Enterococci cansurvive longer than fecal coliforms, thus providinga more accurate indication of the presence offecal waste; and

(2) Studies show a positive correlation betweenincidences of human gastrointestinal illness andconcentrations of Enterococci found in publicwaters. However, there is one exception.

In tropical regions, some of these organismsare commonly found in unpolluted waters,making them less reliable indicators of fecalcontamination. This may apply to Florida waters,so caution should be used before this method isselected over the total and fecal coliform testspresently used.

Within the Enterococcus group, chemistsgenerally agree there are two main species thathold the most potential as bacterial indicators:Enterococcus faecalis and Enterococcus faecium(formerly known as Streptococcus faecalis andStreptococcus faecium, respectively). These speciesoccur in large numbers in both human and animalfeces and are thought to be appropriate indicatorsfor determining the presence of fecal contamina-tion in a waterbody.

It should be noted however, that two otherbacteria within the same genus, Enterococcusavium and Enterococcus gallinarium (formerlyknown as Streptococcus avium and Streptococcusgallinarium, respectively), have been known topose health problems, even though they areprimarily associated with bird feces.

Until recently, the greatest hurdle in usingEnterococci as bacterial indicators was thelack of reliable testing methods. This haschanged with the development and (EPA)approval of a new mE culturing medium. Whilethe process is similar to fecal coliform tests,13

there are drawbacks: the medium used to testfor Enterococci is more expensive than me-dium used for fecal coliform tests, and itcontains a toxic ingredient.

11 Richard R. Facklam and Sahm, D.F. 1995. Manual ofClinical Microbiology. Page 308.

12 Richard R. Facklam and Sahm, D.F. 1995. Manual ofClinical Microbiology. Pages 308-309.

13 Enterococci require incubation at 41° C (106° F).

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Enterococcus

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W ithin the scientific community, there havebeen numerous discussions about using

bacteriophages (viruses that attack bacteria) or otherbacteria as possible indicators of contamination.These organisms include coliphages, such asBacteroides fragilis viruses, and F-Specific coliph-ages, such as Staphylococcus aureus, Salmonella,Shigella, Aeromonas, Campylobacter jejuni, andLegionella.

Many of these have merit as potential indicatororganisms, but they also have major problemswhen it comes to detection methods. For example,some of the organisms are naturally occurring inaquatic environments, which would make it difficultto determine if there is an outside source of contami-nation. Additionally, the expense of detection andthe use of new DNA sequencing techniques oftenplaces these tests outside the budgetary constraints

Other Indicators

imposed on most monitoring agencies. For now, itseems prudent to continue testing for total and fecalcoliforms, to eliminate the most probable andimmediate health risk, and let the researchers worryabout detecting other organisms.

In addition to bacterial indicators, there are a fewchemical agents currently being considered asindicators of human fecal pollution:*

Detergents and optical brighteners are associatedwith laundry discharge and their presence in surfacewater may indicate an upstream source of waste-water from leaky septic tanks or sewer pipes.

Coprostanol—a by-product of the bacterialbreakdown of cholesterol in the human body.

Caffeine.

* Non-point Source News. Number 63. U.S. EPA, 2000

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Rebecca Varner counts bacteria for FloridaLAKEWATCH’s statewide bacteria surveyproject.

Disposable “Whirl-Pak” bags are popular foruse in bacteria water sampling because theydon’t require sterilization.

The membrane filtration method involvesfiltering samples through filters and incubatingthem for a specified time and temperature.

Once filters have been incubated, coliformbacteria colonies are then identified andcounted based on their coloration.

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In addition to learning about indicator bacteria,described on pages 15-23, it’s also helpfulto know a little about the laboratory methods

used for detection. The information may come inhandy when trying to decide which method touse for bacterial monitoring. There are severalvariations, including:

Membrane Filtration (MF)

Most Probable Number (MPN)

Plate Counts

Presence/Absence (P/A)

Each of these methods generally involvesthe use of an incubator14 as well as specificmedia (i.e., agars or broth) designed for sup-porting the growth of the targeted bacteria,while inhibiting the growth of others. Thefollowing pages provide brief descriptions ofeach method, with an emphasis on the twotechniques most widely used in lake monitoringthe Membrane Filtration method and MostProbable Number method.

Membrane Filtration (MF)The Membrane Filtration (MF) method

involves filtering a measured amount of samplewater through a membrane filter that is designedto retain the targeted bacteria. This is usuallyaccomplished with an electric or hand vacuumpump that pulls sample water through the filter,leaving behind bacteria cells that are too large topass through the pores.

After the filtration process, the filter itself is

placed on an appropriate agar medium or a padsaturated with a special broth medium, and thenincubated. If the targeted organism is present,colonies will grow. Filters are then examined andbacteria are identified by size, color, shape andsheen. Because bacteria colonies grow from asingle bacteria cell, the number of coloniespresent is considered to be representative of thenumber of bacteria present in the water sample.

Results are usually reported as the numberof colony forming units per 100 mL (CFUs/100mL). This method is one of the easiest, leastexpensive methods for counting total coliforms.

Most Probable Number (MPN)The Most Probable Number (MPN) method

usually involves 10-15 test tubes that are preparedwith different amounts of bacteria growth mediumand sample water. The medium is designed tosupport only the growth of a targeted bacteriaspecies.15 Once the test tubes are “inoculated”with sample water, they are incubated for up tofour days and then examined.

The test tubes are observed for a positive ornegative reaction from the target organism. Apositive result would show bacteria growth andthe presence of gas within the tube. (e.g., When

14 Incubators range from large expensive “stand-up”models to something as simple as a box with a 40-wattbulb. See Suppliers List in the back of this circular formore information.

15 Four types of media that are used for the MPN methodinclude: minerals-modified glutamate medium, lauryltryptose broth, MacConkey broth, and lactose broth.

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Part 5Laboratory Methods for CountingIndicator Organisms

testing for fecal coliforms, a positive tube is onethat shows evidence of growth and gas.) Tubeswith positive growth are counted and the resultsare used to estimate the “most probable number”of bacteria in a water sample. This estimate isachieved by using statistical probabilities—bycomparing the number of positive tubes with atable of statistically determined numbers.16 Aswith anything statistical, the accuracy of thismethod is improved by increasing the number ofinoculated test tubes for each group of samples.

Compared with the MF method, the MPNtest has several disadvantages, especially forindividuals wanting to do their own samplingand bacteria testing:

(1) it’s considerably more expensive and laborintensive;

(2) because it involves the use of 10 to 15 testtubes, this method also takes up quite a bit moreincubator space; and

(3) the MPN test does not yield a direct bacteriacount.

It does have one advantage, however;suspended sediments within a water sample donot affect the MPN process, whereas the MFmethod involves the use of filters that canbecome clogged with sediments and/or algae.17

This is something to consider if your watersample is from a lake or waterbody with highalgal counts or turbidity problems (i.e., lots ofsuspended solids).

Plate CountsPlate count methods are traditionally used

for monitoring drinking water. The reference bookStandard Methods for the Examination of Waterand Wastewater18 describes three variations:

Pour plate method –(a.k.a., the standard platemethod) involves pouring liquefied agar mediuminto petri dishes and then adding a measuredamount of sample water. Once the sample ismixed with the medium, the plates are left to sitso the contents can solidify. They are then

inverted and placed in an incubator. Once thesamples are incubated, bacteria colonies arecounted and reported as “colony-forming units”per milliliter of water sample (CFUs/mL).

Spread plate method– is different from thepour plate method in that agar is poured onto theplate and allowed to solidify before it is exposedto the sample. Once the agar is solidified, thesample is spread onto the plate surface with asterilized bent glass rod and allowed to be absorbedinto the agar medium before it is incubated.Colonies, that appear after a period of incubation,are identified and counted.

Membrane Filtration technique – seeMembrane Filtration on page 25.

Presence/Absence (P/A)This method is just what its name implies.

Similar to the plate methods, it is mostly used formonitoring drinking water. The theory holds thatas long as there are zero coliform organisms withina large number of samples, actual bacteria countsare not necessary. In other words, testing is donesimply for the presence or absence of organisms.

While there may be problems with thisapproach as it relates to the use of recreationalwaters, it can be an effective screening tool. Forexample, if there are no total and/or fecal coliformsfound in a sample, there is a high probability thatthere is not a bacteria problem. Conversely, iftotal and/or fecal coliforms are present, one canthen go ahead and do more specialized testingfor identifying specific bacterial organisms orgroups such as fecal coliforms, Pseudomonasaeruginosa, Enterococcus spp., etc.—whateverone’s budget will allow.

16 These tables are developed and used in bacterialaboratories to calculate statistical probabilities.

17 The Volunteer Monitor. Fall ’98. Bacteria TestingPart 1. Methods Primer. Page 9.

18 Often abbreviated as Standard Methods, this book isconsidered to be the foremost authority on the science ofwater analysis.

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Which Laboratory Method Does Florida LAKEWATCH Use?

In the year 2000, Florida LAKEWATCHbegan a preliminary statewide surveycollecting bacteria data on more than 80lakes. The objectives of the survey aretwo-fold. Using data from the survey,researchers are:

1Trying to determine if there are patterns inthe abundance of total coliform bacteria and

the fecal coliform known as Escherichia coli(E. coli) in Florida lakes and waterbodies.

Note: E. coli are a subgroup of fecal coliformbacteria. Both fall under the larger category knownas total coliforms. See page 20 for more information.

2 Looking for relationships that can be drawn between coliform abundance and

other environmental factors such as changes inwater temperature, rainfall, aquatic plantabundance, algae blooms, etc.

Florida LAKEWATCH uses the membranefiltration technique for fast, simultaneousdetection of total coliforms and the fecal coliformknown as E. coli. Test kits are purchased fromthe HACH Company and are identified asMethod 10029 m-ColiBlue24 Broth.

Most Florida LAKEWATCH bacteria sampleshave been collected one time only from each ofthe lakes involved in the survey and thereforeshould only be considered as a description ofthe bacteria concentrations for that day; dataposted in the annual LAKEWATCH Data Sum-mary book 1986-2001 are not intended for usein making public safety decisions. However,they are helpful in looking at patterns amongbacteria counts and other environmental factors.

Preliminary analyses of the data shows that15% of the (approximately) 1,000 samplescollected had total coliform counts that wouldexceed Florida’s state criteria for total coliforms.However, less than 0.01% of the samples hadE. coli counts that would have exceededFlorida’s state criteria for fecal coliforms.

What does this mean?

High total coliform counts, as found in 15% of thesamples, are generally associated with abundantplant material, and may indicate the potential fora variety of infections, including skin rashesand/or external ear infections in swimmers.The presence of abundant plant material alsointroduces the possibility of other water-relatedillnesses such as swimmer’s itch.

The low E. coli counts suggest that there is not amajor problem with fecal contamination in thissampling of Florida lakes (i.e., even though thedata are preliminary).

Details related to bacteria detection

techniques are sure to change in the

coming years as improvements continue to

be made, on an almost daily basis, in the micro-

biology field. For this reason, we are reluctant

to get too specific about the many techniques,

agars, broths, incubation temperatures, etc.

For a historical perspective we recommend

that you refer to a copy of Standard Methods

for the Examination of Water and Wastewater.

For the latest up-to-date information, we

suggest you contact any of the laboratory

suppliers listed in the back of this booklet.

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ATTENTION: Water quality standards for bacteria vary from state to

state; residents living outside of Florida should consult with their own

state public health agencies for more information about bacteria standards.

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Like many other states, Florida has establishednumerical bacteria counts that are used asthe legal standard for determining the

presence of total and/or fecal coliform contamina-tion in Class III waters.19 The criteria are thesame for both fresh and marine waters:

Florida’s fecal coliform standard * MPN or MF counts shall not exceed a monthly

average of 200, nor exceed 400 in 10% of thesamples, nor exceed 800 on any one day. Monthlyaverages shall be expressed as geometric meansbased on 10 samples taken over a 30-day period.

The following criteria for fecal coliforms,were established by the Florida DEP and arebased on the legal criteria established byFlorida law:

Fecal coliforms:

Good = 0-199 fecal coliforms per 100 milliliters (mL)of marine water

Moderate = 200-799 fecal coliforms per 100 mL

Poor = 800 or greater fecal coliforms per 100 mL

Note: If a fecal coliform count is observed to exceed 800colonies per 100 milliliters of beach water and a re-samplingresult also exceeds this value, then a health warningwould be issued for the sampling site.

19 Class III waters are defined as “waters designated forthe purpose of recreation and the propagation andmaintenance of healthy, well-balanced populations of fishand wildlife.”

20 The abbreviation MPN stands for “Most ProbableNumber.” The MPN technique refers to a specific method,used in laboratories, to estimate the number of bacteriacolonies in a measured amount of water, usually 100 ml.

The abbreviation MF stands for “Membrane Filter.” TheMF technique refers to a specific method used to count thenumber of bacteria colony forming units (or CFUs) on amembrane filter after 100 milliliters of sample water havebeen poured through it.

* Florida Department of Environmental Protection;Chapter 62-302.530, Florida Administrative Code.

In August 2000, the Florida Department ofHealth initiated the Florida Healthy BeachesProgram. The program was designed to assessthe bacteriological quality of coastal beaches in34 counties. To do this, the Department of Healthmeasures both fecal coliforms and enterococci.

The following criteria for enterococci bacteriahave been recommended by the U.S. EPA asa saltwater quality indicator. As of 2002, theyhave not been established as legal criteria.

Enterococci:

Good = 0-34 enterococci per 100 milliliters (mL) ofmarine water

Moderate = 35-103 enterococci per 100 mL

Poor = 104 or greater enterococci per 100 mL

Note: If Enterococci results are observed to equal orexceed 104 colonies per 100 milliliters of beach watersampled and a re-sampling result also exceeds this value,an “Advisory” (not as strong as a “Warning”) would beissued for the sampling site.

Florida’s total coliform standard * Less than or equal to 1,000 as a monthly aver-age; nor to exceed 1,000 in more than 20% of thesamples examined during any month; less than2,400 at any time. Monthly averages shall be ex-pressed as geometric means based on a minimumof 10 samples taken over a 30-day period usingeither the MPN or MF counts.20

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Part 6Criteria Used for AssessingColiform Contamination in Florida Waters

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With careful thought and good detective work,it is possible to locate the source(s) of bacterial contamination.

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Unless there is a catastrophic failure of amajor sewage collection line, findingthe source of bacterial contamination in

a lake or waterbody can be difficult, time consum-ing and, depending on which testing regimen youchoose, it can also be expensive. In fact, lack offunding is often the largest hurdle that citizensrun into when sampling is proposed.Because of this, public agenciesare often hard-pressed to conductbacteria testing in a timely orconsistent manner. If they have theresources to sample at all, it’s oftenlimited to one sampling event,which usually tells little.

The Good NewsWith careful thought and

some good detective work, it is possible to locatethe source(s) of bacterial contamination. Workingtogether, lakeside communities can raise moneyto pay for sampling by private laboratories orthey can do it themselves. Regardless of whichapproach you take, Florida LAKEWATCH’s FourStep process—described on the followingpages—provides a simple framework and relativelyinexpensive testing strategy to follow. It wasdeveloped by LAKEWATCH staff in responseto hundreds of inquiries and a pilot study thatwas conducted in several counties.

When reading through the steps, you maynotice that re-sampling often, and in many loca-tions, is a major component of our plan. It’s beenour experience that a willingness to do this willhelp assess risks related to water usage and, if

there is evidence that bacterial contamination maybe present, it can help pinpoint possible sources.While there is no guarantee that these efforts willfind every source, there is a high probability thatmost of the important ones can be identified.

Also, the LAKEWATCH approach is basedlargely on the use of total and fecal coliform

counts. These methods are recom-mended because they are generallyeasier and less expensive to processthan other tests currently availableand are therefore, more accessibleto the average citizen or monitoringgroup. In fact, more and morevolunteer groups are investing inbasic laboratory equipment (i.e.,incubator and test kits) and aredoing the testing themselves. Now,

thanks to the development of several new cultur-ing mediums, E. coli counts are just as easy as toprocess as total and fecal coliform counts.

See page 27 for more on the E. coli count testingmethod used by LAKEWATCH.

One more thing: the fecal coliform count“criteria” in Steps 2 and 3 are roughly based onFlorida’s state regulatory codes. This is not acoincidence. However, the importance of thefollowing four step plan goes well beyond stateregulatory codes, which are apt to change in thenear future. Our main goal in presenting thisinformation is to: (1) enable you to determine ifthere is a problem to begin with; (2) enable youto spot patterns in your test results; and (3) helpyou locate the source of contamination.

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Re-sample!

Re-sample!

Re-sample!

Re-sample!

Part 7

A Four Step Process for Identifying andLocating Bacterial Contamination

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If contamination is suspected, sampling at asingle site will not provide sufficient informationto make an accurate assessment of the problem.Therefore, it’s recommended that water samplesbe collected from approximately 12 sites, spacedas uniformly as possible around the lake orwaterbody. Nine of the sampling sites should belocated near shore.

It’s also recommended that three sites besampled offshore in open water, as this will permita judgment of the magnitude of contamination.

If the waterbody has a large amount ofaquatic plants, try to sample just away from theplants. If there are not a lot of aquatic plants, thesamples should be collected in water less thanthree feet deep, as this offers the best possiblechance of detecting contamination.

All samples should then be analyzed for fecalcoliform counts. This can be done in a professionallaboratory or even with the help of some home-monitoring kits that are now on the market.

See List of Suppliers in the back of this circular.

Once fecal coliform counts have beenobtained from various sampling sites on yourlake, classify them using the three categorieslisted below. Generally speaking, if the sampleresults fall within Low Risk category, the water-body would generally be considered “safe,” asthey are within Florida’s criteria for Class IIIwaters. However, if samples fall into the Poten-tial Risk or High Risk categories, they may notmeet Florida’s Class III water standards and re-sampling is strongly recommended.

Low Risk CategorySampling sites with fecal coliform counts of lessthan 200 (CFUs per 100 mL)

As a general rule, sampling sites with fecalcoliform counts of 0 -199 colonies per 100 milli-liters of water (CFUs per 100 mL) are mostlikely not a problem and for all practical pur-poses, the bacteriological quality of these sitescan be ranked as good. Furthermore, if all thesites in the waterbody have results in thiscategory, there is a strong possibility that thewaterbody is not being contaminated.

Note: It must always be recognized that even a count ofzero bacteria does not absolutely preclude the possibilityof contamination.

Potential Risk CategorySampling sites with fecal coliform counts rangingbetween 200 and 799 (CFUs per 100 mL)

Sampling sites with fecal coliform countsranging between 200 and 799 CFUs per 100 mLof water represent sites with potential fecalcontamination. One of the first things to do whensuch results are obtained, is to examine thesampler’s field notes and any comments fromlocal residents regarding possible reasons as towhy the counts would be high at the sites.Move to Step 3.

Note: There is really no need to re-sample areas that meetFlorida’s fecal coliform criteria [see Chapter 62-302.530,Florida Administrative Code]

While disposable Whirl-Pak baggies are popularfor the collection of bacteria water samples, plasticNalgene bottles can also be used. The only draw-back is that they need to be sterilized each time.

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Step 1Collect Water Samples from Multiple Sites

Step 2Identify Sites with ElevatedFecal Coliform Counts

Once you have determined (from Step 2)that fecal coliform counts are high, the objectiveat this stage should be:

To determine whether or not there are E. coliorganisms present in the fecal coliform tests; and

To rule out the possibility of “false positives”that may have occurred due to large concentrationsof birds (i.e., bird waste) and/or the presence ofthe naturally occurring soil bacterium known asKlebsiella.

Test for E. coli – It is recommended that youhave a private laboratory do the testing for E. coli.If it is demonstrated that the vast majority ofdetected fecal coliforms belong to the E. colibacteria group, there is a high probability that thecontamination source is human and continued re-sampling at the water body is warranted until thesource of contamination is found and eliminated.It is also recommended that you contact yourlocal public health agency and move on to Step 4.

Rule out false positives – If E. coli are notdetected, yet the fecal coliform counts remainhigh, two possibilities should be considered:Contamination from birds (ducks, geese, seagulls, etc.) or false positives from soil bornebacteria.

When testing for false positives, the primaryfocus should begin with birds. Are birds residingin these areas on a regular basis or being routinelyfed at these sites? If the answer is yes to either ofthese questions, birds may be the most logicalexplanation rather than septic tanks or sewagelines. If you want to be sure that birds are the culprit,you can test for two specific organisms that maybe showing up in your fecal coliform testingregimen, Enterococcus avium and Enterococcusgallinarium. To do this, you will need to contractwith a private laboratory.

If it is indeed a bird-induced problem,various management strategies can be tried.Steps can be taken to encourage the birds toleave and/or discourage them from roosting inthe area. Hunting (when legal) and noise devicescan be effective, but you’ll need to check withyour local wildlife agency before implementingeither of these approaches. The good news is,this usually means you have eliminated the needfor further testing.

If high fecal counts are not related to birds,the next thing you should do is test specifically forthe Klebsiella bacteria. The presence of theseorganisms in a fecal coliform test can also givefalse positives—especially in Florida. If testsindicate that high fecal coliform counts are dueto Klebsiella, then there is no serious health riskand the need for further testing can most likelybe eliminated.21 If tests indicate that high fecalcounts are not related to Klebsiella, then it istime to move to Step 4.

21 There is no evidence to suggest that Klebsiella bacteriahave caused any healthy individuals to experienceillnesses due to exposure in the natural environment.

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High Risk CategorySampling sites with fecal coliform countsof 800 or greater (CFUs per 100 mL)

When a fecal coliform result is observedto exceed 800 CFU/100 mL of water sampled,consideration should be given to issuing a healthwarning for the sampling site until re-samplingcan be done. State rules indicate that healthwarnings should only be issued after additionalsamples provide high counts. This is consideredthe best approach to prevent undue public con-cern, but the public should at least be notifiedthat additional testing is planned. Move to Step 3.

Step 3Test for E. coli and Look for False Positives

Because false positives have been ruled outby now, the remainder of your bacteria testingcan be done using the less expensive fecal coliformtest. The objective of this sampling regimen is toidentify the location of a contamination source.Sites that have been identified as potentialsources should be re-sampled as soon as possible.With these results, it may be possible to narrowthe search down to a smaller area.

Once re-sampling is initiated, new sitesshould be chosen near previously identified sites(i.e., those with high fecal coliform counts).

Attention should be given to the locations of in-flowing streams, ditches, stormwater pipes, and/orwater currents, with additional considerationgiven to larger point sources such as farms.

If fecal coliforms are higher in one area,you will have narrowed down your search areaand greatly improved the chances of identifyingthe source.

See page 35 for Locations to Consider WhenIdentifying and Locating Possible Sources ofContamination.

If the source for contamination is notreadily found, the assistance of local propertyowners should be enlisted in the effort. Specifi-cally, they should be asked to examine their

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Step 4Re-sample Sites with Elevated FecalColiform Counts

When tracking down suspected sources of bacterialcontamination, special consideration should be givento the following locations:

In-flowing pipes, ditches or streams – If you knowof a place where water comes into a lake or waterbody, it’sa good idea to follow (i.e., on foot) the pipe or stream andidentify any other locations where water may be enteringthe system. Make an effort to determine what water sourcethe pipe is linked to. It may be coming from a previouslyunidentified source.

Water currents – For example, look at the way sub-mersed aquatic vegetation (i.e., aquatic plants) may bebending or leaning, as it could be an indication of thedirection that water is flowing into a lake. Follow thatsource and collect water samples at evenly spaced intervals.

Potential point sources – Identify areas with highdensities of animals that might represent potential problems(i.e., farms, ranches, pet parks, etc.). Keep in mind that evenif these areas are not visible from the shoreline or are locatedaway from the waterbody, stormwater runoff could still drainfrom them. However, it must also be said that larger “pointsources” such as farms sometimes attract misdirected atten-tion when it comes to suspected bacterial contamination.Nothing should be assumed until the actual source is confirmedwith additional sampling. Quite often, the real culprit turnsout to be something other than the original suspected source,such as a leaking sewer pipe between the farm and the lake.

Septic systems – When a contamination source is notreadily found, the assistance of local property owners can beenlisted to help find the source. Specifically, they should beasked to examine their septic drainage field for possiblebreach sites. If a sewage smell is detectable, it may be anindication that additional sampling is needed in the area.

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Locations to Consider When TrackingPossible Sources of Contamination

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septic drainage field for possible breach sites.They should also be encouraged to use the “smell”test. If they can smell a sewage odor, this aloneis evidence for supporting additional sampling.

Once the source of contamination is identifiedand it is determined that the problem cannot beeasily remedied by the private homeowner orcommunity, report it to your public healthagency. If the source happens to be on publicland, you may have to recruit assistance to raisefunds to solve the problem or to exert pressureon governmental agencies to fix it.

ConclusionFranklin Delano Roosevelt once stated,

“We have nothing to fear, but fear itself!” Lifeitself is not without risk, and aquatic activitiesare certainly not exempt. It is impossible toguarantee with 100% confidence that an indi-vidual will not become ill upon contact with water.However, with the technology and informationnow available, bacterial contamination of water

is much less of a problem than it used to be. Asthey say, “the cup is at least half full.” Ratherthan being fearful, citizens are encouraged toremain vigilant and solve problems as theyemerge.

As far as the future is concerned, we allneed to pay close attention to the developingtechnology for measuring bacterial contamina-tion. Things are changing almost daily and bettertechniques are becoming available. For the timebeing, however, the use of total coliform, fecalcoliform and E. coli counts continues to do thejob in most instances—especially when combinedwith the Four Step approach described in thiscircular.

So for now, one can take comfort in know-ing that if total and fecal coliform counts arebelow the legal state-established criteria, there isa strong probability that the water is safe forrecreation. With that knowledge, we hope you’llenjoy Florida’s wealth of unique and refreshingaquatic environments—in good health!

Hach CompanyLoveland, COPhone: (800) 227-4224Website: http://www.hach.com

Millipore CorporationBedford, MAPhone: (800) MILLIPOREPhone: (800) 221-1975 or (800) 645-5476Website: http://www.millipore.com

Micrology Laboratories (for Coliscan products)Goshen, INPhone: (888) 327-9435Website: http://www.micrologylabs.com

IDEXX Laboratories (for Colilert products)Westbrook, MEPhone: (207) 856-0300Website: http://www.environmental-center.com/technology/idexx/idexx.htm

Suppliers

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Books

American Public Health Association. 1998. STANDARD METHODS for the Examination of Water and Wastewater. 20th Edition. American Public Health Association. Waldorf, Maryland.

Canadian Council of Ministers of the Environment. 1999. Canadian Water Quality Guidelines. Eco-Health Branch. Ecosystem Sciences and Evaluation Directorate. Environment Canada. Ottawa, Canada.

Publications

Hach Company. 2000. Hach’s Technical Information Series—Booklet No. 13, The Use of IndicatorOrganisms to Assess Public Water Safety (Literature #7015.)

Hach Company. 2000. Microbiological Laboratory Start-up Guide. See Microbiological TestingSection, pages 135-182.

Hach Company. 2000. Analytical Procedures. Coliforms: Membrane Filtration (simultaneousdetection) for the detection of total coliforms and E. coli from potable water, non-potablewater, wastewater.

Hach Company. 1997. Products for Analysis Catalog (Literature #3226).

The Volunteer Monitor. 1998. Issue Topic: Monitoring Estuaries. Special Section: Bacteria Testing,Part 1. Volume 10, No. 2. Fall. Pages 8-15.

Note: This publication is a must for individuals or groups interested in doing their own bacteria testing.Numerous testing methods are discussed and compared and information is even provided on howto build an incubator.

Toranzos, G. A. 1991. Current and possible alternate indicators of fecal contamination in tropicalwaters: a short review. Environmental Toxicology and Water Quality 6: 121-130.

U.S. EPA. 2000. Non-point Source News-Notes. Special Focus: On-site Wastewater Treatment.December. Number 63.

Note: News-Notes are accessible on EPA’s website: www.epa.gov/OWOW/info/NewsNotes/index.html

Selected References

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