CHAPTER ONE
1.0
INTRODUCTION/LITERATURE REVIEW
All cells, at least those that are metabolically active, contain
approximately 85.95% water, it is therefore a truism to state that
any environmental factor that affects, the activity , structure or
physical state of water poses a threat to life in one s health.
Oceans have historically been the dumping grounds for the wastes
from society. Fortunately, this view has changed and regulations
have become much more stringent, but the effects of the past still
lingers. Pollution has been very damaging to aquatic ecosystems,
and may consist of agricultural, urban, and industrial wastes
containing contaminants such as sewage, fertilizer, and heavy
metals that have proven to be very damaging to aquatic habitats and
species. Many of the pollutants entering aquatic ecosystems (e.g.,
mercury, lead, pesticides, and herbicides) are very toxic to living
organisms (USEPA, 2007). They can lower reproductive success,
prevent proper growth and development, and even cause death. T he
organisms that are most directly and adversely affected by toxic
pollutants consist of larvae, eggs, and other organisms that live
at the surface or near the bottom of aquatic habitats where
pollutants tend to settle. Filter feeders (e.g., clams, and mu
ssels) and other organisms higher up in the food chain (e.g.,
swordfish, tuna) are also affected by the presence of toxicants.
Filter feeders and predatory fin -fish are not directly affected by
the presence of toxic chemicals in the water column or sediments,
instead they bioconcentrate and bioaccumulate the toxicants. For
example, humans, animals, and birds have been known to suffer from
mercury poisoning, lead poisoning, and other neurological diseases
from eating fish and shellfish that are contaminated with high
levels accumulated toxicants.1
In addition to toxic pollutants, increased nutrients, especially
nitrogen and phosphorus, from city sewage and fertilizers from
agricultural areas (e.g. animal feed lots) have also proven to be
very damaging to aquatic ecosystems. Certain levels of these
nutrients are known to cause harmful algal blooms in both
freshwater and marine habitats. In turn, algal blooms impact
aquatic biodiversity by affecting water clarity, depleting oxygen
levels, and crowding out organisms within an ecosystem. In some
instances algal blooms have produced neuro -toxins that have led to
species die -offs and illnesses such as Paralytic shellfish
poisoning. Other pollutants affecting biodiversity in aquatic
ecosystems are solid pollutants like plastic bags, plastic rings,
abandoned fishing gear, and other man -made materials that result
from garbage dumped from shore and ships. Trash and debris of this
nature floating in aquatic environments, have been known to
entangle and even kill marine mammals and birds. Animals such as
sea turtles have often died through ingesting bits of plastic and
other discarded materials. In addition, abandoned fishing gear such
as lobster pots and nets are self-baiting and will continue to
catch and kill fish and othe r organisms for years after the gear
has been discarded or lost (USEPA, 2007). 1.1 INLAND WATER
Inland water systems can be fresh or saline within continental
and island boundaries. They include lakes, rivers, ponds, streams,
groundwater, springs, cave waters, floodplains, as well as bogs,
marshes and swamps, which are traditionally grouped as inland
wetlands. The biodiversity of inland waters is an important source
of food, income and livelihood, particularly in rural areas in
developing countries. Other values of these ecosystems include:
water supply, energy production, transport, recreation and t
ourism, maintenance of the hydrological balance, retention of
sediments and nutrients, and provision of habitats for
2
various fauna and flora. But since all terrestrial animals and
plants depend on fresh water, the boundaries between aquatic and
terrestria l are blurred. At the species level, inland water
biodiversity generally includes all life forms that depend upon
inland water habitat for things other than simply drinking (or
transpiration in plants). Besides the obvious life living within
water itself (e.g., fish), this also includes many terrestrial
species of animals (e.g., water birds), semi-aquatic animals (e.g.,
hippopotamus, crocodiles, and beaver) and plants (e.g., flooded
forest, mangroves, vegetation associated with the margins of water
bodies ). The majority of amphibians, for example, breed in fresh
water. As for all biodiversity, for inland waters the concept
includes diversity at the species, genetic and ecosystem level.
Species which are restricted to inland waters (e.g., freshwater
fish) cannot move easily between different areas. Inland waters are
therefore characterized by high endemicity of freshwater species
for example between different lakes or the upper reaches of sub
catchments of rivers, often even where located physically close to
each other. This is also reflected in high levels of genetic
diversity. Most importantly, ecosystem diversity (including
hydrological and physical diversity within the landscape) is an
extremely important aspect of the biodiversity of inland waters.
Thi s ecosystem diversity is very complex and includes both aquatic
and terrestrial (landscape) influences; maintaining it is critical
to maintaining ecosystem services. Also, human interventions in the
ecosystem tend to deliberately reduce this diversity (e.g., by
modifying the form, and therefore function, of river channels
and/or hydrology).
3
1.2
LAGOON POLLUTION
Lagoons have a less well defined drainage network and larger
open areas and are usually shallow often less than 2 m (6.5 ft)
deep. A raised ridge, or sand barrier, is characteristic of
lagoons. This feature was formed during the interglacial stage of
the Pleistocene Epoch, some 80,000 years ago, when sea shorelines
were about 6 m (20 ft) above present average levels. During the
last ice age, fluvial and atmospheric processes eroded the earlier
coast. When sea levels rose anew, the areas behind the barrier were
once again flooded. Lagoon s are present on all continents (Encarta
2008). Water pollution may come from point sources or nonpoint
sources. Point sources discharge pollutants from specific
locations, such as factories, sewage treatment plants, and oil
tankers. The technology exists to monitor and regulate point
sources of pollution , although in some areas this occurs only
sporadically. Pollution from nonpoint sources occurs when rainfall
or snowmelt moves over and through the ground (USEPA). 1.2.1 POINT
SOURCE POLLUTION Point source pollution refers to co ntaminants
that enter the lagoon through a discrete conveyance, such as a pipe
or ditch. Examples of sources in this category include discharges
from a sewage treatment plant, a factory, or a city storm drain.
The U.S. Clean Water Act (CWA) defines point source for regulatory
enforcement purposes 1.2.2 NON-POINT SOURCE POLLUTION Non-point
source (NPS) pollution refers to diffuse contamination that does
not originate from a single discrete source. NPS pollution is often
a cumulative effect of small amounts of contaminants gathered from
a large area. Nutrient runoff in stormwater from sheet flow
4
Contaminate stormwater washe off of parking lots roads and
highways called urban runoff is sometimes included under the
category of NPS pollution. However this runoff is typically
channeled into storm drain systems and discharged through pipes to
local surface waters and is a point source. The CW definition of
point source was amended in 1987 to include municipal storm sewer
systems as well as industrial stormwater such as from construction
sites. F G R 1.1
5
ve ic l l iel
est is sometimes cite as e amples of NPS poll tion.
1.3 PARAMETERS OF INTEREST The parameters considered in
determining the quality of water are many and varied. The choice of
parameters therefore rests on the researcher s interest and
objectives. Possible choice of parameters may be centered on the
following:
Geographical location Economic activities Source of pollution
Availability of appropriate instrument and reagent.This project
would focus on the conventional and nutrient parameters. 1.4
CONVENTIONAL/PHYSICAL PARAMETERS
pH Temperature TDS Turbidity Conductivity Salinity1.4.1 NUTRIENT
PARAMETERS These parameters are the result of life activities in
the lagoon. They provide the nutrient requirement of organisms and
such explain why life may exist in water. They include:
Nitrate Phosphate Sulphate6
1.5 SPECTROPHOTOMETRY In spectrophotometer analysis, a source of
radiation is used that extends into the ultraviolet region of the
spectrum. The instrument employ is the spectrophotometer. It
consists of two components;
An optical spectrometer- it is an instrument possessing an
optical system which canproduce dispersion of incident
electromagnetic radiation, and with which measurements can be made
of the quantity of transmitted radiation at selected wavelengths of
the spectral range.
A photometer is a device for measuring the intensity of
transmitted radiation or afunction of this quantity. The variation
of the colour of a system with change in concentration of some
components forms the basis of calorimetric analysis. The colour is
usually due to the formation of a coloured compound by the addition
of an appropriate reagent. Colorimetry is concerned with the
determinat ion of the concentration of a substance by measurement
of the relative absorption of light with respect to a known
concentration of the substance. 1.5.1 BEER-LAMBERT S LAW
The law states that there is a logarithmic dependence between
the transmission (or transmissivity), T, of light through a
substance and the product of the absorption coefficient of the
substance, , and the distance the light travels through the
material (i.e. the path length), . The absorption coefficient can,
in turn, be written as a product of either a molar
7
absorptivity of the absorber, , and the concentration c of
absorbing species in the material, or an absorption cross section,
, and the (number) density N of absorbers.
For liquids, these relations are usually written as
Whereas for gases, and in particular among physicists and for
spectroscopy and spectrophotometry, they are normally written
Where I0 and I are the intensity (or power) of the incident
light and that after the material, respectively
The transmission (or transmissivity) is expressed in terms of an
absorbance which for liquids is defined as
Whereas for gases, it is usually defined as
This implies that the absorbance becomes linear with the
concentration (or number density of absorbers) according to
8
And
For the two cases, respectively
Thus, if the path length and the molar absorptivity (or the
absorption cross section) is known and the absorbance is measured,
the concentration of the substance (or the number density of
absorbers) can be deduced.
Although several of the expressions above often are used as Beer
Lambert law, the name should strictly speaking only be associated
with the latter two. The reason is that historically, the Lambert
law states that absorption is proportional to the light path
length, whereas the Beer law states that absorption is proportional
to the concentration of absorbing species in the material.
If the concentration is expressed as a mole fraction i.e. a
dimensionless fraction, the molar absorptivity ( ) takes the same
dimension as the absorption coefficient, i.e. reciprocal length
(e.g. cm 1). However, if the concentration is expressed in moles
per unit volume, the molar absorptivity ( ) is used in Lmol 1cm 1,
or sometimes in converted units of mol1
cm2.
The absorption coefficient ' is one of many ways to describe the
absorption of electromagnetic waves. For the others, and their
interrelationships, see the article: Mathematical descriptions of
opacity. For example, ' can be expressed in terms of the
9
imaginary part of the refractive index, , and the wavelength of
the light (in free space), according to
0,
In molecular absorption spectrometry, the absorption cross
section of line strength, S, and an (area-normalized) line shape
function,
is expressed in terms
. The frequency scale in
molecular spectroscopy is often in cm 1, wherefore the line
shape function is expressed in units of 1/cm 1, which can look
funny but is strictly correct. Since N is given as a number density
in units of 1/cm 3, the line strength is often given in units of cm
2cm 1/molecule. A typical line strength in one of the vibrational
overtone bands of smaller molecules, e.g. around 1.5 m in CO or CO
2, is around 1023
cm2cm 1, although it can be larger for species
with strong transitions, e.g. C 2H2. The line strengths of
various transitions can be found in large databases, e.g. HIT AN.
The line shape function often takes a value around a few 1/cm , up
to around 10/cm
broadened, and below this under atmosph eric pressure
conditions, when the transition is collision broadened. It has also
become commonplace to express the linestrength in units of cm 2/atm
since then the concentration is given in terms of a pressure in
units of atm. A typical linestrength is then often in the order of
103
detectability of a given technique is often quoted in terms of
ppm m.
The fact that there are two commensurate definitions of
absorbance (in base 10 or e) implies that the absorbance and the
absorption coefficient for the cases with gases, A' and ', are ln
10 (approximately 2.3) times as large as the corresponding values
for liquids, i.e. A
1
under low pressure conditions, when the transition is
Doppler
cm 2/atm. Under these conditions, the
10
and , respectively. Therefore, care must be taken when
interpreting data that the correct form of the law is used.
The law tends to break down at very high concentrations,
especially if the m aterial is highly scattering. If the light is
especially intense, nonlinear optical processes can also cause
variances.
Figure 1.2
Diagram of Beer Lambert absorption of a beam of light as it
travels through a cuvette of width .
1.5.2 CALIBRATION OF THE SPECTROPHOTOMETER The spectrophotometer
is operated by first of all standardizing the instrument with the
respective chemical. A given number was entered on the instrument.
After which it displayed a wavelength with respect to the parameter
of interest. The instrument was t hen
11
turned to the wavelength and the necessary parameter
concentrations were then read after treating the samples with the
appropriate reagent.
1.6 CONVENTIONAL PARAMETERS 1.6.1 pH pH is probably the most
commonly measured quantity on environmental resea rch and water
quality control. This expresses the acidity or basicity of a
solution. The concentration of hydrogen in solution determines the
pH . It s expressed mathematically as:
An acid is a substance that produces hydrogen ion in an aqueous
solution. A base is a hydroxyl ion in an aqueous solution. In
acidic water, more acid materials are present. Alkalinity is the
condition in which more alkaline or basic materials are present.
Acidic water has to be less than 7.0, with neutral at a pH of 7.0 .
Alkaline water has pH greater than 7.0. Acidity and alkaline are
determined with various colorimetric papers, pH meters or titration
devices.
1.6.2 TEMPERATURE Temperature affects the density and
stratification of the water. It affects density and viscosity of
sediment transportation, vapour pressure on evaporation rates, and
partial pressures of gases on gas solubility, particularly oxygen
and its impact on aera tion. Temperature affects many physical
properties of water, the solubility of dissolved gases and the
toxicity of many other parameters. The rate of evaporation
increases as the
12
temperature rises and water vapour pressure increases. It is
important that a n adequate oxygen supply is present in the water
because most living organisms depend on oxygen in one way or the
other.
1.6.3 TDS (Total Dissolved Solids) It is a measure of the total
dissolved solids in a water sample. The dissolved solids are most
readily changed by biological, chemical or physical processes. The
concentration of dissolved solids is directly related to the
conductivity. The quantity of TDS in a body of water depends on
several factors including:
Precipitation contributing to the body o f water The type of
soil and rock the water passes over and human activities.The major
dissolved substances found in water that can cause the above
problems are positively charged ions of Na, Ca, Mg, K, and Fe, and
anions such as CI, HCO , CO and SO . High levels of TDS may cause
objectionable taste and laxative effect on animals. An excessive
level of TDS in water also leaves the water unsuitable for
irrigation purposes. It also causes foaming and may corrode some
metals. 1.6.4 TURBIDITY
It is a measure of the clarity of water. Turbidity is the
presence of suspended materials such as clay, silts, finely divided
organic materials, plankton and other inorganic material. Turbidity
although not a hazard itself, may be an indication that pollution
ha s been introduced into the water. High levels of turbidity
decrease the amount of oxygen coloration
13
and taste, which is not characteristic of quality water. It may
also cause irritation of the throat.
1.6.5 CONDUCTIVITY The electrical conductivity measurement of a
solution determines the ability of the solution to conduct an
electrical current. The electrical conductivity of water is
directly related to the concentration of dissolved salts and
anions. The dissolved ions increase the ability of water and
aqueous solution to transfer electrons and as a result conduct
electricity. Accordingly, conductivity meters are used to measure
the electrical conductivity of water. A factor that determines the
degree to which water will carry an electrical current
includes;
Concentration Mobility of ions Oxidation state Temperature of
waterHigh levels of dissolved solids can cause mineral tastes in
drinking water. Also, water high in dissolved solids corrodes metal
surfaces. 1.7 NUTRIENT PARAMETERS 1.7.1 NITRATES Nitrates impart a
bitter taste to water at levels of 20 to 50ppm. Nitrate levels of
about 25ppm often indicate contamination of lagoons from human
sources such as animal waste, inorganic compounds and chemical
fertilizers.
14
Nitrates are converted within the body to nitrates by bacterial
action. The nitrates react with haemoglobin to cause a condition
known as methemoglobinemia, in which haemoglobin loses the ability
to carry oxygen. This is particularly better growth conditions for
the bacteria. 1.7.2 PHOSPHATES Phosphorous is closely associated
with water because of its use in the production of algae blooms.
Phosphorous exists commonly in the oxidized state. Most waters
generally contain low levels of phosphorous (approximately 0.01
-0.5mg/l). The primary source of phosphorous in water is of
geologic origin. The main sources of phosphate in lagoons
include;
Fertilizers Sewage Detergents And rain waterPhosphates are not
toxic people or animals unless they are present in very high
levels. 1.7.3 SULPHATES Sulphates can be naturally occurring as a
result of municipal or industrial discharges. They occur naturally
as a result of breakdown of leaves that fall into a stream of water
passing through rock soil containing Gypsum and other common
minerals of atmospheric decomposition. Sulphur is an essential
plant nutrient and reduced concentration has a
15
detrimental effect on algae growth. The commonest form of sul
phur in well- oxygenated water is sulphate.
1.7.4 SALINITY This refers to salts dissolved in the water. The
anions commonly present include CO , HCO , SO , NO , Cl , PO and F.
The cations include; Ca , Mg , Na and K . It may be measured as TDS
and is expressed in ppm units. It may also be measured by
electrical conductivity and is expressed as reciprocal micro ohms
per cm ( omhs/cm). Salinity says nothing about which elements are
present but this may be of critical importance. So when the
salinity is elevated, the water should be analyzed for the specific
anions and cations. An abrupt change of water of high salinity to
one of low salinity may cause animals harm while a gradual change
would not. Animals can consume water of high salinity for a few
days without harm, if they are then given water of salinity. The
cations may have toxic effects because of their solubility effect
or interference with other elements. High salinity levels may also
be treated to physiological effects upon animals and p lants
exposed to the water, corrosion and encrustation of equipment and
detrimental effects on soil structure and chemical fertility. 1.8
STATEMENT OF PROBLEM Fosu Lagoon has suffered from large volumes of
waste, both liquid and solid, from the final disposal site at
Nkanfoah in Cape Coast. Waste Oil, metals and other forms from
garages at siwdu, as well as the waste product from palm kernel
extraction around Ad isadel Village and free-range defecation in
the lagoon catchment area, had added to its current highly16
contaminated state. Various individuals have conducted research
to ascertain the extent of pollution of the lagoon. The problem
which keeps on lingering on the minds of people is how to remedy
the rate at which pollution is helping to degrade this natural
habitat of some fishes and organisms.
1.9 OBJECTIVES 1.To identify specific existing or emerging water
quality problems as a result of the presence of different potential
pollution sources and their particular waste -water management
along the banks of Fosu Lagoon 2. To gather information to design
specific pollution prevention or remediation programs 3 To
determine the water quality of the Fosu Lagoon through physical,
chemical and biochemical analysis
17
C A2.1 STUDY A EA
TWO !
METHODOLOG
The Fosu lagoon is one of the most important closed lagoons in
the central region of Ghana. It is termed closed because it is
separated from the sea by a sand bar. This sand bar is formed by
the influence of the coastal wind regimes and long shore drifts.
TheFosu lagoon lies (5 07 N 1 16 W and covers an estimated area of
61ha. It has an average water depth of 16cm and hence considered
shallow (Blay and sabre -Ameyaw 1993) The geology of the lagoons is
a mud soil its salinity is relatively low (about 25 ).
18
A glance at the mangrove community indicates that it has been
extensively degraded due to changes in the sedimentary
environments, expect for a strand of Avicennia Africana and
Paspalum vaginatum near the Fosu shrine. The degradation of the
mangrove community has also resulted in the loss of roosting sites
of some migratory birds. Also, large portions of the lagoon had
dried up and were over grown with weeds which had also made it
possible for people to walk on it to dump garbage. Sediments are
washed into the lagoon during heavy rains owning to the fact that
the vegetation that stabilizes the banks from erosion has been
removed (CCMA, 2007). The lagoon is heavily polluted due to the
inflow of effluents from surrounding settlement (Washing bays and
households). It was observed that waste oil, metal scarps and other
wastes from garbage and waste generated from palm kernel extraction
in siwdu have contributed to the contamination of the lagoon among
other negative human practices like defecating at the banks of the
lagoon. Most of the indigenes of this community are either involved
in fishing or fish processing activities such as smoking, salting
and fermenting of fish. The fishermen practice artisanal fishery by
use of cast nets and hook and also practice hand fishing. The main
fish species found in the Lagoon is Sarotherodon melanotheron.
Sarotherodon melanotheron is relatively eurythermal species and its
temperature range in its natural habitat is about 18-33C (Philipart
and uwet, 1982). No breeding occurs below 20 -30C (Trewavas, 1983).
It constitutes about 90% by weight of the total catch and annual
yield of 452 -664 kg/ha is higher than those reported for other
tropical lagoons (Blay and Asabre -Ameyaw, 1993). It is
"
19
gradually becoming the only fish species in the lagoon. This is
because it is a hardy fish species and it has prolific breeding
habits.
20
2.2 SAMPLE COLLECTION The samples were collected along the banks
and middle of the lagoon. The samples were collected during a
period of prolonged dryness and continued into the rainy season.
The duration of this exercise was eight weeks. The sample
containers were washed in the laboratory and rinsed with the sample
water at the point of collection. Containers were labeled with
Site Time Temperature Date2.3. SAMPLE TREATMENT/STORAGE The
samples were stored in a cool dry place till the analysis was
completed. The samples were collected with a plastic bucket from
the lagoon and transferred into the labeled bottles. 2.4
INSTRUMENTS/APPARATUS
pH meter (mettle Toledo MP 125) Conductivity meter (Hach co 150)
Turbid meter (Hach CO 150) Spectrophotometer (HACH D /2000)
#
21
2.5 REAGENTS/CHEMICALS USED
Standard Buffer for pH (4.0 and 7.0) Phosver 3 phosphate reagent
Sulfaver 4 sulphate reagent Distilled water
2.6
METHOD AND PRINCIPLE
The study methods used to collect data for this project included
Personal Observations and Surveys, Water Sampling and Analyses,
Desk Study and Interviews. Water quality parameters measured
included pH, Temperature, Conductivity, Total Dissolve So lids,
Nitrates, turbidity, salinity, phosphate and sulphate. Institutions
involved in the interviews were Environmental Protection Agency,
Institute of enewable Natural esources, Waste and Sewerage
Department, Ghana Water Company Limited and Ghana Statistical
Service all based in the Cape Coast Metropolis.
2.7 Conductivity Meter. The conductivity meter was first
calibrated using the calibration constant solution. The probes from
the various conductivity meters were dipped into the calibration
solution. The units were calibrated by adjusting the value on the
meter to read the value of the constant
22
$
$
(0.1413 milli-siemens (mS). This was done by using either
increase/decrease buttons on the meter or using a small tool
supplied with the meters to adjust a small potentiometer.
CALIB ATION OF THE METE S WITH pH 7 and Ph 2 buffers 1. Select
the pH mode and set the temperature control knob to 25 C. Adjust
the cal 2 knob to read 100%
(Shurwipes or Kimwipe are available in the lab.) 3. Place the
electrode in the solution of pH of 7 buffer, allow the display to
stabilise and, then, set the display to read 7 by adjusting cal 1.
emove the electrode from the buffer.
(Shurwipes or Kmwipes are available in the labs). 5. Place the
electrode in the solution of pH 2 buffers, allow the display to
stabilise and, then, set the display to read 2 by adju sting cal 2.
emove the electrode from the buffer.
2.8 ANALYSIS OF PARAMETERS 2.8.1 pH.
This was determined by first of all standardizing the pH meter
with buffer solutions of pH 7.0 and pH 4.0. The electrode was
rinsed with distilled water. The sample was put into a
%
6.
inse the electrode with deionised water and blot dry using a
piece of tissue.
23
%
%
4.
inse the electrode with deionised water and blot dry using a
piece of tissue
%
%
2.
inse the electrode with deionised water and blot dry using a
piece of tissue
%
%
25ml beaker. The electrode was then put into the beaker. Then
the meter switched on and pH selected. The meter blinks until
stable, and then the readings were t aken.
2.8.2 CONDUCTIVITY, TDS and SALINITY The conductivity meter was
used in determining these parameters. It was standardized by
dipping its electrode into de -ionized water to ensure that it
reads zero. The electrode was then dipped into the sample and the
respective parameters were read by switching to the mode of each
parameter.
2.8.3 TURBIDITY This was determined by the turbid meter. The
cell of the instrument was rinsed with distilled water and filled
to the given mark on the cell (5ml). This was then placed in the
cavity and the light shield closed. The instrument displays the
reading after been switch on. 2.8.4 NITRATE A pillow of nitrate
reagent was added to 25ml of the sample in the cell. This was then
swirled to mix and then the concentration determined using the
spectrophotometer. 2.8.5 TEMPERATURE The temperature was determined
with a temperature at the point of collection. 2.8.6 SULPHATE
24
This was determined using the spectrophotometer. Sulfaver 4
sulphate reagent was added to the sample and swirled gently to mix
and its concentration determined on the spectrophotometer.
25
CHAPTER 3TABLE OF RESULTS AND GRAPHS
3.0 RESULTS TABLE OF ESULTS 3.1The results obtained from the
analysis of samples are presented in the table below
PARAMETERSpH
TEMPE ATU E/C
TURBIDTY/NTU
TDS/ppm
SALINITY/ CONDUCTIVITY/ppm
PHOSPHATE/mg/l
SULPHATE/ mg/l
NITRATE/ mg/l
&
JANUARY 9.03 30.30 33.67
February 8.70 31.33 34.33
March 9.19 30.67 34.67
April 8.87 31.33 24.73
Mean 8.95 30.90 31.85
W.H.O6.5-8.5
VARIES
'
'
5
2.09
2.21
1.85
2.02
2.04
1000
2.40 455.0
1.33 433.0
1.67 446.0
0.14 447.0
1.385 445.3
0.1 1000
2.90 127.9 2.50
1.30 139.8 7.25
2.61 157.4 3.50
1.40 124.5 4.30
2.05 137.4 4.39
0-0.4
250
0.1-0.5
26
VARIOUS LEVELS OF PARAMETERS STUDIED. Figure 3.1
9.39.2 9.1 9
8.9 8.8 8.7 8.68.5 8.4
January
February
27
0)
p against
n th
(
March
April
Figure 3.2
31.6
31.4
31.2
31
30.8
30.6
30.4
30.2
30
29.8
29.6
January
February
28
31
Te p erature / against
n th
2
1
March
April
Figure 3.3
Turbidity /NTU against Month
40
35
30
25
20
15
10
5
0
January
February
March
April
29
Figure 3.4
TDS /ppm against Month
9
8
7
6
5
4
3
2
1
0December January February March April
30
Figure 3.5
sali ity/
agai st m
3
2.5
2
1.5
1
0.5
0January February March April
31
6 45t
4
4
Figure 3.6
4.6
4.55
4.5
4.45
4.4
4.35
4.3
4.25
4.2
32
9
8
Ja uary
Fe ruary
Marc
A@
G CB F Cr il
F EE
DCB
c
uctivity/
agai s t
t
7
Figure 3.7
NO /mg/l against month
8
7
6
5
4
3
2
1
0
January
February
March
April
33
Figure 3.8
Phosphate/mg/l against month 3.5
3
2.52
1.51
0.50
January
February
March
April
34
CHAPTER 4Discussion4.1 pH
The acceptable limit for pH is 6.5-8.5. The pH for Fosu lagoon
was found to be slightly alkaline and therefore could not support
life of fishes in the lagoon. This was because; they were above the
acceptable limit. (I.e. 8.70-9.19). This could be attributed to the
presence of hydroxyl ions in the water. 4.2 TEMPERATURE The
temperature for Fosu lagoon was within the range of (30.30 -31.33).
The water body is said to be warm. This could be attributed to the
direct heating fro m the sun and also due to the landscape. There
could also be a lot of dissolved substances in the lagoon.
Temperatures such as that of Fosu Lagoon supports more plant life
and fishes like bass, bluegill, carp, catfish, leeches, caddis
fly.
4.3
TURBIDITY
The turbidity for Fosu Lagoon was below the acceptable limit of
(500mg/l -1000mg/l). The range fell within (24.73mg/l-34.67mg/l).
Turbidity measures the cloudiness of a body of water. This could be
attributed to the presence of suspended materials su ch as sand,
clay, silt etc. This covers sunlight from reaching the bottom of
the lagoon. Oil spillage from the Siwdu and some effluent from the
Palm kernel plant at Adisadel could be a contributing factor to the
high rate of turbidity in the lagoon.35
4.4 TOTAL DISSOLVED SOLIDS and CONDUCTIVITY Although Fosu Lagoon
is not a drinking water, TDS is used to estimate the quality of
drinking water, because it represents the amount of ions in the
water. Water with high TDS often has a bad taste and/or high water
hardness, and could result in a laxative effect.2+ 2+
Hardness mitigates metals toxicity, because Ca and Mg help keep
fish from absorbing metals such as lead, arsenic, and cadmium into
their bloodstream through their gills. The greater the hardness,
the harder it is for toxic metals to be absorbed through the gills.
Because hardness varies greatly due to differences in geology,
there are no general standards for hardness. The hardness of water
can naturally range from zero to hundreds of milligrams per liter
(or parts per million). Water hardness has a connection with the
conductivity of the water. Conductivity determines the amount of
charged particles in a water sample, therefore, the harder the
water sample the higher its conductivity. The TDS as well as the
conductivity of the Fosu Lagoon were high and thus likely to pose
some danger to the aquatic life. The filthiness of it is because of
the high suspended solids caused by dumping of refuse from domestic
homes. It renders the Lagoon unworthy for any recreational
purposes. Dirty oils from the fitting shops around the Lagoon
poisons the fishes in it, this affects the human health, because
the fishes caught in the Fosu Lagoon are mainly for human
consumption.
36
4.5
PHOSPHATE
The acceptable limit is 0.3 mg/l. The phosphate levels for Fosu
lagoon were above the acceptable limit. (I.e. 1.30-2.61). This
explains why weeds and aquatic plants are found on the Fosu
lagoon.
4.7
SULPHATE
The acceptable limit is 400mg/l. The level of Sulphate in Fo su
Lagoon was within the range of 124.5-157.4. Sulphates at a
concentration of about 250ppm can have a laxative effect on people.
High levels of sulphates form slimes, encrustations and odorous
water.
4.8
NITRATE
The acceptable limit for nitrate in drinking water is 10mg/l.
The range of nitrate in Fosu Lagoon was 2.50-7.25. Nitrates impart
a bitter taste to the water at levels of 20-50ppm. Nitrate levels
of about 25ppm often indicate contamination of water bodies from
human sources such as human waste, inorganic compounds and chemical
fertilizers. Nitrates are converted within the body to nitrites by
bacteria action. 4.9 SALINITY The recommended W.H.O value for
salinity ranged from 0.0 to 0.1% of NaCl. The salinity for the
lagoon ranged 0.14 and 2.14. This means the lagoon is more salty.
It indicates the intrusion of sea water into the lagoon.
37
CHAPTER 55.1 CONCLUSION From the Analysis, it can be deduced
that, most of the pollutants in the Fosu Lagoon are as a result
of;
Wrong sitting of facilities such as building the district
hospital close to the Lagoonand the garages at Siwdu.
lack of demarcated sites for refuse disposal relatively
inaccessible refuse dump sites lack of awareness of the health
implication of insanitary practices indifference to the presence of
waste lack of the requisite equipment for disposal poor siting of
refuse disposal sites (e.g. along river banks and marshy areas,
nearwater sources)
lack of the technical know -how to add value to waste (e.g.
composting)
5.2
RECOMMENDATION
There is the need for an enforcement of aquatic pollution
control in our nation andin particular Fosu Lagoon to ensure the;
1. Protection of Fishes and other aquatic organisms. 2. Effects on
the environment and the human health. 3. Protection of the coastal
areas and the use for recreational purposes
38
There should be a local legislation on the management of Fosu
Lagoon. SuchPollution Control measure should defined those
technical, administrative and legal steps needed to check,
regulate, reduce, remove or eliminate, within certain limits, the
undesirable effects of the presence of certain substances in waters
minimize those activities that results in the alteration of the
physical, chemical, microbiological or aesthetic properties of the
l agoon.
Fishing is a means of survival for the study population
contributing to lowerperceived risk. The value of fishermen
understands of the environment and fishing practices may not be
enough to help reduce their exposure to risk of eating polluted
fish. Therefore educational programs based on the importance of
tradition, experience and scientific information may be an
appropriate intervention
A cost-benefit analysis on the fencing of the lagoon should be
carried out toascertain the importance of fencing the lagoon. One
importance to nature will be to allow the lagoon to get rid of some
pollutants through Biodegradation.
The garage at Siwdu should as a matter of urgency be re-settled
at another place andthis needs the involvement of city authorities,
traditional authorities and the managers of the garage.
Whilst infrastructural initiatives to deal with bulk pollution
will be required, forexample improved sewage treatment systems,
actions at the individual and community levels are also
desirable
39
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41