Soil Pollution

INTRODUCTION

Environmental Issue

Pollution is the introduction of contaminants into the environment that cause harm or

discomfort to humans or other living organisms, or that damage the environment which can

come in the form of chemical substances, or energy such as noise, heat or light. Pollutants

can be naturally occurring substances or energies, but are considered contaminants when in

excess of natural levels.

In one word, environmental pollution takes place when the environment cannot

process and neutralize harmful by – products of human activities (for example, poisonous gas

emissions) in due course without any structural or functional damage to its system.

There are three major types of environmental pollution: Air Pollution, Water

Pollution, and Soil Pollution (Contamination). In this term paper Soil Pollution will be

studied and discussed among these major types of pollutions.

What is Soil Pollution?

Soil pollution!! One of the most grave problems existing on the earth. Well, the earth

itself is getting contaminated and polluted! Collectively, are not we all responsible for this?

The conquest of utilizing land and soil resources and conducting experiments on it, for our

benefits, is quite understandable, but it certainly is not, at the cost of its health and wellness!

Mankind has been trying out several different things and has made several arrangements in

the soil, to make life happy and comfortable. However, how often have we thought of

contamination of soil? It’s never too late in life, so I think this is the right time, to know

about soil pollution causes and effects.

What is soil pollution anyways? Soil pollution is defined or can be described as the

contamination of soil of a particular region. Soil pollution mainly is a result of penetration of

harmful pesticides and insecticides, which on one hand serve whatever their main purpose is,

but on the other hand, bring about deterioration in the soil quality, thus making it

contaminated and unfit for use. Insecticides and pesticides are not to be blamed alone for soil

pollution, but there are many other leading causes of soil pollution too.

From other sources, soil pollution defined as: Soil contamination or soil pollution is

caused by the presence of xenobiotic (human-made) chemicals or other alteration in the

natural soil environment.

Figure 1. Excavation showing soil contamination at a disused gasworks.

Figure 2. Soil which has been poisoned by high concentrations of lead, arsenic, nickel, cobalt, and cadmium.

This type of contamination typically arises from the rupture of underground storage

tanks, application of pesticides, percolation of contaminated surface water to subsurface

strata, oil and fuel dumping, leaching of wastes from landfills or direct discharge of industrial

wastes to the soil. The most common chemicals involved are

petroleum hydrocarbons, solvents, pesticides, lead and other heavy metals. This occurrence

of this phenomenon is correlated with the degree of industrialization and intensities of

chemical usage.

The concern over soil contamination stems primarily from health risks, from direct

contact with the contaminated soil, vapors from the contaminants, and from secondary

contamination of water supplies within and underlying the soil. Mapping of contaminated

soil sites and the resulting cleanup are time consuming and expensive tasks, requiring

extensive amounts of geology, hydrology, chemistry, modeling skills, and GIS in

Environmental Contamination.

The Relationship of Soil Pollution with Air Pollution, and Water Pollution

Soil pollution can lead to water pollution if toxic chemicals leach into groundwater,

or if contaminated runoff reaches streams, lakes, or oceans. Soil also naturally contributes to

air pollution by releasing volatile compounds into the atmosphere. Nitrogen escapes through

ammonia volatilization and denitrification. The decomposition of organic materials in soil

can release sulfur dioxide and other sulfur compounds, causing acid rain. Heavy metals and

other potentially toxic elements are the most serious soil pollutants in sewage. Sewage sludge

contains heavy metals and, if applied repeatedly or in large amounts, the treated soil may

accumulate heavy metals and consequently become unable to even support plant life.

The ever-increasing pollution of the environment has been one of the greatest

concerns for science and the general public in the last fifty years. The rapid industrialization

of agriculture, expansion of the chemical industry, and the need to generate cheap forms of

energy has caused the continuous release of man-made organic chemicals into natural

ecosystems. Consequently, the atmosphere, bodies of water, and many soil environments

have become polluted by a large variety of toxic compounds. Many of these compounds at

high concentrations or following prolonged exposure have the potential to produce adverse

effects in humans and other organisms. Some of these man-made toxic compounds are also

resistant to physical, chemical, or biological degradation and thus represent an environmental

burden of considerable magnitude.

Numerous attempts are being made to decontaminate polluted soils, including an

array of both in situ (on-site, in the soil) and off-site (removal of contaminated soil for

treatment) techniques. None of these is ideal for remediating contaminated soils, and often,

more than one of the techniques may be necessary to optimize the cleanup effort.

DISCUSSION (BODY)

All soils (weather polluted or un-polluted) contain a variety of compounds

(contaminants) which are naturally present. Such contaminants include metals, inorganic ions

and salts (e/g., phosphates, carbonates, sulfates, nitrates), and many organic compounds (such as

lipids, proteins, DNA, fatty acids, hydrocarbons, PAHs, alcohols, etc.). These compounds are

mainly formed through soil microbial activity and decomposition of organisms (e.g., plants and

animals). Additionally, various compounds get into soil from the atmosphere (with precipitation

water, as well as by wind activity or other types of soil disturbances) and from surface water

bodies and shallow groundwater flowing through the soil. When the amounts of soil

contaminants exceed natural levels (what is naturally present in various soils) pollution is

generated. There are the following main mechanisms that generate soil pollution.

What Causes Soil Pollution?

1. Anthropogenic – through human activity including:

Accidental spills and leaks during storage, transport or use of chemicals (e.g.,

leaks and spills of gasoline and diesel at gas stations).

Foundry activities and manufacturing processes that involve furnaces or other

processes resulting in possible dispersion of contaminants in environment.

Mining activities involving crushing and processing of raw materials (such as

mining activity).

Construction activities.

Agricultural activities involving the spread of herbicides/ pesticides/insecticides

and fertilizers.

Transportation activities (e.g., vehicle emissions).

Dumping of chemicals (accidental or intended – such as illegal dumping).

Storage of wastes in landfills (which may leak to groundwater or generate

polluted vapors).

Cracked paint chips falling from building walls, especially lead-based paint.

2. Natural

Natural accumulation of compounds in soil due to imbalances between

atmospheric deposition and leaching away with precipitation water (e.g.,

concentration and accumulation of per chlorate in soils in arid environments).

Natural production in soil under certain environmental conditions (e.g., natural

formation of per chlorate in soil in the presence of a chlorine source, metallic

object and using the energy generated by a thunderstorm).

Leaks from sewer lines into subsurface (e.g., adding chlorine which could

generate trihalometanes such as chloroform).

The intensity of all these causes on a local or regional level might appear very small and you

may argue that soil is not harmed by above activities if done on a small scale! However, thinking

globally, it is not your region or my place that will be the only sufferer of soil pollution. In fact,

it is the entire planet and mankind that will encounter serious problems, as these practices are

evident almost everywhere in the world.

What are the Effects of Soil Pollution?

The effects of pollution on soil are quite alarming and can cause huge disturbances in the

ecological balance and health of living creatures on earth. Some of the most serious soil pollution

effects are mentioned below.

Decrease in soil fertility and therefore decrease in the soil yield. Definitely, how can one

expect a contaminated soil to produce healthy crops?

Loss of soil and natural nutrients present in it. Plants also would not thrive in such a soil,

which would further result in soil erosion.

Disturbance in the balance of flora and fauna residing in the soil.

Increase in salinity of the soil, which therefore makes it unfit for vegetation, thus making

it useless and barren.

Generally crops cannot grow and flourish in a polluted soil. Yet if some crops manage to

grow, then those would be poisonous enough to cause serious health problems in people

consuming them.

Creation of toxic dust leading is another potential effect of soil pollution.

Foul smell due to industrial chemicals and gases might result in headaches, fatigue,

nausea, etc. in many people.

Soil pollutants would bring in alteration in the soil structure, which would lead to death

of many essential organisms in it. This would also affect the larger predators and compel

them to move to other places, once they lose their food supply.

What are these Soil Pollutants?

Main Soil pollutant

Potential Specific SourcesSome Common Symptoms/Effects of Poisoning with the Polluted Soil

Lead (Pb) Lead paint Mining Foundry activities.

Vehicle exhausts (historical exhaust since lead is not used in gasoline anymore).

Construction activities. Agriculture activities.

(Pesticide with lead such as lead arsenate that was banned but has been historically used).

Affect the nervous system and memory, growth and development, as well as cognitive development (lower IQs).

Learning difficulties. Autism in genetically

predisposed people. Growth reduction and weight

loss. Impair pituitary-thyroid

endocrine system. Favor osteoporosis at old age.

Mercury (Hg) Mining. Incineration of coal. Alkali and metal processing. Medical and other waste. Volcanoes and geologic

deposits (natural sources). Accumulation in plants and

vegetables grown on polluted soils.

Itching, burning, pain. Damage to brain kidney and

lungs. Pink disease (acrodynia) –

skin discoloration (pink cheeks, fingertips, toes), while red cheeks and nose in affected children.

Desquamation (peeling off in layers of dead skin)

High blood pressure and hypersalivation

Tachycardia. Loss of hair, teeth, nails,

photofobia, kidney disfunction, memory impairment, insomnia -  in children.

Arsenic (As) Mining. Coal-fired power plants. Lumber facilities (used as

CCA – chromate copper arsenate in pressure treated wood).

Electronic Industry. Foundry activities. Agriculture (Pesticides -

including some of those

If ingested –the most specific effects relates to skin pattern changes andcancer (including liver, kidney, bladder, prostate and lung cancer); also at lower doses the digestive system may be affected with symptoms such as: nausea vomiting, stomach irritation, diarrhea, damage of blood

currently used). Natural accumulation under

specific conditions.

vessels. If inhaled – skin changes;

irritation of throat and lungs, circulatory problems, nervous system disorders.

Other metals Mining. Foundry activities. Construction activities.

Depend on metals – please follow individual links.

PAHs (Polyaromatic)

Coal burning. Harm to skin.

Hydrocarbons Vehicle emissions. Accumulation in plants and

vegetables grown on polluted soils.

Cigarette smoke. Wildfires. Agricultural burning. Wood burning. Asphalt roads (construction

activities). Industrial plants (e.g., coal tar,

bitumen, coal-gasification). Construction activities.

Autoimmune system. Eye irritation, nausea,

vomiting, diahrea. Cataracts. Kidney and liver damage. Cancer (skin, lung, bladder,

gastrointestinal). Difficulty in reproduction in

animals (not yet confirmed in humans).

Herbicides or Insecticides

Agricultural activities. Gardening.

Large range of effects from skin rashes to death.

Threat to Food Quality and Safety

Food safety is a basic need for any population, yet people hear warnings of hidden

dangers on the dining table — of unsafe rice and poisoned vegetables. Via the food chain,

harmful substances from the soils find their way into the crops and into humans, where they can

cause a variety of illnesses. Hence, soil pollution is now receiving the kind of attention once only

accorded to air and water pollution

Rice is the staple food in most Asian countries, but many paddy soils are now

contaminated by illegal discharges of waste water from local factories. Results from field studies

in Taiwan showed that rice variety and soil Cd concentration are major factors affecting edible

rice safety, with the Indica type rice absorbing significantly more Cd from contaminated soil

than Japonica type. In Korea, previous studies have shown that metal contents in rice grown

nearby abandoned mines are higher than those in unpolluted areas. Among various

anthropogenic sources for soil pollution, heavy metals from mining activities are known to be the

major contributors to accumulated metals in crops in the country. In China, an estimated 12

million tons of grain are contaminated by heavy metals every year, causing direct losses of 20

billion yuan (US$2.57 billion).

Of all the elements, the most important to consider in terms of food-chain contamination

are arsenic (As), cadmium (Cd), mercury (Hg), lead (Pb) and selenium (Se). The propensity for

plants to accumulate and translocate these contaminants to edible and harvested parts depends

largely on soil and climatic factors, plant genotype and agronomic management.

Excessive human intake of Cd is of concern as this element accumulates over a lifetime

in the body, with impairment of kidney function being the main adverse effect. Cadmium inputs

to soil in fertilizer, biosolids, soil amendments, and atmospheric deposition often exceed outputs

in crops and drainage waters, so that Cd concentrations in many agricultural soils are slowly

increasing. However, evidence for increases in Cd concentrations in crops over time is

contentious, as is the evidence for human health problems due to low-level Cd contamination of

the food chain. Adverse health effects due to Cd intake have been manifested only in situations

of gross soil contamination, with a predominantly rice-based diet, where soil-plant and plant-

human transfer of Cd would have been enhanced.

Impact of Soil Pollution

Effect on Human

Contaminated or polluted soil directly affects human health through direct contact

with soil or via inhalation of soil contaminants which have vaporized; potentially greater

threats are posed by the infiltration of soil contamination into groundwater aquifers used

for human consumption, sometimes in areas apparently far removed from any apparent

source of above ground contamination.

Health consequences from exposure to soil contamination vary greatly depending

on pollutant type, pathway of attack and vulnerability of the exposed population. Chronic

exposure to chromium, lead and other metals, petroleum, solvents, and many pesticide

and herbicide formulations can be carcinogenic, can cause congenital disorders, or can

cause other chronic health conditions. Industrial or man-made concentrations of

naturally-occurring substances, such as nitrate and ammonia associated with livestock

manure from agricultural operations, have also been identified as health hazards in soil

and groundwater.

Chronic exposure to benzene at sufficient concentrations is known to be

associated with higher incidence of leukemia. Mercury and cyclodienes are known to

induce higher incidences of kidney damage, some irreversible. PCBs and cyclodienes are

linked to liver toxicity. Organophosphates and carbamates can induce a chain of

responses leading to neuromuscular blockage. Many chlorinated solvents induce liver

changes, kidney changes and depression of the central nervous system. There is an entire

spectrum of further health effects such as headache, nausea, fatigue, eye irritation and

skin rash for the above cited and other chemicals. At sufficient dosages a large number of

soil contaminants can cause death by exposure via direct contact, inhalation or ingestion

of contaminants in groundwater contaminated through soil. 

People living near polluted land have higher incidences of migraines, nausea,

fatigue, miscarriage, and skin disorders. Long-term effects of pollution include cancer,

leukemia, reproductive disorders, kidney and liver damage, as well as central nervous

system failure. Children often suffer from developmental problems and weakened

immune systems.

In addition to direct health effects, soil pollution also harms plants. Chemicals can

sometimes absorb into food like lettuce and be ingested. Other times, the pollutants

simply kill the plant, which has created widespread crop destruction and famine in other

parts of the world. The entire ecosystem changes when new materials are added to the

soil, as microorganisms die off or move away from contaminants.

Effect on Animals

Predators who feed off the microorganisms and worms in the polluted soil will

also be affected. Researchers found that some species of birds -- like the Peregrine

Falcon, the Brown Pelican and the Bald Eagle -- fell prey to DDT poisoning, which

caused egg shells of future generations to thin. Mother birds would arrive home to

omelets in their nests, as the thin shells could not support the weight of the incubating

offspring. It also can alter metabolism of microorganisms and arthropods in a given soil

environment; this may destroy some layers of the primary food chain, and thus have a

negative effect on predator animal species

Small life forms may consume harmful chemicals which may then be passed up

the food chain to larger animals; this may lead to increased mortality rates and

even animal extinction.

Environmental Effects

Not unexpectedly, soil contaminants can have significant deleterious

consequences for ecosystems. There are radical soil chemistry changes which can arise

from the presence of many hazardous chemicals even at low concentration of the

contaminant species. These changes can manifest in the alteration of metabolism of

endemic microorganisms and arthropods resident in a given soil environment. The result

can be virtual eradication of some of the primary food chain, which in turn has major

consequences for predator or consumer species. Even if the chemical effect on lower life

forms is small, the lower pyramid levels of the food chain may ingest alien chemicals,

which normally become more concentrated for each consuming rung of the food chain.

Many of these effects are now well known, such as the concentration of persistent DDT

materials for avian consumers, leading to weakening of egg shells, increased

chick mortality and potential extinction of species. Effects occur to agricultural lands

which have certain types of soil contamination. Contaminants typically alter plant

metabolism, most commonly to reduce crop yields. This has a secondary effect upon soil

conservation, since the languishing crops cannot shield the Earth's soil mantle

from erosion phenomena. Some of these chemical contaminants have long half-lives and

in other cases derivative chemicals are formed from decay of primary soil contaminants.

How to Remediate Soil Pollution?

Many soil remediation techniques have been developed and applied in the field scale of

contaminated sites of rural soils, including excavation, attenuation by mixing, chemical

stabilization, soil washing, phytoremediation, and thermal desorption. The most popular

remediation techniques used in Asia, as well as new strategies for monitoring of soil quality and

food safety for human health, are as follows:

Dilution technique. If the heavy metal concentration is lower in the subsurface soil than

that in the surface soil, deep plowing and consequently mixing the two layers can

significantly decrease the metal levels to meet pollutant regulation.

Chemical stabilization or chemical washing techniques. This technique involves the

application of chemical amendments to decrease the mobility or solubility of metals in

the contaminated paddy soil and thus decrease the metal uptake of plants.

Phytoremediation. This consists of depolluting contaminated soils with plants able to

contain, degrade or eliminate metals, pesticides, solvents, explosives, crude oil and its

derivatives, and various other contaminants, from the media that contain them.

New aspects and strategies of soil remediation. Some fundamental principles in the

development of remediation strategies in developed countries include: precautionary

principle; risk-based philosophy for identifying, prioritizing and assessing the need for

remedial action; necessity to prevent future pollution; and 'polluter pays' principle, with a

mechanism for helping innocent landowners.

There are many study analyses how to perform this clean – up operation with regards to this Soil

Pollution, this methods shown as follows:

Excavate soil and take it to a disposal site away from ready pathways for human or

sensitive ecosystem contact. This technique also applies to dredging of mud containing

toxins.

Aeration of soils at the contaminated site (with attendant risk of creating air pollution).

Thermal remediation by introduction of heat to raise subsurface temperatures sufficiently

high to volatize chemical contaminants out of the soil for vapour extraction.

Technologies include ISTD, electrical resistance heating (ERH), and ET-DSP.

Bioremediation, involving microbial digestion of certain organic chemicals. Techniques

used in bioremediation include land farming, biostimulation  and bioaugmentatingsoil

biota  with commercially available microflora.

Extraction of groundwater or soil vapor with an active electromechanical system, with

subsequent stripping of the contaminants from the extract.

Containment of the soil contaminants (such as by capping or paving over in place).

Reducing Soil Pollution

We can take the following steps:-

Encourage organic farming.

Proper garbage disposal.

Recycle garbage.

Reduce use of herbicides and pesticides.

Avoid over packaged items.

Efficient utilization of resources and reducing wastage.

How to Prevent soil Pollution?

Naturally, prevention is the best cure for soil pollution. Most states have enacted tougher

legislation to stop illegal dumping. For instance, one can expect five years in jail and a fine of

$100,000 for soil pollution in Texas.

Educating consumers about the dangers of littering, while encouraging recycling

programs, is a good way to ensure everyone does their part to keep debris where it belongs.

Consumers can also make a concerted effort to buy organic foods to demand that chemical

pesticides aren't used on their foods.

People who grow their own food can keep excess nitrogen and phosphorus out of the soil

by choosing crops that do not need as many nutrients from the soil, by applying fertilizer during

the growing season to replenish the soil, by shortening the grazing season / cattle density, by

using organic compost, by keeping the surface moist and mulched, and by choosing fruiting

crops like tomatoes, squash, peas and corn. Gardens should be situated away from old painted

buildings and roadways. Outer leaves of lettuce should be discarded and all vegetables should be

washed before eating.

Over the years, stronger and more indestructible bins were created to store hazardous

materials. Researchers will continue to look for ways to improve manufacturing and agricultural

processes to avoid the need for toxic byproducts. Business leaders, miners and community

officials will work together to reduce wastefulness and contaminants to keep the world a clean

place for future generations.

SUMMARY, CONCLUSION, AND RECOMMENDATION

Summary

Soil pollution is widespread in industrial, urban and agricultural areas and is often the

result of years of intentional or accidental discharge of pollutants. The methods of remediation

are as varied as the pollutants and have to be adapted to each locality. Urban soil pollution is

most commonly caused by lead previously used in cars and in house paint, or by insecticides

used in gardens or under and around houses.

The health effects of lead on children can be greatly diminished by eliminating bare,

dusty areas in the garden and play areas, and by scrupulous hygiene and removal of dust from the

house. Vegetables grown in lead-polluted soil must be carefully washed and peeled, but the best

idea is not to use root vegetables from such soil.

Pesticide pollution is mostly due to the use of arsenic or the long persistent

organochlorine chemicals in past termite treatments. Although no longer in use, these

organochlorines may still be present and may continue to emit toxic vapours which can penetrate

into the living areas of the treated houses. The risk can be minimised by providing good

ventilation under the houses. This also decreases the risk of future termite infestation by keeping

the area dry.

If the area around the house has been treated, risk from insecticide vapour can be reduced

by either removing the top 10 cm of the soil to somewhere further away from the house, or by

sealing it with concrete. While the soil is being moved or disturbed the exposure to the pesticide

vapour will be increased. Industrial soil pollution can take many forms. Old gasworks sites are

always heavily polluted with phenols and sulphur compounds. Heavily polluted industrial sites

may contain chlorinated benzenes, chlorophenols, pesticides, dioxins and furans. Sometimes they

can be remediated by a combination of biological methods and entombment of the most toxic

soil in a constructed impervious area on the site. Biological methods involve selecting bacteria,

which can decompose the particular chemicals found on the site, and assisting the bacteria's

growth. The method is completely site specific and slow to be effective. Another technique for

remediation is thermal adsorption and decomposition. In this the soil is heated and the desorbed

contaminants decomposed by further heating. This technology has been used on some of the

most contaminated soil at the Homebush Bay Olympic site.

Other sites, like oil depots or service stations with leaking underground tanks, are

sometimes treated by digging up the soil and exposing it to air oxidation over many months.

However, this is not sufficient if leaded petrol has leaked into the ground.

Chemical pollution of agricultural land is found in fields which have been treated with

organochlorine pesticides (DDT, aldrin) in the past, or on fence lines where they have been used

to protect the fence posts. Dip sites where chemicals were used to treat sheep and cattle are often

heavily contaminated with arsenical compounds and organochlorines. There are many hundreds

of such dip sites throughout the country and their rehabilitation for other uses is a major problem.

If you suspect the soil on your property may be contaminated, contact your local council or state

environment protection authority for advice.

Conclusion

Environmental pollution is causing a lot of distress not only to humans but also animals,

driving many animal species to endangerment and even extinction. The transboundary nature of

environmental pollution makes even more difficult to manage – we cannot build stone walls

along the borders of our country or put customs cabins at every point of entry to regulate its

flows into our country.

Everything in our planet is interconnected, and while the nature supplies us with valuable

environmental services without which we cannot exist, we all depend on each other’s actions and

the way we treat natural resources. It’s widely recognized that we are hugely overspending our

current budget of natural resources – at the existing rates of its exploitation, there is no way for

the environment to recover in good time and continue “performing” well in the future.

Perhaps we should adopt a holistic view of nature – it is not an entity that exists

separately from us; the nature is us, we are an inalienable part of it, and we should care for it in

the most appropriate manner. Only then can we possibly solve the problem of environmental

pollution.

I hope the above discussion was enough to make we understand the severity of the soil

pollution causes and effects. This is not only done as one of the curriculum requirements but also

to advocate saving our home planet even in small things. As a student of Cavite State University

may this paper help or contribute to inform my fellow student to be aware of this pollutions

happening on our surroundings. However, let us remember the proverb, 'prevention is better than

cure' and environmental rule system, maintaining its balance and avoid the overuse of our natural

resources. So let us begin the movement of pollution prevention from our own lands itself!!!

Recommendations and Future Prospects

Rapid urbanization and industrialization makes soil pollution an inevitable problem and a

big challenge to scientists and environmental policy makers. For healthy and sustainable future

generations, the soil resource should be protected against a slow and insidious poisoning by

heavy metals released from mining, industrial, and agricultural activities. While there are lots of

available literatures on soil pollution, the guidelines established by individual countries

worldwide to control the pollution of agricultural soils are not consistent and standardized. These

points to the complexity of heavy metal behavior in agro-environmental system, the various

climatic, geologic, and hydrological conditions in different countries, and the political and

nonscientific factors affecting the establishment of regulations.

Site-specific and health-based risk assessments are deemed to be the most reliable and

practical approaches in resolving the problem of soil pollution. More scientific evidence from

case-specific research, especially from long-term field trials involving all kinds of key conditions

and factors are necessary to understand the bioavailability of heavy metals in various soil types

after long periods of time and to provide reliable parameters for health-based risk assessments.

Lastly, the collection of reliable data on heavy metal concentrations in soils and crops in

various countries must be given utmost importance. From this database, a variety of useful

information and methodologies can be developed toward achieving the ultimate goal of

providing safe and quality foods to the people of the region.

REFERENCES

Adriano, D.C.; Bollag, J.-M.; Frankenberger, W.T.; and Sims, R.C., eds. (1999). Bioremediation of Contaminated Soils. Agronomy monograph 37. American Society of Agronomy.

Davenport et al. (2005). Environmental impacts of potato nutrient management. American Journal of Potato Research.

Michael Hogan, Leda Patmore, Gary Latshaw and Harry Seidman, Computer modeling of pesticide transport in soil for five instrumented watersheds, prepared for the U.S. Environmental Protection Agency Southeast Water laboratory, Athens, Ga. by ESL Inc., Sunnyvale, California (1973).

Miller, R.W., and Gardiner, D.T. (1998). Soils in Our Environment, 8th edition. Upper Saddle River, NJ: Prentice Hall.

Pierzynski, G.M.; Sims, J.T.; and Vance, G.F. (2000). Soils and Environmental Quality, 2nd edition. Boca Raton, FL: CRC Press.

Risk Assessment Guidance for Superfund, Human Health Evaluation Manual, Office of Emergency and Remedial Response, U.S. Environmental Protection Agency, Washington D.C. 20450.

Snyder C (2005). "The dirty work of promoting "recycling" of America's sewage sludge". Int J Occup Environ Health 11 (4): 415–27.

S.K. Gupta, C.T. Kincaid, P.R. Mayer, C.A. Newbill and C.R. Cole, "A multidimensional finite element code for the analysis of coupled fluid, energy and solute transport", Battelle Pacific Northwest Laboratory PNL-2939, EPA contract 68-03-3116 (1982).

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http://treehuggerusa.com/pollution/soil-pollution/Solution-To-Soil-Pollution.html