NREM 907 Environmental Quality And Remediation

NREM 907 Environmental Quality And Remediation

NREM 907 – ENVIRONMENTAL QUALITY AND REMEDIATION

COURSE LECTURER: PROF. IKECHUKWU AGBAGWA

Institute of Natural Resources, Environment & Sustainable Dev.,

University of Port Harcourt,

Rivers State, Nigeria.

TOPICS

Key Pollutants;
Factors impacting fate and transport of pollutants;
Effects on human health and ecology.
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Course Aim and Objectives

This aspect of the course is aimed at examining the concept of pollution, its forms and causes (pollutants especially chemicals) and distribution in space and time; and the impacts of these pollutants on the human health and environment. The specific objectives include:
Identify the different forms of pollution and key pollutants
Describe the processes that dilute and distribute pollutants in soil, air and water.
Define some of the characteristics of pollutants that affect their environmental fates in air, water and soil.
Explain the concept of bioaccumulation and biomagnifications.
Understand the effects of different pollutants on humans and the environment.
*NREM 907 Environmental Quality And Remediation

Background and Introduction

Pollution, also called environmental pollution is the addition of any substance (solid, liquid, or gas) or any form of energy (such as heat, sound, or radioactivity) to the environment at a a quantity or rate faster than it can be dispersed, diluted, decomposed, recycled, or stored in some harmless form.
The major kinds of pollution are classified based on environmental media into air, water and land pollution.
Recently, other specific types of pollution such as noise/sound, light and thermal pollution have been recognized.
A pollutant is a waste material that pollutes air, water or soil. Three factors determine the severity of a pollutant: its chemical nature, the concentration and the persistence.
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Background and Introduction

Some of our most toxic wastes tend to concentrate in food chains rather than decompose or diffuse.
Since we are often exposed to these pollutants in higher concentrations, they are very important to our health and understanding the processes of bioaccumulation and biomagnifications remains very significant.
Our emphasis shall be on man-made pollutants especially chemicals; their movement through water, air, and soil; and their eventual fate.
We shall be examining the various forces of physical transportation, as well as chemical and biological sources and pollutants sinks.
Finally we shall provide information on the linkages to health effects and toxicity of chemicals from their point of origin to the point of human exposure.
*NREM 907 Environmental Quality And Remediation

Different Types of Pollution

Pollution is categorized based on the part of the environment which they affect or impacts of the pollution.
Each of these types has its own distinctive causes and consequences.
The main types of pollution are:

Air Pollution
Light Pollution
Noise Pollution
Radioactive Pollution
Soil Pollution
Thermal Pollution
Water Pollution
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Different Types of Pollution

Air Pollution

The contamination of the air present in the atmosphere is known as “Air pollution”.
Respiration is an important life process of all living things. We breathe in the air present in the atmosphere.
Therefore, if the air around us is contaminated with poisonous gases, it would have a fatal effect on us.
The air naturally comprises of 78% of nitrogen, 21% of oxygen, 0.9% of oxide gases and 0.1% of inert gases.
When this balance is disturbed, it causes disruptions of severe proportions.
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Different Types of Pollution

Causes and Effects of Air Pollution

Air pollution can result from both human and natural actions. Natural events that pollute the air include

forest fires,
volcanic eruptions,
wind erosion,
pollen dispersal,
evaporation of organic compounds and
natural radioactivity.
Pollution from natural occurrences is not very often.
Human activities that cause air pollution are numerous and varied.
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Different Types of Pollution

Causes and Effects of Air Pollution

Human activities that cause air pollution include:

1. Emissions from industries and manufacturing activities

Waste incinerators, manufacturing industries and power plants emit high levels of carbon monoxide, organic compounds, and chemicals into the air.
This happens almost everywhere that people live.
Petroleum refineries also release lots of hydrocarbons into the air
2. Burning Fossil Fuels

Fumes from car exhausts contain dangerous gases such as carbon monoxide, oxides of nitrogen, hydrocarbons and particulates.
These gases cause great harm to people who breathe them.
In addition, they react with environmental gases to create further toxic gases.
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Different Types of Pollution

Causes and Effects of Air Pollution

Human activities that cause air pollution include:

3. Household and Farming Chemicals

Crop dusting, fumigating homes, household cleaning products or painting supplies, over the counter insect/pest killers, fertilizer dust emit harmful chemicals into the air and cause pollution.
In many cases, when we use these chemicals at home or offices with no or little ventilation, we may fall ill if we breathe them.
4. Emissions from open dumpsites

Open dumpsites apart from creating terrible aesthetic appeal, emit putrefaction gases such as carbon monoxide, carbon dioxide and methane, which themselves are toxic.
These gases become even more toxic when they react with atmospheric gases
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Different Types of Pollution

Causes and Effects of Air Pollution

Thus there are many sources and agents of air pollution including biological (pollens, microbes, mites, biotoxins)
chemical (inorganic and organic) and
physical (dusts, aerosol, smog, mists).
Chemical sources of air pollution remains the most widely investigated due to their deleterious effects.
There are six most common pollutants which are also known as Criteria Pollutants. (Fig. 1)
They include ozone, carbon monoxide, sulfur dioxide, lead, nitrogen oxides, and particulate matter.
Greenhouse gases are another form of hazardous air pollution
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Different Types of Pollution

Causes and Effects of Air Pollution

Criteria Pollutants

Particulate matter (PM10 and PM2.5)
Ozone (O3)
Nitrogen dioxide (NO2)
Carbon monoxide (CO)
Sulphur dioxide (SO2)
Lead (Pb)
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Sources and Effects of Air Pollution

1. Carbon Monoxide (CO): Fuel combustion from vehicles and engines.

Reduces the amount of oxygen reaching the body’s organs and tissues; aggravates heart disease, resulting in chest pain and other symptoms.

Ground-level Ozone (O3): Secondary pollutant formed by chemical reaction of volatile organic compounds (VOCs) and NOx in the presence of sunlight.
Decreases lung function and causes respiratory symptoms, such as coughing and shortness of breath, and also makes asthma and other lung diseases get worse.
Gas Ozone can affect people’s health and can damage vegetation types and some animal life too.
Lead (Pb): Smelters (metal refineries) and other metal industries; combustion of leaded gasoline in piston engine aircraft; waste incinerators (waste burners), and battery manufacturing.
Damages the developing nervous system, resulting in IQ loss and impacts on learning, memory, and behavior in children. Cardiovascular and renal effects in adults and early effects related to anaemia.

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Sources and Effects of Air Pollution

Nitrogen Dioxide (NO2): Fuel combustion (electric utilities, big industrial boilers, vehicles) and wood burning.
Worsens lung diseases leading to respiratory symptoms, increased susceptibility to respiratory infection.
Particulate Matter (PM): This is formed through chemical reactions, fuel combustion (e.g., burning coal, wood, diesel), industrial processes, farming (plowing, field burning), and unpaved roads or during road constructions.
Short-term exposures can worsen heart or lung diseases and cause respiratory problems. Long-term exposures can cause heart or lung disease and sometimes premature deaths.
Sulfur Dioxide (SO2): SO2 comes from fuel combustion (especially high-sulfur coal); electric utilities and industrial processes as well as natural occurrences like volcanoes.
Aggravates asthma and makes breathing difficult. It also contributes to particle formation with associated health effects.

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Sources and Effects of Air Pollution

Carbon Dioxide: This greenhouse gas is a natural byproduct of respiration. It is also associated with the burning of fossil fuel.
It causes global warming and respiratory ailments
Methane: Comes from the gas emitted by livestock, decaying waste dumps, swamps.
It causes global warming and respiratory ailments
Chlorofluorocarbons: Once used as propellants in aerosol items and in refrigerants.
CFCs have been outlawed due to the hazardous effect on the ozone layer.
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Sources and Effects of Air Pollution

Other effects of air pollution are:

Acidification
Chemical reactions involving air pollutants can create acidic compounds which can cause harm to vegetation and buildings.
Sometimes, when an air pollutant, such as sulfuric acid combines with the water droplets that make up clouds, the water droplets become acidic, forming acid rain.
When acid rain falls over an area, it can kill trees and harm animals, fish, and other wildlife.
Acid rain destroys the leaves of plants.
Eutrophication – excess deposit of nitrogen from pollutants by rain can lead to pollution of soil and rivers, and eutrophication of lakes.
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Light Pollution

Light pollution is the excessive and prolonged use of artificial lights, in a way that results in brightening of night skies, disrupting natural cycles and activities of wildlife, health problems in humans, as well as preventing humans from observing stars and other planets.
In other definitions, it does not only have to do with the sky, but anywhere that artificial lights are used, where they are not intended to.
Other terms often used for light pollution are ‘photopollution’ and ‘luminous pollution’.
Light pollution is an increasing problem threatening astronomical facilities, ecologically sensitive habitats, all wildlife, our energy use as well as our human heritage
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Types of light pollution

Sky glow: This is the bright orange-pink glow that hangs over cities and towns in the night. This is also common in the Niger Delta where gas flaring leaves a continuous sky glow at night
Glare: This is the effect produced when the eyes are exposed to bright light.
Bright flashlight directed at your face in a dark place almost blinds you and suddenly you cannot see other objects or shadows around you.
This is particularly dangerous when driving, because bright lights from cars coming towards you reduce your vision and puts pedestrians and other road users at risk.
The most common causes of glare include bright streetlights and car lights.
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Types of light pollution

Light trespass (Spillover): This occurs when light goes over its intended range.
Think of your neighbor’s security light shining through your bedroom windows and lighting up your room all night.
Light spillover is a very common subject of complaint by many residential dwellers.
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Sources of Light Pollution

Electronic Advertising Boards and Commercial Centers: Several large electronic sign boards in the cities and on highways are lit up by powerful lights that focus on the boards from below. These light reflect upwards brightening everywhere;
Streetlights and car lights: In some cities, miles of powerful streetlights stay on all night;
Night Sports grounds: Floodlights that light stadiums and other places of sports often contribute to light pollution as the powerful lights end up upwards. These include the large light posts on the car parks.
City Parks, Airports, public places: Many of these areas use many old-fashioned lights that are not shielded and have a lot of it emitting light upwards.
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Sources of Light Pollution

Residential Areas: mainly glare and spillover type. Garden and landscape lights for aesthetics often end up as a nuisance at night, because they tend to cause irritation to people as they walk or drive in these areas.
Oil & Gas Flare lights: Forest and neighbouring communities
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Effects of Light Pollution

Waste of resources: It costs a lot of money to light up homes, public places, sports and commercial places.
Loss of historical and cultural value: loss of sky view with stars and other space objects that we used to enjoy especially for young people growing up in cities.
Health implications: Disability glare, eye strain, loss of vision and stress from glare and spillovers are huge problems as much light can harm our eyes and also the harm the hormones (such as melatonin) that adjusts visions.
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Effects of Light Pollution

Wildlife: Many insects, birds, mammals and reptiles are photoperiodic in nature and aspects of their physiology and behavior are influenced by day–night or circadian rhythms including their eating, mating, growth and development; also killed accidentally and persecuted by light.
Interference/alteration of photosynthetic and entire metabolic activities in plants
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Noise Pollution

Sound is essential to our daily lives, but noise is not.
Noise is generally used as an unwanted sound, or sound which produces unpleasant effects and discomfort on the ears.
Sound becomes unwanted when it either interferes with normal activities such as sleeping, conversation, or disrupts or diminishes one’s quality of life.
Not all noise can be called noise pollution. – if it does not happen regularly, it may be termed as ‘Nuisance’..
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Noise Pollution

Generally, noise is produced by household gadgets, big trucks, vehicles and motorbikes on the road, jet planes and helicopters, loud speakers etc.
Noise (or sound) is measured in the units of decibels and is denoted by the dB.
Noise which is not more than 115 dB is tolerant.
The industrial limit of sound in the industries must be 75 dB according to the WHO.
Noise is considered as environmental pollution, though not as damaging on humans as water, air or land pollution.
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Sources of Noise Pollution –

Household sources:
Gadgets like food mixer, grinder, vacuum cleaner, washing machine and dryer, cooler, air conditioners, can be very noisy and injurious to health.
Others include loud speakers of sound systems and TVs, iPods and ear phones.
A dog barking all night everyday at every shadow it sees, disturbing everyone else in the apartment.
ii. Social events: Places of worship, discos and gigs, parties and other social events

In many market areas, people sell with loud speakers; others shout out offers and try to get customers to buy their goods.

It is important to note that whey these events are not often, they can be called ‘Nuisance’ rather than noise pollution.
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Sources of Noise Pollution –

Commercial and industrial activities:

Printing presses, manufacturing industries, construction sites, contribute to noise pollutions in large cities.
In many industries, it is a requirement that people always wear earplugs to minimize their exposure to heavy noise. People who work with lawn mowers, tractors and noisy equipment are also required to wear noise-proof gadgets.
Transportation: aero planes, trains, vehicles on road—these are constantly making a lot of noise and people always struggle to cope with them.
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Effects of noise pollution
Problems caused by noise pollution include stress related illnesses, speech interference, hearing loss, sleep disruption, and lost productivity. Most importantly, there are three major effects:
Hearing: The immediate and acute effect of noise pollution to a person, over a period of time, is impairment of hearing via eardrum & hearing impairment.
Animals: Noise affect most animals by frightening and scaring them. Excessive noises are causing a lot of injuries and deaths to whales.
Effects on general health: Health effects of noise include anxiety and stress reaction and in extreme cases fright. The physiological manifestations are headaches, irritability and nervousness, feeling of fatigue and decreases work efficiency..
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Soil (Land) Pollution

Land pollution is the deterioration (destruction) of the earth’s land surfaces, often directly or indirectly as a result of man’s activities and their misuse of land resources.
It occurs when waste is not disposed of properly, or can occur when humans throw chemicals onto the soil in the form of pesticides, insecticides and fertilizers during agricultural practices.
Exploitation of minerals via mining has also contributed to destroy the earth’s surface.
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Sources and Types of land pollution

Agricultural sources: These include waste matter produced by crop, animal manure and farm residues. They also include the chemical left over of all pesticides, fertilizers and insecticides used for agricultural activities
Ashes: The residual matter that remains after solid fuels are burned.
Two types of ashes are produced when waste is burnt in incinerators. (i) Bottom ash is the debris from burnt metal and glass waste. Bottom ash is not bio-degradable. (ii) fly ash often trapped by filters in the chimney of incinerators.

These ashes are known to be toxic (poisonous).

Ashes easily leak into the soil and water tables causing land and water pollution.

Mining sources: This includes piles of coal refuse and heaps of slag and underground debris.
Additionally, iron and other chemicals such as copper, mercury and lead from mining practices leach into the soil, polluting it and leaving it exposed to water bodies as well.

Industrial sources: These include paints, chemicals, metals and aluminum, plastics and so on that are produces in the process of manufacturing goods.
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Sources and Types of land pollution

Sewage Treatment: Wastes that are left over after sewage has been treated, biomass sludge, and settled solids. Some of these are sent directly to landfills whiles other treatment plants burn them to generate electricity. Both end up polluting the environment.
Garbage or waste: These include household or municipal waste such as glass, metal, cloth, plastic, wood, paper, and so on. Some of these can decay and others cannot. They are usually collected and sent to landfills where the pollution action begins.
Construction sources: These include waste like debris, wood, metals and plastics that are produced from construction activities.
Deforestation: This is when trees are cut down for economic purposes, mining, farming and construction.
In forests areas, trees absorb and reflect about 20% of the intense heat from the sun, protecting and preserving its surface soils.
Cutting down trees mean that the land is exposed to direct sunlight and rain, resulting in soil erosions, desertification and land degradation
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Sources and Types of land pollution

Chemical And Nuclear Plants: Chemical waste from chemical industries that are disposed of into landfills.
Oil Refineries: Crude oil refined into usable petrol, gas or diesel, there are by-products that end up as waste.
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Effects of land pollution.

There can be catastrophic consequences of land pollution in relation to humans, animals, water and soils.
The effects are even worse if the garbage is not separated into organic, reusable and recyclable waste.
Cause problems in the human respiratory system; the skin and various kinds of cancers.
The toxic materials in the soil can get into human body directly by:
Contact with the skin;
Dump sites and landfills also come with serious problems like bad smell and odour in the town; breeding of rodents like rats, mice and insects, who in turn transmit diseases.
Burning landfill also cause further air pollution.
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Thermal Pollution

Thermal Pollution is the rise in the temperature in the ecosystem due the release of excessive heat energy into the environment by artificial methods or natural disasters.
Industries release a lot of heat energy which gets transferred to the air and water bodies.
Combustion engines release a lot of heat energy as they require high temperatures to function.
Carbon dioxide block heat from exiting the atmosphere and so the heat coming in from the sun is trapped in the atmosphere.
Another common cause of thermal pollution is the use of water as a coolant by power plants and industrial manufacturers.
The water often leaks or is discharged out of these facilities into the natural environment.
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Effects of Thermal Pollution

Oxygen Supply: The most important impact of warm water thermal pollution is a decrease in dissolved oxygen. Less oxygen in the environment may affect aquatic organisms and the overall health of the ecosystem.
Plant growth: Warm water may speed up the growth of plants by encouraging photosynthesis. Increases in algae and other plant populations may affect the amount of plant material decomposing in the environment. Bacteria require oxygen for decomposition, which means there is less available for other organisms. Harmful algal blooms occur when certain types of algae grow quickly in water, forming patches that may block sunlight and decrease the amount of dissolved oxygen in the water. The algae that may negatively affect human health include cyanobacteria, which may contaminate drinking water and have been associated with gastroenteritis, skin irritation, and liver damage.
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Effects of Thermal Pollution

Toxins and Bioaccumulation: Harmful marine algae that proliferate in warm condition produce toxins that can build up in shellfish. When ingested, these toxins may cause neurological or gastrointestinal problems or even death. Breathing the toxins may contribute to asthma attacks in susceptible individuals.
Animal reproduction: The reproduction of aquatic species is often temperature-dependent. A change in water temperature may change when organisms spawn or if they do at all. For example, some marine bivalves (such as clams and oysters) spawn in the summer. Warmer water temperatures will encourage the organisms to spawn at an inappropriate time and for longer. This may affect the health of the population if the appropriate food is unavailable. On the other hand, the lugworm spawns in cold water and may not spawn at all if the water is too warm.
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Effects of Thermal Pollution

Adaptation to thermal pollution: Thermal pollution may increase water temperatures by as much as 30 degrees. Such drastic changes may be lethal to cold water organisms, such as trout and salmon.
Thermal shock, or a sudden and rapid rise in temperature, can denature proteins, disrupt metabolic processes, and result in death.
Thermal discharge has been found to affect coral reefs. Coral living in thermal discharges.
Thermal enrichment: Thermal enrichment is also a potential side effect of thermal pollution. Thermal enrichment is considered to be beneficial to aquatic organisms.
Warmer water temperatures may speed up the growth of commercial fishing stocks, extend fishing seasons, or encourage the migration of more desired organisms to an area.
The benefits of thermal pollution are generally thought to not outweigh the negative consequences.
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Water Pollution

Water pollution is the contamination of water bodies (e.g. lakes, rivers, oceans, aquifers and groundwater), very often by human activities.
Water pollution occur when pollutants (particles, chemicals or substances that make water contaminated) are discharged directly or indirectly into water bodies without enough treatment to get rid of harmful compounds.
Pollutants get into water mainly by human causes or human factors.
Water pollution can be a Point-source, Non Point-source, or Transboundary in nature.
Water pollution is the second most imperative environmental concern along with air pollution.
Any change or modification in the physical, chemical and biological properties of water that will have a detrimental consequence on living things is water pollution.
*NREM 907 Environmental Quality And Remediation

Sources and Types of water pollution.

Nutrients Pollution: Some wastewater, fertilizers and sewage contain high levels of nutrients. If they end up in water bodies, they encourage algae and weed growth in the water. This will make the water undrinkable, and even clog filters. Too much algae will also use up all the oxygen in the water and other water organisms in the water will die out of oxygen starvation.
Surface water pollution: Surface water includes natural water found on the earth’s surface, like rivers, lakes, lagoons and oceans. Hazardous substances coming into contact with this surface water, dissolving or mixing physically with the water can be called surface water pollution.
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Sources and Types of water pollution.

Ground water pollution: When humans apply pesticides and chemicals to soils, they are washed deep into the ground by rainwater. This gets to underground water, causing pollution underground.
Microbiological: In many communities in the world, people drink untreated water (straight from a river or stream). Sometimes there is natural pollution caused by microorganisms like viruses, bacteria and protozoa. This natural pollution can cause fishes and other water life to die. They can also cause serious illness to humans who drink from such waters.
Suspended Matter: Some pollutants (substances, particles and chemicals) do not easily dissolve in water. This kind of material is called particulate matter. Some suspended pollutants later settle under the water body. This can harm and even kill aquatic organisms that live at the bottom of water bodies.
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Sources and Types of water pollution.

Chemical Water Pollution: Many industries and farmers work with chemicals that end up in water. This is common with Point Source Pollution. These include chemicals that are used to control weeds, insects and pests. Metals and solvents from industries can pollute water bodies. These are poisonous to many forms of aquatic life and may slow their development, make them infertile and kill them.
Oil Spillage: Oil spills usually have only a localized effect on wildlife but can spread for miles. The oil can cause the death to many fish and get stuck to the feathers of seabirds.
Sewage and wastewater: Every day, we cook, do laundry, flush the toilet, wash our cars, shower and do many things that use water. Think about how we use water in schools, hospitals and public places. Where do you think all the water, liquid waste, poop and urine end up? In many developed communities, wastewater and soluble waste (called sewage) is treated, cleaned and dumped into the sea or river. Even though they are treated, they are never the same as fresh water. In some not-so-developed countries, the sewage is not treated but quickly dumped into the sea or water bodies. This is dangerous because they contaminate the environment and water bodies and bring many deadly diseases to us.
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Sources and Types of water pollution.

Septic Tanks: Every domestic (home) toilet is connected to septic tank usually located outside the house. Each time poop is flushed down the toilet, it goes into this tank, where the solid part is separated from the liquid part. Biological processes are used to break down the solids and the liquid is usually drained out into a land drainage system. From this stage, it can escape into the soil and nearby water bodies.
Ocean and marine dumping: Again, think of the rubbish we all make each day. Paper waste, food waste, plastic, rubber, metallic and aluminum waste. In some countries, they are deposited into the sea. These waste types take some time to decompose. For example, it is known that paper takes about 6 weeks, aluminum takes about 200 years and glass takes even more years. When these end up in the sea, they harm sea animals and cause a lot of water animal deaths.
Underground storage and tube leakages: Many liquid products (petroleum products) are stored in metal and steel tubes underground. Other sewage systems run in underground tubes. Over time, they rust and begin to leak. If that happens, they contaminate the soils, and the liquids in them end up in many nearby water bodies.
Atmospheric: Atmospheric deposition is the pollution of water bodies caused by air pollution. Each time the air is polluted with sulphur dioxide and nitrogen oxide, they mix with water particles in the air and form a toxic substance. This falls as acid rain to the ground and gets washed into water bodies. The result is that water bodies also get contaminated and this affects animals and water organisms.
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Effects of water pollution.

Water pollution is very harmful to humans, animals and water life.
Death of aquatic (water) animals:
Disruption of food-chains: Pollution disrupts the natural food chain as well.
Diseases: Eventually, humans are affected by this process as well.
Destruction of ecosystems: Ecosystems can be severely changed or destroyed by water pollution.
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Radioactive (Nuclear Waste) Pollution

Radiation pollution is a physical type of environmental pollution and radiation hazards come from ionizing and non-ionizing radiations.
Radioactive material is unstable energy whose exposure causes extreme effects on human beings, plants and animals.
Radioactive pollution via the release of radioactive substances or high-energy particles into the air, water, or earth as a result of human activity, either by accident or by design.
Nuclear fallout is the distribution of radioactive contamination by a nuclear explosion and the amount of radioactive material released in an accident is called the source term.
Contamination may occur from radioactive gases, liquids or particles
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Sources of Radioactive pollution

Natural: Sometimes natural sources of radioactivity, such as radon gas emitted from beneath the ground, are considered pollutants when they become a threat to human health.
Nuclear weapon testing or detonation;
The nuclear fuel cycle, including the mining, separation, and production of nuclear materials for use in nuclear power plants or nuclear bombs;
Accidental release of radioactive material from nuclear power plants.
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Effects of Radioactive Pollution

Since even a small amount of radiation exposure can have serious (and cumulative) biological consequences, and since many radioactive wastes remain toxic for centuries, radioactive pollution is a serious environmental concern even though natural sources of radioactivity far exceed artificial ones at present.
The problem of radioactive pollution is compounded by the difficulty in assessing its effects
Atmospheric Radioactive Pollution
Radioactive Pollution on Land and Water
The mining of uranium, for example, produces highly radioactive tailings which can be blown into the air, contaminate soil , or leach into bodies of water.
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Contaminant Fate and Transport in the Environment

Chemical Transport are the processes that move chemicals through environmental media while Chemical Fate is the eventual disposition of a chemical contaminant.

This can include destruction or long term storage in a sink and/or exposure-biotransformation in ecological and human receptors

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Contaminant Fate and Transport in the Environment

The existence of contaminated sites may result in the release of chemicals into:
air – volatilization and fugitive dust emissions,
surface water (from surface runoff/overland flow and groundwater seepage),
groundwater (through infiltration/leaching),
soils (due to erosion – including fugitive dust generation/deposition and tracking),
sediments (from surface runoff/overland flow),
biota (due to biological uptake and bioaccumulation).
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Contaminant Fate and Transport in the Environment

Contaminants released into the environment are controlled by a complex set of processes including transport, transformation, degradation and decay, intermedia transfer, and biological uptake.
In addition, many toxic chemicals are persistent and undergo complex interactions in more than one environmental medium.
Environmental fate analyses can be used to assess the movement of chemicals between environmental compartments.
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Contaminant Fate and Transport in the Environment

The fate of chemical compounds released into the environment forms an important basis for evaluating the exposure of biological receptors to hazardous chemicals.
Multimedia transport models are generally employed in the prediction of the long-term fate of such chemicals in the environment.
Chemicals released into the environment do not respect media boundaries or political boundaries.
Exchanges continually occur between different environmental media so modeling transport within only one medium will not completely describe the chemicals fate.
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Contaminant Fate and Transport in the Environment

Knowledge of the principals of fate and transport allows predictive capability of the movement of chemicals for both environmental monitoring validation and development of engineering, institutional and/ or administrative controls.
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Contaminants Distribution between Environmental Compartments

Environmental media include: Air, surface water, sediment, groundwater-saturated zone, soil-topsoils, subsurface area -Vadose Zone (unsaturated zone) and food chain.
Chemicals present in one environmental medium are affected by several complex processes and phenomena, facilitating transfers into other media.
The potential for intermedia transfer of pollutants from soil medium to other media is particularly significant; in fact, contaminated soil can be a major source for the contamination of groundwater, atmospheric air, subsurface soil gas, sediments, and surface water.
Eg. chemical constituents with moderate to high degree of mobility can leach from soils into gw; volatile constituents may contribute to subsurface gas in the vadose zone and releases into the atmosphere. .
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Contaminant Distribution between Environmental Compartments

Conversely, the potential for intermedia transport of constituents from other media into soils does exist; for example, chemical constituents may be transported to soils via atmospheric deposition, and also through releases of subsurface gas.
Chemical constituents having a moderate to high degree of mobility can leach from soils into ground water; volatile constituents may contribute to subsurface gas in the vadose zone and also possible releases into the atmosphere.
A natural processes work to lessen or attenuate contaminant concentrations in the environment; the mechanisms of natural attenuation include dispersion, dilution, ion exchange, precipitation, adsorption and absorption, filtration, gaseous exchange, and biodegradation.
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Important Fate and Transport Properties/Parameters

As pollutants are released into various environmental media, several factors contribute to their migration and transport.
For instance, in the groundwater system, the solutes in the porous media will move with the mean velocity of the solvent by:
Advective mechanism;
hydraulic dispersion and molecular diffusion (which is caused by the random Brownian motion of molecules in solution that occurs whether the solution in the porous media is stationary or has an average motion).
the transport and concentration of the solute(s) are affected by reversible ion exchange with soil grains,
chemical degeneration with other constituents, fluid compression and expansion, and in the case of radioactive wastes by the radioactive decay.
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Important Fate and Transport Properties/Parameters

In addition, several site characteristics may influence the environmental fate of chemicals:
the amount of ambient moisture,
humidity levels,
temperatures
wind speed,
the geologic characteristics,
Hydrologic characteristics,
Pedologic characteristics
watershed characteristics,
topographic features of the site and its vicinity,
vegetative cover of site and surrounding area,
land use characteristics.