The Eight (8) Main Types of Water Pollutants

The major water pollutants are chemical, biological, or physical materials that degrade water quality. Pollutants can be classed into eight categories, each of which presents its own set of hazards.

1. Petroleum Products

Oil and chemicals derived from oil are used for fuel, lubrication, plastics manufacturing, and many other purposes.

These petroleum products get into water mainly by means of accidental spills from ships, tanker trucks, pipelines, and leaky underground storage tanks.

Many petroleum products are poisonous if ingested by animals, and spilled oil damages the feathers of birds or the fur of animals, often causing death.

Land- based petroleum pollution is carried into waterways by rainwater runoffs. This includes drips of oil, fuel, and fluid from cars and trucks; dribbles of gasoline spilled onto the ground at the filling station; and drips from industrial machinery.

2. Pesticides and Herbicides

Pesticides that get applied to farm fields and roadsides and homeowners’ lawns run off into local streams and rivers or drain down into groundwater, contaminating the fresh water that fishes swim in and the water we humans drink.

It’s tempting to think this is mostly a farming problem, but on a square-foot basis, homeowners apply even more chemicals to their lawns than farmers do to their fields! Still, farming is a big contributor to this problem.

Chemicals used to kill unwanted animals and plants, for instance on farms or in suburban yards, may be collected by rainwater runoffs and carried into streams, especially if these substances are applied too lavishly.

Some of these chemicals are biodegradable and quickly decay into harmless or less harmful forms, while others are non-biodegradable and remain dangerous for a long time.

When animals consume plants that have been treated with certain non-biodegradable chemicals, such as chlordane and dichlorodiphenyltrichloroethane (DDT), these chemicals are absorbed into the tissues or organs of the animals. When other animals feed on these contaminated animals, the chemicals are passed up the food chain.

With each step up the food chain, the concentration of the pollutant increases. This process is called bio-magnification. Animals at the top of food chains may, as a result of these chemical concentrations, suffer cancers, reproductive problems, and death.

Many drinking water supplies are contaminated with pesticides from widespread agricultural use.

3. Heavy Metals

Heavy metals, such as copper, lead, mercury, and selenium, get into water from many sources, including industries, automobile exhaust, mines, and even natural soil can pollute the water resources. Like pesticides, heavy metals become more concentrated as animals feed on plants and are consumed in turn by other animals.

When they reach high levels in the body, heavy metals can be immediately poisonous, or can result in long-term health problems similar to those caused by pesticides and herbicides.

For example, cadmium in fertilizer derived from sewage sludge can be absorbed by crops. If these crops are eaten by humans in sufficient amounts, the metal can cause diarrhea and, over time, liver and kidney damage. Lead can get into water from lead pipes and solder in older water systems; children exposed to lead in water can suffer mental retardation.

4. Hazardous Wastes

Hazardous wastes are chemical wastes that are either toxic (poisonous), reactive (capable of producing explosive or toxic gases), corrosive (capable of corroding steel), or ignitable (flammable). If improperly treated or stored, hazardous wastes can pollute water supplies.

Read Also : The Four (4) Traditional Waste Management Methods

5. Excess Organic Matter

PCBs, a class of chemicals once widely used in electrical equipment such as transformers, can get into the environment through oil spills and can reach toxic levels as organisms eat one another.

Fertilizers and other nutrients used to promote plant growth on farms and in gardens may find their way into water. At first, these nutrients encourage the growth of plants and algae in water.

However, when the plant matter and algae die and settle underwater, microorganisms decompose them. In the process of decomposition, these microorganisms consume oxygen that is dissolved into the water.

Oxygen levels in the water may drop to such dangerously low levels that oxygen-dependent animals in the water, such as fish, die. This process of depleting oxygen to deadly levels is called eutrophication.

6. Sediment

Sediment, soil particles carried to a streambed, lake, or ocean, can also be a pollutant if it is present in large enough amounts.

Soil erosion produced by the removal of soil-trapping trees near waterways, or carried by rainwater and floodwater from croplands, strip mines, and roads, can damage a stream or lake by introducing too much nutrient matter.

This leads to eutrophication. Sedimentation can also cover streambed gravel in which many fishes, such as salmon and trout, lay their eggs.

7. Infectious Organisms

Many disease-causing organisms that are present in small numbers in most natural waters are considered pollutants when found in drinking water. Such parasites as Giardia lamblia and Cryptosporidium parvumoccasionally turn up in urban water supplies.

These parasites can cause illness, especially in people who are very old or very young, and in people who are already suffering from other diseases.

8. Thermal Pollution

Water is often drawn from rivers, lakes, or the ocean for use as a coolant in factories and power plants. The water is usually returned to the source warmer than when it was taken.

Even small temperature changes in a body of water can drive away the fishes and other species that were originally present, and attract other species in place of them. Thermal pollution can accelerate biological processes in plants and animals or deplete oxygen levels in water.

The result may be fishes and other wildlife deaths near the discharge source. Thermal pollution can also be caused by the removal of trees and vegetation that shade and cool streams.

In summary, clearly, the problems associated with water pollution have the capabilities of disrupting life on our planet to a great extent. Congress has passed laws to try to combat water pollution thus acknowledging the fact that water pollution is, indeed, a serious issue. But the government alone cannot solve the entire problem.

It is ultimately up to us, to be informed, responsible and involved when it comes to the problems we face with our water.

We must become familiar with our local water resources and learn about ways for disposing harmful household wastes so they do not end up in sewage treatment plants that can’t handle them or landfills not designed to receive hazardous materials.

In our yards, we must determine whether additional nutrients are needed before fertilizers are applied, and look for alternatives where fertilizers might run off into surface waters.

We have to preserve existing trees and plant new trees and shrubs to help prevent soil erosion and promote infiltration of water into the soil. Around our houses, we must keep litter, pet waste, leaves, and grass clippings out of gutters and storm drains.

These are just a few of the many ways in which we, as humans, have the ability to combat water pollution.

As we head into the 21st century, awareness and education will most assuredly continue to be the two most important ways to prevent water pollution. If these measures are not taken and water pollution continues, life on earth will suffer severely.

Global environmental collapse is not inevitable. But the developed world must work with the developing world to ensure that new industrialized economies do not add to the world’s environmental problems. Politicians must think of sustainable development rather than economic expansion.

Conservation strategies have to become more widely accepted, and people must learn that energy use can be dramatically diminished without sacrificing comfort. In short, with the technology that currently exists, the years of global environmental mistreatment can begin to be reversed.

Read Also : Water Pollution Sources and Classifications

Water Pollution is the contamination of streams, lakes, underground water, bays, or oceans by substances harmful to living things. Point source pollution occurs when harmful substances are emitted directly into a body of water.

Nonpoint source pollution occurs when pollutants are indirectly introduced into the environment through transport or environmental change. Major water pollutants are chemical, biological, or physical materials.