Water pollution refers to the introduction of harmful substances into our rivers, lakes, oceans and groundwater. Our water bodies are becoming more and more polluted. Pollutants come from several sources including but not limited to the following:
- Households: Waste water from sinks and washing machines often flows into drains and eventually into nearby rivers and the sea. This water often contains detergents, other harmful chemicals or organic matter. In some instances, people dispose of garbage, including plastics, directly into rivers, lakes or oceans. Plastics are of particular concern as they are not biodegradable.
- Industries: Many industries, especially manufacturing industries, produce large amounts of waste. This waste often contains harmful chemicals or organic matter. Many industries dispose of their waste into nearby water bodies such as rivers or the sea.
- Sewage: The term sewage refers to waste matter such as urine, faeces and waste water. The chemicals and organic matter present in sewage can damage the environment. Therefore, sewage requires proper treatment to deal with the chemicals and organic matter it contains. After treatment, it can be safely released into water bodies without harming the environment. Sadly much much untreated or improperly treated sewage is released into our rivers and seas.
- Agriculture: Many farmers use chemical fertilizers, herbicides and pesticides. Heavy rainfall may wash these dangerous chemicals into nearby rivers, lakes or the sea.
- Surface runoff: The water that runs off the surface during heavy rain picks up debris, sediment, chemicals and other pollutants. This water eventually flows into rivers or the sea.
Effects of Water Pollution
Solid waste in our rivers and oceans is very unsightly. Plastics pose a serious threat to the environment because they take hundreds or even thousands of years to degrade. This means that almost every piece of plastic ever made still exists somewhere. Much of it is in our rivers and oceans.
Aquatic animals and seabirds often mistake bits of plastic for food and may die after eating them. Other animals become entangled in plastic materials and may die as a result.
Many of the pollutants in our water are toxic. These include pesticides, herbicides and heavy metals such as lead. These can kill aquatic animals in high concentrations. Sometimes, toxic chemicals build up in the tissues of fish and other aquatic animals. We take these toxins into our bodies when we eat fish, shellfish and other creatures which come from polluted water bodies. Some of the chemicals found in water bodies are known to cause cancer, damage the nervous and reproductive systems and create other health issues.
Organic matter and fertilizers also pose a threat to the environment. They add nutrients to the water which causes microorganisms to grow and reproduce rapidly. These organisms may use up most of the oxygen in the water causing larger creatures such as fish to die. Water contaminated with untreated sewage poses a health risk as it may contain microorganisms which cause diseases such as gastroenteritis and cholera.
Generally, contact with polluted water may result in skin irritations, diarrhea, respiratory problems and a host of other health issues depending on the pollutants that the water contains. The video below shows some of the major sources and effects of water pollution.