Sources of Water Pollution

Water pollution comes from point sources or non-point sources.

Point sources

They include factories, sewage pipes and specific spills from pipelines or containers.

Non-point sources

They do not have a specific point of origin. Runoff from storms and melting snow carry fertilizers, pesticides, oil and gasoline, litter such as plastic bags and animal feces into storm drains, creeks, rivers, lakes and, ultimately, the ocean.

Major pollutants

• Runoff from agricultural fields, industrial sites, or urban areas . Agricultural runoff typically includes fertilizer or toxic chemicals. Fertilizer can cause algal blooms.

• Raw sewage

• Trash such as plastic bags, fishing line, and other material

• Oil spills

Major pollutant types

Major types of water pollution around the world is caused by microbial pathogens (mostly disease-causing bacteria and viruses), nutrients from fertilizers and feces, heavy metals such as arsenic and mercury, chemicals from roads and industry, and litter.

Heat pollution, especially near power plants, can also severely impact local ecosystems.

Effects of Water Contamination

• Diarrhea, skin diseases and other infections

• Bioaccumulation occurs as heavy metals like mercury move up through the food chain contaminate shellfish and fish like mackerel, tuna and sharks, exposing consumers to these toxic chemicals.

• Mercury poses higher health risks to children under 6 and to child-bearing women because it interferes with brain development.

• Oil floats on water, cutting off oxygen for plankton. Oil causes tissue damage in coral and coral larvae, causes heart defects in bluefin tuna larvae and other fish and even small amounts of oil impairs the ability of seabirds to fly, swim and dive for food