Point source pollution is when dangerous matter is released into a creek, lake, or any body of water, including the ocean. Industrial facilities can provide point source pollution by releasing effluents, liquid waste or sewage discharged into a river or a sea, in a pipe that empties right into a river. Point source pollution is regulated in the US, although politics can cause difficulties in doing it well.

Non-point source pollution is when dangerous matter enters a body of water indirectly, like from rain carrying it through a gutter to a creek. This source of pollution is very hard to regulate, because most of the time it is discreet. Most of the contamination of the streams is caused by Non-point sources (Jeantheau).

Nitrate and pesticide problems are the most persistent in surface water quality. In countries with severe agriculture and fast urbanization, the water has been degraded in its quality.  

Since over the last few years large amounts of wetlands in the world have been lost, the ability for freshwater systems to purify itself has been weakened   (Revenga). This means that we will have to work even harder to have clean water in the future.  

"Water pollution remains one of the most visible and persistent signs of our impact on the natural world. Cleanup of some older pollutants has been offset by new contaminants that threaten freshwater ecosystems and foul our drinking water" (Revenga).

Pesticides

• Pesticides are used in agricultural fields, roadsides, and lawns of the everyday person. If used inappropriately, they get washed away by sprinklers or rain and run off into local waters. Pesticides can even seep into our groundwater.
• Farmers can increase crop yields by using pesticides, and we can get those nasty critters out of our garden.
• The pesticides that enter our rivers contaminate them, making it dangerous to the fish and creatures that swim and live around it. The nutrients that are in them break down, and the algae feed off of them, causing them to bloom. This overgrowth of algae is called eutrophication. These plants use up the oxygen in the water, in turn suffocating the aquatic life living in it (Revenga).

• Negative Health affects arise with exposure to pesticides, including cancer, damage to the reproductive system, nervous system, and can stunt children's learning and development (Lopez).

Fact: $400 million is spent to clean our water for one pesticide, Atrazine, in the Midwestern US (Revenga).

Household Sewage

• Household sewage has microbial bacteria and diseases that spread diseases through water. These diseases are one of the main causes of childhood mortality in the world.
•        Toxic organic compounds from many things, including automobiles, farming, industrial sites, and lawns causes mild immune suppression, acute poisoning, and reproductive failure in all life (Revenga).

Heavy Metals

• Heavy metals that result from industries and mining sites stay in river environments for long periods of time, accumulating in the tissues of fishes. The metals are toxic for aquatic organisms, and humans who eat the fish (Revenga).

Personal Products

            Personal products like toothpaste and shaving cream leak right through the wastewater treatment facilities, going right into the local waterways. Nobody regulates this supposedly clean water (Revenga).

Over Irrigation, Over Grazing, Deforestation, and Urban Development

• Over irrigation leaches dissolved salts that lead to salt build-up in soil, which can kill crops or cut fields, and can render freshwater supplies undrinkable (Revenga). The rest cause excessive erosion in watersheds.
• The rate of runoff pollution increases with the removal of the forests and grass with the removal of the forests and grass around the waters. The running water then carries the sediment through the river, creating an adverse effect on the creatures living on the bottom of the river. It decreases the habitat of the species, decreasing the abundance of organisms (Welch).

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