From Envirowiki

Nonpoint water pollution is the contamination of bodies of water — such as lakes, streams, ponds, and water reservoirs — that is caused by multiple activities that are difficult to measure and specifically hold one accountable for. Nonpoint pollution is important because it is the major contribution to water contamination today. It can lead to “toxic algal blooms, loss of oxygen, fish kills, loss of seagrass beds and other aquatic vegetation, degradation of coral reefs, and loss of biodiversity — including species important to commercial and sport fisheries and shellfish industries. Thus, nutrient fouling seriously degrades our marine and freshwater resources and impairs their use for industry, agriculture, recreation, drinking water, and other purposes”^[1].

Contents 1 Causes 2 Outccomes 2.1 Algal Blooms 3 See also 4 References

[edit] 1 Causes

Some of the activities that result in water pollution include agricultural runoff, industrial waste, and leaching from cattle pastures. Fertilizers, pesticides, manure, and other chemicals run off from these sites by methods of erosion and leaching. It is hard to measure exactly where all of the pollutants in a body of water come from due to this variety of sources. Also, different seasons and the variation of weather cause different amounts of pollutants to enter into the streams and lakes. The most common and also most significant pollutants are nitrogen and phosphors. These lead to deadly algal blooms that can decrease biodiversity.

[edit] 2 Outccomes

[edit] 2.1 Algal Blooms

Scientists have a detailed understanding of how algal blooms occur and why they are bad for the environment: nitrogen is a limiting resource for algae, so when nonpoint inputs of nitrogen occur, the algae’s carry capacity increase and they essentially take over the water surface—eutrophication. As they naturally die the decomposers begin breaking them down, using the oxygen in the water. Since there are more algae, the decomposers have more to decompose, using more of the oxygen. The oxygen level steadily decreases, resulting in hypoxia (no oxygen). This then leads to the death of the organisms in the lake — dead zones — which, overall, decreases biodiversity. Scientists have a very thorough scientific understanding of the consequences and causes of nonpoint water pollution^{[reference needed]}. It is also evident^{[reference needed]} that human activity is a significant factor to this nonpoint water pollution. Therefore, the process for fixing the problem must not only include scientific ideas, but also incorporate humans into the plan, where information needs to be available and understandable for the local public and society as a whole.

[edit] 3 See also

• The problem of agriculture - for solutions to nonpoint water pollution

[edit] 4 References

1. ↑ (ESA)

• Issues in Ecology. “Nonpoint Pollution of Surface Waters with Phosphorus and Nitrogen.” Issue 3 p. 1-14, 1998.