Water - Non-Point Sources

Pollution Control: Non-Point Sources

Substantial loads of pollutants enter water bodies from non-point sources. Non-point pollution is much less visible and has not been subjected to the same level of management as point-source pollution.

Runoff from agricultural activities is a typical non-point pollution source, since it can occur throughout large areas of agricultural land rather than from a small number of well defined points. Other non-point pollutants include sediments from construction or forestry operations, heavy metals and acid drainage from mining projects, oil, grease, metals, and chemicals from urban areas; and deposition of airborne pollutants from cars and factories.

Key Challenges
The most successful interventions to control non-point pollution have been preventitive, although polluted runoff can sometimes be treated, for example in natural and constructed wetlands. First, the sources, by definition, occur over large areas at low concentrations. Secondly, they often involve large numbers of property owners who can be difficult to reach efficiently.

The most successful interventions to control non-point pollution have been preventive, although polluted runoff can sometimes be treated in, for example, natural and constructed wetlands. The most cost-effective interventions are usually those that invest in widespread changes in behavior and the decentralized investments to support those changes, rather than centralized infrastructure.

Non-point source pollutants move in very complicated ways from their sources into receiving waters and, without modeling, it is very difficult to assess the benefits of various interventions.

World Bank Response
The Bank assists countries in reducing non-point pollution, such as sediments, nutrient losses, and agrochemicals. Bank projects increasingly replace traditional "command and control" approaches for the regulation of point-source pollution with one that that treats all users of land as stakeholders in a partnership engaged in sustainable land use. Under this approach, farmers and other landusers receive education, technical support, and financial assistance in their efforts to conserve soils, protect water resources, and maintain habitats.