Water Quality:

Problems in the New River and Imperial County, California

RCED-99-268R: Published: Aug 5, 1999. Publicly Released: Aug 13, 1999.

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Peter F. Guerrero
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Pursuant to a congressional request, GAO examined a number of issues concerning water quality problems in the New River and Imperial County in southern California, focusing on the: (1) types and the sources of pollutants entering the New River; (2) agencies and the organizations responsible for monitoring and regulating pollution in the New River; (3) risks to human health and the environment from water pollution in Imperial County; (4) health advisories and the precautions in place to protect the public from pollution in the New River; and (5) actions being taken to reduce the flow of pollutants into the Salton Sea.

GAO noted that: (1) the New River in southern California has been a severely polluted waterway for decades; (2) a major source of this pollution has been untreated and undertreated municipal and industrial wastewater, including raw sewage, discharged into the river from the city of Mexicali in Mexico; (3) drainage from agricultural lands in the United States, however, has contributed most of the water in the river and is also a major source of pollution; (4) bacteria from sewage, nutrients, and pesticides have been identified as the major water quality problems for the New River and have been found in sufficient quantities to prevent the river from supporting its designated uses, such as fishing and swimming; (5) the Colorado River Basin Region of the California Regional Water Quality Control Board and the State Water Resources Control Board are the primary agencies responsible for monitoring water quality in the portion of the New River that flows within its borders; (6) the Environmental Protection Agency (EPA) is the lead federal agency that works with Mexico on border pollution issues; (7) untreated and undertreated wastewater in the New River poses a serious potential threat to human health and the environment and could cause serious illnesses, such as typhoid and hepatitis; (8) however, the Imperial County Health Department has reported no documented cases of adverse effects on human health from exposure to the river, primarily because most residents stay away from the river; (9) the sewage has affected environmental conditions in the river; (10) other pollutants in the river, such as pesticides and volatile organic compounds, also pose potential threats to human health and the environment; (11) as a result of sewage contamination, the Imperial County Health Department has had an advisory warning against contact with the river and consumption of fish from it for over 20 years; (12) precautions related to pollution problems include Mexico's notifying the United States when raw sewage releases in excess of what typically occurs are expected; (13) several actions are underway to address the level of pollutants flowing into the Salton Sea; (14) the U.S. section of the International Boundary and Water Commission and EPA are leading efforts with Mexico to upgrade existing wastewater treatment facilities and to construct new facilities in Mexicali, Mexico; and (15) California's Regional Control Board is in the process of developing additional strategies to reduce the level of bacteria in the New River.

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