Seven Percent Of Urban Streams Have Pesticide Levels That Harm Humans


Despite conservation efforts, 57 percent of streams in agriculture areas and 83 percent of streams in urban areas have levels of pesticides in them high enough to harm aquatic life. More alarmingly, 7 percent of urban stream show pesticide levels high enough to be harmful to people, announced the United States Environmental Protection Agency.

Of particular concern is nitrate run off that causes algae blooms in the nation’s water that are so large that they can be spotted from outer space. These blooms recently forced Toledo, Ohio, officials to warn people not to use the city’s water in any way. Large algae blooms have caused dead zones in Puget Sound, Chesapeake Bay, Long Island Sounds, and the Gulf of Mexico despite years of warning people about the harmful effects of nitrate and other harmful chemicals to the nation’s water supply.

Nancy Rabalais with the Louisiana Universities Marine Consortium says that when the nitrate level becomes too high it chokes out the oxygen in the water causing the dead zones. The top fish swim away, but the bottom fish cannot leave the area and die. This has caused a $82 million loss in shrimp catches and charter fishing trips on the lower Mississippi River basin and in the Gulf of Mexico. The dead zone in the Gulf of Mexico is the world’s second largest dead zone and is currently about the size of the state of New Jersey.

There are several reasons for the increase in nitrate in the water. About 16 percent of all nitrate put on the ground as fertilizer runs off and ends up in the nation’s water supply. More farmers than ever before are growing corn switching over from soybeans. Additionally, as the population in urban areas along the river grows, the nitrate levels rise because more people in those areas are using nitrates to landscape their yards. Even the increase in the number of dogs in this area can cause an increase in the nitrate levels, as dog manure contains a high level of nitrate.


Alan Vicory, the chair of the Water Environment Federation’s Government Affairs Committee, says that it is vital to continue monitoring the nitrate levels in the nation’s water. The Environmental Protection Agency recommends a 45 percent decrease in nitrate use. Some officials would like to see the government stop subsidies to agriculture so that farmers will use less fertilizer to raise a larger crop. In addition, they say that the government needs to institute a public education campaign so that people do not pour things into water, pick up after their dogs, and not litter.

Progress can be made says scientist Suzanne Bricker with the National Estuarine Eutrophication Assessment. As an example, she points to Tampa Bay, Florida, where nitrate levels have dropped 60 percent over the last 34 years that the bay has been monitored. The bay now has restored sea-grass beds, and more fish are living in those beds. Bricker says that most of that improvement has occurred through a public education campaign teaching area residents about the harmful effects of nitrates.


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