Water pollution starts at home

Pesticides and fertilizers from homes are a major and overlooked source of water pollution, according to new research from the University of California, Davis. Previous estimates may have underestimated water pollution from homes by up to 50%, the study says.

Researchers monitored homes in eight different neighborhoods in California, and say that the estimates likely extend to households across the country.

Pesticides, particularly for ant control, were the most common source of pollution. Surprisingly, pesticides made from organophosphate chemicals, which have been off the market in California since 2002, turned up in many of the samples.

“We expected to find pesticides, but I think we were surprised at how consistently we found them,” says Lorence Oki, a landscape expert who lead the research.

E.coli bacteria was also found in water samples, and could have come from wildlife like rabbits and birds, but also from peoples’ dogs and cats.

Previous models underestimated home water pollution because they relied on data only from the rainy season, which measured pollution washed into municipal storm drains after rainfall. But these newer models tracked pollutants during both the rainy and dry seasons, and found that activities such as garden watering or car washing washes a significant amount of pollutants into storm drains, and that the concentration of pesticides is higher during the dry season.

Oki says that outreach programs focused on pest management and irrigation control could help reduce the number of pesticides and fertilizers and decrease the amount of water used on gardens.

By Monica Heger
Photo: Sources of polluted runoff. (National Oceanic and Atmospheric Administration)

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