Urban pesticide use is poisoning waterways - The Modesto Bee - Sun, Aug. 02, 2009
A study of Northern California waterways has made some troubling discoveries about a widely used group of pesticides and the role of homeowners and businesses in putting them there.
The findings should prompt residents to reflect on their household practices. It also should lead to further scientific investigation of the role these pesticides are playing in the multifaceted crisis of the Sacramento-San Joaquin Delta.
The study, led by a University of California at Berkeley toxicologist, focused on pyrethroids. These are man-made pesticides commonly used in household insecticides, lawn care products and pet sprays.
Before this study, what happened to these substances after they killed unwanted pests was something of a mystery. Now it's a worry.
That's because the study discovered three things that hadn't previously been known about pyrethroids' penetration of local water systems:
These pesticides in the American River were present in sufficient quantities to poison the tiny shrimp that are among the early links of the aquatic food chain. That may come as a surprise to many people who view the American River as more pristine than it apparently is.
The pesticides were present in all of the urban runoff flowing out of regional storm drains.
Pyrethroids routinely were detected in local waste water.
Experts say this doesn't necessarily mean the pesticides play a key role in the devastation of the delta ecosystem, including the decline of nine fish species ranging from the tiny delta smelt to the giant green sturgeon. But that question must be answered by further study.
A group called Pesticide Watch says urban areas use more pesticides per acre than agricultural ones. Valley farmers long have been saying that to their critics, but it's mostly fallen on the deaf ears of those who like to bash agriculture.
What's obvious is residents across California should be using household pesticides with much more care. They are dangerous.
The pesticide study is a reminder that everything done in the watershed has consequences for the delta. While Northern California environmentalists like to blame farming for endangering threatened species, you don't hear much out of them about cities such as Sacramento dumping treated sewage in the delta.
We must protect the delta, and that means regulating all sources contributing to the problem, including cities and the pesticides that homeowners carelessly use.
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