Fertilizers, Pesticides Threaten Groundwater

The U.S. Geological Survey has released a series of reports on the quality of water in 20 major basin regions, including the San Joaquin-Tulare basins, which cover most of central California and are a major source of drinking water for most of the state’s population.

The U.S. Geological Survey has released a series of reports on the quality of water in 20 major basin regions, including the San Joaquin-Tulare basins, which cover most of central California and are a major source of drinking water for most of the state’s population.

The study examined water in streams and ground water, and aquatic ecology, focusing on the distribution of pesticides and nitrate. It concluded nitrate and ammonia generally do not adversely impact drinking water and aquatic life uses of the San Joaquin River.

But it said drinking-water sources from ground water have been degraded by fertilizers and pesticides. In particular, nitrate and DBCP have frequently exceeded drinking water standards.

And it said the potential exists for toxicity to aquatic organisms from water-borne pesticides because concentrations of seven pesticides have exceeded aquatic life criteria at times.

Neil Dubrovsky, one of the authors, said, “Although nitrate concentrations in the San Joaquin-Tulare Basins have been increasing for over 40 years, they are still below the drinking water standard.

“Nitrate concentrations in ground water in the eastern part of the basin, in contrast, exceed the drinking water standard in 25 percent of the samples collected from household wells.”

In comparison with the other 19 basin areas, Dubrovsky said that streams in the San Joaquin-Tulare Basins have more degraded fish communities, and higher concentrations of pesticides in water and PCBs and organochlorine insecticides in streambed sediment and fish tissue.

He said, “Detections and concentrations of nitrate and pesticides in ground water exceed national averages. In many cases, the presence of nitrate or particular pesticides can be attributed to present, or often past, use of agricultural chemicals.”

But he said only two pesticides, both banned long ago, have been found in ground water at concentrations that exceed drinking water standards.

The report summarized major findings that emerged from the USGS’s National Water Quality Assessment program, which assesses water-quality conditions in sources of drinking water used by about 70 percent of the U.S. population.

Congressional outlook

With relatively few days remaining on the legislative calendar before Congress adjourns in October, no key water legislation is expected to pass.

Congressional outlook

The focus will be on appropriations this summer as committees in both houses work on the administration’s fiscal 1999 budget request.

Congressional outlook

The administration has proposed increased funding for the drinking water state revolving fund but less spending on water research. It also wants Congress to fund its Clean Water Action Plan.

Congressional outlook

Congressional committees also may hold oversight hearings on the Safe Drinking Water Act this summer.

Congressional outlook

Committees have indicated they may want to look at how the SDWA reforms are working.

Congressional outlook

Congress has enacted the Intermodal Surface Transportation Efficiency Act (ISTEA), which contained a one-call excavation notification provision.

Congressional outlook

The law would require that excavators participate in a one-call system if their state elects to apply for a federal one-call grant. The bill allows states to exempt utilities if they judge the costs will outweigh the benefits, or if there is minimal risk to the environment.

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