Collecting samples for mercury and other constituents. Courtesy U.S. Geological Survey
The Sacramento River and its tributaries have been deemed healthy for drinking and irrigation, despite high levels of the insecticide diazinon and seasonally high concentrations of mercury at locations throughout the watershed, according to a recent U.S. Geological Survey (USGS) report.

Samples from the Sacramento River show that concentrations of diazinon, an insecticide commonly used by homeowners on lawns and gardens and currently being phased out for use in urban areas, were among the highest measured by the USGS in more than 20 urban streams throughout the nation.

The USGS reports groundwater in the Sacramento Valley is of good quality and usually meets federal and state standards for drinking water quality.