USGS scientists have developed a method to detect chlorothalonil (a fungicide) and three of its environmental degradates in sediment and soil. After the target compounds are extracted from the sediment the samples are analyzed by gas chromatography/mass spectrometry (GC/MS). Chlorothalonil is widely used on peanut crops.

USGS studied the transport and fate of pyrethroid insecticides absorbed on sediment in streams in the Carpinteria Marsh, Calif. USGS scientists collected bed sediments at different depths in the channel to account for tidal inundation cycles.

USGS scientists use cone splitters, such as this one on board a research vessel, to separate a water sample into several subsamples. Each subsample will be analyzed for a different suite of organic chemicals such as pyrethroid insecticides and other pesticides. The water sample being collected here is from the San Francisco Bay, Calif., near Mallard Island.

USGS scientist operating a grab sampler to collect bottom sediment from the Salton Sea, Calif. The sediment sample was analyzed for pyrethroid insecticides as part of a study of the occurrence and distribution of pyrethroids in California.

USGS scientist collecting a suspended sediment sample from the Yolo Bypass, Calif., during a study of the occurrence and distribution of pyrethroid insecticides in California. The scientist is pumping water from the Bypass into stainless steel soda kegs. The large-volume water samples collected during the project were then centrifuged to separate suspended sediment from the water for later analysis of pyrethroids.

USGS scientist collecting water samples for the analysis of pesticide concentrations in Cedar Creek near Pansey, Ala. (site ID 02343848). Samples were collected as part of a reconnaissance of pesticides in stream waters in peanut production areas in the Southeastern United States (circa 2003).

USGS scientist measuring field parameters (pH, temperature, ...) in Cedar Creek near Pansey, Ala. (site ID 02343848), as part of a reconnaissance of pesticides in stream waters in peanut production areas in the Southeastern United States (circa 2003).

USGS scientist collecting water samples for the analysis of pesticides downstream from peanut fields along Cedar Creek near Pansey, Ala. (site ID 02343848) (circa 2003).

Collecting water-quality samples from a bridge on Big Creek near Rehobeth, Ala. (site ID 02358765). The samples were analyzed for pesticides as part of a reconnaissance of stream waters in peanut production areas in the Southeastern United States (circa 2003).

An autosampler set up to collect water samples for analysis of pesticides during storm events. The autosampler was located on Black Creek near Blitchton, Ga. (circa 2003).

The USGS sampled 52 sites on Midwestern streams during post-application runoff in 1989, 1990, 1994, 1995, and 1998 as part of a reconnaissance of herbicide concentrations in streams.

USGS scientist lowering a water-quality sampler into the Iowa River near Marengo, Iowa (site ID 05453100), during the 1993 flood of the upper Mississippi River Watershed. The samples were analyzed for nutrients and pesticides.