The shore crab, Hemigrapsus oregonensis, collected from a rocky cove near Bodega Bay, California. These crabs are reproductively active during the summer months and carry hundreds of embryos under their carapace until hatching occurs. Scientists found crab embryos from the bay's salt marsh with accumulations of mixtures of currently used and discontinued pesticides.

USGS scientist collecting sand crabs for analysis from an urban estuary near Richmond, California. Crabs utilize these rocky intertidal areas as breeding grounds. Scientists detected pyrethroid insecticides as well as 21 other pesticides, including DDT, in crab embryos.

Aerial spraying of fungicides on row crops in Iowa. A soybean field is in the foreground, and a cornfield is in the background. The soybean crop is the target of the aerial application. Fungicides are used to combat soybean rust, a fungal disease, and have been detected in streams in areas of application.

USGS scientist lifting a filter caked with sediment that's on top of a filter plate used for filtering suspended sediment from water samples. The filter was saved for later analysis for pyrethroid insecticides in the sediment. USGS scientists have developed a method to determine the concentration of a suite of pyrethroid insecticides absorbed to sediment particles.

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.

Collecting a water sample (grab sample) for the reconnaissance of herbicide concentrations in streams.

USGS scientists collecting large-volume water samples off of a bridge across the San Joaquin River near Vernalis, Calif., in support of a study of pesticides in runoff from agricultural fields in the watershed (circa 2000).

The analysis of pesticides sometimes requires large-volume water samples to detect pesticides that are toxic at low concentrations. This is a view of a pump used to collect samples from the San Joaquin River near Vernalis, Calif. (circa 2000).

Collecting water-quality samples for pesticide analysis off of a bridge over the San Joaquin River near Vernalis, Calif. (site ID 11303500, circa 2000). Safety plans for work on bridges includes the use of safety cones and signs, lane blockage, and traffic control.

Packing in supplies as part of a study of herbicides transported by rain to Isle Royale National Park, Mich. USGS scientists detected trace concentrations of herbicides in the remote island's lakes and streams.

USGS scientists studied the transport of herbicides by rain to the pristine waters of Isle Royale National Park, Mich., located in Lake Superior on the United States-Canadian border. Results of the study showed that herbicides can be transported to pristine areas and result in detectable concentrations in streams and lakes.

The supplies for the analysis of pesticides by enzyme-linked immunosorbent assay (ELISA). ELISA is a cost effective way to conduct studies on the occurrence of pesticides, such as atrizine, in water resources that involve the collection of large numbers of samples.

USGS scientists used gas chromatography/mass spectrometry (GC/MS) to analyze water-quality samples during a reconnaissance study of herbicides and their metabolites in surface water of the Midwestern United States. The study also compared the results of immunoassay and GC/MS analysis.

USGS scientist using an autotrace to extract pesticides from water samples in preparation for gas chromatography/mass spectrometry (GC/MS) analysis. The autotrace automates the processing of large numbers of samples.

A liquid chromatography/mass spectrometry (LC/MS) instrument with an on-line solid phase extraction (SPE) system used for the analysis of pesticides in water. SPE provides for shorter total analysis times, the ability to automate analysis procedures, and much smaller sample volumes for analysis.

USGS scientist preparing a sediment sample for the analysis of herbicides. USGS scientists developed an analytical method for the ultratrace analysis of herbicides in soil that combined solid-phase extraction (SPE) and enzyme-linked immunosorbent assay (ELISA).

Incorporating an encapsulated herbicide (atrazine) into the soil as part of an experiment to determine if encapsulating herbicides reduces runoff. The white pipes are suction cup lysimeters used to sample water from the unsaturated zone.