Environmental Health - Toxic Substances Hydrology Program

EH Science Feature Email Signup

Measuring Antidepressants, Fungicides, and Insecticides in the Environment

USGS scientist collecting sediment from the bottom of the Salton Sea, CA
USGS scientist collecting sediment from the bottom of the Salton Sea, Calif. The sediment sample was analyzed for the presence of pesticides, such as pyrethroid insecticides. The analytical method used was developed by USGS scientists as part of the USGS Toxic Substances Hydrology Program's investigation on the fate of pesticides in the environment.

U.S. Geological Survey (USGS) scientists are developing new laboratory analytical methods to measure contaminants in samples of environmental water, sediment, and soil. The work is part of a continuing effort to provide information on new and understudied contaminants to water-resource managers, environmental regulators, and the public. The new methods are used by USGS scientists and others to determine the occurrence and behavior of contaminants in the environment--information that is key to assessing potential ecological health effects and establishing priorities for additional research. USGS scientists have developed new methods for the analysis of (1) antidepressant pharmaceuticals, (2) an agricultural fungicide (chlorothalonil) and its environmental degradation byproducts, and (3) pyrethroid insecticides in the environment.

Among the Top 200 Prescribed Drugs

Several of the antidepressants detected in this study—bupropion, citalopram, duloxetine, paroxetine, sertraline, and venlafaxine—were among the top 200 prescribed drugs in 2007.

Photo Credit: ©iStockphoto.com/Marcelo Wain

Antidepressant Pharmaceuticals

USGS scientists have developed a laboratory analytical method to measure the concentrations of eight currently used antidepressants and two of their pharmaceutically active degradation byproducts (or metabolites) in environmental waters. Many of these antidepressants are from the class of antidepressant pharmaceuticals called Selective Serotonin Reuptake Inhibitors (SSRIs). This widely prescribed class of antidepressants, which includes citalopram (Celexa), escitalopram (Lexapro), fluoxetine (Prozac and Sarafem), fluvoxamine (Dumyrox, Luvox, …), paroxetine (Paxil and Pexeva), sertraline (Zoloft), and others, has been prescribed to millions of people worldwide. Recent studies by the USGS and others have detected other widely prescribed pharmaceuticals in wastewater and in streams downstream of the discharge from wastewater treatment plants (WWTPs). An initial application of the method to a stream in Texas receiving wastewater detected several antidepressant pharmaceuticals, such as bupropion (Wellbutrin and Zyban), citalopram, duloxetine (Cymbalta), fluoxetine, fluvoxamine, norfluoxetine (a metabolite of fluoxetine), norsertraline (a metabolite of sertraline), paroxetine, sertraline, and venlafaxine (Effexor). Concentrations ranged from less than one nanogram per liter (ng/L) to over 1,000 ng/L. The scientists conducting the study were the first to report detection of bupropion, duloxetine, and venlafaxine in natural aquatic environments.

The 2002 average annual agricultural use of chlorothalonil in the southeastern United Sates
The 2002 average annual agricultural use of chlorothalonil in the southeastern United Sates (based on National 2002 Pesticide Use Maps). Chlorothalonil is widely used on peanuts, potatoes, and other crops.


Schultz, M.M., and Furlong, E.T., 2008, Trace analysis of antidepressant pharmaceuticals and their select degradates in aquatic matrixes by LC/ESI/MS/MS: Analytical Chemistry, v. 80, no. 5, p. 1756-1762, doi:10.1021/ac702154e. In addition please use a smaller font.

Agricultural Fungicide - Chlorothalonil

USGS scientists have developed analytical methods to measure the fungicide chlorothalonil and its environmental degradation byproducts in water, sediment, and soil. Chlorothalonil is used to control fungal diseases in peanuts, potatoes, fruit, and vegetable crops. The analytical method for water samples has been applied to study streams in areas of Alabama, Florida, Georgia, Oklahoma, and Texas where peanuts are grown. The method for sediment and soil has been applied to study sediments in Alabama, Florida, and Georgia streams draining areas where peanuts are grown. Chlorothalonil and its degradation byproducts were detected infrequently, and when detected, were found at relatively low concentrations (less than one microgram per liter).


Battaglin, W.A., Kuivila, K., Winton, K., and Meyer, M., 2008, Occurrence of chlorothalonil, its transformation products, and selected other pesticides in Texas and Oklahoma streams, 2003-2004: U.S. Geological Survey Scientific Investigations Report 2008-5016, 9 p.

Hladik, M.L., and Kuivila, K.M., 2008, Analysis of chlorothalonil and three degradates in sediment and soil: Journal of Agricultural and Food Chemistry, v. 56, no. 7, p. 2310-2314, doi:10.1021/jf703695s.

Scribner, E.A., Orlando, J., Battaglin, W.A., Sandstrom, M.W., Kuivila, K., and Meyer, M.T., 2006, Results of analysis of the fungicide chlorothalonil, its degradation products, and other selected pesticides at 22 surface-water sites in five southern States, 2003-04: U.S. Geological Survey Open-File Report 2006-1207, 59 p.

Pyrethroid Insecticides

USGS scientist collecting a suspended sediment sample from the Yolo Bypass, Calif.
USGS scientist collecting a suspended sediment sample from the Yolo Bypass, Calif. 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.

USGS scientists and their partners have developed a sensitive analytical method to measure several pyrethroid insecticides in sediments from streams--sediments suspended in water as well as on the bottom of streams. Pyrethroids are a class of insecticides that are widely used, including for agricultural purposes, home and garden use, and mosquito control. USGS scientists applied the new method to study pyrethroids in stream sediments in three California watersheds where the chemicals are widely used. The scientists detected pyrethroids in sediments in streams downstream of application areas in all of the watersheds. Concentrations of individual pyrethroids (such as bifenthrin and permethrin) in sediment ranged as high as tens of nanograms per gram dry weight. This study was one part of a multi-agency effort where the USGS has partnered with the California Departments of Pesticide Regulation and Fish and Game, with funding from the CALFED Bay-Delta Program, to develop analytical methods to detect pyrethroids in water, sediments, and biological organisms.


Hladik, M.L., and Kuivila, K.M., 2008, Occurrence of pyrethroids in bed and suspended sediments in California, in Gan, J.J., Spurlock, F., Hendley, P., and Weston, D., eds., Synthetic Pyrethroids--Occurrence and Behavior in Aquatic Environments: ACS Symposium Series 991.

Hladik, M., 2007, Methods development for the analysis of pyrethroid pesticides in environmental samples--Final Report for CALFED, Recipient Agreement No. ERP-02-P42: CALFED Final Report ERP-02-P42.

More Information

Related Science Features

More Information on...

Selective Serotonin Reuptake Inhibitors (SSRIs)



Note: Trade and copyrighted names presented on this page are for informational purposes only and do not indicate endorsement or disapproval by the U.S. Geological Survey.


More Science Features


USGS Home Water Land Resources Science Systems Ecosystems Energy and Minerals Environmental Health Hazards

Accessibility FOIA Privacy Policies and Notices

USA.gov logo U.S. Department of the Interior | U.S. Geological Survey
Page URL: toxics.usgs.gov/highlights/measuring_contaminants.html
Page Content Contact Information: webmaster@toxics.usgs.gov
Page Last Modified: 27-Jun-2018 @ 07:15:38 PM EDT