Environmental Health - Toxic Substances Hydrology Program

Environmental Occurrence

Experienced personnel collecting environmental samples
Experienced personnel use proven field methodologies that enable representative environmental samples to be collected.
USGS scientists collecting water samples from a well
USGS scientists collecting water samples from a well in the well network for the National Groundwater Reconnaissance for Emerging Contaminants.
USGS scientists sampling ground water from a well installed at a beach
USGS scientists sampling ground water from a well installed at a beach as part of a study of bacterial contamination at beaches.

The first step in the road to understanding the fate of a contaminant is determining if contamination is actually taking place.

Emerging Chemical Contaminants

An important component of emerging contaminant research is to determine the environmental occurrence by answering the fundamental questions: What compounds enter the environment? How often and at what levels do they occur? In what mixtures do they occur? These questions are addressed by field reconnaissance studies at national, regional, and local scales.

Emerging Microbial Contaminants

There is no question that bacterial pathogens, viruses, and protozoa, and antibiotic-resistant bacteria can enter the environment. The source of these contaminants is generally fecal contamination through release of human and animal wastes to the environment. However, little is known about the actual occurrence of specific microbial pathogens in the environment, or their relation to traditional microbiological water quality criteria. This project investigates the occurrence of selected bacterial pathogens in water at the national and watershed scales, determines their potential for virulence and antibiotic resistance by examining the occurrence of genes for these traits, and relates findings to microbial water quality criteria and to chemical measures of water quality, including the occurrence of emerging chemical contaminants.

Related Science Features

More Information

New Publications

Upcoming Publications

Newly Published


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/investigations/cec/environmental_occurrence.html
Page Content Contact Information: webmaster@toxics.usgs.gov
Page Last Modified: 19-Jun-2017 @ 09:42:39 AM EDT