Exposure Pathways

U.S. Geological Survey (USGS) scientists used a mass–balance solute–transport model to enhance an understanding of factors affecting chlorinated ethene (CE) concentrations in a public supply well. They found that long–term simulated and measured CEconcentrations were affected by dense nonaqueous phase liquid (DNAPL) volume, composition, and by the bioavailability of organic carbon that drives...

U.S. Geological Survey (USGS) scientists studying a midwestern stream conclude that pharmaceuticals and other contaminants in treated wastewater effluent discharged to the stream are transported into adjacent shallow groundwater. Other mobile chemicals found in wastewater are expected to have similar fates.

Landfill leachate contains a variety of chemicals that reflect our daily activities, U.S. Geological Survey (USGS) scientists concluded as a result of a nationwide study. Landfills are a common disposal mechanism for our Nation's solid waste from residential, commercial, and industrial sources. The scientists found that pharmaceuticals, personal-care products, and other contaminants of emerging...

Research at a 1979 crude oil spill from a ruptured pipeline has exposed and helped to overcome many challenges facing an effective, cost-efficient cleanup of crude oil, U.S. Geological Survey (USGS) scientists have found. The environmental release of crude oil occurred near Bemidji, Minnesota.

U.S. Geological Survey (USGS) scientists found that mercury concentrations in shallow waters and methylmercury (MeHg) concentrations in fish in four lakes in Voyageurs National Park, Minnesota, were not consistent with decreases in the wet atmospheric deposition of mercury recorded at nearby monitoring stations for over a decade. Methylmercury is a toxic form of mercury (Hg) that accumulates and...

Animal manure and biosolids, the solid byproduct of wastewater treatment, often are applied to agricultural crops to provide nutrients for plant growth and to improve the quality of soil. Earthworms studied in agricultural fields where manure and biosolids were applied have been found to contain organic chemicals from household products and manure. Earthworms continuously ingest soils and may...

Testing of U.S. streams has detected glucocorticoid and androgen biological activity. In a collaborative study between the National Cancer Institute (NCI), Laboratory of Receptor Biology and Gene Expression, the U.S. Geological Survey (USGS), and others, scientists studied the potential for the biological activity in streams of glucocorticoids and androgens hormones—both potential endocrine...

“Legacy contaminants” and “contaminants of emerging concern” that persist in the environment are affecting the health of fish and wildlife in the Chesapeake Bay and its watershed. State continue to report impaired water resources due to the persistence and toxicity of some previously banned pollutants. In addition, other contaminants of emerging concern are released to the environment at levels...

Chemical contaminants including herbicides, veterinary pharmaceuticals, and biogenic hormones have been detected at fish nesting sites in the Potomac River watershed where endocrine disruption in smallmouth bass ( Micropterus dolomieu ) was also observed. Although these contaminants are known to originate from a variety of human and animal-waste sources, results of a recent U.S. Geological Survey...

Natural processes in stream ecosystems such as dilution and microbial degradation are known to attenuate some contaminants to below levels that can cause harm to ecosystems. However, a team of U.S. Geological Survey (USGS) scientists has shown that many chemicals discharged from municipal wastewater treatment facilities persist for miles downstream at levels known, or suspected, to cause adverse...

Hormones from biosolids applied to fields may be present in rainfall runoff at concentrations that are high enough to impact the health of aquatic organisms if the runoff reaches streams, report scientists from the U.S. Geological Survey (USGS) and Colorado State University in Environmental Science and Technology . Artificial rainfall runoff from agricultural test plots where biosolids were...

A detergent degradation product (4-nonylphenol) and a biogenic hormone (17β-estradiol) added to the Redwood River, Minnesota, were attenuated by biodegradation and other natural processes. These are the findings of a team of U.S. Geological Survey (USGS) and University of Colorado scientists.