Bioassays

Cyanobacterial bloom magnitude during 2003–11 was quantified and ranked in Florida and Ohio lakes with a newly developed modelling tool that allows for the use of multiple satellite data sources and user-defined thresholds. This tool was designed to identify the magnitude of algal blooms, but one metric alone cannot adequately represent the severity of a bloom of interest in terms of toxicity. The...

Refinement of the existing national-scale “de facto reuse incidence in our nation’s consumable supply” (DRINCS) model, complemented by field measurements, provides a screening tool to understand human and wildlife exposure to toxicants and pathogens associated with the incidental reuse of treated wastewater in the Shenandoah River watershed. The model results can be accessed in a companion web...

Raised black lesions observed in 30 percent of the brown bullhead collected from two sites in Lake Memphremagog from 2014 through 2017 were identified microscopically as malignant melanoma. Malignant melanoma in freshwater fishes has been reported before, but this cancer occurrence cluster is raising questions about the cause of the tumors and the implications for the long-term health of fish...

Science from the U.S. Geological Survey (USGS) and other entities has shown that a mixture of natural and synthetic estrogens and other similar chemicals are discharged from wastewater treatment plants (WWTPs) to streams and rivers.

The Fishing, Hunting, and Subsistence Living Integrated Science Team focuses on contaminant and pathogen exposures in the environment that could impact the presence and vitality of fish and wildlife populations that drive commercial, recreational and subsistence activities such as hunting and fishing. If actual risks are identified this project will inform how to economically and effectively...

Scientists optimized existing endocrine active chemical screening tests to improve their precision, accuracy, and ability to screen more samples in a shorter time-frame. The optimization was done to more rapidly obtain results from the bioassays so that research on the risks of endocrine active chemical exposure can proceed more rapidly.

The Chesapeake Bay is the largest estuary in the United States and provides critical resources to fish, wildlife and people. For more than a decade, recreational fish species have been plagued with skin lesions and intersex conditions (the presence of male and female sex characteristics in the same fish) that biologists attributed to exposures to endocrine disrupting chemicals (EDCs)...

A riparian zone rich in terrestrial insects can provide an alternate food source for fish in metal-impacted watersheds.

U.S. Geological Survey (USGS) scientists developed 129 sediment-toxicity benchmarks for use in evaluating currently used pesticides in whole sediment.

Estrogens are recognized as modulators of immune responses in mammals, but how these effects might occur in fish was not understood. U.S. Geological Survey (USGS) scientists published findings that fish white blood cells (leukocytes) have specific estrogen receptors (ERs)—a discovery that moves scientists one step closer to understanding the connection between exposure to estrogenic substances and...

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...