Mary Ann Rempel-Hester, PhD

Senior Aquatic Toxicologist

Mary Ann is a senior aquatic toxicologist based in EcoAnalysts’ Port Gamble, Washington office. She has over 25 years of experience that has varied from toxicological assessment of water and sediments to ecological investigations of underwater habitats near wastewater outfalls and collection of fisheries data. She has conducted every step of sediment contamination assessments, from developing the conceptual site model of the fate and transport of contaminants, through sampling and analysis planning, execution, reporting and interpretation, including phase I risk assessments for human and ecological receptors. She has extensive experience determining the toxicity of wastewater, stormwater, and water treatment products to aquatic organisms under the Clean Water Act. She has performed literature reviews for projects involving biofouling regulation development, Net Environmental Benefit Analysis, state-of-the-science reviews for marine toxicology, and research in endocrine-disrupting effects in fish. She also acted as the Toxicology Part Coordinator for Standard Methods for the Examination of Water and Wastewater, which publishes internationally used protocols to standardize measurement of chemical and biological contamination of water.

Areas of toxicology expertise include investigating sources of toxicity and the effects of site conditions on the availability and toxicity of chemicals. Past projects include toxicity identification evaluations to determine the source of toxicity in several municipal effluents to both salt and freshwater organisms, water-effects-ratio studies to determine the site-specific toxicity of copper and ammonia to help inform water quality standards, and identifying and minimizing transient toxicity caused by placing freshwater sediments under marine conditions. She has also assessed the difference in response to estrogen exposure of fish acclimated to polluted conditions versus those from more pristine conditions.

Education 

B.A. Biology
University of Puget Sound

Ph.D. Environmental Toxicology
University of California