“Interlaboratory Calibration Comparisons for Pulsed Exposure Toxicity Testing” by Ms. Marienne Colvin (ESTCP Project ER-201727)
Department of Defense (DoD) facilities are regularly required to conduct toxicity tests where test organisms are exposed to stormwater samples for 96-hours or longer despite the stormwater events often lasting less than 24-hours. The DoD needs environmentally-relevant, scientifically-defensible, and conservative toxicity test designs to assess potential for receiving water impacts from episodic discharges (e.g., stormwater, dry-dock discharges, etc.). The existing whole effluent toxicity test methods, which were developed to assess continuous point source discharges, are typically also used for episodic discharges. These methods, however, do not adequately reproduce discharge conditions at the point of compliance or where the discharge mixes with the receiving environment, and often overestimate toxicity at a given site.
To better test the toxicity of episodic discharges, pulsed toxicity tests expose the test organisms to end-of-pipe samples temporarily and then transfer organisms to clean laboratory water or receiving water for the remainder of the standard test period. This project developed and validated pulsed toxicity testing that requires minimal modification to the standard methods, but more accurately reproduces the environmental conditions to protect the beneficial uses of the receiving waters. This presentation summarized results from an Interlaboratory Calibration Study conducted to assess the modified pulsed toxicity methodology. The study also evaluated the consistency among labs in performing the modified test procedure and meeting the standard method test acceptability.
“Rapid-flow Engineered Media Filters to Prevent Sediment Contamination from Stormwater” by Dr. Richard Luthy (SERDP Project ER18-1145)
This project aimed to treat stormwater runoff through the design of rapid-flow engineered media filters for use at DoD facilities and, more broadly, in urban settings. Stormwater capture, treatment, and recharge can also be used to boost the water supply in drought-prone regions. The presentation described long-term testing of engineered filter media for contaminant removal from stormwater runoff and the development of filter performance curves with kinetic and flow-rate design parameters. Replicate column tests with a suite of contaminants and background dissolved organic carbon were conducted at 20, 40, and 60 cm/hr, which are flow rates applicable to a full-scale design. Synthetic stormwater was generated using stormwater catchment-basin material from a Navy site and augmented with naturally-sourced dissolved organic carbon and a suite of contaminants including six metals, twenty-one hydrophilic and hydrophobic organic compounds, and perfluorochemicals from an aqueous film-forming firefighting foam. The results showed that media containing high-temperature gasification biochar or regenerated activated carbon are remove both hydrophobic and hydrophilic organic contaminants. The test data suggested that hydrophilic organic contaminant mixtures in concentrations of several micrograms per liter may be controlled effectively for several thousand bed volumes or more with flow control and particle management to prevent clogging.
Ms. Marrienne Colvin is an aquatic toxicologist and manager of the Naval Information Warfare Center Pacific Bioassay Laboratory in San Diego, California. She has over 15 years of experience designing and leading a wide variety of field and laboratory-based ecotoxicology studies. With a general focus on marine ecotoxicology, Ms. Colvin conducts basic and applied research in support of improved site characterization and management of contaminated discharges, surface waters, and sediments. Several of her research projects are funded by SERDP and ESTCP and the Navy’s Environmental Sustainability Development to Integration (NESDI) Program. Her research focuses on understanding the bioavailability and toxicity of DoD-relevant contaminants to biota. In addition, Ms. Colvin works on developing better ecological risk assessment tools, technologies and methods. Ms. Colvin received a bachelor’s degree in ecology, behavior and evolutionary biology from the University of California, San Diego and a master’s degree in ecology from San Diego State University.
Dr. Richard G. Luthy is the Silas H. Palmer Professor of Civil and Environmental Engineering at Stanford University, California. He is the Director of the National Science Foundation (NSF) Engineering Research Center for Re-inventing the Nation’s Urban Water Infrastructure (ReNUWIt) that seeks more sustainable solutions to urban water challenges. Dr. Luthy’s area of teaching and research is environmental engineering and water quality with applications in water reuse, stormwater use, and systems-level analysis of urban water challenges. His research addresses organic contaminants and contaminants of emerging concern in both engineered and natural systems. He is a member of the National Academy of Engineering. Dr. Luthy earned a bachelor’s degree in chemical engineering and master’s and doctoral degrees in civil engineering at the University of California, Berkeley. He also received a master’s degree in ocean engineering at the University of Hawaii, Honolulu.