Pulsed Toxicity Exposure Methodology Summary of Results: Interlaboratory Calibration Exercise
Abstract
Episodic discharges (e.g. stormwater, dry-dock discharges, and pesticide applications, etc.) require environmentally-relevant, scientifically-defensible, and conservative toxicity test designs to assess potential for receiving water impacts. Currently, permittees in highly industrialized areas are regularly required to conduct 96-hour (or longer) toxicity tests on discharges associated with events that are often less than 24 hours in duration. Existing EPA whole effluent toxicity (WET) test methods developed to assess continuous point source discharges are now being applied to episodic discharges as well. However, these methods do notadequately reflect episodic discharge conditions at either the point of compliance (i.e. storm drain) or as it mixes with the receiving environment (e.g. a riverine or marine system), which can result in an overestimation of toxicity at a given site. In order to capture representative toxicity at a site, an alternative toxicity test approach is described, incorporating pulsed exposures to end-of-pipe samples. Following pulsed exposures, organisms are transferred to uncontaminated seawater (or receiving water) for the remainder of standard test period. This presentation presents the results of an Interlaboratory Calibration Study conducted in order to assess the ability of the modified methodology to provide consistent and defensible data for the assessment of episodic discharges. The study characterized 1) Completion Rate; 2) False Positive Rate; and 3) Precision on three WET methods that were modified for pulsed exposures and included acute tests with Ceriodaphnia dubia and Americamysis bahia and the larval development/short-term chronic test using Strongylocentrotus purpuratus.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 2021
- Accession Number
- AD1152337
Entities
People
- B. C. Stransky
- Gunther H. Rosen
- Jeff Vanvoorhis
- Molly A. Colvin
- Nicholas T. Hayman
- Steve Carlson
Organizations
- Naval Information Warfare Center Pacific