PARENT SESSION
TP7 - Water Quality Criteria
Chair: Canton, Steve1, 1 Chadwick Ecological Consultants, Littleton, CO
2:10 PM to 5:30 PM - Tuesday, 19 November 2002
Room Ballroom A
(460) Toxicological Endpoints: Are Sublethal Effects and Other Nonstandard Endpoints More Sensitive?
Cardwell, Rick*,1, Coyner, Angela2, DeForest, David2, Wisdom, Charles2, Wirtz, Jeffrey1, 1 Parametrix, Inc., Corvallis, OR, USA2 Parametrix, Inc., Kirkland, WA, USA
ABSTRACT- We addressed the question of whether sublethal effects and other nonstandard toxicological endpoints used in acute and chronic toxicity tests were more sensitive than standard endpoints (i.e., growth, immobilization, mortality and reproductive success). The results were evaluated with respect to protection of aquatic communities of species, protection of endangered salmon and trout, and water quality criteria. The EPA database ecotox constituted the source of toxicity data for acrolein, cadmium, copper, 2,4-D, 2,4-dichlorophenol, diazinon, malathion, methoxychlor, nonylphenol, tributyltin and trichloromethane. These were chosen in part to represent a variety of modes of action. Endpoints were segregated into nonstandard and standard, acute (≤96 hr) and chronic (>96 hr)exposures. Data for fish and invertebrates were used except for inclusion of plant data for herbicides. Otherwise, all toxicity data were used as is, although questionable data are identified and discussed. From these datasets, species sensitivity distributions (SSDs) were constructed. The analysis showed that standard chronic endpoints generally were the most sensitive, but that a combination of standard and nonstandard chronic endpoints may provide a similar level of protection as the traditional approach used in the U.S. to derive water quality criteria. In fact, the lowest acute and chronic endpoints, standard and nonstandard, were very similar to each other and to water quality criteria. In all cases, salmon and trout appeared to be protected by the most sensitive standard endpoint. Similarities and dissimilarities between SSDs are discussed with respect to endpoints, acute-chronic ratios, and water quality criteria derivation methodologies
Key words: endpoints, sensitivity, water quality criteria, toxicity