PARENT SESSION
PS13 - Risk Assessment of Non-Chemical Stressors
Sunday, 17 November 2002
8:00 AM to 6:30 PM
Exhibit Hall
(P135) Total Suspended Solids - Aquatic Risks on a Cross-Section of Natural Waters.
Volosin, Joe*,1, Cardwell, Rick1, 1 Parametrix, Inc., Kirkland, WA, USA
ABSTRACT- This study examined the effects of total suspended solids on aquatic communities. Total suspended solids (TSS) is one of many non-chemical stressors that potentially affect aquatic communities. Effects may include, for example, gill abrasion and impaired visual-feeding. A database of predicted acute and chronic no effect concentrations (PNECs) was developed for TSS based on the scientific literature. The relationship between exposure duration and measured response was evaluated for individual species as well as for communities of species. Laboratory and field data were very comparable. Because the tests were conducted using many different exposure durations, the PNECs were normalized for exposure duration. However, the relationship between exposure duration and effects for all species tested appears weak (R2 = 36%). Finally, to judge reliability, laboratory based and field based PNECs were very comparable, when normalized to exposure duration. Species sensitivity distributions for acute and chronic PNECs and predicted exposure concentrations (PEC) from various sites in the United States, based on long-term and stormwater monitoring, were used to evaluate the probability of risk to aquatic communities based on different assumptions concerning exposure durations.
Key words: non-chemical stressors, total suspended solids, probabilistic risk assessment, aquatic life