Field evaluation of pollution tolerance and stress protein accumulation in grass shrimp

Contaminant-specific stress proteins (CSSPs) have been identified in estuarine organisms as biomarkers of pollutant exposure. This study evaluated ambient levels and cadmium-challenge accumulation of 20 kD and 51 kD CSSPs in grass shrimp, Palaemonetes pugio, collected from nine contaminated or reference sites in Galveston and Lavaca Bays, TX. Grass shrimp from contaminated sites contained significantly higher levels of the 21 kD protein than did those form reference sites, and only shrimp from contaminated sites demonstrated further accumulation of this protein when exposed to the cadmium challenge. The 51 kD protein was higher in shrimp collected from contaminated sites, however this protein was accumulated in all shrimp exposed to cadmium. The 21 kD protein was associated with increased tolerance to the cadmium challenge, whereas the 51 kD protein was not. Results obtained from summer samples did not differ significantly from those obtained during the winter. The roles and usefulness of both of these CSSPs as field biomarkers is being investigated. (DBO)