RESUMO
The present study investigated the feasibility of the use of the burrowing amphipod Tiburonella viscana for sediment toxicity assessments. The effects of reference toxicants, salinity, sediment particle size, and sediment contamination on amphipod survival were analyzed. The sensitivity of T. viscana to zinc, chromium, and sodium dodecyl sulfate (SDS) in acute tests was similar to that of other crustaceans. The 48-h LC(50) (lethal concentration to 50% of the test organisms in a 48-h exposure) values for T. viscana (95% confidence intervals in parenthesis) were 0.79 (0.56-1.12), 5.85 (4.9-7.0), and 3.41 (2.87-4.04) mg L(-1) for zinc, chromium, and SDS, respectively. The species tolerated salinity as low as 19 ppt under laboratory conditions, indicating its suitability for use in tests with some estuarine sediments. The survival of T. viscana was not affected by grain size in field-collected sediments ranging from 60.6% silt and clay to 95.5% sand, but survival was significantly reduced in laboratory-sieved sediments containing only one or two particle sizes, e.g., only medium and coarse sand, or medium sand, or fine sand, or only fines, suggesting that a mixed grain size distribution is necessary for amphipod survival.