Toxicity of East Sumatra River Sediments – Bacterial Luminescence,Brine Shrimp and Acetylcholinesterase Inhibition Tests

Abstract

Bioassays employing the luminescent bacterium Vibrio fischeri (LUMIStox system), the brine shrimp (Artemia salina) as well as the acetylcholinesterase inhibition test were used to evaluate sediment toxicity of surface sediments from five East Sumatra rivers. In March and November of 2008 samples were collected from Rokan, Siak, Kampar, Indragiri and Musi rivers from overall 52 stations. The sediments were extracted with a sediment/water ratio of 1:1 (w/v). The most toxic sediments were found at the stations 529 (Kampar), 543 (Musi) as well as 517 (Siak) during the November 2008 campaign. Of the bioassays employed in this study, the acetylcholinesterase inhibition test was the most responsive to the extracts (EC $_{50}$ : 0.4 ± 0.1 to 1.02 ± 0.3 g/L), whereas the invertebrate lethality assay using Artemia salina was less sensitive (EC $_{50}$ : 6.1 ± 0.6 to 9.3 ±; 0.4 g/L). While it was not possible to correlate the observed ecotoxicological effects with a specific and/or class of contaminants it is notable that the Siak sediment extracts were consistently ranked the most toxic with all test species and all test phases.