Abstract
To protect the aquatic ecosystem, it is important to evaluate the toxicity of contaminated sediments. Moreover, the identification of chemical compounds responsible for the toxicity is needed for effective remediation. In this study, we aimed to identify the principal toxicants of urban river sediments, applying Toxicity Identification Evaluation (TIE) methods to the toxicity test with an ostracod (a benthic crustacean). The toxicity test was conducted using sediments amended with three adsorbents: Zeolite, Chelex-100 and Ambersorb-572. Four of the nine urban river sediment samples showed lethal toxicity to the ostracod, but none of the three adsorbents reduced the mortality of the ostracod. Growth inhibition was observed in all the samples; however, the addition of the carbonaceous adsorbent Ambersorb-572 suppressed the growth inhibition in the 6 samples. This indicates that hydrophobic substances in the sediments inhibit the growth of the ostracod.
