Comparison of porewater and elutriate bivalve larval development toxicity testing in a sediment quality triad framework

Concurrent porewater (PW) and elutriate (ELU) toxicity testing using newly fertilized larvae of the bivalve Mytilus galloprovincialis was conducted as part of sediment quality triad (SQT) investigations for urban harbor locations. PW samples were consistently more toxic to bivalve larvae than the corresponding ELU sample, including samples collected from uncontaminated reference locations. Ammonia was identified as the most likely toxic agent. EC20 and EC50 values of 0.028 and 0.036 mg/L un-ionized N, respectively, were determined for M. galloprovincialis. The limitations of incorporating PW bivalve larval development toxicity tests using M. galloprovincialis for routine SQT investigations, as well as possible alternative methods, are discussed.