Technical Notes ro A Chronic Sublethal Sediment Bioassay with the Marine

This note provides a general overview of a new 28-day chronic sublethal sediment bioassay designed for the regulatory evaluation of dredged material. The bioassay uses survival and growth rate endpoints with the polychaete Nereis (Neanthes) arenaceodentata. The primary technical reference for this new bioassay is Dillon, Moore, and Reish (in press), upon which this overview is based. Background Sediment bioassays are used to assess the aggregate toxicity of sediment-associated anthropogenic chemicals. Historically, these bioassays have mea-sured survival of highly sensitive species following acute exposures (10 days). A new generation of sediment bioassays is being developed in which the sub-tle, sublethal response of test species is measured following chronic sediment exposures (Dillon 1993). This sediment bioassay was developed for the regulatory evaluation of dredged material under section 103 of the Marine Protection, Research, and Sanctuaries Act of 1972 (Public Law (PL) 92-532) and section 404(b)(1) of the Federal Water Pollution Control Act of 1972 (PL 92-500), as amended. The bio-assay, which utilizes both survivorship and growth endpoints, was designed specifically to assess the toxicity of bedded sediments. Research and test devel-opment were targeted for eventual use by the commercial bioassay contracting community. Thus, great emphasis was placed on logistical feasibility, practi-cality, and low capital start-up and operating costs.