SAND SPIKED WITH COPPER AS A REFERENCE TOXICANT MATERIAL FOR SEDIMENTTOXICITY TESTING - A PRELIMINARY EVALUATION

Routine use of solid-phase sediment toxicity tests for scientific and regulatory purposes necessitates the development of solid-phase refere nce toxicant materials. In order to evaluate an approach for developin g such materials, 12 solid-phase 96-h reference toxicant tests were co nducted over 12 weeks with the marine bivalve Mulinia lateralis. Refer ence toxicant material was clean muffled sand spiked with copper used in a conventional dilution series with unspiked sand as the diluent. C ontrol survival ranged from 92 to 100% and during the exposure weights increased by a factor of about 3 relative to initial weights. Measure d concentrations of copper in the water column above the reference mat erial during testing showed that the toxicant exposures were relativel y consistent between tests. Coefficients of variation (CV) for mortali ty and sublethality (growth) endpoints were 39% and 42%, respectively. Coefficients of variation for other solid-phase reference toxicant ma terial studies do not exist, but comparison of the results of this stu dy with water-only literature values are favorable. Values for CVs in the literature range from 4 to 120% and 2 to 48% for acute and subleth al endpoints, respectively, for water column organisms and about 45% f or an acute test using the marine amphipod (Ampelisca abdita). This ev aluation demonstrates that use of sand spiked with copper is a credibl e approach for developing a solid phase reference toxicant material; h owever, further development is required to reduce both biological and chemical sources of variability.