Availability of sediment-absorbed heavy metals to benthos with particular emphasis on deposit-feeding.
Biological laboratory studies were conducted to evaluate the bioavailability of sediment-absorbed heavy metals to benthic invertebrates. For these studies, five test organisms (Rangia cuneata, Palaemonetes kadiakensis, Neanthes arenaceodentata, and Tubifex sp.) were exposed to metal-enriched natural sediments for periods up to six weeks at different salinities. The test sediments came from Texas City and Corpus Christi, Texas ship channels and Ashtabula, Ohio, harbor. The accumulation of eight heavy metals (cadmium, chromium, copper, iron, manganese, nickel, lead, and zinc) by all species and of two metals (mercury and vanadium) by selected species was measured. Statistically significant accumulation of metal from sediment was demonstrated only 36 times (26.5%) out of 136 metal-species-sediment test combinations. Variations in bioaccumulation were observed between species, metals, sediments, and salinities. In these studies, correlation was not observed between accumulation and specific metal forms as determined by selective chemical extraction of test sediments. Bulk metal analyses of the test sediments also did not correlate with metal bioavailability.