Abstract

Sediment total organic carbon (TOC) content is considered to be a primary food source for benthic invertebrates and a major factor influencing the partitioning and bioavailability of sediment-associated organic contaminants. Most studies report that both toxicity and uptake of sediment-associated contaminants by benthic organisms are inversely proportional to sediment TOC content. The aim of this study was to determine the importance of the TOC quality for the bioavailability of sediment-associated organic contaminants and the growth of benthic macrofauna. The common infaunal brittle star Amphiura/filiformis was exposed to a base sediment covered by a (14)C-polychlorobiphenyl (3,3'4,4'-(14)C-tetrachlorobiphenyl (TCB)) contaminated top layer (0-2 cm), enriched to the same TOC content with 31 g TOC/m(2) of different quality and origin. The following carbon sources, ranging from labile to refractory, were used: (I) green macroalga (Ulva lactuca), (2) brown macroalga (Ascophyllum nodosum), (3) eelgrass (Zostera marina), (4) phytoplankton (Ceratium spp.), and (5) lignins of terrestrial origin. Characterization of the organic matter quality was accomplished by measuring the content of amino acids, lipids, C, N, and polyphenolic compounds. The reactivity of the sedimentary organic matter was assessed by means of respiration and dissolved inorganic nitrogen flux measurements. The experiment was carried out in I-L glass jars, each containing four brittle stars and the contaminated and enriched sediment. The jars were circulated in a flow-through mode with filtered seawater. Somatic growth (regeneration of a precut arm) and bioaccumulation of (14)C-TCB were measured at 10 sampling occasions during 48 d of exposure. Growth rates, TCB uptake rates, and steady-state concentrations differed significantly between treatments and were correlated to the qualities of the organic substrates. The greatest TCB accumulation and growth were observed in treatments with the most labile organic substrates and the lowest accumulation and growth were seen with the most refractory substrates. Results from this experiment suggest that the bioaccumulation of organic contaminants in benthic infauna is dependent on the nutritional quality of the sedimentary organic matter.

Keywords

arm regeneration; benthos; bioaccumulation; bioturbation; total organic carbon

Published in

Environmental Toxicology and Chemistry
1999, Volume: 18, number: 7, pages: 1534-1543
Publisher: WILEY-BLACKWELL

UKÄ Subject classification

Ecology


Publication identifier

DOI: https://doi.org/10.1897/1551-5028(1999)018<1534:IOSOMQ>2.3.CO;2

Permanent link to this page (URI)

https://res.slu.se/id/publ/42779