USE OF NONPOLAR RESIN FOR REDUCTION OF FLUORANTHENE BIOAVAILABILITY IN SEDIMENT

Abstract

The objective of our study was to evaluate the effectiveness of Amersorbb® 1500, a carbonaceous resin, for reducing the bioavailability of polycyclic aromatic hydrocarbons (PAHs) in sediment. Initial studies were conducted with a model PAH, fluoranthene, to determine how effective the resin would be at reducing fluoranthene concentrations in water and sediment pore water. Fluoranthene concentrations were reduced by more than 70% within 24 h when 0.1 g of unconditioned resin was added to 500-ml solutions containing 160 μg/L fluoranthene. Within 48 h, concentrations decreased by more than 92%. Addition of Ambersorb to fluoranthene-spiked sediment showed similar reductions of fluoranthene concentrations in pore water. Based on these initial results, a 10-d bioaccumulation/toxicity experiment was conducted in which the oligochaete Lumbriculus variegatus was exposed to fluoranthene-spiked sediment with and without resin. Chemical analyses showed that sediment amended with resin had greatly diminished pore-water fluoranthene concentrations compared with sediment without resin. Proportional reductions in whole-body fluoranthene concentrations were observed in oligochaetes exposed to resin-amended sediments. As would be expected from enhancement of fluoranthene toxicity by ultraviolet light, organisms exposed to fluoranthene-spiked sediment exhibited significant mortality upon subsequent exposure to ultraviolet light. Consistent with their lower body burdens, organisms from resin-treated sediment lacked this sensitivity (100% survival). These experiments demonstrate that Ambersorb 1500 effectively reduces the bioavailability of fluoranthene in spiked sediment. Additional studies are needed to define the boundaries of the resin's effectiveness in influencing the bioavailability of other PAHs and nonpolar organic chemicals in spiked and field-contaminated sediments.