Use of nonpolar resin for reduction of fluoranthene bioavailability in sediment

The objective of our study was to evaluate the effectiveness of Ambersorb(R ) 1500, a carbonaceous resin, for reducing the bioavailability of polycycli c 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 whe n 0.1 g of unconditioned resin was added to 500-ml solutions containing 160 mu g/L fluoranthene. Within 48 h, concentrations decreased by more than 92 %. Addition of Ambersorb to fluoranthene-spiked sediment showed similar red uctions of fluoranthene concentrations in pore water. Based on these initia l results, a 10-d bioaccumulation/toxicity experiment was conducted in whic h the oligochaete Lumbriculus variegatus was exposed to fluoranthene-spiked sediment with and without resin. Chemical analyses showed that sediment am ended with resin had greatly diminished pore-water fluoranthene concentrati ons compared with sediment without resin. Proportional reductions in whole- body fluoranthene concentrations were observed in oligochaetes exposed to r esin-amended sediments. As would be expected from enhancement of fluoranthe ne toxicity by ultraviolet light, organisms exposed to fluoranthene-spiked sediment exhibited significant mortality upon subsequent exposure to ultrav iolet light. Consistent with their lower body burdens, organisms from resin -treated sediment lacked this sensitivity (100% survival). These experiment s demonstrate that Ambersorb 1500 effectively reduces the bioavailability o f fluoranthene in spiked sediment. Additional studies are needed to define the boundaries of the resin's effectiveness in influencing the bioavailabil ity of other PAHs and nonpolar organic chemicals in spiked and field-contam inated sediments.