|ANDRADE, N. - University Of Maryland|
|CENTOFANTI, T. - University Of Maryland|
|MCCONNELL, L.L. - University Of Maryland|
|TORRENTS, A. - University Of Maryland|
|BEYER, W.N. - Us Geological Survey (USGS)|
|ANDERSON, M.O. - University Of Maryland|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 7/1/2014
Publication Date: 8/10/2014
Citation: Andrade, N., Centofanti, T., Mcconnell, L., Hapeman, C.J., Torrents, A., Nguyen, A., Beyer, W., Chaney, R.L., Novak, J.S., Anderson, M., Cantrell, K.B. 2014. Utilizing thin-film solid-phase extraction to assess the effect of organic carbon amendments on the bioavailability of DDT and dieldrin to earthworms [abstract]. American Chemical Society. AGRO 351.
Technical Abstract: Improved approaches are needed to rapidly and accurately assess the bioavailability of persistent, hydrophobic organic compounds in soils at contaminated sites. The performance of a thin-film solid-phase extraction (TF-SPE) assay using vials coated with ethylene vinyl acetate polymer was compared to an earthworm bioassay (Lumbricus terrestris). Experiments utilized, as a control, contaminated soil from a former orchard that received routine DDT and dieldrin applications >40 years ago. The soil was amended with four different organic carbon materials at 5% by weight to assess the change in pesticide bioavailability. In both assays, bioavailability of 4,4'-DDE, 4,4'-DDD, and dieldrin was higher than 4,4'-DDT in the control soil. Addition of organic carbon amendments significantly lowered bioavailability for all compounds except for 4,4'-DDT where bioavailability was significantly higher for three out of four amendments. Equilibrium concentrations of dieldrin and 4,4'-DDT + 4,4'-DDE in the polymer coating were strongly correlated with uptake by earthworms after 48 d exposure (R2 = 0.97; p < 0.001) indicating TF-SPE provided an accurate simulation of uptake by L. terrestris. In a further test of the TF-SPE method, estimated bioavailability of dieldrin and DDX residues in the orchard soil was compared with a soil that was spiked with the same compounds and aged for 90 days in the laboratory. Differences in residue bioavailability in the two soils were observed using TF-SPE. Dieldrin and DDX were only 18% and 11% less bioavailable, respectively, in the orchard soil relative to the spiked soil despite >40 years of aging. Results show that TF-SPE will be a useful tool in examining the potential risks associated with contaminated soils and to test the effectiveness of remediation efforts.