|CENTOFANTI, T. - UNIVERSITY OF MARYLAND|
|MCCONNELL, L.L. - UNIVERSITY OF MARYLAND|
|CHANEY, R. - COLLABORATOR|
|BEYER, W.N. - PATUXENT WILDLIFE RESEARCH CENTER|
|ANDRADE, N. - UNIVERSITY OF MARYLAND|
|TORRENTS, A. - UNIVERSITY OF MARYLAND|
|NGUYEN, A. - FORMER ARS EMPLOYEE|
|ANDERSON, M.O. - UNIVERSITY OF MARYLAND|
Submitted to: Environmental Pollution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/23/2015
Publication Date: 12/21/2015
Citation: Centofanti, T., Andrade, N., Mcconnell, L., Hapeman, C.J., Torrents, A., Breyer, W., Chaney, R.L., Nguyen, A., Anderson, M., Novak, J.S., Jackson, D.M., Jackson, D.S. 2015. Organic amendments for risk mitigation of organochlorine pesticide residues in old orchard soils. Environmental Pollution. 210:182-190.
Interpretive Summary: From 1940’s to the late 1970’s, the use of organochlorine pesticides was quite common, especially in orchards. These pesticides are quite persistent, and in some historical orchards, the soil concentration is high enough for the soil to be a potential risk to terrestrial wildlife. Strategies to mitigate these soils, however, are limited and often quite expensive. Thus, methods need to be developed to treat these soils in place and at the same time decrease the exposure risks. In this laboratory study, several composts and biochar were added to historical orchard soils contaminated with the organochlorine pesticides, DDT and dieldrin, to access the potential exposure risk to earthworms and the potential risk to small animals that eat the worms. In some treatments, grass was added. Results showed that the addition of grass and aged manure decreased the potential risks to the terrestrial food chain. This information will be useful in designing lower cost, effective mitigation approaches for soils contaminated with these pesticides.
Technical Abstract: Performance of compost and biochar amendments for in situ risk mitigation of aged DDT, DDE and dieldrin residues in an old orchard soil was examined. The change in bioavailability of pesticide residues relative to an unamended control soil was assessed using Lumbricus terrestris in 4-L soil microcosms with and without plant cover in a 48-day experiment. The use of aged dairy manure compost and biosolids compost was found to be effective, especially in the planted treatments, at lowering the bioavailability factor (BAF) by 18 to 39%; however, BAF results for DDT in the bare soil treatments were unaffected or increased relative to the control. The US EPA Soil Screening Level approach was used with our measured values. Addition of 10% of the aged dairy manure compost reduced the average hazard quotient values to below 1.0 for DDT+DDE and dieldrin. Results indicate this sustainable approach is appropriate to minimize risks to wildlife in areas of marginal organochlorine pesticide contamination.