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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Adaptive Cropping Systems Laboratory » Research » Publications at this Location » Publication #326094
Title: Assessment of trace element accumulation by earthworms in a DDT remediation study

Author
item CENTOFANTI, TIZIANA - University Of Maryland
item Chaney, Rufus
item BEYER, W - Us Geological Survey (USGS)
item MCCONNELL, LAURA - Bayer Cropscience
item DAVIS, ALLEN - University Of Maryland
item Jackson, Dana

Submitted to: Journal of Water Air and Soil Pollution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/17/2016
Publication Date: 8/31/2016
Citation: Centofanti, T., Chaney, R.L., Beyer, W.N., Mcconnell, L.L., Davis, A.P., Jackson, D.S. 2016. Assessment of trace element accumulation by earthworms in a DDT remediation study. Journal of Water Air and Soil Pollution. 227(9):350. https://doi.org/10.1007/s11270-016-3055-0.
DOI: https://doi.org/10.1007/s11270-016-3055-0

Interpretive Summary: We conducted a microcosm test of whether incorporation of organic amendments could reduce the bioaccumulation by earthworms (common nightcrawler, Lumbricus terrestris ) of DDT and related compounds from a contaminated orchard soil at the Beltsville Agricultural Research Center, Beltsville, MD. Because organic matter can strongly adsorb such organic compounds, we found that incorporated manure and biosolids composts could significantly reduce the bioaccumulation of DDT compounds, and the results are accepted for publication. Because trace element bioaccumulation by earthworms is a separate concern about contaminated orchard soils, we measured common trace elements which contaminated the soils, or were added in the soil amendments. We tested microcosms with and without orchardgrass or perennial ryegrass cover and analyzed the plants as well as the earthworms. Because birds ingest earthworms with soil still in the digestive tract, we did not purge soil before analysis. The soil was significantly contaminated with Pb from orchard sprays. Adding the composts significantly reduced Pb accumulation by the plant shoots, but other elements remained within normal concentrations. Lead in the earthworms was somewhat reduced by one manure compost, but the other treatments did not alter work lead or other elements. From these studies we conclude that addition of manure and permitted quality biosolids composts to DDT contaminated soils to alleviate the risk of DDT bioaccumulation by earthworms has no adverse effect on trace element residues in the earthworms.

Technical Abstract: In this study, organic amendments were used to remediate an orchard field soil contaminated with organochlorine and Pb pesticide residues. Organic amendments can enhance the metabolic activity of microorganisms and chemically complex the contaminants but they can also introduce further contamin ation (trace elements), depending on the quality and source of the amendments and the chemistry of the contaminated soil. This study assessed potential bioaccumulation of various trace elements in grasses and earthworms as a consequence of soil incorporation of organic amendments for in situ remediation. In this experiment, four organic amendments of differing total organic carbon content and quality (two types of composted manure, composted biosolids, and biochar) were added to a contaminated orchard field soil, planted with two types of grasses, and tested for their ability to reduce bioaccumulation of organochlorine pesticides in earthworms. The experiment was carried out in 4-L soil microcosms in a controlled environment for 90 days. After 45 days of orchardgrass or perennial ryegrass growth, Lumbricus terrestris L. was added to the microcosms and exposed to the soil mix for 45 days before the experiment was ended. Total trace elements concentrations in the added organic amendments were below recommended safe levels and their bioavailability remained low during a 90 day bioremediation study. At the end of the experiment, total tissue concentrations of Cu, Cd, Mn, Pb, and Zn in earthworms and grasses were below recommended safe levels. Total concentrations of Pb in field soil were similar to maximum background levels of Pb recorded in soils in the Eastern U.S. (100 mg/kg d.w.) because of previous application of pesticides. Addition of aged dairy manure and presence of grasses were most effective in reducing the accumulation of soil derived Pb in earthworms, thus reducing the risk of Pb entry into wild life food chains.