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Mobility of pesticides in water, sediment, plants and soils, including soil columns

Understanding mobility of pesticides is an important part of environmental toxicology and chemistry. Pesticides need to be mobile enough to allow them to be transported to the site of action. On the other hand, pesticides that are too mobile will rapidly dissipate once applied to the target area and contaminate water and sediment. Many factors can affect the mobility of pesticides in soil and water including soil characteristics, pesticide properties, and timing of application.

Picture of a soil column experiment. The packed soil column is placed vertically in a formulated insecticide which moves up the column through capillary action, to determine how far a pesticides will travel in soil.Research in the lab has primarily focused on the transport of herbicides and their metabolites through soil profiles and into groundwater and surface water bodies. Recent research has focused on testing various formulations for their ability to increase the mobility of insecticides. Using formulations to increase mobility is essential for ensuring that insecticides are capable of moving through the soil to reach the habitats of ground-dwelling insect pest such as termites.

 

Some relevant publications:

Zhao, S., J.B. Belden, J.H. Cink, and J.R. Coats. 2010. Mobility of five termiticides in soil columns. Chapter in Proceedings of the 2010 NCUE. NCUE, Portland, OR, pp 169-174

Arthur, E.L., P.J. Rice, P.J. Rice, T.A. Anderson, and J.R. Coats.  1998.  Mobility and degradation of pesticides and their degradates in intact soil columns, Chapter 7 in Environmental Behavior of Pesticides:  The Lysimeter Concept.  F. Führ, J. Plimmer, R. Hance, and J. Nelson, eds.  American Chemical Society, Washington, D.C. pp. 88-114.

Kruger , E.L., B.  Zhu, and J.R. Coats. 1996. Relative mobilities of atrazine, five atrazine degradates, metolachlor, and simazine in soils of Iowa.  Environ. Toxicol. Chem. 15: 691-695.

Kruger, E.L., P.J. Rice, J.Anhalt, T.A. Anderson, and J.R. Coats. 1996. Use of undisturbed soil columns under controlled conditions to study the fate of [14C]deethylatrazine, J. Agric. Food Chem. 44: 114-1149.

Somasundaram, L., J.R. Coats, V.M. Shanbhag, and K.D. Racke. 1991. Mobility of pesticides and their hydrolysis metabolites in soil. Environ. Toxicol. Chem. 10: 185-194.

Fate of transgenic insecticides in soil and water, including insecticidal Bt protein toxins and vaccines

In recent years, transgenic crops have increased significantly in their usage in agriculture. Many of these crops produce insecticidal Bt proteins that target specific insect pests. As with conventional chemicals, it is important to know the fate of these insecticidal Bt proteins in the environment. The fate data is used in the risk assessment process to determine potential exposure of the insecticidal Bt proteins to non-target organisms.

Picture of a typical ELISA plate.Prior work in the lab has focused on the fate of some of these insecticidal Bt proteins in aquatic and soil microcosm. Current work in the lab aims to improve detection of these insecticidal Bt proteins in environmental samples with enzyme-linked immunosorbent assays (ELISAs), to ensure that only intact, bioactive proteins are being detected.

Double-stranded RNA (dsRNA) is the future of transgenic insecticides. Double-stranded RNA kills insects by inducing RNA interference (RNAi) pathways to inhibit gene expression. The lab plans to being studying the fate of these dsRNA molecules in aquatic environments.

 

Some relevant publications:

Prihoda, K, and J.R. Coats. 2008. Fate of Bacillus thuringiensis (Bt) Cry3Bb1 protein in a soil microcosm. Chemosphere 73: 1102-1107.

Prihoda, K., and J.R. Coats. 2008. Aquatic fate and effects of Bacillus thuringiensis Cry3Bb1 protein: Toward risk assessment. Environ. Toxicol. Chem. 27: 793-798.

Kosaki, Hirofumi, Jeffrey. D. Wolt, Kan Wang, and Joel Coats. 2008. Subacute effects of maize-expressed vaccine protein, Escherichia coli heat-labile enterotoxin subunit B (LTB), on the springtail, Folsomia candida and the earthworm, Eisenia fetida. J. Agric. Food Chem. 56: 11342-11347.

Clark, B.W., K.R. Prihoda, and J.R. Coats. 2006. Subacute effects of transgenic Cry1Ab Bacillus thuringiensis corn litter on the isopods Trachelipus rathkii and Armadillidium nasatum. Environ. Toxicol. Chem. 25(10): 2653-2661.

Clark, B.W., T.A. Phillips, and J.R. Coats. 2005. Environmental fate and effects of Bacillus thuringiensis (Bt) proteins from transgenic crops: a review. J. Agric. Food Chem. 53(12):  4643-4653.

Bioassays for testing insecticides against arthropod pests

We perform various bioassay tests for various companies and agencies to quantify the ability of new insecticidal formulations to kill and repel a wide array of arthropod pest species. Some of the species we utilize in our testing includes, but is not limited too: house flies, cockroaches, ticks, bed bugs, mosquitoes, fleas, crickets, corn rootworms, corn borers, cutworms, aphids, and spider mites. The fees for service, as well as the types of testing to be performed, are negotiated via a contract basis.

Photograph of an insecticide being applied to a mosquito with a needlePhotograph of toxicity testing for a commercial product against crickets

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