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Measurement of Pyrethroids and Their Environmental Degradates in Fruits and Vegetables using a Modification of the Quick Easy Cheap Effective Rugged Safe (QuEChERS) Method
Li, W., J. Starr, AND M. Morgan. Measurement of Pyrethroids and Their Environmental Degradates in Fruits and Vegetables using a Modification of the Quick Easy Cheap Effective Rugged Safe (QuEChERS) Method. American Chemical Society National Meeting, Boston, MA, August 16 - 20, 2015.
The National Exposure Research Laboratory (NERL) Human Exposure and Atmospheric Sciences Division (HEASD) conducts research in support of EPA mission to protect human health and the environment. HEASD research program supports Goal 1 (Clean Air) and Goal 4 (Healthy People) of EPA strategic plan. More specifically, our division conducts research to characterize the movement of pollutants from the source to contact with humans. Our multidisciplinary research program produces Methods, Measurements, and Models to identify relationships between and characterize processes that link source emissions, environmental concentrations, human exposures, and target-tissue dose. The impact of these tools is improved regulatory programs and policies for EPA.
Pyrethroid insecticides are used extensively in agriculture and they, as well as their environmental degradates, may remain as residues on food products such as fruits and vegetables. Since pyrethroid degradates can be identical to the urinary markers used in human biomonitoring of pyrethroid exposure, it is important to understand the contribution of these degradates when studying sources of human pyrethroid exposure. We modified a widely used pesticide extraction and clean-up method (QuEChERS) to measure several commonly used pyrethroids (cis/trans-permethrin, cypermethrin, deltamethrin, esfenvalerate, bifenthrin, cyfluthrin, and cyhalothrin) and their degradates (3-PBA, cis/trans-DCCA, 4-F-3-PBA, DBCA, and MPA) in selected fruits and vegetables. We determined extraction efficiencies from: tomatoes, oranges (whole, peeled, peel only), grapes, apples, bananas (peeled, peel only), onions, lettuce, green peppers, carrots and broccoli. For a subset of these items (apples, grapes, tomatoes, lettuce and banana peel), we also established limits of detection and quantitation (LOD/LOQ). Each sample was homogenized then fortified with pyrethroids and degradates. 15 g sub-samples were extracted with acetonitrile, then salted and partitioned with NaCl and MgSO4. The extract was divided and further cleaned using graphitized carbon black (pyrethroids) or C18 (degradates). Sample analysis was via liquid chromatography/tandem mass spectrometry (LC/MS/MS). Considering the mean recoveries each of the 14 analytes in all 13 matrices: 41% of the recoveries were ≥ 90%, 73% were ≥ 80%, and 94% were ≥ 70%. All LOD’s were less than 100 ng/kg, except 3-PBA (132 ng/kg, tomato), MPA (129 ng/kg, tomato), and trans-permethrin (141 ng/kg, banana peel).We applied the method to samples (subset of 5) collected weekly for four weeks from local supermarkets. At least one pyrethroid was present in measureable concentrations in all matrices except banana peels. In contrast the only metabolites detected were cis/trans-DCCA, in one lettuce sample.