@article{henson-ramsey_schneider_stoskopf_2011, title={A Comparison of Multiple Esterases as Biomarkers of Organophosphate Exposure and Effect in Two Earthworm Species}, volume={86}, ISSN={["0007-4861"]}, DOI={10.1007/s00128-011-0236-9}, abstractNote={Two different earthworm species, Eisenia fetida and Lumbricus terrestris, were exposed to 5 μg/cm2 of malathion to evaluate their usefulness as sentinels of organophosphate exposure and to assess three different esterases, as biomarkers of malathion exposure and effect. Tissue xenobiotic burdens and esterase activity were determined for each species and each esterase in order to assess variability. E. fetida exhibited 4-fold less variability in tissue burdens than did L. terrestris and had less variable basal esterase activities. An attempt was made to correlate malathion and malaoxon tissue burdens with esterase activity post-exposure. There was no malaoxon present in the earthworm tissues. No significant correlations were determined by comparing acetylcholinesterase, butyrylcholinesterase, nor carboxylesterase activities with malathion burdens.}, number={4}, journal={BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY}, author={Henson-Ramsey, Heather and Schneider, Ashley and Stoskopf, Michael K.}, year={2011}, month={Apr}, pages={373–378} }
 @article{henson-ramsey_kennedy-stoskopf_levine_taylor_shea_stoskopf_2008, title={Acute toxicity and tissue distributions of malathion in Ambystoma tigrinum}, volume={55}, ISSN={["1432-0703"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-51849109593&partnerID=MN8TOARS}, DOI={10.1007/s00244-007-9091-4}, abstractNote={The kinetics of the bioaccumulation of malathion (O,O-dimethyl phosphorodithioate of diethyl mercaptosuccinate) and the biological impact of exposure for tiger salamanders, Ambystoma tigrinum, were assessed through exposure to soil surface contaminated with 50 microg/cm(2) or 100 microg/cm(2 )malathion and ingestion of an earthworm exposed to soil contaminated with 200 microg/cm(2) malathion. Malathion and malaoxon burdens in salamanders sampled at different times after exposure(s) were measured by gas chromatography in four tissue/organ subgroups: liver, epaxial muscle, pooled viscera (except the liver and brain), and pooled avisceral carcass (muscle, skin, and bone). The total tiger salamander xenobiotic burdens were calculated from these data. The malathion/malaoxon burden 1 day after exposure was greatest in the avisceral carcass and 2 days after exposure was greatest in the viscera. Bioconcentration and bioaccumulation factors remained less than unity throughout the experiment and did not support the hypothesis of bioaccumulation of malathion in the tiger salamander. Biological impact was assessed with a colorimetric brain cholinesterase microassay. Brain cholinesterase activities in salamanders exposed to malathion-contaminated soil (50 microg/cm(2) or 100 microg/cm(2 )malathion) were suppressed approximately 50-65% and 90%, respectively, compared to unexposed controls. The exposed animals did not exhibit overt clinical signs of malathion toxicosis.}, number={3}, journal={ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY}, author={Henson-Ramsey, H. and Kennedy-Stoskopf, S. and Levine, J. F. and Taylor, S. K. and Shea, D. and Stoskopf, M. K.}, year={2008}, month={Oct}, pages={481–487} }