%0 Journal Article %J Xenobiotica %D 2011 %T Organophosphorus pesticide degradation product in vitro metabolic stability and time-course uptake and elimination in rats following oral and intravenous dosing. %A Norman D Forsberg %A Rodriguez-Proteau, R %A Ma, L %A Morré, J %A Christensen, J M %A Maier, C S %A Jeffrey J Jenkins %A Kim A Anderson %K Administration, Oral %K Animals %K Environmental Monitoring %K Humans %K Injections, Intravenous %K Male %K Mass Spectrometry %K Organophosphorus Compounds %K Pesticides %K Rats %K Rats, Sprague-Dawley %K Time Factors %X

Levels of urinary dialkylphosphates (DAPs) are currently used as a biomarker of human exposure to organophosphorus insecticides (OPs). It is known that OPs degrade on food commodities to DAPs at levels that approach or exceed those of the parent OP. However, little has been reported on the extent of DAP absorption, distribution, metabolism and excretion. The metabolic stability of O,O-dimethylphosphate (DMP) was assessed using pooled human and rat hepatic microsomes. Time-course samples were collected over 2 h and analyzed by LC-MS/MS. It was found that DMP was not metabolized by rat or pooled human hepatic microsomes. Male Sprague-Dawley rats were administered DMP at 20 mg kg(-1) via oral gavage and i.v. injection. Time-course plasma and urine samples were collected and analyzed by LC-MS/MS. DMP oral bioavailability was found to be 107 ± 39% and the amount of orally administered dose recovered in the urine was 30 ± 9.9% by 48 h. The in vitro metabolic stability, high bioavailability and extent of DMP urinary excretion following oral exposure in a rat model suggests that measurement of DMP as a biomarker of OP exposure may lead to overestimation of human exposure.

%B Xenobiotica %V 41 %P 422-9 %8 05/2011 %G eng %N 5 %1 http://www.ncbi.nlm.nih.gov/pubmed/21446834?dopt=Abstract %R 10.3109/00498254.2010.550656 %0 Journal Article %J Environ Sci Technol %D 2005 %T Environmental stresses and skeletal deformities in fish from the Willamette River, Oregon. %A Villeneuve, Daniel L %A Curtis, Lawrence R %A Jeffrey J Jenkins %A Warner, Kara E %A Tilton, Fred %A Kent, Michael L %A Watral, Virginia G %A Cunningham, Michael E %A Markle, Douglas F %A D Sethajintanin %A Krissanakriangkrai, Oraphin %A Johnson, Eugene R %A Grove, Robert %A Kim A Anderson %K Animals %K Benzofurans %K Bone and Bones %K Dioxins %K Female %K Fishes %K History, Ancient %K Hydrocarbons, Chlorinated %K Metals, Heavy %K Oocytes %K Oregon %K Organophosphorus Compounds %K Ovary %K Pesticides %K Polychlorinated Biphenyls %K Polycyclic Hydrocarbons, Aromatic %K Rivers %K Trematoda %K Trematode Infections %K Water Pollutants, Chemical %X

The Willamette River, one of 14 American Heritage Rivers, flows through the most densely populated and agriculturally productive region of Oregon. Previous biological monitoring of the Willamette River detected elevated frequencies of skeletal deformities in fish from certain areas of the lower (Newberg pool [NP], rivermile [RM] 26 - 55) and middle (Wheatland Ferry [WF], RM 72 - 74) river, relative to those in the upper river (Corvallis [CV], RM 125-138). The objective of this study was to determine the likely cause of these skeletal deformities. In 2002 and 2003, deformity loads in Willamette River fishes were 2-3 times greater at the NP and WF locations than at the CV location. There were some differences in water quality parameters between the NP and CV sites, but they did not readily explain the difference in deformity loads. Concentrations of bioavailable metals were below detection limits (0.6 - 1 microg/ L). Concentrations of bioavailable polychlorinated biphenyls (PCBs) and chlorinated pesticides were generally below 0.25 ng/L. Concentrations of bioavailable polycyclic aromatic hydrocarbons were generally less than 5 ng/L. Concentrations of most persistent organic pollutants were below detection limits in ovary/oocyte tissue samples and sediments, and those that were detected were not significantly different among sites. Bioassay of Willamette River water extracts provided no evidence that unidentified compounds or the complex mixture of compounds present in the extracts could induce skeletal deformities in cyprinid fish. However, metacercariae of a digenean trematode were directly associated with a large percentage of deformities detected in two Willamette River fishes, and similar deformities were reproduced in laboratoryfathead minnows exposed to cercariae extracted from Willamette River snails. Thus, the weight of evidence suggests that parasitic infection, not chemical contaminants, was the primary cause of skeletal deformities observed in Willamette River fish.

%B Environ Sci Technol %V 39 %P 3495-506 %8 05/2005 %G eng %N 10 %1 http://www.ncbi.nlm.nih.gov/pubmed/15954223?dopt=Abstract