Detections of organophosphate and pyrethroid insecticide metabolites in urine and sweat obtained from women during infrared sauna and exercise: A pilot crossover study.

Synthetic pesticides such as organophosphates and pyrethroids are commonly used worldwide yet the metabolic and long-term human health effects of these environmental exposures are unclear. Urinary detections of metabolites involving both classes of insecticides have been documented in various global populations. However, reports documenting similar detections in human sweat are sparse. In this study, the concentrations of four insecticide metabolites were measured using liquid chromatography coupled with tandem mass spectrometry in repeated sweat and urine collections (n = 85) from 10 women undergoing three interventions (control, infrared sauna and indoor bicycling) within a single-blinded randomised crossover trial. The Friedman test with post-hoc two-way analysis of variance, the related-samples Wilcoxon signed rank test and the Spearman's rank-order correlation test were used to analyse the results. Organophosphate metabolites were detected in 84.6% (22/26) and pyrethroids in 26.9% (7/26) of the collected sweat samples (pooled per individual, per intervention). Urinary concentrations of three of the four metabolites marginally increased after infrared sauna bathing: 3,5,6-trichloro-2-pyridinol (z = 2.395, p = 0.017); 3-phenoxybenzoic acid (z = 2.599, p = 0.009); and trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid (z = 2.090, p = 0.037). Urinary 3-phenoxybenzoic acid also increased after exercise (z = 2.073, p = 0.038) and demonstrated the most temporal variability (days to weeks) of any of the urinary metabolites. Definitive sweat/urine correlations were not demonstrated. These results indicate metabolites from organophosphate and pyrethroid pesticides can be detected in human sweat and this raises intriguing questions about perspiration and its role in the metabolism and excretion of synthetic pesticides.

Predictors of Urinary 3-Phenoxybenzoic Acid Levels in 50 North Carolina Adults.

Limited data are available on the non-chemical stressors that impact adult exposures to pyrethroid insecticides based on urinary biomonitoring. The urinary metabolite, 3-phenoxybenzoic acid (3-PBA), is commonly used to assess human exposure to a number of pyrethroids. In a further analysis of published study data, we quantified urinary 3-PBA levels of 50 adults over a single, 24-h sampling period and examined the associations between the biomarker measurements and selected non-chemical stressors (demographic, lifestyle, and dietary factors). A convenience sample of 50 adults was recruited in North Carolina in 2009-2011. Participants collected individual urine voids (up to 11) and filled out activity, food, and pesticide use diaries over a 24-h sampling period. Urine voids (n = 326) were analyzed for 3-PBA concentrations using high-performance liquid chromatography-tandem mass spectrometry. 3-PBA was detected in 98% of the 24-h composited urine samples. The geometric mean urinary 3-PBA level was 1.68 ng/mL in adults. Time spent outside (p = 0.0006) was a highly significant predictor of natural log-transformed (ln) urinary 3-PBA levels, while consumption of coffee (p = 0.007) and breads (p = 0.019) and ln creatinine levels (p = 0.037) were significant predictors of urinary 3-PBA levels. In conclusion, we identified specific factors that substantially increased adult exposures to pyrethroids in their everyday environments.

Urinary concentrations of environmental contaminants and phytoestrogens in adults in Israel.

BACKGROUND: The Ministry of Health Biomonitoring Study estimated exposure of individuals in the Israeli population to bisphenol A (BPA), organophosphate (OP) pesticides, phthalates, cotinine, polycyclic aromatic hydrocarbons (PAHs), and the phytoestrogenic compounds genistein and daidzein. METHODS: In 2011, 250 individuals (ages 20-74) were recruited from five different regions in Israel. Urine samples were collected and questionnaire data were obtained, including detailed dietary data (food frequency questionnaire and 24hour recall). Urinary samples were analyzed for BPA, OP metabolites (dialkyl phosphates), phthalate metabolites, cotinine, PAH metabolites, genistein, and daidzein. RESULTS AND DISCUSSION: BPA urinary concentrations were above the limit of quantification (LOQ) in 89% of the samples whereas urinary concentrations of phthalate metabolites were above the LOQ in 92-100% of the samples. PAH metabolites were above the LOQ in 63-99% of the samples whereas OP metabolites were above the LOQ in 44-100% of the samples. All non-smoking participants had detectable levels of cotinine in their urine; 63% had levels above the LOQ, and the rate of quantification was high compared to the general non-smoking population in Canada. Median creatinine adjusted concentrations of several OP metabolites (dimethyl phosphate, dimethyl thiophosphate) were high in our study population compared to the general US and Canadian populations. Median creatinine adjusted urinary BPA concentrations in the study population were comparable to those in Belgium and Korea; higher than those reported for the general US, German, and Canadian populations; and very low compared to health-based threshold values. Phthalate concentrations were higher in our study population compared to the general US population but values were very low compared to health-based threshold values. Median creatinine adjusted PAH concentrations were generally comparable to those reported for the general US population; median creatinine adjusted daidzein concentrations were high in our population compared to the general US population whereas genistein concentrations were comparable. CONCLUSIONS: We interpreted observed urinary contaminant levels observed in our study by comparing values with health-based threshold values and/or values from international human biomonitoring studies. Using this data interpretation scheme, we identified two contaminants as being of potential public health concern and high priority for public health policy intervention: environmental tobacco smoke (ETS) and OP pesticides. We used the data collected in this study to support public health policy interventions. We plan to conduct a follow-up biomonitoring study in 2015 to measure ETS and OP exposure in the general population in Israel, to evaluate the effectiveness of relevant policy interventions.

Metabonomic responses in rat urine following subacute exposure to propoxur.

Metabolic profiling of urine from pesticide-treated rats was investigated by the nuclear magnetic resonance (NMR)-based metabonomic strategy. Twenty-four-hour urine samples of rats were collected after administration with propoxur at doses of 0.85, 1.70, and 8.51 mg/kg, respectively, for 28 consecutive days. Liver tissue was fixed and the histopathological alterations were examined. The results showed that propoxur at high dose induced liver histopathological injury. Metabonomic analysis demonstrated that the levels of creatine and taurine markedly increased together with slight elevation of hippurate, glucose, and amino acids in low- and medium-dose groups. However, concentrations of urinary lactate, acetate, acetone, succinate, citrate, and 2-oxoglutarate increased in high-dose group. All these results suggested that propoxur could inhibit liver function through altering the energy and lipid metabolism. These data also supported the contention that the NMR-based metabonomic approach represents a promising new technology for the development of pesticide toxicity screening and mechanism exploration.

Comparative chlorpyrifos pharmacokinetics via multiple routes of exposure and vehicles of administration in the adult rat.

Chlorpyrifos (CPF) is a commonly used organophosphorus pesticide. A number of toxicity and mechanistic studies have been conducted in animals, where CPF has been administered via a variety of different exposure routes and dosing vehicles. This study compared chlorpyrifos (CPF) pharmacokinetics using oral, intravenous (IV), and subcutaneous (SC) exposure routes and corn oil, saline/Tween 20, and dimethyl sulfoxide (DMSO) as dosing vehicles. Two groups of rats were co-administered target doses (5 mg/kg) of CPF and isotopically labeled CPF (L-CPF). One group was exposed by both oral (CPF) and IV (L-CPF) routes using saline/Tween 20 vehicle; whereas, the second group was exposed by the SC route using two vehicles, corn oil (CPF) and DMSO (L-CPF). A third group was only administered CPF by the oral route in corn oil. For all treatments, blood and urine time course samples were collected and analyzed for 3,5,6-trichloro-2-pyridinol (TCPy), and isotopically labeled 3,5,6-trichloro-2-pyridinol (L-TCPy). Peak TCPy/L-TCPy concentrations in blood (20.2 micromol/l), TCPy/L-TCPy blood AUC (94.9 micromol/lh), and percent of dose excreted in urine (100%) were all highest in rats dosed orally with CPF in saline/Tween 20 and second highest in rats dosed orally with CPF in corn oil. Peak TCPy concentrations in blood were more rapidly obtained after oral administration of CPF in saline/Tween 20 compared to all other dosing scenarios (>1.5 h). These results indicate that orally administered CPF is more extensively metabolized than systemic exposures of CPF (SC and IV), and vehicle of administration also has an effect on absorption rates. Thus, equivalent doses via different routes and/or vehicles of administration could potentially lead to different body burdens of CPF, different rates of bioactivation to CPF-oxon, and different toxic responses. Simulations using a physiologically based pharmacokinetic and pharmacodynamic (PBPK/PD) model for CPF are consistent with these possibilities. These results suggest that exposure route and dosing vehicle can substantially impact target tissue dosimetry. This is of particular importance when comparing studies that use varying exposure paradigms, which are then used for extrapolation of risk to humans.

Cross validation of multiple methods for measuring pyrethroid and pyrethrum insecticide metabolites in human urine.

The objective of our study was to compare three vastly different analytical methods for measuring urinary metabolites of pyrethroid and pyrethrum insecticides to determine whether they could produce comparable data and to determine if similar analytical characteristics of the methods could be obtained by a secondary laboratory. This study was conducted as a part of a series of validation studies undertaken by the German Research Foundation's Committee on the Standardization of Analytical Methods for Occupational and Environmental Medicine. We compared methods using different sample preparation methods (liquid-liquid extraction and solid-phase extraction with and without chemical derivatization) and different analytical detection methods (gas chromatography-mass spectrometry (single quadrupole), gas chromatography-high resolution mass spectrometry (magnetic sector) in both electron impact ionization and negative chemical ionization modes, and high-performance liquid chromatography-tandem mass spectrometry (triple quadrupole) with electrospray ionization). Our cross validation proved that similar analytical characteristics could be obtained with any combination of sample preparation/analytical detection method and that all methods produced comparable analytical results on unknown urine samples.

Reference values for metabolites of pyrethroid and organophosphorous insecticides in urine for human biomonitoring in environmental medicine.

Pesticides are widely used throughout the world in agriculture to protect crops, and in public health to control diseases transmitted by vectors or intermediate hosts. After the prohibition of organochlorines, such as DDT, today mainly pyrethroids and organophosphorous insecticides are used. With reliable and sensitive analytical methods for detecting metabolites of organophosphorous and pyrethroid insecticides in urinary specimens of the general population several studies have been published on internal exposure to these insecticides of the population in Germany. In total, data on levels of metabolites of organophosphorous acids in urine of about 1200 children and adults have been published, as well as data on levels of pyrethroid metabolites in urine of about 2100 children and adults. In Germany, reference values for environmental pollutants related to the population are established continuously by the Human Biomonitoring Commission of the German Federal Environmental Agency, preferably based on data gained by representative studies. Reference values are defined as the 95th percentile, rounded off within the 95% confidence interval of the population studied. Since there is a need for reference values to characterise the population's exposure to organophosphates and pyrethroids, and since there are different studies available from Germany that agree quite well with data from other industrialised countries, the Commission has derived reference values from the available data, though none of the studies had fulfilled criteria on representativity. Reference values for metabolites of organophosphorous acids are as follows: DMP 135 microg/l, DMTP 160 microg/l and DEP 16 microg/l and for metabolites of pyrethroids: cis-Cl2CA 1 microg/l, trans-Cl2CA 2 microg/l and 3-PBA 2 microg/l. As the volume-related concentrations of organophosphate and pyrethroid metabolites show no significant age-dependence, the reference values derived are not age-stratified. Though based merely on statistical and not on toxicological data, levels analysed above the reference levels, when reliably measured (verified several times), should prompt environmental health practitioners to search for sources, within the bounds of proportionality. In addition to accidental poisoning, possible sources include indoor contamination following improper pest control operations in homes as well as in pets and food products contaminated by these pesticides.

New gas chromatographic-mass spectrometric method for the determination of urinary pyrethroid metabolites in environmental medicine.

We have developed and validated a new, reliable and very sensitive method for the determination of the urinary metabolites of the most common pyrethroids in one analytical run. After acidic hydrolysis for the cleavage of conjugates, the analytes cis-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid (cis-Cl(2)CA), trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid (trans-Cl(2)CA), cis-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid (Br(2)CA), 4-fluoro-3-phenoxybenzoic acid (F-PBA) and 3-phenoxybenzoic acid (3-PBA) were extracted from the matrix with a liquid-liquid extraction procedure using n-hexane under acidic conditions. For further clean-up, NaOH was added to the organic phase and the carboxylic acids were re-extracted into the aqueous phase. After acidification and extraction into n-hexane again, the metabolites were then derivatised to volatile esters using N-tert.-butyldimethylsilyl-N-methyltrifluoroacetamid (MTBSTFA). Separation and detection were carried out using capillary gas chromatography with mass-selective detection (GC-MS). 2-Phenoxybenzoic acid (2-PBA) served as internal standard for the quantification of the pyrethroid metabolites. The limit of detection for all analytes was 0.05 microg/l urine. The RSD of the within-series imprecision was between 2.0 and 5.4% at a spiked concentration of 0.4 microg/l and the relative recovery was between 79.3 and 93.4%, depending on the analyte. This method was used for the analysis of urine samples of 46 persons from the general population without known exposure to pyrethroids. The metabolites cis-Cl(2)CA, trans-Cl(2)CA and 3-PBA could be found in 52, 72 and 70% of all samples with median values of 0.06, 0.11 and 0.16 microg/l, respectively. Br(2)CA and F-PBA could also be detected in 13 and 4% of the urine samples.

Ibuprofen interference in the determination of 3-phenoxybenzoic acid in urine.

Pyrethroid insecticides are widely used in agriculture and private households. Analysis of urine for pyrethroid metabolites is one way to detect human exposure to these insecticides and is carried out regularly as part of the Occupational and Environmental Medicine Monitoring Program recommended by the Deutsche Forschungsgemeinschaft (DFG). Samples are analyzed using GC-MS (selected ion monitoring) following acid hydrolysis, solid phase extraction, esterification with methanol/sulfuric acid, and liquid-liquid extraction. The metabolite, 3-phenoxybenzoic acid (3-PBA), can be derived from several pyrethroids and is, therefore, a useful diagnostic analyte; however, the presence of the over-the-counter drug, ibuprofen ((R,S)-2-(4-isobutylphenyl)propionic acid), interferes with this determination, even after the ingestion of only one 200-mg tablet. The interfering analyte is carboxy-ibuprofen which is not removed by the cleanup step. Experimental work shows that it takes two days for most of the ibuprofen to clear the body before 3-PBA can reliably be determined in urine.