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In this work, the potential of layered double hydroxide/graphene (LDH-G) hybrid as a sorbent for extraction and preconcentration of fifteen organochlorine pesticides (OCPs) in urine samples was evaluated. The LDH-G hybrid was synthesized by co-precipitation method and it was then characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy and X-ray diffraction. The sorbent was then employed in membrane-protected stir-bar supported micro-solid-phase extraction (SB-μ-SPE) of OCPs in urine samples. This extraction approach is highly suitable for the samples representing matrix complexity such as urine because the sorbent is effectively protected inside the membrane. The extracted samples were analyzed by gas chromatography mass spectrometry. The factors that affect the performance of SB-μ-SPE were suitably optimized. This method demonstrated good linearity with coefficients of determination up to 0.9996. The limits of detection ranged between 0.22 and 1.38ngmL -1 . The RSD values for intra and inter-day precision were also in a satisfactory range (2.7-9.5%)., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Several studies have suggested that exposure to DDT may be related to changes in thyroid hormone levels in animals and humans, even though results across studies are inconsistent. The aim of this study was to assess the association between exposure to p,p'-DDE (a stable metabolite of DDT) and serum levels of thyroid hormones in floriculture workers. A longitudinal study was conducted on 136 male subjects from the States of Mexico and Morelos, Mexico, who were occupationally exposed to pesticides, during agricultural periods of high (rainy season) and low (dry season) levels of pesticide application. Using a structured questionnaire, a survey was carried out on socio-demographic characteristics, anthropometry, clinical history, alcohol and tobacco consumption, residential chemical exposure, and occupational history. Blood and urine samples were collected to determine serum levels of TSH, total T3, total T4, and p,p'-DDE, and metabolites of organophosphate pesticides (OP), respectively. The analysis of the associations between p,p'-DDE levels and thyroid hormone profile adjusting by potential confounding variables including urinary OP metabolites was carried out using multivariate generalized estimating equation (GEE) models. Our results showed that the geometric means of p,p'-DDE levels were 6.17 ng/ml and 4.71 ng/ml in the rainy and dry seasons, respectively. We observed positive associations between the serum levels of p,p'-DDE and those of total T3 (β=0.01, 95% CI: -0.009, 0.03), and total T4 (β=0.08, 95% CI:0.03, 0.14) and negative but no significant changes in TSH in male floricultural workers, supporting the hypothesis that acts as thyroid disruptor in humans., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Due to a technical rule issued by the Ministry of Labour, in Germany toxicological analysis in blood and urine for biological monitoring must be carried out under quality assurance. Since 1982 the German Society for Occupational and Environmental Medicine has offered 13 intercomparison programmes. The 1994 round robin considered 7 metals and 5 solvents in blood, 12 organochlorine compounds in plasma and 14 inorganic, as well as 11 organic, compounds in urine in the occupational and in the environmental exposure range. Reference values and tolerance ranges are established by reference laboratories. Successful participation was certified if the results for 2 concentration adjustments were in tolerance range (assigned value +/- 3 S.D.). In 1994 in 119 laboratories the percentage rate of accurate results was 59%. This mean success rate is in agreement with the last 12 round robins.

The use of municipal wastewater treatment plants for the disposal of industrial wastes creates the potential for the exposure of treatment plant workers to hazardous chemical compounds that may be present in these wastes. Urine from workers and air and wastewater samples from a municipal wastewater treatment plant receiving wastes from a pesticide manufacturer were analyzed on several occasions by electron-capture gas chromatography for the presence of the compounds hexachlorocyclopentadiene (HEX) and hexachlorobicycloheptadiene (HEX-BCH) which are present in the waste stream from this industry. HEX-BCH was detected more frequently in urine from these workers than in urine from workers at another municipal wastewater treatment plant in the same city. Urine concentrations of HEX-BCH were found to be higher in specimens collected late in the work shift than in those collected earlier. The primary rate of exposure is thought to be by inhalation. This is the first known report of these compounds being detected in human urine and it demonstrates the potential for wastewater treatment plant worker exposure to industrial wastes.