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Chlorpyrifos is a neurotoxic insecticide that is widely used in the agricultural sector of Ghana. The main objective of this study was to evaluate the levels of chlorpyrifos exposure and health risk among applicators (n = 21) on irrigated rice farms in Ghana, based on a typical application event. Pre- and post-application urine samples (24-h) were collected from the applicators and analysed for 3,5,6-trichloro-2-pyridinol (TCP), using LC-MS/MS. The levels of chlorpyrifos-absorbed dose with the applicators were estimated from the urinary TCP levels. Prior to application, the median absorbed dose of chlorpyrifos (background exposure) with the applicators was 0.2 μg/kg/day (range 0.05 to 2 μg/kg/day). Following application, the median absorbed dose of chlorpyrifos (application exposure) increased 30-fold to 6 μg/kg/day (range 0.7 to 74 μg/kg/day). The mean elimination half-life (t1/2) of chlorpyrifos was calculated to be 50 h. Hazard quotient (HQ) values (HQ > 1) obtained with the chronic (10 μg/kg/day) and acute (100 μg/kg/day) guideline values of the WHO suggested no risk of chronic or acute health effects, respectively, among both the median and 5% highly exposed groups. However, HQ values (HQ > 1) obtained with the chronic (0.3 μg/kg/day) and acute (5 μg/kg/day) guideline values of the USEPA suggested risk of chronic and acute health effects, respectively, among both the median and 5% highly exposed groups. The quantity of chlorpyrifos formulation applied, spraying duration, and the number of spray tanks applied significantly correlated with the absorbed dose levels of chlorpyrifos from application exposure. Therefore, these factors suggest means to reduce exposure and consequent health risk among the applicators. [ABSTRACT FROM AUTHOR]

A broad survey of regulated trihalomethanes (THM) and haloacetic acids (HAA) concentrations in Queensland drinking water was undertaken and the data were evaluated to assess the overall compliance of the region to Australian Drinking Water Guidelines (ADWG). The results presented here indicate that drinking water total trihalomethane (tTHM) concentrations were predominantly compliant with ADWG, with regions using chlorination being the only regions that exceeded the ADWG for THM. tTHM levels were highest in chlorinated water, whereas levels in combined chlorinated/chloraminated water were much lower. Chloraminated water produced the lowest tTHM levels in the regions examined. tTHM levels generally increased during summer and decreased in winter regardless of disinfection method. Surface waters formed a higher proportion of more highly chlorinated THM species relative to more highly brominated THM species, whereas bore water had a higher proportion of more highly brominated THM species due to the frequently higher bromide concentration and lower natural organic matter (NOM) concentration of these waters. The majority of regions were continuously compliant with ADWG for HAA concentrations, with primarily the trichloroacetic acid guideline value being exceeded, in chlorinated waters only. [ABSTRACT FROM AUTHOR]