Presence of polychlorinated biphenyls (PCBs) in bottled drinking water in Mexico City

Occurrence and exposure risk evaluation of polyhalogenated carbazoles (PHCZs) in drinking water

Although polyhalogenated carbazoles (PHCZs) can be generated and detected in drinking water, their occurrence and potential health risks to humans via drinking water ingestion are not well known. In this study, 11 PHCZs were screened in drinking water samples from Wuhan, the most populous city in central China. The total concentration of PHCZs could be up to 53.48 ng/L with a median level of 8.19 ng/L, which was comparable to polychlorinated biphenyls and poly- and perfluoroalkyl substances reported in the literatures for drinking water. Composition profiles revealed that 3,6-dichlorocarbazole, 3-chlorocarbazole, 3-bromocarbazole and 3,6-dibromocarbazole were the predominant PHCZ congeners in the tested samples. Regional differences in the levels and patterns of PHCZs suggested that anthropogenic releases should be the dominant source compared to natural generation. Boiling of the water samples caused no significant change in PHCZs concentrations after correcting the volume change due to evaporation. Potential health risks associated to the levels of PHCZs in drinking water were assessed using the toxic equivalent (TEQs) method. The estimated daily intake of PHCZs via drinking water ingestion is up to 0.38 pg-TEQ/kg body weight/day for infants, nearly 4.5 times higher than that for adults, and appears to reach the maximum permissible concentration set by certain authority agencies. Overall, drinking water ingestion represents an important exposure pathway for PHCZs. This is the first comprehensive study on the abundance and health risks of PHCZs in drinking water.

Factors affecting the quality of bottled water

The ever-increasing popularity of bottled water means that it is important to analyze not only its mineral content but also, above all, its content of possible contaminants, especially the organic ones. In this respect, bottled waters are a special case, because apart from organic chemical contaminants derived from the well from which they were acquired, their secondary contamination is always possible, during treatment or storage or transport in unsuitable conditions (sunlight and elevated temperature). This paper describes how various factors, from the area around the well, and the method of drawing and treating water, to the manner in which the finished product is stored and transported may affect the quality of bottled waters. It also summarizes literature information on the levels of organic contaminants in various kinds of bottled water samples.

Factors influencing combined exposure to three indicator polychlorinated biphenyls in an adult cohort from Bolivia

Polychlorinated biphenyls are persistent organic pollutants that have been used for decades in several industrial applications. Although production of polychlorinated biphenyls was restricted from the 1970s in most countries, substantial amounts remain in old equipment and buildings and they have been detected in various environmental and biological matrices. The main objective of this study was to analyze predictors of the combined exposure to three non-dioxin-like polychlorinated biphenyls (congeners 138, 153 and 180) in serum and adipose tissue from an adult cohort (n=112) living in the city of Santa Cruz de la Sierra (Bolivia) and surrounding towns/villages. A second aim was to identify modifiers that might influence the statistical associations found, using crude, partially-adjusted, and global multiple linear regression models. Main predictors of serum concentrations were occupation and fatty food consumption, while those for adipose tissue concentrations included age, smoking habit, fatty food consumption, and residence. The differences between the two matrices might be derived from their biological meaning, given that adipose tissue concentrations are an indicator of chronic exposure to polychlorinated biphenyls while serum levels are a good predictor of ongoing exposure and the mobilization of polychlorinated biphenyls stored in fatty tissues. Body mass index was found to be an important modifier of these associations.