and inhalation exposures from contaminated air). Children have similar exposures to adults, although developing biological systems and places of play may complicate matters (Perera et al., 2009). Prenatal exposure has also become a recent concern. Edwards et al. (2010) investigated the relationship between prenatal PAH exposure and child intelligence at 5 years of age, controlling for potential confounders suspected to play a role in neurodevelopment. A cohort of pregnant, healthy, nonsmoking women was enrolled in Krakow, Poland, between 2001 and 2006. They found that higher prenatal exposure to airborne PAHs was associated with decreased IQ points at 5 years of age, after adjusting for potential confounding variables. These results suggest that prenatal exposure to airborne PAHs adversely affects children’s cognitive development by 5 years of age, with potential implications for school performance. They are consistent with a recent finding in a parallel cohort in New York City, where Perera et al. (2009) found that after adjustment for maternal intelligence, quality of the home caretaking environment, environmental tobacco smoke exposure, and other potentially confounding factors. Children in the high-exposure group had full-scale and verbal IQ scores that were 4.31 and 4.67 points lower, respectively, than those of less-exposed children.
DISINFECTANT BY-PRODUCTS (DBPs) & TRIHALOMETHANES (THMs) Disinfection of public drinking water supplies with chlorine or other disinfectants has been integral to the prevention of infectious waterborne diseases. The highly reactive nature of chlorine or other oxidants used as disinfectants, which aids in microbial inactivation, also causes them to form a number of disinfection by-products (DBPs) with naturally occurring organic and inorganic substances in the source water. Since the discovery of DBP formation in the mid-1970s, there has been increasing apprehension about the possible health effects posed by DBPs. Toxicological studies have shown that certain DBPs cause cancer in the liver, kidney and/or large intestine of laboratory animals and that particular DBPs cause adverse reproductive or developmental effects (Krasner, 2009). Epidemiological studies have indicated a slightly increased risk for bladder, colon and rectal cancers in individuals who were exposed to chlorinated surface waters for many years. In addition, some epidemiology studies have shown an association between the consumption of chlorinated drinking water and adverse reproductive or developmental health effects, such as spontaneous abortion or fetal anomalies (Hoffman et al., 2008). Exposures to drinking water disinfection by-products (DBP) during pregnancy may increase the risk of adverse pregnancy outcomes. Some studies report a moderately increased risk of delivering a smallfor- gestational-age (SGA) infant among women exposed to high levels of total trihalomethanes (TTHMs), while other studies have shown exposure to high levels of TTHMs have been associated with decreased mean birth weight and an increased risk of delivering a low birth weight infant. Although they have been associated with having effects on fetal growth, these studies have not established a clear and consistent relationship (Hoffman et al., 2008). Toxicologic data suggest that brominated THMs are likely to be more harmful to the fetus than chloroform. However, results of epidemiologic studies as a whole have not implicated any particular constituent of TTHM as being more or less harmful with respect to fetal growth. Hoffman et al. (008)’s study is the most extensive study of DBP exposure and fetal growth restriction conducted to date. The 25