Environmental Health Perspectives is an Open Access journal published by the National Institute of Environmental Health Sciences. Environmental Health Perspectives is an Open Access journal published by the National Institute of Environmental Health Sciences.

Lead is neurotoxic at very low dose and there is a need to better characterize the impact of domestic sources of lead on the biological exposure of young children. A cross-sectional survey evaluated the contribution of drinking water, house dust and paint to blood lead levels (BLLs) of young children living in old boroughs of Montréal (Canada). Three hundred and six children aged 1 to 5 years and currently drinking tap water participated in the study. For each participant, residential lead was measured in kitchen tap water, floor dust, windowsill dust and house paint and a venous blood sample was analyzed. Multivariate logistic regression was used to evaluate the association between elevated BLL in the children (≥ 75th percentile) and indoor lead contamination by means of odds ratios (OR) using 95% confidence intervals (CI). There was an association between BLL ≥75th percentile (1.78 μg/dL) and water lead when the mean water concentration was >3.3 μg/L: adjusted OR=4.7 (95% CI: 2.1–10.2). Windowsill dust loading >14.1 μg/ft² was also associated with BLL ≥1.78 μg/dL: adjusted OR=3.2 (95% CI: 1.3–7.8). Despite relatively low BLLs, tap water and house dust lead contribute to an increase of BLLs in exposed young children.

Drinking water quality is paramount for public health

There is concern about possible effects of disinfection by-products on reproductive outcomes. The purpose of this study was to evaluate the association between maternal exposure to chlorination by-products and the risk of delivering a small for-gestational-age (SGA) neonate. We conducted a population-based case-control study in the Québec City (Canada) area. Term newborn cases with birth weights <10th percentile (n = 571) were compared with 1925 term controls with birth weights ≥10th percentile. Concentrations of trihalomethanes and haloacetic acids in the water-distribution systems of participants were monitored during the study period, and a phone interview on maternal habits was completed within 3 months after childbirth. We estimated chlorination by-products ingestion during the last trimester of pregnancy and trihalomethanes doses resulting from inhalation and dermal exposure. We evaluated associations between chlorination by-products in utero exposure and SGA by means of unconditional logistic regression with control of potential confounders. When total trihalomethanes and the 5 regulated haloacetic acids concentrations were divided into quartiles, no clear dose-response relationship was found with SGA. However, increased risk was observed when haloacetic concentrations were above the fourth quartile and when either trihalomethanes or haloacetic acids concentrations were above current water standards (adjusted OR= 1.5 [95% confidence interval = 1.1-1.9] and 1.4 [1.1-1.9], respectively). Inhalation and dermal absorption of trihalomethanes did not contribute to this risk, but a monotonic dose-response was found with haloacetic acids ingestion. Oral exposure to high levels of chlorination by-products in drinking water could be a risk factor for term SGA.