The influence of lead content in drinking water, household dust, soil, and paint on blood lead levels of children in Flin Flon, Manitoba and Creighton, Saskatchewan.

Lead exposure continues to be an important health issue despite the general removal of lead sources in commercial and industrial applications. Low levels of lead exposure have been found to produce adverse neurodevelopmental effects in children with no evidence that a threshold exists for this critical endpoint. Blood lead levels (BLLs) were measured in children (n=118) under the age of 7years in the northern Canadian smelter community of Flin Flon, Manitoba and Creighton, Saskatchewan. An environmental sampling component was included to examine the relationship between lead content in outdoor soil, household dust, tap water, and paint within a given household and the corresponding BLLs in participating children. The geometric mean (GM) BLL for study participants was 1.41µg/dL. Blood lead levels varied slightly by age category with the lowest levels found among the children under age 2 (GM=1.11µg/dL) and the highest levels found among children between 2 and 3years of age (GM=1.98µg/dL). Results from the multivariate modeling indicated that BLLs had a significant positive association with the age of housing (p<0.05), with children living in households constructed prior to 1945 being more likely to have higher levels (p=0.034). Outdoor soil (GM=74.7µg/g), household dust from kitchen floors (GM=1.34µg/ft2), and maximum household lead paint were found to be significantly correlated (p<0.05) to BLLs. Although a statistically significant association between concentrations of lead in these household media and the corresponding BLLs exists, the variability in BLLs was poorly explained by these factors alone (r2=0.07, 0.12 and 0.06 for soil, household dust, and paint, respectively). Lead concentrations in flushed (GM=0.89µg/L) and stagnant (GM=2.07µg/L and 1.18µg/L) tap water samples were not significantly correlated (p>0.05) to BLLs.

Risk Perception and Disaster Preparedness in Immigrants and Canadian-Born Adults: Analysis of a National Survey on Similarities and Differences.

Research has documented that immigrants tend to experience more negative consequences from natural disasters compared to native-born individuals, although research on how immigrants perceive and respond to natural disaster risks is sparse. We investigated how risk perception and disaster preparedness for natural disasters in immigrants compared to Canadian-born individuals as justifications for culturally-adapted risk communication and management. To this end, we analyzed the ratings on natural disaster risk perception beliefs and preparedness behaviors from a nationally representative survey (N = 1,089). Factor analyses revealed three underlying psychological dimensions of risk perception: external responsibility for disaster management, self-preparedness responsibility, and illusiveness of preparedness. Although immigrants and Canadian-born individuals shared the three-factor structure, there were differences in the salience of five risk perception beliefs. Despite these differences, immigrants and Canadian-born individuals were similar in the level of risk perception dimensions and disaster preparedness. Regression analyses revealed self-preparedness responsibility and external responsibility for disaster management positively predicted disaster preparedness whereas illusiveness of preparedness negatively predicted disaster preparedness in both groups. Our results showed that immigrants' risk perception and disaster preparedness were comparable to their Canadian-born counterparts. That is, immigrant status did not necessarily yield differences in risk perception and disaster preparedness. These social groups may benefit from a risk communication and management strategy that addresses these risk perception dimensions to increase disaster preparedness. Given the diversity of the immigrant population, the model remains to be tested by further population segmentation.

The bioaccessibility of soil-based mercury as determined by physiological based extraction tests and human biomonitoring in children.

Environmental contaminants associated with soil particles are generally less bioavailable than contaminants associated with other exposure media where chemicals are often found in more soluble forms. In vitro methods, such as Physiological Based Extraction Tests (PBET), can provide estimates of bioaccessibility for soil-based contaminants. The results of these tests can be used to predict exposure to contaminants from soil ingestion pathways within human health risk assessment (HHRA). In the current investigation, an HHRA was conducted to examine the risks associated with elevated concentrations of mercury in soils in the northern Canadian smelter community of Flin Flon, Manitoba. A PBET was completed for residential soils and indicated mean bioaccessibilities of 1.2% and 3.0% for total mercury using gastric phase and gastric+intestinal phase methodologies, respectively. However, as many regulators only allow for the consideration of in vitro results for lead and arsenic in the HHRA process, in vitro bioaccessibility results for mercury were not utilized in the current HHRA. Based on the need to assume 100% bioaccessibility for inorganic mercury in soil, results from the HHRA indicated the need for further assessment of exposure and risk. A biomonitoring study was undertaken for children between 2 and 15 years of age in the community to examine urinary inorganic mercury concentrations. Overall, 375 children provided valid urine samples for analysis. Approximately 50% of urine samples had concentrations of urinary inorganic mercury below the limit of detection (0.1 µg/L), with an average creatinine adjusted concentration of 0.11 µg/g. Despite high variability in mercury soil concentrations within sub-communities, soil concentrations did not appear to influence urinary mercury concentrations. The results of the current investigation indicate that mercury bioaccessibility in residential soils in the Flin Flon area was likely limited and that HHRA estimates would have been better approximated through inclusion of the in vitro study results.

Urinary inorganic arsenic in residents living in close proximity to a nickel and copper smelter in Ontario, Canada.

OBJECTIVES: The current study determines whether internal exposure to inorganic arsenic for residents living in close proximity to an operating smelter is any different from that for residents living in a similar community without anthropogenic sources of inorganic arsenic. Furthermore, the study examines factors that may contribute to internal inorganic arsenic exposure in these populations. METHODS: A cross-sectional study was used to determine whether recent internal exposure to inorganic arsenic for residents living in close proximity to an operating smelter with known elevated soil arsenic content is any different from exposure for residents living in a similar socio-demographic community without point sources of arsenic. Personal information was collected from participants during in-home interviews, and first morning void urine samples were obtained to assess recent internal exposure to arsenic. RESULTS: The mean concentration of urinary inorganic arsenic of residents living in the exposed community was 7.11 ug/L (Standard deviation (SD) 4.53, N = 368) and in the non-exposed community was 7.19 ug/L (SD 5.63, N = 321). The difference in urinary inorganic concentration was not statistically significant (p = 0.83). Regression analysis showed that age and sex were significant predictors of internal exposure, with males and younger age groups having higher exposure levels. CONCLUSIONS: Based on analyses of data collected, the results did not demonstrate a statistically significant difference in recent internal exposure to inorganic arsenic between the community with and the one without industrial or other point sources of environmental arsenic contamination. However, individual characteristics such as age and sex are important contributors to urinary inorganic arsenic levels.