Effects of residential exposure to steel mills and coking works on birth weight and preterm births among residents of Sydney, Nova Scotia

Abstract

The Sydney Tar Ponds in Sydney, Nova Scotia, Canada, have been referred to as the most contaminated industrial site in the country. Area residents, aware of the contamination for close to 25 years, are very concerned about their health: past, present and future. In particular, they are concerned about cancer; this is followed closely by reproductive health concerns. The objective of this study was to assess the prevalence and determinants of birth weight and preterm birth among residents living in proximity to an industrial site contaminated with a mix of industrial wastes arising from a former steel mill and coking works (the Tar Ponds) in Sydney, Nova Scotia, Canada. A telephone survey was administered to 500 randomly selected women living in proximity to the site to document reproductive histories. The respondents reported 904 live birth pregnancies occurring in Sydney. The mean birth weight reported for live birth pregnancies was 3,391 g (standard deviation: 570). The reported prevalence of preterm births was 7 percent. Linear regression analyses showed a reduction in birth weight of approximately 85 g among residents in a zone estimated to have higher levels of deposition of airborne effluent from the site. Multivariate logistic regression analyses showed a decrease in the risk of preterm birth as residential distance from the site increased (odds ratio 0.65, 95 percent confidence interval 0.42, 0.98). These data suggest that community exposure to industrial contaminants had some, but little, impact on reported birth weights in this sample of respondents. The apparent increase in risk for preterm births suggests further investigation may be warranted, particularly in light of community concerns. Follow‐up investigations using validated birth records and more sensitive measures of environmental exposure could be used to confirm the findings and further explore the intra‐urban variation in health outcomes. These findings underscore the importance of ongoing clean‐up efforts in Sydney.