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.

Comparison of Bayesian and frequentist approaches in modelling risk of preterm birth near the Sydney Tar Ponds, Nova Scotia, Canada

“…The plots also show that there is no clear relationship between distance and risk. This result is consistent with the results of two of the studies conducted in this area using primary data [ 1 , 3 ]. They both concluded that a causal association between preterm births and maternal/residential proximity to the Tar Ponds could not be inferred from the statistical analysis.…”

“…This concern has led to an increased demand for public health authorities and researchers to investigate potential clustering of diseases around putative sources of hazards [ 1 - 10 ]. Evidence of significant association between maternal proximity to hazardous waste sites and risk of low birth-weight and congenital anomalies has been reported in some studies [ 4 - 12 ], but other studies have reported otherwise [ 1 , 3 , 6 , 13 - 15 ]. Some studies have also shown that women exposed to PCB are at increased risk of giving birth to infants with low birth weight [ 16 , 17 ].…”

Spatial Mapping of Lead, Arsenic, Iron, and Polycyclic Aromatic Hydrocarbon Soil Contamination in Sydney, Nova Scotia: Community Impact From the Coke Ovens and Steel Plant

“…10,11 In studies after the industrial complex closed, for the period 1988-1998 a 25% increase in rate ratio for all major congenital anomalies was observed in Sydney relative to Nova Scotia, 12 and a small increase in low-birth-weight and preterm births have been reported for an area most impacted from the industrial emissions relative to other areas in Sydney. 13 In addition, adolescents living near the tar ponds have health-related concerns about themselves and their families. 14 This study contributes to understanding the role of environmental pollution in the health effects observed in Sydney by evaluating the spatial impact from the industrial emissions through analysis of soil contamination.…”

Using satellite derived land cover information for a multi-temporal study of self-reported recall of proximity to farmland

“…Examples include proximity to toxic releases from industries (Burra et al, 2006;Choi et al, 2006), as well as proximity to non-point sources of aqueous nitrates, petrochemicals (Yu et al, 2006) and other environmental contaminants (Wickre et al, 2004). Proximity measures prove especially valuable when estimating exposures that occurred many years ago, and when present-day biomarkers are not appropriate measures of past exposures.…”