Assessment of impact on health of residents living near the Nant-y-Gwyddon landfill site: retrospective analysis Commentary: Impact on health needs assessing from different angles

Abstract

Objectives: To compare indices of health in a population living near a landfill site with a population matched for socioeconomic status and to review environmental monitoring data. Design: Ecological study with small area statistics and environmental reports. Setting: Electoral wards in valleys of South Wales. Subjects: Populations in the five wards near the landfill site who had formally complained of odours (exposed population), and comparison populations in 22 wards in the same unitary authority within the same fifth of Townsend score. Outcome measures: Mortality, rates of hospital admission, measures of reproductive health (proportion of all births and stillbirths of infants weighing <2500 g; rates of admissions for spontaneous abortion; rates of all reported congenital malformations). Environmental data on site emissions. Results: There were no consistent differences in mortality, rates of hospital admissions, or proportion of low birthweight infants between the two populations. There was an increased maternal risk of having a baby with a congenital abnormality in residents near the site, both before its opening (relative risk 1.9; 95% confidence interval 1.3 to 2.85; P<0.001) and after (1.9; 1.23 to 2.95; P=0.003 ). Environmental monitoring showed that hydrogen sulphide from the site was probably responsible for odours. Conclusions: The area surrounding the landfill site has an increased rate of reported congenital malformations, which predated the opening of the landfill, although the cluster of cases of gastroschisis postdated its opening. Several chemicals emitted from the site, including hydrogen sulphide and benzene, were found in air samples in the nearby community. Further studies of the reproductive risk in such communities are needed to examine the safety of waste disposal sites.