Health risk analysis of Elemental component of respirable particulate matter in an urban area in South Africa

Abstract

TPS 761: Health effects of pollution sources and components, Johan Friso Foyer, Floor 1, August 28, 2019, 3:00 PM - 4:30 PM Background: Particulate matter with an aerodynamic diameter of less than 2.5 μm (PM2.5) is an indicator of air pollution, and a key environmental and public health threat. The paucity of studies in South Africa on the toxicity of the heavy metal content of PM2.5 represents a significant gap in knowledge. This study determined the cancer and non cancer health risks associated with exposure to PM2.5-bound heavy metal in an industrial area in Pretoria. Methods: The study comprised three parts: (i) ambient air monitoring for PM2.5; (ii) sampling and analyses of PM2.5 for its the heavy metal content; and (iii) application of the human health risk assessment model of the United States Environmental Protection Agency for estimating the health risks among specified age groups. Samples of PM2.5 were collected during winter and summer on 47 mm glass fibre filters for 16 weeks. The filters were analysed for heavy metals using standard methods. Estimates of cancer and non-cancer risks were determined. Results: The mean winter (38.20±8.4 μg/m3) and summer (22.3±4.1 μg/m3) concentration levels of PM2.5 levels were lower than the stipulated 40 μg/m3 daily limit. However, the carcinogenic risks of exposure to PM2.5 were higher than the standard value (10−6 to 10-4). The average concentrations of Arsenic, Cadmium, Chromium, Manganese, Nickel, Lead and Zinc in PM2.5 exceeded the recommended safe limits. The carcinogenic risks from Arsenic, Cadmium, Chromium, Nickel and Lead through the inhalation, ingestion and dermal pathways were higher than the acceptable limits for all age groups. Conclusion: Human exposure to an ambient concentration of PM2.5 and its heavy metal contents will induce cancer and non-cancer morbidities even at levels below regulatory standards. This is a pointer for policymakers to advance the course for the formulation of regulatory standards for PM2.5-bound heavy metal in South Africa.