Concentration levels and carcinogenic and mutagenic risks of PM2.5-bound polycyclic aromatic hydrocarbons in an urban-industrial area in South Africa.

Abstract

Concerns over the health effects of exposure to particulate matter of aerodynamic diameter of less than 2.5μm (PM2.5) led the South African Government to establish the national standard for PM2.5 in the year 2012. However, there is currently no exposure limit for polycyclic aromatic hydrocarbons (PAHs) and PM2.5-bound PAHs. The understanding of the concentration levels and potential health risks of exposure to PM2.5-bound PAHs is important in ensuring a suitable risk assessment and risk management plans. This study, therefore, determined the concentration levels and carcinogenic and mutagenic health risks of PM2.5-bound PAHs. A hundred and forty-four PM2.5 samples were collected over 4months during the winter and summer seasons of 2016 in an industrial area. The concentrations of 16 PAHs were analysed by gas chromatography-mass spectrometry, and their carcinogenic and mutagenic risks were determined using the Human Health Risk Assessment model. The mean winter (38.20 ± 8.4μg/m3) and summer (22.3 ± 4.1μg/m3) concentrations of PM2.5 levels were lower than the stipulated 40μg/m3 daily limit. The daily inhalation and ingestion exposure to PAHs for all age groups were higher than the daily exposure through the dermal contact. Children and adults are more likely to inhale and ingest PAHs in PM2.5 than infants. The excess cancer risk and excess mutagenic risk values were below the priority risk level (10-4). There is a potential risk of 1-8 per million persons developing cancer from exposure to benzo[a]anthracene, benzo[a]pyrene, indeno[1,2,3-cd]pyrene, and dibenz[a,h]anthracene over a lifetime of 70years.