Polycyclic Aromatic Hydrocarbons (PAHs) in park and playground soils: A comparative health risk assessment in two South Asian cities of Brahmaputra Valley, India.

Polycyclic Aromatic Hydrocarbons (PAHs) in parks and playgrounds soils of two fast-growing cities of South Asia, namely Jorhat and Sivasagar, located in the Brahmaputra Valley, India were studied over a period of three consecutive years (2020-2022) to appreciate the concentrations, sources, and associated health risk. The study envisages a holistic viewpoint of the interplay of urban planning and public health in defining pollutant exposure within rapidly-urbanizing cities with limited space for parks and playgrounds, and looks into exposure of vulnerable age groups to PAHs in urban recreational spaces. The mean concentrations of 16 PAHs in parks and playground were found to be 11.653 ± 3 mg/kg and 14.323 ± 8 mg/kg in Jorhat and Sivasagar, respectively. Due to highly variable nature and history of urban soils, sources are mix of pyrogenic and petrogenic origin, which was supported by diagnostic ratios. The total BaP equivalent (BaPeq) concentration of the 7 carcinogenic PAHs was observed to be higher in parks and playground soils of Sivasagar (0.8358 mg/kg) than in Jorhat (0.806 mg/kg). The incremental lifetime cancer risks (ILCR) due to exposure to PAHs in parks and playgrounds soils were found to be in the range of 10-5-10-6 for all age groups, implying potential health risk. The risk was observed to be highest for adolescents between the ages of thirteen to twenty years. Dermal and ingestion pathways were found to be the major pathways contributing to cancer risk exposure in all age groups accentuating socio-environmental dynamics and behavioural vulnerabilities of different age groups.