Polycyclic Aromatic Hydrocarbons (PAHs) in Exposed-Lawn Soils from 28 Urban Parks in the Megacity Guangzhou: Occurrence, Sources, and Human Health Implications

Abstract

Polycyclic aromatic hydrocarbons (PAHs) in urban soils may pose a serious threat to human health via oral ingestion, dermal absorption, and particulate inhalation, especially in public parks and playgrounds, with children and senior citizens showing the highest susceptibility. Several studies have been undertaken identifying PAHs in urban soils, but no studies to date have assessed PAHs in urban parks, in particular in exposed-lawn soils. In recent decades, unprecedented rates of urbanization and industrialization in China have resulted in significant levels of urban environmental pollution. However, concentrations, sources, and the health risk associated with PAH exposure via urban park lawn soils in China remain unknown. The concentrations, sources, and health risk of exposure to 16 PAHs in surface-exposed lawn soils were studied in 28 urban parks in Guangzhou. Concentrations of Σ16PAHs ranged from 76.44 to 890.85ng/g with a mean of 286.11ng/g. PAH composition was mostly characterized by 2- and 4-ring PAHs in most sampling parks; Nap, Flua, Pyr, Phe, and Chr were the dominant constituents. Principle component analysis coupled with multivariate linear regression indicated that vehicular and coal combustion emissions contributed to 50.53 and 49.46% of PAHs in Guangzhou's urban park soils, respectively. Total cancer risk (TCR) analysis found that 22 parks (accounting for 78.57% total parks) designed for children's use and general-use park areas presented a potentially high risk (>1×10-4) for all users.