Urban park soil contamination by potentially harmful elements and human health risk in Peshawar City, Khyber Pakhtunkhwa, Pakistan

• Urban park soils were analyzed for total and available potentially harmful elements.
• Ni and Cd concentrations were exceeded their respective safe limits.
• Vehicular emission, sewage/waste disposal and wastewater irrigation were the sources of selected harmful elements.
• Hazard index values were lower than safe level (= 1) except a few parks.
• Proper management strategies need to decrease soil contamination in urban parks.

Urban soils may be highly contaminated with potentially harmful elements because of intensive anthropogenic activities. This study aimed to investigate the concentrations, sources, pollution levels and human health risk of potentially harmful elements in the soil of urban parks present in Peshawar, Khyber Pakhtunkhwa, Pakistan. For this purpose, the soil samples (n = 85) were collected from different parks (n = 8) and playgrounds (n = 3) and analyzed for total and bioavailable (EDTA extracted) potentially harmful elements (Cd, Cr, Cu, Pb, Ni and Zn) using an atomic absorption spectrophotometer. The basic soil properties such pH, electrical conductivity, organic matter, and soil particle size were also determined. The data revealed a significant (P = 0.01) variation in the concentrations of selected harmful elements among the different parks. The mean concentrations of Cd exceeded its maximum permissible limit (MPL) in all sites set by China (1995), India (2000), UK (1989) and EU (2000), while Ni concentrations exceeded its MPL in 5 sites. However, observed Zn, Cu, Cr and Pb concentrations were within their respective MPLs. Pollution indices (PI) of potentially harmful elements indicated low, moderate or high level of contamination in park soils linked with vehicular emissions, waste disposal and wastewater irrigation. The health risk was calculated using health quotient (for children) and total risk (for adults). Both non-carcinogenic and carcinogenic vulnerability were also calculated. The health risk data indicated that the main exposure pathway of potentially harmful elements to both children and adults was ingestion followed by dermal contacts. Hazard index (HI) values were lower than safe level (= 1) but few parks showed the health risk existence. Children showed higher possible health risk than adults in the studied parks/playgrounds. The results of this study are important for the development of proper management strategies to decrease soil contamination with potentially harmful elements in the urban parks.