Traffic-related lead pollution in roadside soils and plants in Khyber Pakhtunkhwa, Pakistan: implications for human health

The contamination of lead in roadside soils and in the leaves of selected trees grown on the corresponding roadside land was investigated. Roadside soil and leaf samples of four tree species were collected along the national and provincial highways in five towns of the Khyber Pakhtunkhwa province, Pakistan. The mean lead concentrations in roadside soil samples were 44.8, 39.4, 32.7, 28.4 and 41.7 mg kg⁻¹ for Peshawar, Charsadda, Swabi, Upper Dir and Lower Dir, respectively. For leaves, the mean concentrations were 4.44, 3.48, 5.56 and 5.93 mg kg⁻¹ for Eucalyptus camaldulensis, Dalbergia sissoo, Platanus orientalis and Morus nigra, respectively. Human health risks via ingestion, inhalation and dermal contact were estimated numerically in terms of average daily dose, hazard quotient and hazard index for the exposed adults and children. The mean hazard index value for adults was 0.37, and mean hazard index value for children was 3.23. Thus, children were found at high risk of lead-related health issues due to roadside soil pollution.