Different pollution levels and source profiles of heavy metals in the soil and surface dust of children's playgrounds in a coastal city; source-specific health risk assessment

Abstract

This study compared the pollution levels, health risks, and sources of heavy metals (HMs) in the dust accumulated on the play equipment and the soil of children's playgrounds located in a humid subtropical city (Bandar Abbas, Iran). Therefore, a total of 74 samples of soil and equipment dust were collected from 37 children's playgrounds and the concentrations of HMs were analyzed by Inductively Coupled Plasma Optical Emission spectroscopy (ICP-OES). The concentration levels of all the studied HMs including As, Cd, Co, Cr, Cu, Mn, Ni, Pb, and Zn in dust were higher than those of soil. Health risks attributed to the HMs in soil and dust were assessed using Monte Carlo simulation approach. Accordingly, the non-carcinogenic (2.60E+1) and carcinogenic (1.71E-5) risks associated with the children's exposure to HM-polluted dust in these places were relatively high. Positive Matrix Factorization (PMF) model and its integration with health risk assessment models showed that the lithogenic source was the main contributor to both HMs concentrations and HMs-induced health risks with >65% contribution. The HMs in the dust accumulated on the equipment surface were found to be originated from the local (suspended local soil) and distant (industrial and traffic airborne emissions) sources, and from the plastic material of play equipment. The latter showed the highest contribution to the non-carcinogenic risk (37.5%). The results of this study imply the necessity for regularly cleaning of touchable surfaces in children's playgrounds, protecting the play equipment against aggressive environmental conditions, and controlling the critical sources of pollution.