Potential health risks associated to heavy metal contamination of soils in the Yellow River Delta, China

The level of inhalable particulate matter (PM10) in the Yellow River Delta (YERD), an oil production area in north China, are generally high, resulting in an increase exposure to heavy metals (HMs) from soil. This exposure increases during winter and spring periods. In order to determine potential health risks posed by 9 HMs (i.e. Cr, Cd, As, Cu, Hg, Ni, Mn, Zn and Pb) in this area, high density sampling of surface soils across the YERD was undertaken. Results indicate that even through PM10 is generally high, no significant carcinogenic and non-carcinogenic health risks in YERD were identified. Ingestion rather than inhalation or dermal contact is the main exposure pathway. Hazard Index (HI) and total probability of carcinogenic risk (TCR) values indicated that children experienced higher carcinogenic and non-carcinogenic risks. Arsenic contributed the most to carcinogenic and non-carcinogenic health risks, while the effects of other HMs were minor. Our results also demonstrate that, based on the spatial trending of HI and TCR of high-risk areas, oil production will cause an unacceptable level of health risk. Due to the close proximity of this area to the coast, the wash effect of sea water will remove HMs from the soil and lower the health risks. Therefore, investigations related to coastal oilfields should investigate the transfer of HMs to seawater or local sediments. Our results provide a basis for environmental management in the YERD and other rapidly developing industrial regions around the world.