[Levels, Sources, and Health Risk Assessments of Heavy Metals in Indoor Dust in a College in the Pearl River Delta].

Thirty indoor dust samples were collected from staff and study areas in a college in Foshan, and the As, Hg, Cd, Cu, Zn, Ni, Pb, and Cr contents were measured. The Spearman correlation coefficient, principal component analysis, and US EPA health risk assessment model were used to determine the sources and degree of pollution and the health risks. The results showed that the levels of the eight heavy metals were higher than the background values in Guangdong Province and the reported values in other Chinese cities, excluding Hg. The levels of the eight heavy metals were higher in the staff area than in the study area, but the difference was not significant. The eight heavy metals were derived from similar sources; Hg was mainly derived from outdoor anthropogenic sources, while the others were mainly derived from indoor anthropogenic sources. The daily non-carcinogenic exposure dose was in the following order:ingestion > dermal exposure > inhalation. Ingestion was the major pathway of heavy metal exposure from indoor dust. Except for Cr, the non-carcinogenic hazard indexes of ingestion and dermal exposure were taken from partial sample points > 1. All of the health risks were lower than the average risk thresholds of the heavy metals, and would not cause health risks to humans. Printers, copiers, instruments, and equipment were important sources of indoor pollution and risk sources of heavy metals. Thus, protective measures should be taken to reduce the risk of exposure.