Characteristics, source apportionment and health risk assessment of heavy metals exposure via household dust from six cities in China

Highlights: • Concentrations of heavy metals (HMs) in household dust were quantified. • HM concentrations in household dust were higher in urban than in rural study areas during heating and non-heating periods. • Longer ventilation time leads to higher concentrations of HMs, meanwhile, the weight of heating duration was bigger than heating type. • Indoor air, outdoor air, traffic air and soil were the resources of HMs in household dust. • The non-carcinogenic and carcinogenic risks of HMs in household dust were acceptable in study areas. To investigate the characteristics and health risks of heavy metals in household dust in urban and rural areas during heating and non-heating period in 2016–2017, 762 dust samples and 381 questionnaires from 381 households were collected from Dalian, Taiyuan, Lanzhou, Shanghai, Wuhan, and Chengdu in China. The results indicated that Dalian was the most polluted city, while Shanghai and Chengdu were the least polluted cities during the study period. Longer ventilation times led to higher concentrations of heavy metals, and the weighting of heating duration exceeded that of heating type. Soil was the dominant contributor to household dust for Hg, Ni, Cu, Zn, and As, whereas Pb primarily originated from traffic. The non-carcinogenic and carcinogenic risks associated with heavy metals in household dust were acceptable, with ingestion being the primary exposure route. The risk of adverse health effects caused by heavy metal intake via household dust in urban areas was higher than that in rural areas, and increased during household heating period. Ingestion was the most significant route leading to adverse health effects due to heavy metals in household dust. The exception was the carcinogenic risk associated with Ni, which is known to enter the human body mainly via inhalation.