Accumulation status, sources and phytoavailability of metals in greenhouse vegetable production systems in Beijing, China

•Metal contents in greenhouse soil following the order of Cr>Pb>As>Cd>Hg.•As, Cd, Cr and Hg in greenhouse soils mainly originated from anthropogenic source.•Except for Pb, the lowest mean transfer factors was found in fruit vegetables.•10 empirical models were derived by stepwise multiple linear regression analysis.•Leaf vegetables were responsible for the highest intakes of metals, except for Cd.

The accumulation status, sources and phytoavailability of selected metals in greenhouse vegetable production systems in peri-urban areas of Beijing were investigated. The mean concentrations of As, Cd, Cr, Hg and Pb in greenhouse soils were 8.44, 0.25, 69.0, 0.09 and 22.0 mg kg−1, dw, respectively. According to principal component analysis, As, Cd, Cr and Hg are mainly from anthropogenic source, but Pb is likely from natural source. Metal concentrations in all vegetable samples were decreased in the order of Cr>As>Pb>Cd>Hg. Compared with root and fruit vegetables, leaf vegetables had relatively high concentrations and transfer factors of heavy metals, except for Cd. By including soil pH, OM and greenhouse soil metals, 10 empirical models were derived using stepwise multiple linear regression analysis to predict heavy metal concentrations in the edible parts of different vegetables. Among the different vegetable groups, the highest intakes of metals occurred through consumption of leaf vegetables for the two age groups, except for Cd. The HI value of the studied metals were all below 1, indicating that consumption of vegetables grown in greenhouse soils was of low risk to consumers in our study area.