Abstract: Underscoring the characteristics of trace element accumulation and their pollution risk in greenhouse soils is an essential prerequisite of risk management in agricultural settings. In this study, we measured the concentrations of total and speciation of iron (Fe), manganese (Mn), zinc (Zn), copper (Cu), cadmium (Cd), lead (Pb), and chromium (Cr) in representative facilities in Shandong. The geo-accumulation index (I_geo), risk assessment code (RAC), and potential ecological risk index (PERI) were used to evaluate the pollution characteristics of soil trace elements. Positive matrix factorization (PMF) and health risk assessment models were combined to identify potential sources of trace elements and calculate their risk levels. Results demonstrated a distinct trend of accumulation of Fe, Mn, Zn, Cu, Cd, and Cr, with the maximum concentration of Cd surpassing the pollution risk thresholds. A significant increase of the bioavailable speciation of Mn, Zn, Cd, and Cr was observed as planting years increased. According to the PMF model, trace elements were primarily affected by agricultural and industrial activities, with contribution rates of 31.49% and 24.07%, respectively. The evaluation based on I_geo, RAC, and PERI indicated that the total concentrations of Cd, Pb, Cu, and Zn, as well as the concentrations of bioavaliable Pb and Zn, exceeded the standard level. Furthermore, the single ecological hazard index (E_i) of Cd was higher, while no risk appeared in terms of comprehensive potential ecological hazard index (RI). The risk probabilities of trace elements in soil were 36.78% for non-carcinogenic and 0.03% for carcinogenic health risks to adults, respectively. Cr emerged as the risk priority control metal.

Key words: trace element, sequential extraction, pollution assessment, facility greenhouse