Health Assessment of Trace Metal Concentrations in Organic Fertilizer in Northern China

The application of organic fertilizer could be accompanied by potential hazards to soil and humans caused by trace metals. A wide survey of organic fertilizers was carried out in northern China. A total of 117 organic fertilizer samples were collected to analyze the concentrations of seven trace metals. Simulation models were used to estimate the trace metal accumulation risk in soil and non-carcinogenic and carcinogenic risks to the human body. The concentrations of trace metals varied widely (Cr: 2.74⁻151.15; Ni: 2.94⁻49.35; Cu: 0.76⁻378.32; Zn: 0.50⁻1748.01; As: 1.54⁻23.96; Cd: 2.74⁻151.15; and Pb: 1.60⁻151.09 mg·kg^-1). Chinese organic fertilizer standard limits were exceeded by0.85% for Cr, 5.98% for As, 1.71% for Cd, and 4.27% for Pb. Monte Carlo simulations showed that repeated application of organic fertilizer likely significantly increased the concentrations of Zn, Cd, and As in soil compared with the soil background levels according to the Soil Environmental Quality Standards of China. As and Cr pose high risks to human health, especially as carcinogenic risk factors with a skin exposure pathway. Reducing the content of Cr, Cu, Zn, As, and Cd in organic fertilizer would be of great significance for minimizing the damage caused by trace metals.