Human health risk assessment has been extensively employed to derive guidelines/standards for soil environmental quality around the world.Various threshold values for Bezo[a] pyrene (B[a]P) concentration in soil for protection of human health were introduced.Exposure scenarios and parameters of three different patterns of land use were defined to quantify health risk of human exposure to soil B[a]P.A human-health-based methodology for deriving threshold values for B[a]P concentration in soils was proposed for the first time in China,which should be further used to derive threshold concentrations for other persis tent organic pollutants.Four exposure pathways,i.e.soil ingestion,dermal contact,soil inhalation,and consumption of contaminated vegetables,were considered in modeling for calculation.Threshold concentrations of B[a]P at cancer risk levels of 10^-5 and 10^-6,were calculated for agricultural,residential and industrial soils,respectively.Threshold values for B[a]P concentration in soil for protection of groundwater quality were also derived based on the guidelines/standards for protection of groundwater quality.