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This study focused on characterizing the oral bioaccessibilities and human health risks of eight heavy metals (Cd, Pb, Cr, Ni, Cu, Zn, Fe, and Mn) in surface-exposed lawn soils from 28 urban parks in Guangzhou. The physiologically-based extraction test (PBET) method was used to assess bioavailability (in gastric and intestinal phases) and human health risk was assessed via statistical modelling (carcinogenic risk assessment, hazard quotients and hazard indices). Mean bioaccessibilities of Cd, Pb, Cr, Ni, Cu, Zn, Fe, and Mn from all soil samples were 50.90 ± 17.67%, 5.81 ± 1.67%, 7.12 ± 3.24%, 17.91 ± 18.34%, 11.93 ± 2.88%, 34.33 ± 10.02%, 1.68 ± 0.48%, 26.71 ± 5.06%, respectively. The concentrations of most heavy metals were higher in the gastric phase, except for Cr and Ni which remained higher in the intestinal phase. Principal component analysis revealed that the bioaccessibilities of the heavy metals could be split into three groupings, based on the urban park of soil origin. The carcinogenic risk probabilities for Pb and Cr were under the acceptable level (< 1 × 10 −4 ) for both adults and children. The hazard quotient and hazard index values indicated no significant risk of non-carcinogenic effects to children or adults exposed to Guangzhou urban park soils. This research will help inform further risk assessment and management of heavy metal contaminants in urban environments. [ABSTRACT FROM AUTHOR]

The total concentrations and oral bioaccessibility of heavy metals in surface-exposed lawn soils from 28 urban parks in Guangzhou were investigated, and the health risks posed to humans were evaluated. The descending order of total heavy metal concentrations was Fe > Mn > Pb > Zn > Cu > Cr > Ni > Cd, but Cd showed the highest percentage bioaccessibility (75.96%). Principal component analysis showed that Grouped Cd, Pb, Cr, Ni, Cu and Zn, and grouped Cr and Mn could be controlled two different types of human sources. Whereas, Ni and Fe were controlled by both anthropogenic and natural sources. The carcinogenic risk probabilities for Pb and Cr to children and adults were under the acceptable level (<1 × 10 −4 ). Hazard Quotient value for each metal and Hazard Index values for all metals studied indicated no significant risk of non-carcinogenic effects to children and adults in Guangzhou urban park soils. [ABSTRACT FROM AUTHOR]

The total concentrations, fractionation of metals and human health risk in surface-exposed lawn soils from 18 urban parks in Guangzhou were investigated. Cd was predominantly associated with the acid-soluble fraction and Pb mainly with the reducible fraction, whereas Cr, Ni, Cu, and Zn were strongly associated with the residual fraction. The hazard indices for the metals were <1, indicating that exposure to the urban park soil does not pose significant risks of non-carcinogenic effects from the metals analyzed. The probabilities of Cd, Cr, and Ni posing carcinogenic risks to children and adults were negligible (probability <1 × 10 −6 ). [ABSTRACT FROM AUTHOR]

The total concentrations, fractionation of metals and human health risk in surface-exposed lawn soils from 18 urban parks in Guangzhou were investigated. Cd was predominantly associated with the acid-soluble fraction and Pb mainly with the reducible fraction, whereas Cr, Ni, Cu, and Zn were strongly associated with the residual fraction. The hazard indices for the metals were <1, indicating that exposure to the urban park soil does not pose significant risks of non-carcinogenic effects from the metals analyzed. The probabilities of Cd, Cr, and Ni posing carcinogenic risks to children and adults were negligible (probability <1 × 10 −6 ). [ABSTRACT FROM AUTHOR]