Concentration Analysis and Health Risk Assessment of Heavy Metals in Greenhouse Vegetables of Nanjing Suburb

Pb,Cd,Zn and Cu contents in 50 vegetable samples from two greenhouse bases of Nanjing suburb were detected by flame atomic absorption spectrometry,and results were compared with main vegetable standards of China.Possible health risks to local residents caused by the heavy metals through consumption of vegetables were assessed based on target hazard quotient(THQ),and THQ values between adults and children were compared.Results showed that the contents of Pb,Cd,Zn and Cu in vegetables were 0.117 mg/kg,0.206 mg/kg,0.990 mg/kg and 0.117 mg/kg,in which Pb,Zn and Cu contents were in line with Chinese pollution-free green vegetables standard,while Cd content exceeded.THQs of Pb,Cd,Zn and Cu for adults due to consumption of vegetables were 0.158,1.119,0.018 and 0.096,for children were 0.207,1.479,0.023 and 0.125,both of which had potential health risks from Cd.Total metal THQs for adults and children were 1.390 and 1.834,which were mainly caused by Cd.Single heavy metal contribution rate to the combined risk was basically the same for adults and children,but health risks for children caused by heavy metals were bigger than adults.