Heavy Metal Content Survey And Health Risk Assessment Of Rice And Soil In Hunan Province From 2021-2022

Objective : The aim is to understand the heavy metal content of rice and soil in a certain province,evaluate its pollution level,and conduct food safety and health risk assessments for residents in the province.Method: During the period from June 2021 to October 2022,a total of 378 rice samples were collected from 9 Prefecture-level city in a province,including229 rice samples purchased by large supermarkets(all of which originate in the province)and sent to Hunan Shanshui Group for inspection,and 149 rice samples obtained from rice hulling,collectively referred to as rice samples;A total of 136 soil samples were collected from 9 regions in a certain province,and the collection location was far away from factories,enterprises,and other factors that affect heavy metal content.The collection method referred to the "Technical Specifications for Soil Environmental Monitoring".After the samples were treated by microwave digestion,the contents of five heavy metals such as lead(Pb),mercury(Hg),arsenic(As),cadmium(Cd)and chromium(Cr)in the samples were detected by Inductively coupled plasma mass spectrometry(ICP-MS).Single factor pollution index and comprehensive pollution index methods were used to evaluate the pollution of rice and soil,and non carcinogenic risk assessment and carcinogenic risk assessment were used to assess the food safety risk of residents in a certain province.Result:1.The heavy metal detection results of rice samples showed that the exceeding rate of the five heavy metal contents ranged from high to low as As(21.96%)>Cd(15.34%)>Hg(0.26%)=Pb(0.26%)>Cr(0.00%).The median value of heavy metal lead content in rice is 0.000 mg/kg,the 25 th percentile value is 0.000 mg/kg,and the 75 th percentile value is 0.000 mg/kg.The city where the highest value sample is located is YIY City;The median value of heavy metal mercury content in rice is 0.002 mg/kg,the 25 th percentile value is0.001 mg/kg,and the 75 th percentile value is 0.003 mg/kg.The city where the lowest value sample is located is YUY City,and the city where the highest value sample is located is CS City;The median value of heavy metal arsenic content in rice is 0.154 mg/kg,the 25 th percentile value is 0.115 mg/kg,and the 75 th percentile value is 0.195 mg/kg.The city where the lowest value sample is located is YUY City,and the city where the highest value sample is located is YZ City;The median value of heavy metal cadmium content in rice is 0.114mg/kg,the 25 th percentile value is 0.042 mg/kg,and the 75 th percentile value is0.157 mg/kg.The city where the lowest value sample is located is YIY City,and the city where the highest value sample is located is YZ City;The median value of heavy metal chromium content in rice is 0.057 mg/kg,the 25 th percentile value is 0.028 mg/kg,and the 75 th percentile value is 0.112 mg/kg.The city where the highest value sample is located is CS City.The statistical analysis results show that there is a significant difference in the exceeding rate of heavy metal arsenic content and cadmium content among different regions;2.The high content of heavy metals in soil is arsenic and cadmium,with a median value of 16.460 mg/kg,a 25 th percentile value of 11.080 mg/kg,and a75 th percentile value of 22.102 mg/kg.The minimum sample is located in XT city,and the maximum sample is located in YUY city;The median value of heavy metal cadmium content is 0.135 mg/kg,the 25 th percentile value is 0.106mg/kg,and the 75 th percentile value is 1.078 mg/kg.The minimum sample is located in CZ city,and the maximum sample is located in HY city.Some samples have heavy metals such as arsenic and cadmium exceeding the risk screening values,while heavy metals such as lead,mercury,and chromium have not exceeded the risk screening values.All soil samples have not exceeded the risk control values,and there is mild pollution in the HY area soil,but most of them are within the safe utilization range;3.The health risk assessment shows that the target hazard coefficient(THQ)of lead,mercury,and chromium heavy metals in rice from a certain province for different populations is lower than the critical value.According to the results of collecting samples,these three heavy metals in rice do not pose a threat to human health;The total target hazard coefficient(TTHQ)results indicate that the combined effects of the three heavy metals do not pose any harm to the human body,but their impact on children is greater than that of adult males and females.Target Carcinogenic Risk Assessment(TCR): Arsenic and cadmium in rice have potential carcinogenic risks to the human body,with cadmium having the highest carcinogenic risk in children.Although there is a possibility of overestimation of risks in this study,it is still recommended that relevant departments take measures as soon as possible to minimize health risks.Conclusion:1.There are As and Cd pollution phenomena in rice from 9 regions in a certain province,which have potential carcinogenic risks,but the non carcinogenic risks are at a safe level;2.The comprehensive pollution index of the soil in HY city,a province,shows that it is slightly polluted by heavy metals.It is suggested that the government departments should take effective measures to control and repair the heavy metal polluted agricultural soil in this area as soon as possible.