Ecological And Health Risk Assessment Of Heavy Metal Pollution In Soil Of Strawberry Base

Soil is an important part of the earth’s ecology and one of the important natural resources of mankind.Chemicals in the soil not only affect the growth of surface plants and microorganisms in the soil,but also can enter the animal and human body through the food chain,affecting their health.With the rapid development of human industrial society,the use of various chemical products(pesticides and fertilizers)by human beings has also increased soil pollution,which poses a great threat to human environmental safety and agricultural production,thus potentially threatening and threatening human health.Among many types of soil pollution,heavy metal pollution is more prominent.Therefore,it is of great significance to study the spatial distribution and status of soil heavy metal pollution in cultivated land,which is of great significance to the soil pollution of agricultural land in China,and to promote agricultural development and rural revitalization.In this paper,lead(Pb),cadmium(Cd),mercury(Hg),arsenic(As),copper(Cu)and chromium(Cr)in the soil of5000 mu strawberry base in the study area were selected as the research objects.200 soil samples were collected at each sampling point of 100 sampling points in the surface layer of 0 ～ 10 cm depth(shallow layer)and 10 ～ 20 cm depth(deep layer).The contents of these six heavy metals in the soil were analyzed.Geoaccumulation index,Nemerow index,pollution load index and potential ecological risk index were used to evaluate the pollution status of heavy metals in strawberry base.and the sources of heavy metals were discussed combined with statistical analysis.The results show that :1.The soil pH range was 5.33 – 6.35,belonging to acidic soil.The average concentrations of Pb,Cd,Hg,As,Cu and Cr in the shallow surface soil of six heavy metals in strawberry base soil were 28.02 mg/kg,0.118 mg/kg,0.038 mg/kg,8.78mg/kg,28.89 mg/kg and 75.11 mg/kg,respectively.Except that the average concentration of arsenic was lower than the background value of 9 mg / kg,the average concentrations of other lead,cadmium,mercury,copper and chromium were all higher than the corresponding environmental background value.The average concentrations of lead,cadmium,mercury,arsenic,copper and chromium in deep surface soil were 27.96 mg/kg,0.111 mg/kg,0.039 mg/kg,8.86 mg/kg,28.48 mg/kg and 75.94 mg/kg,respectively.Similar to the 0～10 cm shallow soil,except that the average concentration of arsenic was lower than the background value of 9 mg/kg,the average concentrations of Pb,Cd,Hg,Cu and Cr were all higher than the corresponding environmental background values.According to the evaluation of“《 Soil environmental quality agricultural land soil pollution risk control standard(trial)(GB15618-2018)》”,200 samples in 100 sample sites of six heavy metals did not exceed the risk screening value and did not exceed the soil environmental quality standard.The average values of Pb,Cd,Hg,Cu and Cr in soil samples studied in strawberry base exceeded the background values of soil elements in Anhui Province.The average value of arsenic(As)does not exceed the background value,but nearly half of the sample sites still exceed the background value.It indicated that the six heavy metals in the soil in the study area showed different degrees of accumulation.Principal component analysis showed that lead,Pb,As,Cd and Cu were mainly derived from agricultural activities of human fertilizer and organic fertilizer,mercury was mainly derived from irrigation water in strawberry base,and chromium was mainly derived from soil parent material weathering.2.The human health risk assessment model was used to evaluate the non-carcinogenic risk and carcinogenic risk of adult in strawberry base.Arsenic is the most important heavy metal element contributing to the total non-carcinogenic index of adults in 0～10 cm shallow soil and 10-20 cm deep soil in strawberry base area,which means that residents in these areas should pay attention to arsenic pollution in life,followed by chromium and lead,and finally copper,cadmium and mercury.According to the results of carcinogenic risk assessment,the contribution rate of arsenic in 0～10 cm topsoil of strawberry base was 94.80 %.The carcinogenic contribution rate of arsenic in 10～20 cm deep surface soil was 95.13 %.Overall,the carcinogenic contribution rate of arsenic was 94.80 %.Arsenic is the main carcinogenic factor in strawberry base.So overall,the non-carcinogenic risk heavy metals that strawberry bases need to pay attention to are arsenic.3.According to several ecological risk assessment methods,six heavy metals lead,cadmium,mercury,copper,arsenic and chromium have certain pollution to the soil of strawberry base,but the degree of pollution is not high.Most areas of strawberry base were not polluted by these heavy metals.The heavy metal elements of potential ecological hazards in strawberry bases in the study area are mercury and cadmium,and the pollution of these two elements needs attention.The ecological risk of soil heavy metals in the whole area of strawberry base is low,which belongs to the soil that needs protection.4.The heavy metal content of strawberry produced in strawberry base was lower than the limit of pollutants in standard food safety national standard food(GB2762-2017).Soil in strawberry base had no pollution effect on the quality and safety of strawberry products.