Chemical Characteristics And Ecological Risk Assessment Of Heavy Metal Elements In Soil And Fruit Of Main Blueberry Planting Areas In Guizho

The safety of agricultural products has been the focus of widespread social concern,and the quality and safety of blueberries in Guizhou,the largest blueberry-growing province in southern China,is highly valued.In this paper,we analyzed the characteristics and influencing factors of As,Cd,Cr,Cu,Hg,Ni,Pb,and Zn elements in the soil-blueberry fruit system,analyzed the sources of soil heavy metals,and assessed the soil risk and fruit health risk,taking the town of Bandang in Ziyun County,Xuanwei in Majiang County and Jiuzhou in Huangping County,the main blueberry growing areas in Guizhou,as the research objects.The results are as follows:(1)Soil As,Cd,Cr,Ni,Pb,and Zn contents in Majiang Park,Ziyun Park and Huangping 1Park were higher than the phenomenon of agricultural land contamination limit,while Hg and Cu contents were lower than the agricultural land contamination limit.The heavy metal content in the study area shows the pattern that the weathered soil of the Cambrian Loushanguan Group dolomite,the weathered soil of the Permian Wujiaping Group dolomitic tuff and the weathered soil of the Cambrian Gaotai Group dolomite are greater than the weathered soil of the Paleoproterozoic purple sand conglomerate.Compared with the background values of various types of soil heavy metals in Guizhou,the soils in the park have higher As and Hg contents and lower Cd contents,while Cr,Cu,Ni,Pb,and Zn do not differ significantly.(2)The results of the analysis of the factors influencing the soil heavy metals in the park show that the soil heavy metal content in different parks is influenced by various factors such as the parent rock of soil formation,soil weathering leaching,weathering stage characteristics,and soil physical and chemical properties.The results of correlation and redundancy analyses show that the soil-forming parent rock is the main factor affecting the soil heavy metal content,while the physical and chemical properties have less influence on the soil heavy metal content;the results of one-way ANOVA show that there are differences in the heavy metal contents of different parks(P<0.05);the analysis of the heavy metal contents of the parent rocks of different parks shows that the dolomitic tuffs of the Wujiaping Formation have higher Cr and Ni contents,which are much higher than those of the upper land crust and other The content of Cr and Ni in the parent rocks of the Wujiaping Formation is higher than that in the upper terrestrial crust and other parks.The results of multivariate statistics and the positive definite matrix factor decomposition model suggest that the main sources of soil heavy metals in the study area are parent rocks,agricultural sources,traffic sources,industrial activities,and daily life sources,with parent rocks being the most important source.(3)The heavy metal content of blueberry fruit is low,and there are differences in fruit Cr among the parks,and the fruit-heavy metal content shows a pattern of Zn > Cu > Ni > Cr > Pb >As > Cd > Hg.The enrichment index of blueberry fruit for soil heavy metals is much less than 1,showing a pattern of Cu > Cd > Zn > Ni > Hg > Cr > Pb > As,with low bioavailability.The heavy metal elements of blueberry fruit are influenced by the elemental enrichment capacity of the fruit,soil heavy metal content,soil organic matter,cation exchange capacity(CEC),soil p H,and many other factors,and the enrichment capacity of the fruit is more influential.(4)The overall level of soil and fruit contamination in the park was low.Soil pollution evaluation results are higher than the actual fruit risk,and the Nemero pollution index method and pollution load index method are relatively more applicable to the evaluation of soil pollution in blueberry orchards.The soil contamination evaluation results from largest to smallest are HP1 Park > ZY Park > MJ Park > HP2 Park,the soil environmental quality is ranked as HP2 Park > MJ Park > ZY Park > HP1 Park,and the weathered soil of purple sand conglomerate in the Paleocene >weathered soil of dolomite in the Cambrian Gaotai Formation > weathered soil of dolomitic tuff in the Permian Wujiaping Formation > weathered soil of dolomite in the Cambrian Loushanguan Group.The health risk of the fruit HP1 park is greater than ZY and MJ park,HP2 park is the smallest,the target hazard quotient(TTHQ)and combined potential carcinogenic risk(CRT)of the fruit are within the safe range,blueberry fruit is a safe fruit.