【作者】 张洁；

【导师】 刘克；

【作者基本信息】 贵州大学 ， 资源利用与植物保护， 2023， 硕士

【摘要】 本研究选定贵州6个马铃薯产区进行取样,测定了土壤及马铃薯中Cr、Ni、Cu、Zn、As、Cd和Pb 7种重金属含量,并进行土壤、马铃薯重金属污染评价和健康风险评价。通过盆栽试验,得到Cd对植物、微生物效应临界值,并结合大田样品得到马铃薯安全生产时土壤中Cd的阈值。主要结论如下:（1）各产区土壤重金属的平均含量对比贵州省土壤背景值,荔波和赤水较为清洁,盘县Cu元素为背景值的5.84倍,纳雍Cu和Zn分别为背景值的3.75倍和1.52倍,威宁均超过背景值,花溪Cu和Pb分别为背景值的3.39倍和2.21倍。（2）土壤重金属单因子指数显示荔波和赤水为轻度Cd污染,盘县和威宁为Cu、As、Cd污染,纳雍和花溪为Cu、Zn、Cd污染,内梅罗综合污染指数显示荔波和赤水为轻度污染,盘县和纳雍为中度污染,威宁和花溪为重度污染。（3）土壤重金属地累积指数评价显示:荔波和赤水未积累重金属,盘县、纳雍、威宁和花溪均为中度Cu污染,部分元素存在轻度污染,盘县未积累Pb,纳雍未积累Ni、Cu、As和Cd,威宁和花溪均未积累As。（4）污染负荷指数评价显示:污染程度大小为威宁（1.56）>盘县（1.54）花溪（1.32）>纳雍（1.23）>赤水（0.73）>荔波（0.72）,荔波和赤水总体为轻微污染,盘县、纳雍、威宁和花溪总体为轻度污染。（5）潜在生态风险指数评价显示:综合生态风险指数大小为威宁（143.29）>盘县（128.67）>花溪（96.64）>纳雍（80.09）>荔波（50.36）>赤水（42.48）,各研究区土壤重金属潜在风险均主要由Cd引起,Cd对综合潜在风险指数的贡献率最大。（6）致癌风险评价显示:各产区手-口、皮肤暴露途径下,R值均为儿童>成人,对儿童有更大的致癌风险,呼吸暴露途径下R值均为成人>儿童,对成人有更大的致癌风险。非致癌风险评价显示:各产区中手-口暴露途径下Cr和As对成人和儿童的HQ>1,可能会产生非致癌风险且儿童>成人,皮肤和呼吸暴露途径下各重金属HQ<1,对成人和儿童的非致癌风险不明显,各产区儿童可能存在非致癌风险,且非致癌风险大小儿童>成人。（7）马铃薯污染评价显示:马铃薯对As、Ni和Cd三种土壤重金属富集程度较强,各产区中马铃薯均存在Cr和Cd污染。马铃薯重金属健康风险评价显示:各产区中马铃薯Cu、Zn和Pb对成人和儿童的THQ<1,对人体健康风险不明显,其余重金属可能会对成人和儿童产生一定的健康风险,且TTHQ和THQ均为儿童>成人,TTHQ均为盘县>威宁>花溪>荔波>纳雍>赤水。（8）Cd对植物效应临界值:随着Cd浓度的增加马铃薯块茎鲜重在石灰性土和黄壤上均呈现下降的趋势,以块茎鲜重减产10%为依据,拟合方程得出两种土壤中Cd全量和有效态临界值分别为14.042 mg·kg^-1和0.115 mg·kg^-1、24.630mg·kg^-1和0.214 mg·kg^-1。Cd对微生物效应临界值:随着Cd浓度的增加土壤脲酶和碱性磷酸酶活性在两种土壤上均呈现先升高后下降的趋势,以脲酶和碱性磷酸酶活性降低25%为依据,拟合方程得出两种土壤中Cd全量和有效态临界值分别为37.283 mg·kg^-1、0.237 mg·kg^-1、47.532 mg·kg^-1、0.373 mg·kg^-1,62.118mg·kg^-1、0.476 mg·kg^-1、55.186 mg·kg^-1、0.333 mg·kg^-1。土壤Cd有效态比全量能更好的反映Cd污染的植物、微生物效应。（9）产区全量Cd阈值为3.55 mg·kg^-1,有效态Cd阈值为0.179 mg·kg^-1;不同产区土壤全量和有效态Cd阈值:荔波为0.503 mg·kg^-1和0.012 mg·kg^-1,赤水为0.168 mg·kg^-1和0.015 mg·kg^-1,盘县为7.581 mg·kg^-1和0.105 mg·kg^-1,纳雍为8.167 mg·kg^-1和0.010 mg·kg^-1,威宁为2.810 mg·kg^-1和0.010 mg·kg^-1,花溪为22.20 mg·kg^-1和0.041 mg·kg^-1;p H≤5.5、5.5<p H≤6.5、6.5<p H≤7.5、p H>7.5时全量和有效态Cd的阈值分别为2.126 mg·kg^-1和0.016 mg·kg^-1、2.452 mg·kg^-1和0.001 mg·kg^-1、0.859 mg·kg^-1和0.056 mg·kg^-1、6.789 mg·kg^-1和0.024 mg·kg^-1;盆栽试验中石灰性土和黄壤Cd的全量、有效态阈值分别为0.358 mg·kg^-1和0.031 mg·kg^-1、1.586 mg·kg^-1和0.054 mg·kg^-1。更多还原

【Abstract】 In this study,six potato production areas in Guizhou were selected for sampling,and the contents of 7 heavy metals Cr,Ni,Cu,Zn,As,Cd and Pb in soil and potatoes were determined.The heavy metal pollution evaluation and health risk evaluation of soil and potatoes were conducted.Through pot experiment,the critical value of Cd effect on plants and microorganisms was obtained,and combined with field samples,the threshold value of Cd in soil for potato safety production was obtained.The main conclusions are as follows:（1）The average contents of heavy metals in soil from each production areas were compared with the background values in Guizhou Province soil.Libo and Chishui were relatively clean.Cu in Panxian was 5.84 times of the background value,Cu and Zn in Nayong were 3.75 and 1.52 times of the background value,respectively.All elements were higher than the background value in Weining.Cu and Pb in Huaxi were3.39 and 2.21 times of the background value,respectively.（2）The single factor index of heavy metals in soil showed that Libo and Chishui were slightly polluted by Cd,Panxian and Weining were polluted by Cu,As and Cd,Nayong and Huaxi were polluted by Cu,Zn and Cd,Nemeruo comprehensive pollution index showed that Libo and Chishui were slightly polluted,Panxian and Nayong were moderately polluted,and Weining and Huaxi were heavily polluted.（3）The assessment of soil heavy metal accumulation index showed that no heavy metals were accumulated in Libo and Chishui.Panxian,Nayong,Weining and Huaxi were moderately polluted by Cu,and some elements were slightly polluted.Panxian had no Pb accumulation,Nayong had no Ni,Cu,As,Cd and accumulation,and Weining and Huaxi had no As accumulation.（4）The assessment of pollution load index shows that the pollution degree is Weining（1.56）>Panxian（1.54）Huaxi（1.32）>Nayong（1.23）>Chishui（0.73）>Libo（0.72）.Libo and Chishui are generally minor polluted,while Panxian,Nayong,Weining and Huaxi are generally slightly polluted.（5）The assessment of potential ecological risk index shows that the comprehensive ecological risk index is Weining（143.29）>Panxian（128.67）>Huaxi（96.64）>Nayong（80.09）>Libo（50.36）>Chishui（42.48）.The potential risks of heavy metals in soil in each study area are mainly caused by Cd,which has the largest contribution rate to the comprehensive potential risk index.（6）Carcinogenic risk evaluation showed that under the hand mouth and skin exposure routes in all production areas,the R value was children>adults,which had a greater cancer risk for children,and the R value under the respiratory exposure routes was adults>children,which had a greater cancer risk for adults.The non-carcinogenic risk assessment showed that the HQ of Cr and As for adults and children under the hand mouth exposure route in each production areas were greater than 1,which might produce a non-carcinogenic risk for children>adults,and the HQ of heavy metals under the skin and respiratory exposure route was less than 1,which was not significant for adults and children.Children in each production areas might have a non-carcinogenic risk,and children with non-carcinogenic risk were greater than adults.（7）The evaluation of potato pollution shows that potatoes have a strong concentration of heavy metals in As,Ni,and Cd soils,and there are Cr and Cd pollution in potatoes in all production areas.The health risk assessment of heavy metals in potatoes shows that the THQ of Cu,Zn,and Pb in potatoes for adults and children in each production area is less than 1,and the risk to human health is not significant.Other heavy metals may pose certain health risks to adults and children,and TTHQ and THQ are children>adults,and TTHQ are Panxian>Weining>Huaxi>Libo>Nayong>Chishui.（8）Critical value of Cd effect on plants:With the increase of Cd concentration,the fresh weight of potato tubers showed a downward trend in calcareous soil and yellow soil.Based on the 10%reduction of fresh weight of tubers,the critical values of total and available Cd in the two soils were 14.042 mg·kg^-1and 0.115 mg·kg^-1,24.630 mg·kg^-1and 0.214 mg·kg^-1respectively by fitting the equation.Critical value of Cd’s effect on microorganisms:With the increase of Cd concentration,the activities of soil urease and alkaline phosphatase both showed a trend of first increasing and then decreasing in the two soils.Based on the 25%reduction of urease and alkaline phosphatase activities,the critical values of total and available Cd in the two soils were 37.283 mg·kg^-1,0.237 mg·kg^-1,47.532 mg·kg^-1,0.373 mg·kg^-1,62.118 mg·kg^-1,0.476 mg·kg^-1,55.186 mg·kg^-1and 0.333 mg·kg^-1respectively by fitting the equation.The available state of Cd in soil can better reflect the plant and microbial effects of Cd pollution than the total state.（9）The threshold of total Cd in the production area was 3.55 mg·kg^-1,the threshold value of available Cd was 0.179 mg·kg^-1;The threshold value of total and available Cd in soil of different production areas:0.503 mg·kg^-1and 0.012 mg·kg^-1in Libo,0.168 mg·kg^-1and 0.015 mg·kg^-1in Chishui,7.581 mg·kg^-1and 0.105 mg·kg^-1in Panxian,8.167 mg·kg^-1and 0.010 mg·kg^-1in Nayong,2.810 mg·kg^-1and0.010 mg·kg^-1in Weining,22.20 mg·kg^-1and 0.041 mg·kg^-1in Huaxi;When p H≤5.5,5.5<p H≤6.5,6.5<p H≤7.5,and p H>7.5,the threshold values of total and available Cd were 2.126 mg·kg^-1and 0.016 mg·kg^-1、2.452 mg·kg^-1and 0.001 mg·kg^-1、0.859 mg·kg^-1and 0.056 mg·kg^-1、6.789 mg·kg^-1and 0.024 mg·kg^-1respectively;In pot experiment,the total and available threshold of Cd in calcareous soil and yellow soil were 0.358 mg·kg^-1and 0.031 mg·kg^-1、1.586 mg·kg^-1and0.054 mg·kg^-1respectively。更多还原