典型镉污染农田土壤低积累植物种植和超积累植物吸取修复研究

发布时间：2018-04-14 22:46

  本文选题：农田土壤 + 镉　； 参考：《浙江农林大学》2017年硕士论文

【摘要】：随着我国农田土壤重金属污染问题日趋严峻,农产品安全越来越引起社会各界的高度关注。本论文采用田间实际采样、温室盆栽及田间微区试验相结合的方法,分别通过对农田土壤镉(Cd)污染现状、玉米低Cd品种筛选和Cd超积累植物对农田土壤Cd富集吸收等角度,探讨了(i)在Cd污染农田种植低累积作物以提高农产品的食用安全性以及(ii)利用超积累植物进行植物抽取修复以消除土壤污染,这两个应对农田土壤污染策略的可行性。主要研究结果如下:对杭州郊县某典型污染农田土壤Cd污染进行的调查发现,该地50%以上的土壤Cd浓度集中在0.3-0.6 mg/kg,土壤Cd浓度在GB15618-1995《土壤环境质量标准》的二级标准以内的点位占29.1%;稻米Cd浓度主要集中在0.2-1.0 mg/kg,点位比例占87.4%,而稻米Cd浓度符合食品卫生标准(大米≤0.2 mg/kg)的仅占3.9%;对农田土壤进行单因子污染指数法评价,对相应点位稻米进行了健康风险评价,发现研究区农田土壤主要以轻污染为主,但92.3%的稻米存在Cd的潜在健康危害。将124个玉米品种种植于Cd污染农田、测定和计算不同玉米品种对土壤Cd的富集系数,并研究不同施肥、水分管理、土壤耕作等农艺调控措施对玉米籽粒Cd吸收性的影响,分析结果显示仅联创1号和1615/郑58两个品种Cd超标,富集系数偏高,不适宜在Cd污染农田种植,其余均可;施肥处理措施下,玉米品种郑单958籽粒样品的Cd吸收量对肥料施用的响应与先玉335不同;与对照处理比较,单施鸡粪、单施磷肥、单施锌肥、混施磷肥和锌肥均显著降低郑单958玉米品种籽粒中Cd浓度,降低了14.3-20.0%;而先玉335玉米品种籽粒中Cd的浓度分别显著增加了29.0-42.0%;水分管理和土壤耕作措施对两种玉米籽粒中Cd浓度的影响均不显著。温室盆栽试验研究了伴矿景天在不同土壤类型和紧实度条件下的生长状况及对镉吸收富集的影响,结果发现:与无压实处理比较,生长于低紧实度的砂质壤土、壤黏土和黏土中伴矿景天地上部生物量显著下降了66.8-83.5%、59.9-60.4%和57.9-71.4%,总体看来高紧实度对伴矿景天地上部生物量影响更大,高紧实度处理显著提高了伴矿景天的根系活力(142-241%)。高紧实度处理显著降低了壤黏土上伴矿景天地上部Cd浓度(35.6%),但低紧实度对砂质壤土和黏土上伴矿景天地上部Cd浓度无显著影响。与无压实处理比较,低紧实度显著降低了砂质壤土、壤黏土和黏土上伴矿景天的Cd吸取量,分别下降50.4-73.8%、61.4-74.9%和43.4-63.3%,土壤紧实度对壤黏土上伴矿景天的镉锌吸取效率影响最为明显。
[Abstract]:With the pollution of heavy metals in farmland soil is becoming more and more serious, the safety of agricultural products has attracted more and more attention from all walks of life.In this paper, the methods of field sampling, greenhouse potted cultivation and field microregional experiment were used to study the present situation of CD / CD pollution in farmland soil, the selection of maize low CD varieties and the CD enrichment and absorption by CD superaccumulators.This paper discusses the feasibility of planting low accumulation crops in CD polluted farmland to improve the edible safety of agricultural products, and using superaccumulative plants to carry out plant extraction and repair to eliminate soil pollution, and the feasibility of these two strategies to deal with farmland soil pollution.The main results are as follows: the investigation of CD pollution in a typical polluted farmland in a suburb county of Hangzhou,More than 50% of the soil CD concentration in this area is 0.3-0.6 mg / kg, the CD concentration in the soil is 29.1% in the second grade standard of GB15618-1995, and the CD concentration in rice is mainly 0.2-1.0 mg / kg, the percentage of point is 87.4%, and the CD concentration in rice is consistent with that of rice.The proportion of food hygiene standard (rice 鈮，

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