不同阻控技术对蔬菜地重金属生物有效性的影响研究

发布时间：2018-03-18 16:22

本文选题：蔬菜地土壤　切入点：重金属　出处：《杭州师范大学》2015年硕士论文　论文类型：学位论文

【摘要】：由于人类工业活动使得稳定存在于地壳中的重金属进入土壤环境,通过生物富集作用威胁人类健康。农产品中的重金属残留与土壤污染有密切的关系,土壤是影响农产品质量安全的源头因素。本文对杭州市五大蔬菜供应产地土壤环境重金属污染状况的调查评价结果表明Pb、Cu、Zn含量均小于国家土壤质量二级标准,尼梅罗指数小于0.7,土壤清洁。Cr、As、Cd在部分蔬菜产地有轻度或中度污染,可能会对作物造成污染,应当引起警戒。叶菜类、菌菇类和根茎类蔬菜对多种重金属都有较强的富集能力;茄果类、豆荚类尤其是瓜类蔬菜对重金属的富集能力较弱。根据调查的结果,本文进一步选取典型土壤进行重金属的阻控技术研究。植物修复盆栽试验结果表明:1)黑麦草对重金属Cu、Cr和Cd的去除效果较好,对Pb、Cr和Cd的钝化效果较好;2)狗牙根对Pb、Cr的去除效果较好;2)与黑麦草相比,其对土壤环境重金属污染的耐受能力较好;3)重金属对植物的营养吸收存在阻碍作用,随着污染程度的加重,需要较多的有机肥才能维持植物的正常生长。依据上述植物修复盆栽试验结果,本文认为若想进一步优化原土的土壤质量可以选择种植黑麦草,并结合20%的有机肥施用量作为生态修复方案;二级土壤中,选择种植黑麦草并施用10%的有机肥作为生态修复方案;三级土壤中,选择种植黑麦草并施加20%的有机肥作为生态修复方案。此外,可以根据具体关键污染物和污染程度调节土壤重金属生态修复方案。重金属钝化盆栽试验结果表明,生物炭和粉煤灰的重金属钝化作用在酸性土壤中和中性土壤中均有效。粉煤灰在阻碍土壤重金属淋溶方面效果较好,但对于土壤酸化只能起到短期的改善作用;而生物炭对于提高作物产量、降低重金属的生物浓缩系数(Bioconcentration factor,BCF)、改善土壤性质等方面均具有较好的效果。生物炭和粉煤灰的施入都可以发挥一定的肥料缓释剂作用。此外,茄果类蔬菜对于土壤重金属污染和环境变化的耐受性较好。依据上述重金属钝化盆栽试验的结果,本文认为可以选择向酸性良渚土壤中施入5%的生物炭和20%的有机肥作为重金属钝化的生态修复方案;选择向中性乔司土壤中施入5%的粉煤灰和10%的有机肥作为重金属钝化的生态修复方案。
[Abstract]:Due to human industrial activities, heavy metals, which are stable in the earth's crust, enter the soil environment and threaten human health through bioenrichment. Heavy metal residues in agricultural products are closely related to soil pollution. Soil is the source factor that affects the quality and safety of agricultural products. The results of investigation and evaluation on heavy metal pollution of soil environment in five vegetable supply areas in Hangzhou showed that the content of PbCuN Zn was lower than the second grade standard of national soil quality. The Nimero index is less than 0.7, and the soil clean. Crn AsN CD is slightly or moderately polluted in some vegetable producing areas, which may cause pollution to crops, which should be warned. Leafy vegetables, mushroom and rhizome vegetables all have strong enrichment ability to many heavy metals. The enrichment ability of eggplant fruits, pods, especially melon vegetables to heavy metals is weak. According to the results of the investigation, In this paper, the inhibition and control of heavy metals in typical soils were studied. The results of pot experiment showed that the removal efficiency of Cu Cr and CD by ryegrass was better than that of ryegrass. Compared with ryegrass, its tolerance to heavy metal pollution in soil was better than that of ryegrass. With the increase of pollution, more organic manure is needed to maintain the normal growth of plants. According to the results of pot experiment of plant restoration, it is suggested that ryegrass can be planted if we want to further optimize the soil quality of the original soil. Combined with 20% amount of organic fertilizer as ecological restoration plan; in secondary soil, planting ryegrass and applying 10% organic fertilizer as ecological restoration plan; in tertiary soil, Planting ryegrass and applying 20% organic fertilizer as ecological restoration scheme. In addition, the soil heavy metal ecological remediation scheme can be adjusted according to the specific key pollutants and pollution degree. The results of heavy metal passivation pot experiment showed that, The heavy metal passivation of biochar and fly ash is effective in acid soil and neutral soil. Fly ash has a good effect on inhibiting the leaching of heavy metals, but it can only improve soil acidification in a short period of time. Biochar has a good effect on increasing crop yield, reducing bioconcentration factor of heavy metals and improving soil properties. The application of biochar and fly ash can play a role of fertilizer slow-release agent. Tomato fruits and vegetables have better tolerance to soil heavy metal pollution and environmental changes. It is suggested that 5% of biochar and 20% of organic fertilizer can be applied to acid Liangzhu soil as ecological remediation of heavy metal passivation. 5% fly ash and 10% organic fertilizer were applied to neutral Joss soil as ecological remediation schemes for heavy metal passivation.
【学位授予单位】：杭州师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X53;X56

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