【作者】 张敏；

【导师】 涂书新； 廖晓勇；

【作者基本信息】 华中农业大学 ， 环境工程， 2009， 硕士

【摘要】 砷是我国优先控制的污染物。随着社会经济和工业的发展,全球许多国家面临严重的砷污染威胁,砷污染已成为人们普遍关注的环境污染之一。土壤砷污染与修复的研究已成为世界各国的科学热点问题和前沿研究领域。土壤污染物的化学修复技术是一种实用可行的土壤污染治理方法。本项目的研究目的是,通过研究化学添加剂对土壤砷生物有效性调控的效果及其可能的作用机理,筛选出经济有效、易于实施的化学添加剂应用于农业生产,从而为土壤As污染控制和农产品安全提供可靠的技术措施。本项研究针对我国土壤As污染的现状,通过室内恒温恒湿培养试验和温室盆栽试验,选用砷超积累植物蜈蚣草、粮食作物小麦和油料作物油菜以及不同蔬菜品种,通过向砷污染土壤添加不同的化学添加剂,研究其对土壤砷的有效性和形态及不同植物吸收利用砷的影响,明确化学添加剂对土壤砷有效性和形态的调节作用及初步机理。主要研究结果如下:1.在室内恒温恒湿试验条件下,添加石灰石粉、人工沸石、铁矿粉、含钛纳米材料、赤泥和煤渣处理的土壤有效As含量比对照均呈减少趋势(负相关),减少量分别为63.7%、63.6%、58.3%、41.5%、54.6%和49.9%,差异均达到极显著;土壤松散态As、铝结合态As、铁结合态As等有效态砷形态含量也均显著降低。添加EDTA、有机堆肥、过磷酸钙、磷矿粉和聚丙烯酸钠处理的土壤有效As含量随着培养时间的增加呈增加趋势(正相关),增加量分别为32.3%、50.2%、58.7%、44.6%和104%,且差异达到极显著,其中以聚丙烯酸钠增加最为明显;土壤松散态As、铝结合态As、铁结合态As等有效态砷形态含量也均显著提高。这表明,添加不同化学添加剂,一定程度上钝化/活化土壤中的砷,使得砷的可利用性和可移动性降低或提高。2.土壤盆栽条件下,添加EDTA,有机堆肥,过磷酸钙,磷矿粉及聚丙烯酸钠等5种化学添加剂提高土壤砷的有效性、促进土壤砷形态向有效态转化,从而促进蜈蚣草和油菜的生长并提高对砷的吸收积累。如,添加过磷酸钙处理蜈蚣草地上部干物重增加最为明显,平均比对照增长近64%。蜈蚣草砷浓度提高以EDTA处理最高,平均比对照高出近21%。蜈蚣草的砷累积量以过磷酸钙处理最高,比对照增长了近69%。3.土壤盆栽条件下,添加石灰石粉,人造沸石,铁矿粉,赤泥及煤渣等5种化学添加剂降低土壤砷的有效性,有效抑制小麦和油菜对土壤中砷的吸收积累并减小砷对小麦和油菜的毒害。如,添加这5种化学添加剂均显著降低小麦地上部砷浓度,其中铁矿粉、赤泥和煤渣处理的小麦内砷浓度分别平均比对照减少41%、29%和35%,统计分析均达显著水平。4.在土壤中添加EDTA,有机堆肥,过磷酸钙,磷矿粉及聚丙烯酸钠等5种化学添加剂有提高蜈蚣草盆栽土壤中性磷酸酶和脲酶活性及降低土壤蔗糖酶活性的作用。如,蜈蚣草盆栽土壤中性磷酸酶活性与对照相比平均增幅为2%—111%,脲酶活性平均增幅为3%—19%,土壤蔗糖酶平均减幅为9%—36%。在土壤中添加石灰石粉,人造沸石,铁矿粉,赤泥及煤渣等5种化学添加剂使得小麦和油菜盆栽土壤中性磷酸酶和脲酶活性提高,土壤蔗糖酶活性降低。小麦盆栽土壤中性磷酸酶活性与对照相比平均增幅为5%—35%,脲酶活性平均增幅为2%—9%,土壤蔗糖酶平均减幅为10%—55%;油菜盆栽土壤中这三种酶的活性与对照相比平均变幅分别为19—54%,4%—16%和0.6%—33%。5.添加铁矿粉和含钛纳米材料提高蔬菜地上部生物重,同时显著降低砷含量。添加铁矿粉和含钛纳米材料显著减少地上部砷含量,上海五月慢分别是24%和25%,芥菜型油菜品种芥菜50-1分别是3%和8%,芥菜型油菜品种岷县牛尾梢分别是37%和11%,甘蓝型油菜品种苏油15号分别是45%和66%,甘蓝型油菜品种D050-1分别是2%和42%。6.添加铁矿粉和含钛纳米材料处理的蔬菜体内的可溶性蛋白质与对照相比均降低。如,甘蓝型油菜品种苏油15号可溶性蛋白显著减少约21%和39%。但是,添加铁矿粉和含钛纳米材料处理的蔬菜叶片叶绿素a、叶绿素b和叶绿素总量含量与对照差异不显著。7.土壤添加铁矿粉和含钛纳米材料缓解了蔬菜的氧化胁迫。主要表现为,蔬菜叶片中SOD酶和CAT酶活性及GSH含量与对照相比均降低,而MDA积累减少。如,蔬菜叶片中SOD酶活性与对照相比平均减幅为6%—40%,CAT酶活性平均减幅为1%—22%,GSH含量平均减幅为1%—20%,蔬菜叶片中MDA含量与对照相比平均增幅为0.3%—23%。更多还原

【Abstract】 Arsenic is a priority pollutant to be controled in China. With the development of socio-economy and industry, many countries around the world are facing serious arsenic contamination. Nowadays, remediation of arsenic contaminated soil is a hotspot of scientific research and application around the world. Chemical remediation is a feasible and practical method to repair polluted soil. The purpose of this project was to study the influence of chemical additives on bioavailability of soil arsenic and its preliminary mechanisms, to select the best effective chemical additives used in agricultural production, and then to provide reliable measures to control soil arsenic contamination and to assure the security of agricultural products. Based on the status quo of the soil pollution in China, a constant temperature and humidity experiment and pot experiments using a hyperaccumulator Pteris vittata L., a food crop Triticum aestivum L. , and an oil crop Brassica napus L. were carried out to understand the effects of adding different chemical additives on the growth of the plant, the uptake and accumulation of arsenic by the plants as well as its preliminary mechanisms. The main results were as follows:1. Application of limestone, ersatz zeolite, iron powder, titania, red mud and cinder reduced markedly the soil available As under the conditions of constant temperature and humidity experiment, with the percentage decreased by 63.7%, 63.6%, 53.8%, 41.5%, 54.6% and 49.9%, respectively; application of EDTA, compost, calcium superphosphate, rock phosphate and sodium polyacrylate increased significantly the soil available As, with the percentage increased by 32.3%, 50.2%, 58.7%, 44.6% and 104%, respectively, of which the sodium polyacrylate was the most effective. The results showed that application of chemical additives could passivate or activate As in polluted soil by reducing or increasing the availability and movability of soil As.2. Application of EDTA, compost, calcium superphosphate, rock phosphate and sodium polyacrylate increased the amount of the soil available As and the growth and arsenic uptake of P. vittata L. in pot experiment. Calcium superphosphate was the most markedly effective additives, with an increasing percentage of 76% in biomass over the control. EDTA was the most markedly effective in increasing arsenic uptake by P. vittata L., with the increasing percentage of 21%. And the greatest arsenic accumulation of P. vittata L. went to calcium superphosphate, which the increasing percentage was 69%.3. Application of limestone, ersatz zeolite, iron powder, titania, red mud and cinder reduced the soil available As and arsenic uptake of wheat and promoted its growth in pot experiment. Iron powder, red mud and cinder reduced markedly arsenic uptake of wheat with a decreasing percentage of 26% and 35% over the control.4. Application of EDTA, compost, calcium superphosphate, rock phosphate and sodium polyacrylate increased soil neutral phosphatase activity and soil urease enzyme activity, but reduced soil sucrose enzyme activity of potting soil grown P. vittata L. The change range of soil neutral phosphatase activity, urease enzyme activity and sucrose enzyme activity are 2%-lll%, 3%-19% and 9%-36%, respectively. Application of limestone, ersatz zeolite, iron powder, red mud and cinder increased soil neutral phosphatase activity and soil urease enzyme activity, and reduced soil sucrose enzyme activity of wheat and rape, with the change range of soil neutral phosphatase activity, urease enzyme activity and sucrose enzyme activity over the control being 2%-111%, 3%-19% and 9%-36%, and 19%-54%, 4%-16% and 0.6%-33%, respectively.5. Application of iron powder and titania promoted the growth and reduced arsenic uptake of vegetables in pot experiment, with the decreasing percentages of 24% and 25%, 3% and 8%, 31% and 11%, 45% and 66% and 2% and 42%, respectively, for B. campestris L.ssp.chinensis, B. juncea var.50-1, B. juncea var.Minxianniuweishao, B. napus var.Suyou15 and B. napus var.D050-1.6. Application of iron powder and titania reduced soluble protein content in vegetables in pot experiment and the decreases of soluble protein content in napus var.Suyou15 were 21% and 39%, respectively. There was no obvious difference among the content of Chlorophyll a, Chlorophyll b and total Chlorophyll after addition of iron powder and titania. 7. Application of iron powder and titania relieved oxidative stress in vegetables, which was mainly showed as a decrease in activity of SOD and CAT, and the content of GSH and MDA in the shoots of vegetables, with the change range of 6%-40%, 1%-22%, 1%-20%, and 0.3%-23%, respectively.更多还原