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首页> 外文学位 >Chemical remediation of Copper-contaminated soils using Calcium water treatment residue.
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Chemical remediation of Copper-contaminated soils using Calcium water treatment residue.

机译：使用钙水处理残留物对铜污染土壤进行化学修复。

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摘要

Copper (Cu) contamination to agricultural soils is on the rise worldwide due to extensive use of Cu-containing fertilizers, fungicides, farm manures, and waste disposal in agricultural lands. In south Florida, Cu accumulation in soils under citrus production has been accelerated as a result of increased application of Cu-based fungicides for battling canker disease. In this study, laboratory analysis, greenhouse experiments, and field trials were conducted to investigate the status of soil Cu contamination in south Florida, the effectiveness of chemical remediation using lime-based water treatment residue (Ca-WTR) and the biogeochemical processes controlling Cu availability in Ca-WTR amended soils. Soil samples were collected from 18 representative commercial citrus groves in the Indian River area of South Florida and characterized for Cu chemistry and availability. Total Cu in the surface soils ranged from 4.74 (4 yrs grove) to 228 mg kg-1 (30 yrs grove), with approximately 50% of the soil samples having a total recoverable Cu concentration above or close to the critical Cu level of total Cu: 85 mg kg-1. On average, 48% of the total recoverable Cu was Mehlich-3 extractable, indicating high availability of the soil Cu. The largest proportion (25 to 58% of total Cu) of soil Cu was present as organically-bound. Both total recoverable Cu and Mehlich-3 extractable Cu were significantly correlated with this Cu fraction (P<0.001). Most of the Cu was accumulated in the surface soil layer (0-15 cm), but vertical leaching occurred in some soils with pH < 6.5. Two typical soils (a Spodosol and an Alfisol with a total recoverable Cu ~ 100 mg kg -1), which are dominant under citrus production in the Indian River area, were selected for remediation studies. The results from incubation studies indicated that amendment of Ca-WTR (pH 9.1, containing mainly CaCO3 and minor CaO) significantly raised soil pH. Water soluble and exchangeable Cu fraction decreased by 62% in the original and by 90% in the Cu-enriched soils (added with 400 mg Cu kg-1), whereas oxides-bound and residual Cu in the soils increased accordingly. Similar results were obtained from column leaching experiments. The cumulative amount of Cu in the leachates from 10 leaching events was reduced by 80% and 73%, respectively for Alfisol and Spodosol at the highest Ca-WTR amendment rates (20 g kg-1 for Alfisol and 100 g kg-1 for Spodosol). Greenhouse studies with ryegrass (Lolium perenne L.) and lettuce (Lactuca sativa L.) as indicator crop plants indicated that the growth of plants was inhibited in the slightly Cu-contaminated soils (~100 mg kg-1), but no plant survived in the severely Cucontaminated soils (added with 1000 mg kg-1). Amendment of Ca-WTR at 5-20 g kg-1 for the Alfisol (pH 5.45) and 5-100 g kg-1 for the Spodosol (pH 4.66) significantly reduced plant Cu concentrations and thus improved plant growth as evidenced by a significant increase in plant biomass yield (P<0.01).
机译：由于广泛使用含铜肥料，杀真菌剂，农用肥料以及在农田中进行废物处理，对农业土壤的铜（Cu）污染在全球范围内呈上升趋势。在佛罗里达州南部，由于越来越多地使用基于铜的杀真菌剂来对抗溃疡病，加速了柑橘在土壤中的铜积累。在这项研究中，进行了实验室分析，温室试验和田间试验，以调查佛罗里达州南部土壤铜的污染状况，使用石灰基水处理残留物（Ca-WTR）进行化学修复的有效性以及控制铜的生物地球化学过程Ca-WTR改良土壤中的有效性。从南佛罗里达州印度河地区的18个代表性商业柑橘林中收集土壤样品，并对铜的化学性质和有效性进行了表征。表层土壤中的总铜含量范围为4.74（4年树丛）至228 mg kg-1（30年树丛），其中大约50％的土壤样品中可回收的总铜浓度高于或接近总铜的临界铜水平。铜：85mg kg-1。平均而言，可回收的总铜中有48％是可提取的Mehlich-3，表明土壤铜的利用率很高。土壤中铜的最大比例（占总铜的25％至58％）以有机结合的形式存在。总可回收铜和Mehlich-3可提取铜均与该铜含量显着相关（P <0.001）。大部分的Cu积累在表土层（0-15厘米）中，但在pH <6.5的某些土壤中发生了垂直浸出。选择了在印度河地区柑橘生产中占主导地位的两种典型土壤（Spodosol和Alfisol，总可回收Cu〜100 mg kg -1）进行修复研究。孵化研究的结果表明，对Ca-WTR（pH 9.1，主要包含CaCO3和少量CaO）的修正显着提高了土壤pH。水溶性和可交换的铜含量在原始土壤中降低了62％，在富含铜的土壤（添加了400 mg Cu kg-1）中降低了90％，而土壤中氧化物结合和残留的铜相应增加。从柱浸实验获得了相似的结果。在最高的Ca-WTR修正率下（Alfisol为20 g kg-1，Spodosol为100 g kg-1），Alfisol和Spodosol的10个浸出事件中渗滤液中的Cu累积量分别减少了80％和73％。 ）。以黑麦草（Lolium perenne L.）和生菜（Lactuca sativa L.）为指标作物的温室研究表明，在轻度铜污染的土壤（〜100 mg kg-1）中，植物的生长受到抑制，但没有植物存活在重度被铜污染的土壤中（添加1000 mg kg-1）。 Ca-WTR对Alfisol（pH 5.45）的修正为5-20 g kg-1，对Spodosol（pH 4.66）的修正为5-100 g kg-1，显着降低了植物Cu的浓度，从而改善了植物的生长，这一点得到了证明。增加植物生物量产量（P <0.01）。

著录项

  • 作者

    Fan, Jinghua.;

  • 作者单位

    University of Florida.;

  • 授予单位 University of Florida.;
  • 学科 Soil sciences.;Environmental science.;Agronomy.
  • 学位 Ph.D.
  • 年度 2010
  • 页码 123 p.
  • 总页数 123
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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