垃圾堆肥在北方潮土地区的农用研究

研究结果表明：垃圾堆肥具有促进作物增产的作用，并不会引起重金属污染。但在北方潮土地区，垃圾肥施用量以４０～５０ｔ·ｈｍ－２·茬－１为宜。过量施用垃圾肥不仅会引起施肥经济效益明显降低，且会引起土壤砂化。研究还表明，粘质土壤对垃圾肥有更大的容纳量。     

徐州市北郊农田土壤重金属污染趋势面分析及其容量研究

本文把趋势面分析的数学方法应用于土壤重金属污染调查研究中,使重金属含量分布、污染情况等众多信息集中反映在一张图上,结果令人满意。同时结合当地重金属输入、输出情况,建立了动态平衡模式,计算出该区重金属的土壤环境动容量,并进行了土壤环境预测,为综合治理土壤污染提供了科学依据。     

活性污泥对重金属离子混合物的生物吸附

采用城市污水处理厂产生的活性污泥研究了影响污泥吸附Zn^2 ，Cu^2 和Cd^2 三种重金属离子的主要因素，在实验条件下，温度对污泥吸附重金属的影响并不显著，而体系Ph值和吸附时间等的影响较为重要，活性污泥对Cu^2 的吸附符合Langmuir模型，Zn^2 则与Freundlich模型的符合程度优于Langmuir模型，Cu^2 的吸附与两个模型的符合程度一致，另外，活性污泥对Cu^2 离子的吸附性能明显高于其他离子，但在实验中未发现不同金属离子之间存在明显吸附抑制或促进。     

The Impact of the Hyperacid Ijen Crater Lake. Part I: Concentrations of Elements in Crops and Soil

In Asembagus (East Java, Indonesia) irrigation water is contaminated with effluent from the hyperacid Ijen Crater Lake resulting in a low pH and high levels of various elements. As a first step towards a risk assessment, locally produced food items (rice, maize, cassava leaf, cassava root, peanuts) were collected and concentrations of As, B, Ca, Cd, Co, Cu, Fe, Mg, Mn, Mo, Ni, Pb, V, Zn were compared to samples from a reference area and with literature values. Further, concentrations in rice were compared to total soil concentrations in paddy fields. Compared to the reference area, food items produced in the contaminated area had increased levels of Cd, Co, Ni and Mn in particular, while levels of Mo were lower. In contrast, total soil concentrations of Cd and Mn in particular have decreased whereas especially Mo was increased. In combination with the observed soil acidification, it is likely that the bioavailable concentration of most elements in the contaminated soil is higher (except for Mo) due to an increased weathering rate and/or input via the contaminated irrigation water. In terms of human health, concentrations in foods were generally within normal literature values. However, it was observed that essential elements (in particular Fe) known for their inhibitory effects on e.g. Cd and Mn toxicity did not accumulate in crops whereas Cd and Mn did.     

Microorganisms for remediation of cadmium-contaminated soils

An alternative to the cleaning-up of agricultural soil contaminated by heavy metals is to avoid their transfer from soil to plant by inoculating soil with selected microorganisms able to biosorb heavy metals. Here, four bacteria species and a fungus isolated from contaminated soils revealed their ability to grow in the presence of high cadmium level. We tested their growth capacity related to pH and Cd concentration on synthetic and soil extract media. The comparison of their growth rate, the biosorbed cadmium rate and the specific biosorption allowed to select the most efficient microorganism to be used in bioremediation.     

Exposure to Selected Heavy Metals Through Water Ingestion in an Area Under the Influence of Tanneries

This study evaluated the potential toxicological risk posed to human health due to the exposure to heavy metals by water ingestion in an area affected by tanneries – the Cadeia-Feitoria hydrographic basin (Brazil). River water was collected at 10 sites, every 3 months, from July 1999 to April 2000. After acid digestion, total metal concentration was determined by inductively coupled plasma optical emission spectrometry (Cd, Cu, Cr, Ni, Zn), flame atomic absorption (Al, Fe, Pb, Mn), or cold vapor atomic absorption spectrometry (Hg). Cr(VI) was complexed with diphenyl-carbazide and detected by UV–vis spectrometry. In order to quantify the risk of exposure, the risk assessment methodology employed by the Environmental Protection Agency of the United States was applied at a screening level. The assumed scenarios included extreme exposure patterns (ingestion of untreated water, conversion of Cr(III) to Cr(VI), temporal peaks of pollution). Fe, Al, Cd, Hg, and Pb were not included in the risk analysis, since they showed a low toxicity potential or were undetected in the samples. The selected metals presented Hazard Quotients < 1, in the following order of increasing risk: Cu < Cr(III) < Zn < Ni < Mn < Cr(VI). Hazard indexes, representing the additive effect of contaminants, were also low in the basin (< 1), but comparatively increased in the lower reach of Feitoria and Cadeia Rivers. Although noncarcinogenic risk levels did not suggest possible adverse toxicological effects to the human population, a considerable deviation from background conditions was observed downstream the area where tanneries are mainly located.     

几种萃取剂对土壤中重金属生物有效部分的萃取效果

采用6种萃取剂:pH=7的0.01mol/L CaCl_2、pH=7.3的0.005mol/L DTPA+0.1mol/L TEA(三乙醇胺)+0.01mol/L CaCl_2O.1mol/L NaNO_3、0.43mol/L HOAc、pH=7的0.05mol/L EDTA和pH=4.65的0.5mol/L NH_4OAc+0.02mol/L EDTA浸取液.对污染土壤中的重金属Cu、Zn、Cd、Pb、的进行了萃取,并比较了萃取剂的萃取能力。实验结果表明,HOAc、EDTA以及NH_4OAc-EDTA萃取各种重金属的能力远远大于其它几种萃取剂的萃取能力,是比较理想的萃取剂。     

陆地生物配体模型（t-BLM）初探：镁离子降低铜离子对小麦根的毒性

生物配体模型(BLM)同时考虑了水中金属离子的化学形态以及阳离子与金属离子在生物配体(BL)上的竞争对其毒性的影响,能成功预测水体金属的生物毒性/有效性.最近,BLM呈现出向土壤环境中拓展的趋势,发展能预测重金属对土壤生物毒性的陆地生物配体模型(t-BLM)正成为最新的国际研究热点.论文模拟土壤溶液,以土壤溶液中的主要阳离子Mg2+为例,通过单因素浓度控制-恒pH营养液培养-陆生植物根伸长抑制试验,定量探讨了不同浓度Mg2+存在下,铜离子(Cu2+)对小麦(Triticum aestivum)根的毒性.结果表明,Mg2+浓度升高显著减弱了Cu2+对小麦根的毒性,即呈现出保护效应.证实陆地生态系统中也存在阳离子对重金属植物毒性的保护效应,支持了BLM中阳离子和重金属离子在生物配体上存在竞争结合的假设,即BLM概念适用于陆生植物.定量分析表明,小麦根生长抑制的毒性效应指标EC50(以自由铜离子活度表示)与自由镁离子活度间存在良好的相关性,线性回归方程为:pEC50(Cu2+)=-0.36(Mg2+)+6.47(r2=0.9976),Mg2+对Cu2+毒性的影响强度可以通过该方程进行预测.论文积累了重金属铜对典型陆生受试植物小麦的毒性数据,探讨了t-BLM的构建方法学,并为其发展提供了思路.联合了土壤理化性质、金属形态及生物积累和毒性效应的t-BLM,将提供一个环境风险评价和制定土壤质量标准的新工具.     

废铁屑修复汞污染土壤的实验研究

应用工厂废弃物—铁屑做原料,探讨不同铁屑投加量对修复不同土壤类型、不同程度汞污染土壤的能力,并与修复水体汞污染作了对比;另外,首次将淋滤法与国际上新兴的土壤、地下水修复技术-PRB技术结合,研究其修复土壤汞污染的效果。结果表明,废铁屑可很快去除水体中的汞,去除率可达93%;在铁屑存在下,能一定程度预防和修复土壤汞污染,在相同水体汞污染程度条件下,时间是影响土壤汞污染程度的主要因素;在CaCl2淋洗液作用下的模拟PRB实验中,土壤有效汞含量降低,同时淋洗液中汞质量浓度低于1μg·L-1。因此,用废铁屑能有效预防和修复土壤汞污染,且将淋滤法与PRB技术联用,与将铁屑直接撒入土壤中相比效果好得多,且不会引起后续的水体二次污染,是一种很有应用潜力、值得深入研究的土壤修复方法。     

快速PFU微型生物群落毒性试验法对铜、铅、砷联合毒性的研究

采用快速PFU微型生物群落毒性试验法对铜、铅、砷的联合毒性进行了研究 ,并用相加指数法评价其联合效应 .结果表明 ,Cu(Ⅱ )与Pb (Ⅱ ) ,Cu(Ⅱ )与As(Ⅴ )的联合毒性为协同作用 ;Pb(Ⅱ )与As(Ⅴ )的联合毒性为相加作用