污泥农用后土壤中重金属形态的转化

污泥农用后,土壤中重金属的形态会发生转化.用土柱模拟实际土壤,采用棕壤和褐土两种土壤类型,分别施人生活污泥和工业污泥.混合后,对土柱进行淋洗,经过7次淋洗后,测定土柱中0～10 cm均匀混合层中重金属各形态的含量,然后再与污泥和土壤混合后重金属形态不发生变化时重金属的总量相比较,得出污泥农用后土壤中重金属形态的转化规律.结果表明:Cu主要向碳酸盐结合态和残渣态转化,Pb向铁锰氧化物结合态转化,Zn向碳酸盐结合态转化.     

湖泊底泥土地利用对土壤中重金属铅、铜形态影响

采用田区试验研究了田间种植冬小麦条件下,底泥土地利用前后土壤中重金属铅、铜的形态演变及小麦各器官中铅、铜的富集。结果表明,随着底泥施用量的增加,土壤中重金属铅、铜的可交换态、碳酸盐结合态、铁锰氧化物结合态、有机结合态、残渣态均有不同程度的增加,本试验所有处理中,可交换态铅的质量分数范围为0.02~0.10 mg·kg-1,碳酸盐结合态铅的质量分数范围为0.04~0.24 mg·kg-1,铁锰氧化物结合态铅质量分数为0.41~1.88 mg·kg-1,有机物结合态铅质量分数范围为1.23~4.92 mg·kg-1,残渣态铅质量分数范围为4.82~23.66 mg·kg-1;各处理与对照相比,可交换态铜质量分数增加了40.00%~200.00%,碳酸盐结合态铜质量分数增加了36.84%~363.16%,铁锰氧化物结合态铜质量分数增加了7.17~45.15%,有机结合态铜质量分数增加了7.98%~62.61%,残渣态铜质量分数增加了0.12%~9.69%,各处理的残渣态铅、铜质量分数均较高。随着底泥用量增加,小麦根系、茎叶、籽粒中铅、铜质量分数均呈增加趋势,植株对重金属铅、铜的富集顺序为根系>茎叶>籽粒,铜的富集系数均大于铅。小麦籽粒产量、茎叶生物量及地上部生物量随着底泥施用量的增加,均出现了先增加后减少的现象,当小麦籽粒产量达到最大值时,籽粒中铅、铜质量分数未超出我国相应标准,依此确定底泥环境安全施用量为3051.29 t·hm-2。     

南京城市土壤中重金属的化学形态分布

采取Tessier连续提取法，研究了南京市不同城区表层土壤中Fe,Mn,Cr,Ni,Co,V,Cu,Zn,Pb的化学形态分布。结果表明，南京城市土壤中Fe,Mn,Cr,Ni,Co,V,Zn,Pb以残渣晶格态为主，可交换态比例极低；Cu在城市道路旁的土壤中有机物结合态所占的比例最高，其他区域残渣晶格态所占的比例最高，与非城区自然土壤相比，主要来源于人为输入的Mn,Cu,Zn,Pb残渣晶格态所占的比例低，活性态比例大；Cr和主要来源于原土壤物质的Fe,Ni,Co,V在城市土壤与非城区自然土壤中各形态所占的比例相似，残渣晶格态比例大，活性态比例极低。     

施用污泥的土壤重金属元素有效性的影响因素

污泥农用是解决城市污泥出路较为合理的途径.但由于含较高量的重金属,它的应用受到限制.研究发现,进入土壤的重金属在不同的土壤类型、不同的土壤条件下,形态分布各不相同,而不同形态的重金属对植物的有效性和毒性也不相同,本文试图对土壤中影响重金属形态分布的因素及机制作一综述.     

城市污泥好氧堆肥过程中重金属的形态转化

城市污泥是一种富含作物生长需要的多种养分的生物固体废弃物,但重金属问题又成为影响污泥农用的关键因素,而重金属的生物活性、迁移性及毒性不仅取决于总量,很大程度上取决于其存在的形态.该实验通过调节城市污泥的水分和C/N比,利用笔者所在课题组自行开发的好氧堆肥反应器进行城市污泥堆肥处理,经过为期20 d的好氧堆肥处理,研究堆肥前后污泥中的重金属总量和化学形态的变化.实验结果表明:堆肥处理由于添加能源调理剂等,使堆肥产品中的重金属含量低于原污泥,符合了农用污泥污染物控制标准;同时堆肥也改变了重金属的化学形态,降低了剧毒性的Cd的生物有效性.对污泥及堆肥的重金属形态研究发现:大部分重金属主要以残渣态形式存在,生物毒性很小,农用时的重金属污染度也很低.     

可控湿法氧化聚沉工艺对城市污泥中重金属的稳定化影响

采集了长沙市污水厂的剩余污泥（S1）和湿法氧化聚沉工艺处理的深度脱水污泥（S2）,对比分析了处理前后污泥的形貌变化及重金属Zn、Cu、Pb、Cd、Hg和As的形态分布,初步探讨了重金属稳定化机理,对脱水污泥中重金属Zn、Cu、Pb、Cd、Hg和As进行了稳定性评估.结果表明,脱水污泥中重金属的总量均低于我国污泥农用标准中的酸性限值,符合B级污泥泥质要求.处理后,污泥中Zn、Cu、Pb、Cd、Hg和As主要以硫化物有机结合态和残渣态（稳定态）存在,不稳定态在不同程度上向稳定态发生了转变,Cu、Hg的增幅最大,达21.1%.S2中重金属的生物可利用性较S1都有显著的降低,平均降幅达73.1%,S2中重金属的生物可利用性顺序为：Zn〉Pb〉Cu〉Cd〉As〉Hg.污泥经过湿法氧化聚沉工艺处理后,污泥中重金属Zn、Cu、Pb、Cd、Hg和As得到了明显的稳定化,为污泥后续资源化、安全化提供了科学依据.     

上海化学工业区土壤重金属元素形态分析

选取上海化学工业区土壤背景值样品，采用Tessier A连续提取法研究土壤中6种重金属元素的形态分布。研究结果表明，在该化工区土壤中，Cd主要以可交换态和铁锰氧化物结合态为主，分别占总量的41．5％和36．7％，说明元素Cd较活泼，具有潜在的环境影响能力，应该给予更多的关注；Cr、Cu、Ni和Zn等4种元素主要以有机结合态和残余态为主，两者分别占总量的41．4％、58．9％、31．4、32．5％和45．9％、31．5％、57．4％、52．3％；而Pb则主要以有机结合态形式存在，其占总量的87．8％；元素形态分析表明Cr、Cu、Ni、Zn和Pb这5种元素相对比较稳定。     

泉州城市污泥中重金属赋存形态和生物有效性分析

本文以泉州市几种有代表性的污泥为研究对象,通过分析各污泥中重金属总量和形态分布以及污泥中重金属有效态与总量的相关性,探讨重金属生物有效性与总量的关系,为后续的研究提供基础依据;将污泥重金属总量及形态情况与《农用污泥中污染物控制标准》（GB4284—84）进行比较,提出污泥农用可行性的合理建议.     

生物炭对土壤重金属化学形态影响的作用机制研究进展

生物炭作为一种新型的环境修复材料,可以利用其结构特性,通过静电吸附、离子交换、官能团络合以及沉淀等作用机制来直接吸附固定土壤重金属,同时还可以通过间接影响土壤理化性质,比如土壤pH值、有机质、氧化还原电位等,从而影响土壤中重金属形态。重金属形态在更大程度上影响着重金属的生物活性,从而产生不同的环境效应。该研究基于国内外相关文献,概述了不同类型生物炭对土壤重金属化学形态变化的影响,并从物理、化学和微生物3个角度,阐述了生物炭影响重金属化学形态的作用机制。未来的研究侧重于生物炭与微生物的相互作用对重金属形态的影响,通过多组学手段,深入分析两者相互作用影响土壤重金属形态的微生物作用机理。     

Eco-friendly approach for leaching out heavy metals from sewage sludge

Sewage sludge contains rich organic matter and nutrients essential for the growth of plants but the presence of toxic heavy metals restricts its land application. To overcome this, the study aims an eco-friendly approach for leaching out heavy metals. Sewage sludge from sewage treatment plant, Chennai, India was characterised. The analysis of total heavy metal concentration was done by digesting in nitric acid and different forms were extracted by community bureau of reference sequential method. Heavy metals: As, Cd, Cr, Cr, Ni, Pb and Zn were determined using inductively coupled plasma optical emission spectrometry Perkin Elmer Optima 5300 DV. The experimental set-up for heavy metal leaching was held for five consecutive days at different concentrations of humic acid (0.1%, 0.5% and 1%) at varied pH (5–9). Results revealed that at the end of fifth day at pH 8, 1% humic acid is capable of leaching out 75.5% cadmium, 66.0% nickel, 52.0% lead, 51.2% zinc, 31.2% copper and 8.5% cadmium from sewage sludge. Statistically positive correlation (0.7088) existed between the percentage of heavy metals leached out and the sum of soluble and reducible fractions. Thus, from ecological point of view, humic acid can be used to leach out heavy metals from sewage sludge serving the need in restoration of soil fertility upon land application.     

The correlation of total and extractable heavy metals from soil and domestic sewage sludge and their transfer to maize ( Zea mays L.) plants

A study to understand the mobility and transport of heavy metals (HMs) from soil and soil amended with sewage sludge to maize plants was carried out. The total and ethylenediaminetetraaceticacid (EDTA)-extractable HMs in agricultural soil and untreated domestic sewage sludge samples, and the correlation between the total and extractable metals in soil and sewage sludge were carried out. Pot experiments were performed to study the transfer of HMs to maize grains, grown in soil (control) and in soil amended with sewage sludge (test samples). The total and extractable HMs in soil, sewage sludge, and maize grains were analysed by FAAS/ETAAS (flame atomic absorption spectrometer/electrothermal atomic absorption spectrometer) after digestion in microwave oven. Statistically significant correlations were obtained between the total contents of Cu, Cd, As and their respective extractable fractions in soil, while in domestic wastewater sludge (DWS) the better correlation was observed only for Ni and Cd. The edible part of maize plants (grains) from test samples presented high concentration of Zn, Pb, Ni, Cd, Cu, As, and Cr concentrations (80.7–85.6, 3.8–3.95, 2.35–2.5, 0.75–0.82, 3.21–3.29, 0.23–0.27, and 0.22–0.29?mg?kg^?1, respectively). Good correlations were found between metals in exchangeable fractions of both soil and DWS and total metals in control and test samples of maize grains. The transfer factor of all HMs from DWS to maize grains was also determined.     

污泥施用对林地土壤基本性质及酶活性的影响

以无锡卢村污水处理厂厌氧消化的脱水污泥为有机肥源,采用土培盆栽试验的方法,研究了不同用量污泥施用后土壤基本性质的变化及对土壤酶活性的影响。试验设计5种处理,污泥施用量和占土质量的比例分别为0（不施污泥的对照处理,CK）,30（3%）,60（6%）,120（12%）和240（24%）g·kg^-1。结果表明,污泥使用提高了土壤中养分元素和有机质的含量;黄棕壤中过氧化氢酶的活性平均比潮土中的高5.2%,随污泥用量的增加潮土中过氧化氢酶活性提高,而黄棕壤中的无明显变化;与对照相比,土壤脲酶活性在两种土壤上分别增加55.6%～122%（黄棕壤）和46.2%～67.5%（潮土）,且与土壤全氮、全磷、水解氮、速效磷和有机质（黄棕壤）和土壤全氮、水解氮和有机质（潮土）呈正相关;结果还显示污泥使用增加了土壤蔗糖酶活性,但不同污泥用量之间无明显差异。     

Heavy metals from soil and domestic sewage sludge and their transfer to Sorghum plants

We studied the mobility and transport of heavy metals such as Cu, Zn, As, Cd, Cr, Ni, and Pb, from soil and soil amended with sewage sludge to sorghum plants. The total and ethylenediaminetetraacetic acid (EDTA) extractable heavy metals in agricultural soil and untreated domestic sewage sludge (DWS) samples were determined. The correlation between the total and extractable metals in soil and sewage sludge was investigated. The total and extractable heavy metals in soil, sewage sludge and sorghum grain were analysed by flame and electro thermal atomic absorption spectrometer (FAAS/ETAAS), after digestion in microwave oven. Statistically good correlations were obtained between the total contents of all heavy metals and their respective extractable fractions in soil and domestic wastewater sludge. Transfer factors of all heavy metals from domestic sewage sludge to sorghum grains were determined.     

施用城市污泥对土壤生态系统影响的研究进展

城市污泥的合理处置已成为目前环境科学研究领域中的重要课题。因污泥富含有机质和有效营养成分,对土壤改良有积极的促进作用,所以污泥的土地利用普遍被认为是一种积极、有效的处置方式。鉴于此,本文就国内外施用城市污泥对土壤生态系统的．影响及相关的过程和机理进行了综述。结果显示,施用污泥可改善土壤理化性质,提高土壤有机质和氮、磷等养分元素的含量,其改良作用因污泥类型而异。污泥对土壤重金属的积累有所影响,特别是在酸雨频发地区或者长期施用污泥,可能会带来重金属Gu污染的环境风险。污泥普遍有利于提高土壤酶活性,譬如土壤淀粉酶、脲酶和蔗糖酶活性,但污泥施用过量或时间延长,则会抑制多酚氧化酶和磷酸酶的活性,而污泥对过氧化氢酶的影响则不大。污泥对土壤微生物特性短期内有积极的影响,但长期则有负面作用。施用污泥可导致土壤动物活性的增加,但也会对一些土壤动物产生毒性,譬如异壳介虫属和弹尾目昆虫,而且污泥毒性不仅取决于污泥用量,土壤类型也起着重要作用。基于上述分析和评述,提出了未来研究展望如下：（1）针对污泥施用后土壤生态系统生物、物理和化学过程和机理进行系统、综合的基础研究;（2）对污泥土地利用进行长期的系统定位试验和环境监测,并对之进行环境风险评价;（3）对污泥稳定化处理技术的创新及其应用研究。     

Current status and developing trends of the contents of heavy metals in sewage sludges in China

It is essential to determine the heavy metal concentrations in sewage sludge to select appropriate disposal methods. We conducted a national survey of heavy metal concentrations of sewage sludge samples from 107 municipal sewage treatment plants located in 48 cities covering the 31 provinces and autonomous regions, as well as Hong Kong, Macao and Taiwan by Xinjiang Production and Construction Corps in 2006, and identified the temporal trends of heavy metal contents in sewage sludge by comparison with surveys conducted in 1994-2001. In 2006, the average concentrations of As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn in sewage sludge were 20.2, 1.97, 93.1, 218.8, 2.13, 48.7, 72.3, and 1058mg.kg-1, respectively. Because of the decreased discharge of heavy metals into industrial wastewater in China and the increasingly stringent regulations governing the content of industrial wastes entering sewers, the average concentrations of Cd, Cr, Cu, Hg, Ni, Pb, and Zn have decreased by 32.3%, 49.7%, 54.9%, 25.0%, 37.2%, 44.8%, and 27.0%, respectively, during the past 12 years. The concentrations of Cd, Cr, Cu, Ni, and Zn in the samples exceeded the heavy metal limits of the Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant in China （GB 18918-2002） by 6.5%, 3.7%, 6.5%, 6.5%, and 11.2%, respectively. From these results, 85 of the 107 municipal sludges analyzed would be considered suitable for land application.     

城市污泥中重金属镉对苏云金杆菌发酵的影响机制

为揭示苏云金杆菌（Bacillus thuringiensis,简称Bt）富集重金属的可行性,考察重金属对Bt发酵的影响,以生物毒性较大的重金属镉（Cd）为研究对象,以城市污泥为培养基,研究了添加Cd（II）对Bt生长和晶体蛋白合成的影响,分析了Bt发酵过程中Cd有效态质量浓度的变化,利用傅立叶红外光谱（FTIR）和X线光电子能谱（XPS）初步探讨了Cd（II）在Bt表面吸附的作用机制。结果表明：培养基中外加Cd（II）对Bt生长的影响主要取决于Cd有效态质量浓度,污泥培养基在支持Bt生长和降低重金属有效态质量浓度上均明显优于常规培养基;Bt对Cd（II）有较好的耐受性,当Cd有效态质量浓度在20 mg.L-1以下时,Bt能较好地完成生长代谢过程;光谱学分析表明Bt对Cd（II）有少量吸附,吸附位点主要为羟基,少量C=O基团也可与吸附反应,可有效降低重金属的生物有效性。     

施用城市污泥对杨树土壤化学特性及金属含量的影响

采用温室盆栽方法,研究城市污泥对杨树土壤化学特性、金属含量的影响。实验设置6个处理：4个不同用量的污泥处理：30（S1）、60（S2）、90（S3）和120 t.hm-2（S4）,以及对照（Control：不施加污泥和肥料）和无机复合肥处理（F：1.5 t.hm-2）。结果表明,施用污泥后,土壤有机质、全氮及全磷均提高,且随污泥施用量的增加而增加。S1~S4处理的土壤有机质、全氮及全磷较Control处理分别提高了32.50%~52.05%、32.00%~95.30%及75.43%~236.25%;较F处理分别提高了47.60%~69.37%、35.04%~99.70%及77.10%~239.46%。但污泥施用降低土壤pH和全钾质量分数,土壤pH较Control和F处理分别下降了0.11~0.42和0.01~0.32,但仍呈弱碱性;土壤全钾质量分数较Control和F处理分别降低了1.65%~21.51%和1.19%~21.14%。随污泥施用量的增加,土壤Cu、Zn、Ca和Na质量分数呈增加趋势,而Mn、Fe、Al、Mg质量分数呈降低趋势,其中Cu和Zn增加明显,并较Control处理分别增加了31.89%~104.36%和38.93%~358.02%,较F处理分别增加了23.10%~90.75%和37.88%~354.55%。总体而言,污泥施用于杨树后,可明显改善土壤的化学特性,但污泥施用量越大,土壤重金属Cu和Zn的质量分数残留越多。