尾矿库尾砂及周边农田土壤重金属形态分布及其生物有效性

采用BCR（community bureau of reference）连续提取法对大宝山矿山槽对坑尾矿库尾砂和周边农田土壤重金属Cd、Pb、Cu和Zn的形态分布及其生物有效性进行了分析。结果表明,尾砂中Cd、Pb、Cu和Zn残渣态占绝对优势,占其总量的百分数均在85%以上。农田土壤中Cd、Cu和Zn都以残渣态为主,分别占其总量的60%、60%和90%以上,Pb以残渣态和可还原态为主,占其总量的93.44%。农田土壤重金属有效性较尾砂大,尾砂和农田土壤重金属生物有效性均以Pb为最高。     

Bioavailability of Heavy Metals in Sewage Sludge-Amended Thai Soils

Plough and subsoil layers of two majoragricultural soil series, Rangsit and Thonburi, foundin Bangkok area of Thailand were studied fordetermining the bioavailability and solubilitybehavior of heavy metals (Cd, Cu, Zn, Mn, and Fe)following application of sewage sludge from awastewater treatment plant and a series of laboratoryexperiments. The soils contained low indigenous heavymetals while the sludge contained higher amounts ofheavy metals but in an acceptable range forapplication as plant nutrient source in agriculturalsoil. Applications of sewage sludge increased pH ofthe acid soil and available plant nutrients to thesoils. The heavy metal concentration levels in thesoils also increased. Most partitioned into easilymobile pools and later into sparingly mobile poolsfollowing 12 weeks of incubation time. Bioavailabilityforms of Cd in soil solution were low but that of Cu,Zn, and Mn remained elevated even at 12 weeks of thereaction time. Applied inorganic Zn depressed Cdsorption capacity of two soils studied but it had noeffect on Cd desorption.     

污泥中重金属的环境活性及生态风险评估

研究了湖南省长沙市、株洲市和常德市10个污水处理厂剩余污泥中As,Cd,Cu,Ni,Pb,Zn的含量和形态特征,并利用潜在生态危害指数法对污泥农用过程中重金属的生态风险进行了综合评价。结果表明,城市污泥中富含有机质及N,P,K等养分,然而,污泥表现为以Cd为主的多金属污染,不能直接农用。污泥中Cd含量为1.43～260mg/kg,以可还原态为主,占全量比例高于28.9%;As,Pb的可还原态,Ni,Zn的酸可溶态和可还原态,Cu可还原态和氧化态所占比例较高,表明污泥中重金属的潜在环境活性较高。风险指数评价结果表明,污泥中Cd和As是潜在的强生态风险元素;以工业废水处理为主的污水处理厂污泥重金属单因子生态风险相对较高,且综合潜在生态风险严重。     

蚯蚓活动对城市生活污泥重金属的影响

采用塑料温棚内垄式堆积污泥培养蚯蚓方式,研究了蚯蚓处理对污泥重金属的影响。结果表明,污泥经蚯蚓处理后,理化性质发生了显著的变化,污泥的pH值、有机质、总氮和总磷都有不同程度的降低;蚯蚓能吸收富集污泥中的重金属,其中对重金属Cd有较强的富集能力;蚯蚓处理使污泥中重金属含量均出现不同程度的下降,重金属Cr、Zn、Pb、Cd、Cu、Ni分别减少27.98%、31.46%、32.81%、13.85%、23.86%和22.92%。利用盆栽试验,研究了污泥施用于土壤后生菜体内重金属积累的情况,结果表明,生菜体内重金属Zn、Cu、Pb和Ni的含量为污泥处理高于蚓粪处理;Cr和Cd则分别为差异不显著和略有降低。     

Co-application of Red Gypsum and Sewage Sludge on Acidic Tropical Soils

The agroenvironmental impact of co-utilization of red gypsum and sewage sludge was investigated. Both laboratory and greenhouse studies were conducted. The treatments were soil + sewage sludge (5% w/w) + red gypsum (0, 2.5, 5, 10, 20, and 40%, w/w). Corn was grown in the greenhouse, and the highest rate of red gypsum application was excluded. The residual calcite in red gypsum was able to increase the pH of the red gypsum–sewage sludge acidic soil system. Hence, gypsum reduced the zinc (Zn) concentrations in the soil solution released by sewage sludge. Phosphorus (P) and potassium (K) were insufficient for corn growth. At the rate of 2.5% red gypsum and 5% sewage sludge application, no dry-matter reduction was observed compared to the control. The uptake of Zn, copper (Cu), and iron (Fe) by the corn plants decreased. Therefore, co-utilization of red gypsum and sewage sludge is a better option than using these by-products separately.     

贵州省典型城市污水处理厂污泥养分与重金属含量调查

分别采集贵州省8个典型地级城市污水处理厂冬季和夏季的脱水污泥样品,进行室内分析测试,研究其养分和重金属特性。结果表明,贵州省主要地级城市脱水污泥pH为6.5-7.4,盐分含量为0.4-0.9。城市污泥中有机质、全量N、P高于一般农家肥,但全K量较低。污泥中全量重金属Cu、Pb、Ni、Cr、Hg和As均远低于国家农用标准,但一个处理厂污泥Cd、Zn超标,另有一处理厂污泥Cd超标,有3个处理厂污泥存在Zn超标现象。形态分析表明,Cd在多数污泥中化学形态主要是以生物有效态的形式存在,而Zn主要以稳定的化学形态存在,说明Cd存在环境风险,而Zn相对安全,表明贵州地区脱水污泥多数可安全农用,冬季和夏季脱水污泥的养分和重金属浓度没有显著差异。     

污泥与施污土壤重金属生物活性及生态风险评价

将城市污泥以不同质量比施于土壤中构成污泥混合土壤,研究各污泥配比土壤中重金属的生物活性,并采用三种重金属评价方法(地累积指数法、潜在生态风险指数法、综合毒性指数模型)和黑麦草对重金属的吸收富集效果来对施污土壤中重金属具有的生态风险性进行评价。结果表明:污泥的添加使土壤中生物活性态Cd、Cu和Zn含量显著增加,对三种重金属具有活化作用,但对Pb却起到钝化作用。生态风险评价结果表明:污泥的添加使土壤中Pb呈现无污染和低生态风险;Cu和Zn呈现中度污染和低生态风险;Cd达到强度污染和重度生态风险,重金属潜在生态风险(RI)总体处于强度生态风险水平。当污泥添加比例大于6:10(污泥S3处理)时,施污土壤中重金属的综合毒性指数高于土壤对照。黑麦草对Cd、Pb、Cu和Zn的富集浓度与施污土壤中对应重金属的生物活性态含量存在显著正幂指数关系,同时黑麦草对施污土壤中Cd、Cu和Pb的富集能力大小与地累积指数法和潜在生态风险指数法对三种重金属具有的生态风险性的评价结果具有一致性。     

城市污泥农用对不同土壤中有机污染物的影响

应用气相色谱(GC)和高效液相色谱(HPLC)技术对施用城市污泥盆栽植物后的土壤中的多氯联苯(PCBs)、有机氯农药(OCPs)、菲(PA)和苯并[a]芘(B[a]P)进行了系统分析,探讨不同土壤中有机污染物的含量变化情况.结果表明,不同处理土壤中检出的有机化合物,均以PCBs、OCPs和PA为主.强致癌性化合物苯并[a]芘在土壤中的含量远远低于加拿大和荷兰污染土壤治理标准的目标值(0.1 mg/kg和0.025 mg/kg).PA在土壤中的检出率大大高于苯并[a]芘,但均低于加拿大土壤质量控制标准(0.1 mg,kg),极个别高于荷兰土壤质量控制标准(0.045 mg/kg).城市污泥农用后均会造成土壤不同程度的有机污染物污染,有机污染物污染土壤的程度与污泥的性质、有机化合物的性质和土壤的性质等有关.     

皖南茶园土壤重金属化学形态及其生物有效性

以皖南茶园为研究对象,通过Tessier连续提取分级法对茶园土壤重金属(Zn,Cu,Pb,Ni)全量及其化学形态进行了分析,利用活性态重金属占全量之比来评价其生物有效性。结果表明,皖南茶园土壤中Zn,Cu,Pb,Ni含量均未超过国家标准;除Zn外,其他元素均高出背景值,存在较明显的富集现象;土壤中4种重金属在5种形态上表现出不同的分布规律,Zn,Cu,Ni以残渣态为主,分别占总量的72.55%,90.00%和81.79%,而Pb以铁锰氧化物结合态为主,占总量的70.09%;Zn,Cu,Pb,Ni的活性态部分占全量比例分别为5.04%,1.51%,0.97%和0.23%,土壤重金属活性态部分与茶叶中重金属含量之间呈现正相关关系,且皖南茶区的茶叶重金属含量在限量值的安全范围内。     

Environmental Implication of Soils Amended with Anaerobically Digested Sewage Sludge in Hong Kong

Rainfall leaching soil column trials wereused to characterize the downward movement ofpotential contaminants through a sandy loam and sandysoil following the application of an anaerobicallydigested sewage sludge at the rates of 10 and 25%(v/v). Leachate pH did not vary significantly withsludge application except for sandy loam with 25%sludge, while initial electrical conductivity (EC) anddissolved organic carbon (DOC) increased linearly withsludge application and declined shortly to levelsfound in soils without sludge. A higher initialleaching loss of ammonium (NH₄ ⁺) was found in sandy soilthan loamy sand due to its lower cation exchangecapacity. Nitrate (NO₃ ^-) was the dominant anion inleachates with an average in excess of 10 mg L^-1 NO₃ ^- at all loading rates after 12 weeks. The highestconcentration of NO₃ ^- occurred with the highest sludgeapplication rate. Leachate zinc (Zn) content increasedin loamy sand columns at the high sludge loading rateat the end of the experiment owing to the reduced pHfollowing nitrification. No significant difference inleachate copper (Cu) and phosphate (PO₄ ^3-) contents werenoted for both soils receiving various sludgeapplication rates. Evaluation of the soluble nutrientspresent in the soil profiles at the end of theleaching experiment showed that EC, NH₄ ⁺ and PO₄ ^3- increased according to sludge application rate up toa depth of 20 cm. Significant accumulation of NO₃ ^- wasfound in sandy loam with sludge application to thedepth of 50 cm. Analyses of leachates and soils forthe selected contaminants revealed that NO₃ ^- leaching islikely to occur without plant growth at the currentapplication rate. Therefore, the application rate forsludge should not exceed 10% (v/v), and the provisionof vegetation on the amended soil would reduce theleaching loss of NO₃ ^-.     

剩余污泥厌氧消化过程重金属形态转化及生物有效性分析

为研究污泥厌氧消化过程中物理化学性质的变化对典型重金属形态转化的影响,对其农用的可行性及生物有效性进行评估,对取自某城市污水处理厂的剩余污泥进行了序批式厌氧消化实验,在试验过程中测定了污泥理化学性质,采用Tessier分步提取法提取了污泥样品中的典型重金属,并采用电感耦合等离子发射光谱仪（ICP-OES）测定各形态重金属含量及总量。结果表明,厌氧消化过程中重金属的形态发生了显著变化,由不稳定态向比较稳定的残渣态和有机结合态转变,某些重金属形态与污泥理化性质如pH、碱度、VS/TS及氨氮显著相关。厌氧消化可以有效地降低污泥中重金属的潜在迁移能力和生物有效性,经厌氧消化后污泥可以更好地进行土地利用。     

Growth and Heavy-Metal Uptake by Lettuce Grown in Soils Applied with Sewage Sludge Compost

A pot experiment was conducted to investigate the effect of sewage sludge compost (SSC) alone and applied with chemical fertilizer on growth and heavy-metal accumulations in lettuce grown on two soils, a Xanthi-Udic Ferralosol and a Typic Purpli-Udic Cambosol. The treatments included control; nitrogen–phosphorus–potassium (NPK) fertilizer; sewage sludge compost applied at the rates of 27.54 (SSC), 82.62 (3SSC), 165.24 (6SSC) t hm^–2; and coapplication treatment (1/2 SSC + 1/2 NPK), where the N, P, and K inputs from NPK fertilizer, SSC, and coapplication treatments were normalized to the local recommend rates. The SSC application increased the biomass; copper, zinc, and lead contents in lettuce; and soil total and diethylenetriaminepentaacetic acid (DTPA)–extractable metals. However, SSC alone at the recommended rate caused less plant biomass than NPK fertilizer alone. Coapplication treatment obtained greater or similar biomass to NPK fertilizer alone and did not increase heavy-metal accumulation in soils and plants. The results demonstrated that SSC should be applied to soils with chemical fertilizers.     

干旱区绿洲土壤Cd／Pb复合污染下重金属形态转化与生物有效性

采用盆栽试验及连续浸提形态分级方法,研究了Cd和Pb在土壤中的形态分布规律及其对油菜的生物有效性的影响。结果表明,当土壤受外源Cd/Pb污染后,重金属的形态分布特征发生了变化,以可交换态（EXC）响应最大,Cd、Pb的赋存形态分别以碳酸盐结合态（CAB）、铁锰氧化态（FMO）和碳酸盐结合态（CAB）为主;一定浓度范围内的Cd/Pb复合胁迫能促进油菜的生长,油菜根系和茎叶的Cd、Pb含量均随着Cd/Pb复合胁迫水平的升高而持续增加。茎叶中的Cd含量远远高于根系,Pb含量反之。油菜可将更多的Cd从根系转移至茎叶,而将更多的Pb滞留在根系中;对油菜根系吸收Cd最重要的形态为可交换态（EXC）和碳酸盐结合态（CAB）,而对茎叶吸收Cd以及油菜吸收Pb贡献最大的则为碳酸盐结合态（CAB）。     

Leaching of Metals from Oxidising Sulphide Mine Tailings with and without Sewage Sludge Application

A 20-month column experiment investigated leaching of Al, Cu, Mn, Ni, Zn, Cd and Pb during sulphide oxidation in mine tailings with and without sewage sludge (SS) amendment. Leachate pH decreased gradually in all columns during the experiment, irrespective of treatment, due to sulphide oxidation. As the degree of sulphide oxidation, and thus the pH trajectory, differed between replicates (n?=?3), running data for each column used are reported separately and the relationships between sulphide oxidation, metal leaching and treatment in each column compared. Mean pH in the columns correlated negatively with total amounts of leached SO₄ ^2-. In the beginning of the experiment the leachate concentrations of Al, Cu, Zn, Ni and Pb were higher in SS-treated columns due to high initial concentrations of dissolved organic carbon. As leaching proceeded, however, the amounts of Al, Cu, Mn and Ni leached from the columns were closely related to the degree of sulphide oxidation in each column, i.e. to its mean pH. There were no statistically significant differences between treatments regarding the total amounts of metals leached and thus addition of sewage sludge to the tailings appeared to play a minor role for metal leaching patterns. Peak concentrations of Al and Cu in the leachate from untreated tailings and of Zn in the leachate from both untreated and SS-treated tailings at pH 4 exceeded national background values for groundwater.     

Impact of Sewage Sludge Compost Utilization on Chemical Properties of Olive Grove Soils

Field experiments were conducted for four years, between 1998 and 2002, in two olive grove soils of adult olive orchards (Olea europaea L. cv. Cornicabra) in a clay loam soil in Seseña (Toledo, Spain) and in a sandy loam soil in Aranjuez (Madrid, Spain). There were four treatments, sewage sludge compost (SSC), sewage sludge compost plus urea (SSC+U), urea (U) and control (C). Each treatment was replicated four times and two depths were studied (0-15 and 15-30 cm). Once a year, before spreading sewage sludge compost, soil samples were taken at depths of 0 to 15 cm and 15 to 30 cm. Organic matter, total Kjeldhal nitrogen, phosphorus availability, pH, and electric conductivity were measured. No differences were found between treatment on organic matter and electric conductivity after four years of application of sewage sludge compost to two olive grove soils. In relation to nitrogen content, sewage sludge compost, only in Seseña, produced higher nitrogen soil content than the traditional urea treatment. Sewage sludge compost applied on olive grove soils improved the Phosphorus availability for the olive tree. In Aranjuez, the use of sewage sludge compost increased the pH of the soil with respect to Urea and Control plots. In Seseña, the reverse effect was found.     

Heavy Metals in Soil, Plants and Groundwater Following High-Rate Sewage Sludge Application to Land

The concentrations, solubility and mobility of Cr, Cu, Ni, Pb and Zn were measured over a four year period in soil from a site that had received over 1000 t ha^-1 wet, undigested, sewage sludge (on average, 15% dry solids). The pH of this light-textured sandy soil was markedly reduced after sludge application (to ≤4 in some samples), presumably as a result of breakdown of the unstable organic matter, nitrification of the NH₄ ⁺-N and sulphide oxidation. As a consequence, soil solution concentrations of Cu, Ni, and especially, Zn were initially elevated, and this was reflected in high plant uptake of Zn and elevated levels of all three metals in some groundwater wells. An extensive liming programme resulted in soil pH values generally between 5 and 6, more normal for this soil, in the following years. Soil solution metal concentrations were substantially lower, e.g., Zn from a high of 27 mg kg^-1 in 1995 to 0.04 mg kg^-1 in the equivalent sample in 1999. Herbage Zn concentrations declined accordingly and overall there was a strong relationship between plant metal uptake and soil solution concentration of this element (R² = 0.84), although not for any of the other metals. Our results suggested that, for this soil, pH was by far the greatest determinant of metal solubility and that the metal source, whether sewage sludge or geochemical, had little influence. Results from extractants that solubilise other metal phases, i.e., NaNO₃, EDTA and HNO₃, are also presented and discussed.     

Chemical Speciation of Heavy Metals in the Fractionated Rhizosphere Soils of Sunflower Cultivated in a Humic Andosol

Chemical speciation and bioaccumulation factor of iron (Fe), manganese (Mn), and zinc (Zn) were investigated in the fractionated rhizosphere soils and tissues of sunflower plants grown in a humic Andosol. The experiment was conducted for a period of 35 days in the greenhouse, and at harvest the soil system was differentiated into bulk, rhizosphere, and rhizoplane soils based on the collection of root-attaching soil aggregates. The chemical speciations of heavy metals in the soil samples were determined after extraction sequentially into fractions classified as exchangeable, carbonate bound, metal–organic complex bound, easily reducible metal oxide bound, hydrogen peroxide (H₂O₂)–extractable organically bound, amorphous mineral colloid bound, and crystalline Fe oxide bound. Iron and Zn were predominantly crystalline Fe oxide bound in the initial bulk soils whereas Mn was mainly organically bound. Heavy metals in the exchangeable form accumulated in the rhizosphere and rhizoplane soils, comprising <4% of the total content, suggesting their relatively low availability in humic Andosol. Concentrations of organically bound Fe and Mn in soils decreased with the proximity to roots, suggesting that organic fraction is the main source for plant uptake. Concentrations of Mn and Zn in the metal–organic complex also decreased, indicating a greater ability of sunflower to access Mn from more soil pools. Sunflower showed bioaccumulation factors for Zn, Fe, and Mn as large as 0.39, 0.05, and 0.04 respectively, defining the plant as a metal excluder species. This result suggests that access to multiple metal pools in soil is not necessarily a major factor that governs metal accumulation in the plant.     

兰州市城市污泥施用对小麦生长和重金属富集的影响

以兰州市安宁区污水处理厂污泥为研究对象,采用盆栽的方法研究污泥土地利用后对土壤中重金属含量以及对3种小麦生长和重金属富集的影响。结果表明,污泥施用后使污泥混合土壤中重金属Pb、Cu、Zn含量显著增加,但3种重金属含量均未超过我国土壤环境质量二级标准(GB15618-1995)中的限制性标准值。污泥土地施用后,小麦获得了良好的生长响应。污泥低施入量(污泥在混配土壤中的干重比为5%、10%、15%)时不同程度的促进了小麦的生长发育,使3种小麦出苗率提高,植株更高,生物量增加。污泥高施入量(污泥在混配土壤中的干重比为25%、35%)时,小麦的出苗率和根长受抑制明显。污泥的施用使小麦籽实中的Pb、Cu、Zn的含量显著升高,呈现递增趋势,污泥在混配土壤中的干重比超过25%时,籽实中Cu和Pb含量相对国家无公害食品标准有超标现象。综合考虑污泥对小麦生长和重金属富集的影响及土壤中重金属含量的变化,对小麦的耕种土壤中一次性施用污泥时,污泥在混配土壤中的干重比应限量在25%以下。     

Diplopods as Bioindicators of Soils: Analysis of Midgut of Individuals Maintained in Substract Containing Sewage Sludge

Diplopods feed organic matter in decomposition; however, some environmental factors can promote changes in tissues of these animals. Sewage sludge has been applied for recuperation of physical structure of degraded soil. This work analyzed the influence of the sludge from a city of São Paulo in the midgut of the diplopod Rhinocricus padbergi. After the exposition to sludge, the midgut was prepared for histological and ultra-structural analyses. After 1 week of exposition, there were various glycoprotein globules in the fat body, which appeared, ultrastructurally, little electron dense. In the animals exposed for 2 weeks, there was an intensive renovation of the epithelium with the invasion of regenerative cells, which was observed in the histological and ultra-structural analyses. These data showed that the sludge present various substances that were very hazardous for these animals; more studies were necessary before the application of this in agriculture.     

Incinerated Sewage Sludge Products as Amendments for Agricultural Soils: Leaching and Plant Uptake of Trace Elements

Preliminary leaching column and greenhouse plant uptake studies were conducted in two soils with contrasting characteristics amended with varying rates (0 to 148.3 Mg ha^?1) of incinerated sewage sludge (ISS) and weathered sewage sludge (WISS) to estimate the leaching losses of trace elements from the soils amended with incinerated sewage sludge by products and to evaluate the uptake and accumulation of these elements in various parts of Sorghum vulgaris var. sudanense Hitche. (“Sorgrass''), a Sorghum-Sudan grass hybrid. Results of this study indicated that leaching of Cr, Cd, Zn, Cu, Ni, Fe and Mn from soils amended with ISS and WISS increased with increasing rates of amendment. Results of the leaching column study further revealed greater leaching losses from coarse-textured soil compared to medium-textured soil and also from ISS amended soils than with WISS amended soils. Results further suggested that the type of element and the interaction between the element and soil properties affected the leachability of various trace elements. The uptake study indicated uptake and accumulation of trace elements by plant parts increased with increasing rates of amendments. Greater plant uptake and accumulation of trace elements were observed in plant parts grown in soils amended with ISS compared to that of WISS. Results also indicated a greater accumulation of trace elements in below ground part of the plants (roots) compared to that was observed in above ground parts (shoots). Limited data obtained from this one season preliminary studies demonstrated that incinerated sewage sludge products from wastewater treatment plants could be used as soil amendments at low application (no more than 24.7 Mg ha^?1) for optimum plant growth, and dry matter yield without resulting in substantial accumulation of metals in plant parts at concentrations above the recommended critical limits and without causing significant leaching losses of various trace elements. It is imperative that long-term field studies are necessary to evaluate the long-term impact of using these new products in leaching and accumulation of various trace elements in plants and soils.