施用碱稳定污泥污水土壤经γ-辐照后土壤溶液中Cu和Zn

Soil samples collected from several acid soils in Guangdong, Fujian, Zhejiang and Anhui provinces of the southern China were employed to characterize the chemical species of aluminumions in the soils. The proportion of monomeric inorganic Al to total Al in soil solution was in the range of 19% to 70%, that of monomeric organic Al (Al-OM) to total Al ranged from 7.7% to 69%, and that of the acid-soluble Al to total Al was generally smaller and was lower than 20% in most of the acid soils studied. The Al-OM concentration in soil solution was positively correlated with the content of dissolved organic carbon (DOC) and also affected by the concentration of Al³⁺. The complexes of aluminum with fluoride (Al-F) were the predominant forms of inorganic Al, and the proportion of Al-F complexes to total inorganic Al increased with pH. Under strongly acid condition, Al³⁺ was also a major form of inorganic Al, and the proportion of Al³⁺ to total inorganic Al decreased with increasing pH. The proportions of Al-OH and Al-SO₄ complexes to total inorganic Al were small and were not larger than 10% in the most acid soils. The concentration of inorganic Al in solution depended largely on pH and the concentration of total F in soil solution. The concentrat ions of Al-OM, Al³⁺, Al-F and Al-OH complexes in topsoil were higher than those in subsoil and decreased with the increase in soil depth. The chemical species of aluminumions were influenced by pH. The concentrations of Al-OM, Al³⁺, Al-F complexes and Al-OH complexes decreased with the increase in pH.     

施用辐照处理的污水污泥对作物产量和土壤氮的影响

A field experiment was conducted to study the feasibility of irradiated and non-irradiated sewage sludge as a fertilizer for the growth of wheat and rice. The irradiated and non-irradiated sewage sludge were applied at rates of 0 (CK), 75, 150, 225 and 300 kg N ha^-1 for wheat, and 0 (CK), 112.5, 225, 337.5 and 450 kg N ha^-1 for rice, respectively. (NH₄)₂SO₄ at a rate of 150 kg N ha^-1 for wheat, and 225 kg N ha^-1 for rice were added to the control treatments. Additionally, 20 kg ¹⁵N ha^-1 in the form of (NH₄)₂SO₄ was added to each treatment for wheat to study the effect of sewage sludge on chemical nitrogen fertilizer recovery. The results showed that the irradiation of sewage sludge by gamma ray at a dosage of 5 kGy increased crop yield by 11%~27% as compared to the non-irradiated treatments. Irradiation stimulated mineralization of organic nitrogen in the sludge and improved seedling growth. It was found that addition of irradiated sludge could reduce the leaching loss of chemical nitrogen fertilizer. Both irradiated and non-irradiated sewage sludge could increase the content of soil total nitrogen. Based on the preliminary results, it was concluded that irradiated sewage sludge could partly substitute for chemical nitrogen fertilizer in crop production.     

施用碱稳定固体的酸性土壤的Cu和Zn的形态分布

Fractionation of metals in a granite-derived acid sandy loam soil amended with alkaline-stabilised sewagesIudge biosolids was conducted in order to assess metal bioavailability and environmental mobility soil solution was extracted by a centrifugation and filtration technique. Metal speciation in the soil solution wasdetermined by a cation exchange resin method. Acetic acid and EDTA extracting solutions were used forextraction of metals in soil solid surfaces. Metal distribution in different fractions of soil solid phase was determined using a three-step sequential extraction scheme. The results show that the metals in the soilsolution existed in different fractions with variable lability and metals in the soil solid phase were also presentin various chemical forms with potentially different bioavail ability and environmental mobility Alkaline-stabilised biosolids could elevate solubility of Cu and proportion of Cu in organically complexed fractionsboth in soil liquid and solid phases, and may therefore increase Cu mobility. In contrast, the biosolids lowered the concentrations of water-soluble Zn (labile fraction) and exchangeable Zn and may hence decrease bioavailability and mobility of Zn. However, Fe and Mn oxides bound and organic matter bound fractions are likely to be Zn pools in the sludge-amended soil. These consequences possibly result from the liming effect and metal speciation of the sludge product and the difference in the chemistry between the metals in soil.     

γ-辐照对施用碱稳定固体土壤中Cu的提取性影响

An incubation experiment was conducted to investigate the microbial biomass associated Cu in four contrasting soils to which an alkaline stabilised sewage sludge cake was applied. The organisms of sludge-amended and control soils were killed using γ-irradiation technique, and the aqueous and acid-extractable Cu concentrations were determined. Addition of the sludge product increased significantly the concentration of both the aqueous and dilute HOAc-extractable Cu in all the irradiated soils compared to the non-sterilised sludge/soil mixtures, but the increase was more pronounced in the dilute acid-extractable Cu, indicating thatthe Cu rendered extractable in water and dilute acetic acid by γ-irradiation existed in the both soil liquidand solid phases. The additional increase in extractable Cu following the biocidal treatment is likely to bedue to release of Cu from the same fraction of soil microbial biomass.     

阿根廷布宜诺斯艾利斯市施用污泥的城郊农田生态系统净初级生产力和碳输入的潜在变化

Biosolids application in periurban agroecosystems could mitigate climate change by sequestering C, while improving plant net primary production (NPP). Monitoring NPP is useful for studying ecological responses to human management. The values of NPP and C input in periurban agroecosystems are insufficient or missing. The objective was to use local databases to estimate NPP and C input in periurban areas (south, north and west) of Buenos Aires City, Argentina, using different biosolids application scenarios (low and high effects). The NPP varied with crop and vegetable types (P < 0.05), with maize (Zea mays) and wheat (Triticum aestivum) presenting the highest production, soybean (Glycine max) medium and sunflower (Helianthus annuus) the lowest. Tomato (Lycopersicon esculentum Mill.) presented the highest production in the south area (La Plata). West and north areas, where Vertic and Typic Argiudolls are the main soils, presented the lowest NPP and C input. According to the low and high effect scenarios, only vegetables presented significant differences (P < 0.05) in average and cumulative NPP and C input between areas. Vegetables contributed with the highest proportion (> 70%) to NPP in both projected scenarios. For both scenarios, average C input by crops and vegetables presented similar proportions. Biosolids addition in periurban agroecosystems could be a viable practice to elevate NPP and C input.     

长江三角洲地区污水污泥与健康安全风险研究 Ⅲ. 苏、杭二城市污水污泥所施土壤中Cu和Zn的释放动态及其环境风险

未经处理的污泥农业利用后,不仅会增加土壤中污染物的含量,而且会威胁人类和其他生物的健康。室内培养试验结果表明,污泥中的重金属进入土壤后,表现出先释放,后固定的变化趋势,而且随培养时间的增加,施污泥土壤中EDTA和CaCl2提取态Cu和Zn含量逐渐增加,150d时其含量达到最高。与对照处理相比,施污泥土壤中EDTA提取态Cu和Zn含量分别增加了21.4mgkg-1和26.1mgkg-1,而CaCl2提取态Cu和Zn含量分别增加了0.10mgkg-1和3.37mgkg-1。重金属不合格的污泥农业利用存在一定程度的重金属污染风险,且其风险大小与土壤类型、污泥种类和培养时间及污泥的土壤施用量等因素密切相关。选择适宜的土壤类型、污泥种类、施用时间及控制污泥施用量等,能够在一定程度上降低污泥中重金属农业利用的环境风险。     

热带土壤上连续9年施入污水污泥后重金属Zn, Cd和Pb的分离研究

A long-term field experiment was carried out in the experiment farm of the Sao Paulo State University, Brazil, to evaluate the phytoavailability of Zn, Cd and Pb in a Typic Eutrorthox soil treated with sewage sludge for nine consecutive years, using the sequential extraction and organic matter fractionation methods. During 2005-2006, maize (Zea mays L.) was used as test plants and the experimental design was in randomized complete blocks with four treatments and five replicates. The treatments consisted of four sewage sludge rates (in a dry basis) : 0.0 (control, with mineral fertilization), 45.0, 90.0 and 127.5 t ha^-1, annually for nine years. Before maize sowing, the sewage sludge was manually applied to the soil and incorporated at 10 cm depth. Soil samples (0-20 cm layer) for Zn, Cd and Pb analysis were collected 60 days after sowing. The successive applications of sewage sludge to the soil did not affect heavy metal (Cd and Pb) fractions in the soil, with exception of Zn fractions. The Zn, Cd and Pb distributions in the soil were strongly associated with humin and residual fractions, which are characterized by stable chemical bonds. Zinc, Cd and Pb in the soil showed low phytoavailability after nine-year successive applications of sewage sludge to the soil.     

玉米-大豆轮作中耕作方式和磷肥施用对土壤磷组分冬季变化特征的影响

Determining how agricultural management practices affect soil phosphorus(P) over the winter may further our understanding of the soil P cycle under specific environmental conditions in eastern Canada. This study assessed changes over winter for soil P fractions and other selected chemical properties as affected by tillage and P fertilization. In 1992, a long-term corn(Zea mays L.) and soybean(Glycine max L.) rotational experiment was established in the province of Quebec, Canada. Soil samples(0–15 cm) were collected in fall 2001 and 2007 after a soybean harvest, and in the following spring 2002 and 2008 before corn seeding, in main plots under moldboard plow and no-till managements and selected subplots fertilized with 0, 17.5, or 35 kg P ha-1and 160 kg N ha-1. Soil samples were analyzed for P fractions and other chemical properties to assess changes over winter for 2001–2002 and 2007–2008. Changes over winter of all soil P fractions were significant for the two periods, indicating the occurrence of soil P transformation and movement over winter. The Mehlich-3-extractable Fe, Al, Ca, and Mg decreased during the two studied periods. Tillage had no significant effect on all soil P fractions. The resin-extractable P in 2001–2002 and Na HCO3-extractable inorganic P and Na OH-extractable organic P during the two winters were significantly increased under P fertilization. This study demonstrated that P in cultivated soils changed during winter as a result of changes in labile P fractions possibly due to the solubilization of residual fertilizer P combined with environmental factors.     

Changes in soil properties of an eastern Australian vertisol irrigated with treated sewage effluent following gypsum application

Historically many towns in inland Australia disposed of their treated sewage by pumping into local rivers. This is no longer a feasible proposition. Alternatives to river pumping include irrigation and/or aquaculture. As treated sewage effluent may contain large amounts of nitrogen, phosphorus and sodium salts, if not managed carefully, soil salinity, sodicity and nutrient accumulation could increase. The objective of this study was to evaluate if gypsum application had any effect on soil‐quality changes in a Vertisol due to irrigating a cotton–wheat rotation with tertiary treated sewage effluent. The treatments were application of 2·5 t ha⁻¹ of gypsum in June 2000 before commencing irrigation and an untreated control. Annually, between June 2000 and April 2004, irrigation water quality and soil changes in nitrate‐N, EC_1:5, pH, organic carbon, Cl, dispersion index, and exchangeable cations to a depth of 1·8 m were measured and deep drainage inferred with the chloride mass balance method. Cotton lint yield and fibre characteristics were also evaluated. Irrigation with treated sewage effluent increased exchangeable Na in all depths, and exchangeable Ca and K in the clayey‐textured surface 0·6 m, but decreased exchangeable Ca and K, and SOC in the coarser clay‐loam‐textured depths > 0·6 m. Nitrate‐N leaching, associated with deep drainage had occurred, as the crops had not used all the N in irrigation water. Gypsum application decreased exchangeable Ca, increased dispersion and during the 2003–2004 season deep drainage, but had no effect on salinity, sodicity or pH. Application of commercial gypsum at sub‐optimal rates with sodium‐rich irrigation water is, therefore, unlikely to improve soil properties. Stubble incorporation before sowing cotton in 2003 appears to have mobilized gypsum applied during 2000. Gypsum application reduced cotton lint yield and fibre quality during 2003–2004. Copyright © 2006 John Wiley & Sons, Ltd.     

Speciation of Zn,Cu, and Pb in the soil depending on soil texture and fertilization with sewage sludge compost

Background, aim, and scope  Heavy metal (HM) mobility in soil depends on the HM species in it. Therefore, knowledge of the HM speciation in soil allows the prediction of HM impact on the environment. HM speciation in soil depends on the metal chemical origin, soil texture, and other factors such as the origin and level of soil contamination. Recently, the problem of organic waste utilization is of great importance as the amount of this recyclable material is continually increasing. One of the possible ways of recycling is the use of processed organic wastes for agricultural needs. In this research, aerobically composted sewage sludge was used, the utilization of which is of essential importance. But one of the most serious restrictions is HM transfer from such material to the soil. Therefore, a prediction of HM mobility in soil and its migration in the environment is an important issue when using sewage sludge compost (SSC) in agriculture. Zn, Cu, and Pb speciation was performed according to the modified methodology of Tessier et al. (Anal Chem 51:844–851, 1979) in two different (sandy and clay) soils with background HM amounts and in soil samples amended with aerobically digested SSC to find out the predominant species of the investigated HM and to predict their potential availability. Materials and methods  The modified method of sequential extraction initially proposed by Tessier et al. (Anal Chem 51:844–851, 1979) is designed for HM speciation into five species where HM mobility decreases in the order: F1—exchangeable HM (extracted with 1 M MgCl₂ at an initial pH of 7 and room temperature), F2—carbonate-bound HM (extracted with 1 M CH₃COONa buffered to pH 5 at room temperature), F3—Fe/Mn oxide-bound HM (extracted with 0.04 M NH₂OH·HCl at an initial pH of 2 at 96°C), F4—organic matter-complexed or sulfide-bound HM (extracted with 0.02 M HNO₃ and 30% (v/v) H₂O₂ at a ratio of 1:1 and an initial pH of 2 at 85°C), and F5—the residual HM (digested with HNO₃, HF, and HCl mixture). After digestion, HM amounts in solution were determined by atomic absorption spectrometry (AAS ‘Hitachi’). Mixtures of uncontaminated soils of different textures (clay and sandy) with SSC in ratios 20:1, 10:1, and 5:1 were used to simulate the land application with SSC. During a period of 7 weeks, changes in Zn, Cu, and Pb content within species were investigated and compared weekly in soil–SSC mixtures with their speciation in pure soil and in the SSC. Results  Results in the SSC showed that more HM were found as mobile species compared to the soils, and in sandy soil, more were found in the mobile species than in clay soil. But the HM speciation strongly depended on the metal chemical origin. According to the potential availability, HM ranked in the following order: Zn>Pb>Cu. Zinc generally occurred in the mobile species (F1 and F3), especially in sandy soils amended with SSC, and changes of the Zn speciation were insignificant at the end of the experiment. Pb transfer to insoluble compounds (F5) was evident in the SSC–soil mixtures. This confirms that Pb is extremely immobile in the soil. However, the observed increase of Pb amounts in the mobile species (F1 and F2) during the course of experiment shows a critical trend of Pb mobilization under anthropogenic influence. Copper in the soil–SSC mixtures had a trend to form compounds of low mobility, such as organic complexes and sulfides (F4) and nonsoluble compounds (residual fraction F5). Initially, the amounts of mobile Cu species (F1 and F2) increased in the soils amended with SSC, probably due to the influence of SSC of anthropogenic origin with lower pH and high organic matter content, but Cu mobility decreased nearly to the initial level again after 3–4 weeks. Hence, the soil has a great specific adsorption capacity to immobilize Cu of anthropogenic origin. Discussion  Zn mobility and environmental impact was greater than that seen for Cu and Pb, while mobility of both Cu and Pb was similar, but variable depending on soil texture and contamination level. The effect on the shift of HM mobility and potential availability was greater in sandy SSC-amended soils than in clay soils and increased with an increasing amount of SSC. Conclusions  Usage of SSC for land fertilization should be strictly regulated, especially regarding Pb amounts. Recommendations and perspectives  The influence of SSC on Cu and Zn mobility and potential availability was more significant only in the case of sandy soil with a higher SSC ratio. Nevertheless, this waste product of anthropogenic origin increased Pb mobility in all cases in spite of only moderate Pb mobility in SSC itself. Therefore, aerobic processing of sewage sludge must be strictly regulated, especially regarding Pb amounts, and SSC ratios must be in control regarding HM amounts when using it for on-land application.     

皂角苷对几种生活污泥中和的去除

为探讨皂角苷对污泥中Cu和Zn去除的机制,采用化学淋洗的方法研究皂角苷浓度（0~7%）、pH（2~6）、振荡时间（0~48 h）、温度（10、25、40℃）和提取次数（1~4次）对四种生活污泥中Cu和Zn去除率的影响,分析去除前后重金属的形态,并监测去除过程中浸出液pH的变化。结果表明,单次淋洗条件下,皂角苷对Cu的去除率大于Zn;皂角苷溶液的pH对Cu的去除没有显著影响,而Zn的去除率在pH下降到2时明显增加;Cu经过6~12 h的振荡就能达到最大去除,Zn则需要经过较长时间的振荡（48 h）才能达到较好去除;提高振荡温度,Cu的去除率降低而Zn的增加;随着提取次数的增加,Cu和Zn的去除率均增加,Cu的去除以第1次提取为主,Zn的4次提取均有较好效果,用3%的皂角苷溶液连续4次提取后,Cu和Zn的累积去除率最大分别达到32.61%和39.32%;增加振荡时间、提高振荡温度、增加提取次数以及降低皂角苷溶液pH均能降低浸出液的pH。经过3%的皂角苷溶液的提取,污泥中各形态Cu的含量均减少,其中66%以上的酸溶态被去除;而Zn的酸溶态含量减少不明显,可还原态、可氧化态和残渣态均有所降低,但以残渣态的减少为主。     

Microbial activity in grassland soil amended with sewage sludge containing varying rates and combinations of Cu, Ni and Zn

 Cu, Ni and Zn were added at different rates (low and±25% of current limits) and combinations to sewage sludges and the effects on soil microorganisms were monitored in laboratory incubations. Respiration was measured frequently during weeks 1–7, whilst extractable metals (with EDTA and CaCl₂), microbial biomass C and metabolic quotient were recorded at 3 and 7 weeks. Inputs of one metal affected extractable concentrations of that metal and of the second metal tested in each experiment. Cu behaved differently from Ni and Zn, with little extractable by CaCl₂. Whereas CaCl₂-Ni and -Zn increased markedly between weeks 3 and 7, Cu concentrations did not change. Respiration was reduced at 1 week by Ni inputs and by Cu in combination with Ni. Zinc inputs at 1 week, and all metal inputs after 3 weeks, increased respiration. Biomass C was lower at higher metal inputs and with Zn the exception occurred at 3 weeks when biomass C was higher. Metal inputs generally increased metabolic quotient, although responses to Zn were often non-significant. Not all metal responses were additive, with effects of one metal frequently more pronounced with high levels of another. For Cu, the organic bound fraction was a better predictor of microbial response than the exchangeable fraction. For Ni the reverse was the case in one experiment, whilst extractable Zn was not closely correlated with microbial indices. Metal inputs close to permitted levels, in particular Cu, affected microbial processes but responses varied with time after sludge application. Received 26 August 1998     

Availability of Cu and Zn in an acidic sludge-amended soil as affected by zeolite application and liming

Purpose  

Acidic soils exhibit high trace element availability compared to neutral pH soils, and thus, when trace metals are added (e.g. due to sewage sludge application), measures should be taken to reduce their mobility. In this experiment, we tested two such methods, liming and zeolite addition. The aim was to measure the availability, in ryegrass (Lolium perenne L.), of heavy metals (Cu and Zn) added to soil with sewage sludge in both acidic and limed soil.     

Effects of Zn enriched sewage sludge on microbial activities and biomass in soil

An incubation study in closed static microcosms was performed to elucidate Zn effects on N mineralisation in relation to other microbial activities and biomass in a sandy soil. Sewage sludge equivalent to 25 t ha⁻¹ was enriched with five different rates of Zn to add concentrations between 50 and 800 μg Zn g⁻¹ soil. All microbial indices were increasingly depressed with increasing Zn concentration of the sewage sludge, but they were affected with different intensity: Zn had especially large effects on CO₂ production and qCO₂, moderate effects on N mineralisation and relatively small effects on protease activity, biomass C and arginine ammonification.     

Mobilization of Cu and Zn in contaminated soil by nitrilotriacetic acid

Batch and upflow column leaching experiments were used to evaluate the nature and extent of Cu and Zn solubilization from contaminated soil by nitrilotriacetic acid (NTA) in 0.025 M NaClO₄. In batch soil suspensions, NTA levels of 10^?5 to 10^?3 M substantially promoted Cu and Zn release from the metal-enriched soil. The ability of NTA to enhance Cu and Zn solubility decreased with increasing solution acidity probably due to competitive binding of NTA by protons and Fe released by hydrous oxide dissolution. However, in the pH range typically encountered in northeastern U.S. soils, soluble metal levels were nearly constant for a given NTA concentration. Leaching soil columns with NTA solutions enhanced Cu release more than Zn, as the enrichment ratio (cumulative metal leached by NTA compared to the 0.025 M NaClO₄ control leachate) after 85 pore volumes displacements was 23.6 and 4.3 for Cu and Zn, respectively. While Cu release by 0.01 M CaCl₂ differed little from the control, 0.01 M CaCl₂ was substantially more effective than 10^?5 M NTA in displacing bound Zn. The data reflect different retention mechanisms for Cu and Zn in this soil.     

Liming effects on availability of Cd,Cu, Ni and Zn in a soil amended with sewage sludge 16 years previously

A field study was conducted to determine the plant uptake of metals in soils amended with 500 Mg ha^?1 of municopal sewage sludge applied 16 yr previously. Results showed that metals were available for plan uptake after 16 yr, but that liming greatly reduced the plant availability of most metals. The application of sludge also resulted in high rates nitrification and subsequent lowering of the soil pH before the uptake study was started. The sludge-amended soil (a mesic Dystric Xerochrept) was adjusted with lime one month prior to planting from an unlimed pH of 4.6 to pH 5.8, 6.5 and 6.9. Food crops grown were: (i) bush bean (Phaseolus vulgaris L. cv. Seafarer), (ii) cabbage (Brassica oleracea L. v. capitata L. cv. Copenhagen market), (iii) maize (Zea mays L. cv. FR37), (iv) lettuce (Lactuca sativa L. cv. Parris Island, (v) (Solanum tuberosum L. cv. (vi) tomato (Lycopersicum esculentum L. cv. Burpee VF). With the exception of maize, yields were significantly reduced in the unlimed sludge-amended soil. However, liming increased yields above the growth level of the unlimed untreated soil for cabbage, maize, lettuce, potato tuber and tomato fruit. Soluble and exchangeable of Cd. Ni and Zn were also reduced after liming the sludge-amended soil. In both limed and unlimed soils, the majority of the soil Cu was found in insoluble and unavailable soil fractions. To evaluate trace metal uptake, the edible portion of each crop was analyzed for Cd, Cu, ni and Zn. Liming redoced uptake of Cd, Ni and Zn in most crops, but generally did not change Cu, This study shows the benefit of pH adjustment in reducing relative solubility and plant uptake of metals as well as increasing crop yield in acid soils.     

Temporal response of soil biochemical properties in a pastoral soil after cultivation following high application rates of undigested sewage sludge

Soil biochemical properties were measured annually between 1995 and 1999 in soil from an 8-ha site that had received over 1,000 wet tonnes ha^–1 undigested sewage sludge, 1–4 years earlier. Basal respiration generally declined with time and was usually greatest in the untreated control area. This trend was attributed to a similar trend in soil moisture content. In contrast, microbial biomass C increased with time and also generally increased with sludge treatment age. Microbial biomass C, and to a lesser extent sulphatase activity, accurately predicted the order of sludge application to the site. This was perceived as a function of time since tillage and pasture establishment, with activities increasing in parallel to the build up of C residues in the soil, and not an effect of sludge or its composition. Except immediately after sludge application, there was no effect on N mineralisation and nitrification. None of the biochemical properties was strongly correlated with heavy metal concentrations. Our results suggest that there was little effect on soil biochemical properties, either adverse or beneficial, of adding raw sewage sludge to this site. Although a companion study showed considerable mobility and plant uptake of heavy metals, this difference could mainly be attributed to a different sampling strategy and the effects of intensive liming of the site.