长江南京段近岸沉积物和土壤中重金属分布特征分析

通过测定沉积物和土壤中Cd、Pb、Cr、Zn、Cu、Ni 6种重金属元素的平均含量,计算其富集因子,分析长江南京段近岸沉积物和土壤中重金属的空间分布特征,结果表明,几种重金属在沉积物中的富集次序为:CdPbCr1NiCuZn,在土壤中为:CdZnCu1CrPbNi,除Zn和Cu外,其他几种金属在沉积物中的富集程度高于土壤,同时Cd的含量超过土壤环境质量三级标准。以Cd和Pb为例分析了重金属含量与沉积物粒级之间的关系,回归分析显示,Cd、Pb的含量与颗粒物的粒级呈显著的相关性,与细颗粒物的含量有密切关系,细颗粒携带的重金属,在长江水力分选作用下到达下游,成为沉积物中重金属的主要来源。     

Levels and speciation of heavy metals in soils of industrial Southern Nigeria

A knowledge of the total content of trace metals is not enoughto fully assess the environmental impact of polluted soils. Forthis reason, the determination of metal species in solution isimportant to evaluate their behaviour in the environment andtheir mobilization capacity. Sequential extraction procedure wasused to speciate five heavy metals (Cd, Pb, Cu, Ni and Zn) fromfour contaminated soils of Southern Nigeria into sixoperationally defined geochemical species: water soluble,enchangeable, carbonates, Fe-Mn oxide, organic and residual.Metal recoveries were within ± 10% of the independentlydetermined total Cd, Pb, Cu, Ni and Zn concentrations. The highest amount of Cd (avg. 30%) in the nonresidual fractionswas found in the exchangeable fraction, while Cu and Zn weresignificantly associated with the organic fraction. Thecarbonate fraction contained on average 14, 18.6, 12.6, 13 and11% and the residual fraction contained on average 47, 18, 33,50 and 25% of Cd, Pb, Cu, Ni and Zn respectively. Assuming thatmobility and bioavailability of these metals are related to thesolubility of the geochemical form of the metals, and that theydecrease in the order of extraction sequence, the apparentmobility and potential bioavailability for these five metals inthe soil were: Pb > Zn > Cu > Ni > Cd. The mobility indexes ofcopper and nickel correlated positively and significantly withthe total content of metals, while mobility indexes of cadmiumand zinc correlated negatively and significantly with the totalcontent of metals.     

Metal Pollution Assessment of Sediment and Water in the River Hindon, India

The metal pollution in water and sediment of the River Hindon in western Uttar Pradesh (India) was assessed for Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn. The metal concentrations in water showed wide temporal variation compared with bed sediment because of variability in water discharge and variations in suspended solid loadings. Metal concentrations in bed sediments provided a better evaluation of the degree and the extent of contamination in the aquatic environment, Santagarh and Atali being the most polluted sites of the river. The ratio of heavy metals to conservative elements (Fe, Al, etc.) may reveal the geochemical imbalances due to the elevated metal concentrations normally attributed to anthropogenic sources. Metal/Al ratios for the bed sediments of the river Hindon were used to determine the relative mobility and general trend of relative mobility occurred Fe > Mn > Zn > Cr > Ni > Pb > Cu > Cd.     

Interseasonal distribution and partitioning of heavy metals in subtidal sediment of Qua Iboe Estuary and associated Creeks, Niger Delta (Nigeria)

An analysis of the distribution and chemical forms of selected metals: cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni) and lead (Pb) in subtidal sediments of Qua Iboe Estuary and adjourning creeks, collected between June 2000 and January 2001, were studied using a sequential chemical extraction method. The concentration of metals in each extracted fraction was determined using inductively coupled plasma spectrometer (ICP-AES). Pb, Cd and Cu appear to be the most abundant metal in the sediments of the systems, and are predominantly associated with the residual, organic and oxidisable phases. Results indicate that there are also insignificant components that are bound to both the exchangeable and carbonates fractions. Ni is largely associated with bioavailable phases with insignificant bound to organic matter and residual fractions. In general, an insignificant component of Cd and Pb are bound to organic matter phase. Moreover, speciation results indicate that metal contamination in the ecosystems investigated primarily comes from human-mediated sources. Thus, based on index of geoaccumulation calculated, sediments of these ecosystems have been classified as uncontaminated by Cr, Cu and Ni, strongly contaminated by Pb and extremely contaminated by Cd.     

Accumulation and remobilization of metals in superficial sediments in Tianjin, China

The concentrations of Cr, Ni, Cu, Zn, Cd, and Pb in superficial sediment samples collected from three representative sites (Yuqiao Reservoir, Haihe River, and Haihe River Estuary) in Tianjin, North China, were analyzed using various single extraction and sequential extraction procedures to determine their remobilization, extractability, and distribution patterns. Sediments from the Haihe River had higher metal concentrations and geo-accumulation indices, especially for Cd and Zn, than sediments from the other two sites, suggesting that the Haihe River has been heavily influenced by anthropogenic activities. In addition, over 31% and 28.2% of the total Cd in the Haihe River and the Yuqiao Reservoir, respectively, and 18.2% of the total Zn in the Haihe River were found to be associated with the exchangeable form, indicating the significant remobilization of Cd and Zn when compared with Cr and Ni. However, over 98% of the Ni and 78% of the Cr were most closely associated with the residue and oxidizable fractions, which resulted in their becoming environmentally immobile. Based on the Environmental Protection Agency method 3050B, Cd and Zn had the greatest extraction efficiency when a single extraction procedure using 0.5-mol L^???1 HCl, 0.43-mol L^???1 HAcO, and 0.05-mol L^???1 ethylene-diamine-tetra-acetic acid was conducted, with extraction yields of up to 72%, 68%, and 56% for Cd and 50%, 49%, and 29% for Zn, respectively, being obtained for the Haihe River sediments. This was followed by the yields of Cu and Pb and, finally, those of unpolluted metals such as Cr and Ni. HCl and acetic acid extraction provided equivalent information for predicting Cd and Zn mobility in the sediments studied and produced suitable results for quick screening.     

Assessment of heavy metals in sediments from a typical catchment of the Yangtze River, China

An intensive investigation was conducted to study the accumulation, speciation, and distribution of various heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) in sediments from the Yangtze River catchment of Wuhan, China. The potential ecological risks posed by these heavy metals also were estimated. The median concentrations of most heavy metals (As, Cd, Cr, Cu, Ni, Pb, and Zn) were higher than the background values of soils in Wuhan and were beyond the threshold effect level (TEL), implying heavy metal contamination of the sediments. Carbonate-bound Cd and exchangeable Cd, both of which had high bioavailability, were 40.2% and 30.5% of the total for Cd, respectively, demonstrating that Cd poses a high ecological risk in the sediments. The coefficients of the relationship among Pb, Hg, and Cu were greater than 0.797 using correlation analysis, indicating the highly positive correlation among these three elements. Besides, total organic carbon content played an important role in determining the behaviors of heavy metals in sediments. Principal component analysis was used to study the distribution and potential origin of heavy metals. The result suggested three principal components controlling their variability in sediments, which accounted for 36.72% (factor 1: Hg, Cu, and Pb), 28.69% (factor 2: Cr, Zn, and Ni), and 19.45% (factor 3: As and Cd) of the total variance. Overall, 75% of the studied sediment samples afforded relatively low potential ecological risk despite the fact that generally higher concentrations of heavy metals relative to TEL were detected in the sediments.     

Mobility of selected trace elements in Mediterranean red soil amended with phosphogypsum: experimental study

Soil amendment by phosphogypsum (PG) application becomes of increasing importance in agriculture. This may lead, however, to soil, plant, and groundwater contamination with trace elements (TEs) inherently present in PG. Monitoring of selected TEs (Pb, Zn, Cu, and Cd) distribution and mobility in a Mediterranean red soil profile has been performed in soil parcels applied with PG over a 16-month period. Concentrations were measured in soil and plant samples collected from various depth intervals at different points in time. TEs sequential extraction was performed on soil and PG samples. Results showed soil profile enrichment peaked 5 months after PG application for Cd, and 12 months for Pb, Zn, and Cu. Rainwater, pH, total organic carbon, and cationic exchange capacity were the main controlling factors in TEs accumulation in soils. Cd was transferred to a soil depth of about 20 cm. Zn exhibited mobility towards deeper layers. Pb and Cu were accumulated in around 20-55-cm-deep layers. PG increased the solubility of the studied TEs; PG-applied soils contained TEs bound to exchangeable and acid-soluble fractions in higher percentages than reference soil. Pb, Zn, and Cu were sorbed into mineral soil phases, while Cd was mainly found in the exchangeable (bio-available) form. The order of TEs decreasing mobility was Zn > Cd > Pb > Cu. Roots and leaves of existed plants, Cichorium intybus L., accumulated high concentrations of Cd (1-2.4 mg/kg), exceeding recommended tolerable levels, and thus signifying potential health threats through contaminated crops. It was therefore recommended that PG should be applied in carefully established, monitored, and controlled quantities to agricultural soils.     

Trace metal fractionation in the Pichavaram mangrove–estuarine sediments in southeast India after the tsunami of 2004

The geochemistry of coastal sediments of southern India was altered after the tsunami in 2004. A five-step sequential extraction procedure was applied to assess the effects of tsunami on mobility and redistribution of selected elements (Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn). Ten surface sediments and three cores were analyzed for different metal fractions (exchangeable, carbonate, reduced, oxidized, and residual). Total metal concentrations increased in mangrove sediments after the tsunami, but their spatial distribution did not show significant variation (except Mn). The sediments were mixed by the tsunami, and there was lack of variation in metal concentrations in different fractions with depth (except Pb and Mn). High concentrations of Pb and Zn occurred in the oxide fractions, whereas Cu, Cr, Cd, and Ni were high in the organic and sulfide-rich fractions. Metals in the residual fraction (lattice bound) had the highest concentration suggesting their non-availability and limited biological uptake in the system. Most of the metals (except Mn) do not constitute a risk based on the different geochemical indices.     

Risk assessment of trace metals in an extreme environment sediment: shallow,hypersaline, alkaline,and industrial Lake Acıgöl,Denizli, Turkey

The major and trace element component of 48 recent sediment samples in three distinct intervals (0–10, 10–20, and 20–30 cm) from Lake Ac?göl is described to present the current contamination levels and grift structure of detrital and evaporate mineral patterns of these sediments in this extreme saline environment. The spatial and vertical concentrations of major oxides were not uniform in the each subsurface interval. However, similar spatial distribution patterns were observed for some major element couples, due mainly to the detrital and evaporate origin of these elements. A sequential extraction procedure including five distinct steps was also performed to determine the different bonds of trace elements in the <?60-μ particulate size of recent sediments. Eleven trace elements (Ni, Fe, Cd, Pb, Cu, Zn, As, Co, Cr, Al and Mn) in nine surface and subsurface sediment samples were analyzed with chemical partitioning procedures to determine the trace element percentage loads in these different sequential extraction phases. The obtained accuracy values via comparison of the bulk trace metal loads with the total loads of five extraction steps were satisfying for the Ni, Fe, Cd, Zn, and Co. While, bulk analysis results of the Cu, Ni, and V elements have good correlation with total organic matter, organic fraction of sequential extraction characterized by Cu, As, Cd, and Pb. Shallow Lake Ac?göl sediment is characteristic with two different redox layer a) oxic upper level sediments, where trace metals are mobilized, b) reduced subsurface level, where the trace metals are precipitated.     

Mobility and ecological risk assessment of trace metals in polluted estuarine sediments using a sequential extraction scheme

The three-stage sequential extraction procedure for the fractionation of Cd, Cr, Cu, Ni, Pb, and Zn, proposed by the Commission of the European Communities Bureau of Reference, was applied to sediment five samples collected from the Sal estuary, Sergipe State, northeast Brazil, in September 2009. The method showed satisfactory recoveries, detection limits, and standard deviations for determinations of trace metals in the sediments. Cd and Pb were the metals most prevalent in the bioavailable fractions (carbonates, Fe and Mn oxides, organic matter, and sulfides), while Ni, Zn, Cu, and Cr showed higher percentages in the inert fraction. The order of mobility of the metals was Cd (66 %) > Pb (65 %) > Zn (59 %) > Ni (57 %) = Cr (57 %) > Cu (56 %). Possible toxicity related to these metals was examined using the risk assessment code, and by comparing the chemical data with sediment quality guideline ERL-ERM values. Results obtained using the two methods were in agreement, and showed low to medium risk for all metals, indicating that adverse effects on aquatic biota should rarely occur.     

Contamination and ecological risk assessment of toxic trace elements in the Xi River, an urban river of Shenyang city, China

The objectives of this study were to assess the enrichment, contamination, and ecological risk posed by toxic trace elements in the sediments of the Xi River in the industrialized city of Shenyang, China. Surface sediment and sediment core were collected; analyzed for toxic trace elements; and assessed with an index of geoaccumulation (Igeo), enrichment factor (EF) value, potential ecological risk factor (Er), ecological risk index (RI), and probable effect concentration quotient (PECQ). Elemental concentrations (milligram per kilogram) were 8.5–637.9 for As, 6.5–103.9 for Cd, 12.2–21.9 for Co, 90.6–516.0 for Cr, 258.1–1,791.5 for Cu, 2.6–19.0 for Hg, 70.5–174.5 for Ni, 126.9–1,405.8 for Pb, 3.7–260.0 for Sb, 38.4–100.4 for V, and 503–4,929 for Zn. The Igeo, EF, Er, and PECQ indices showed that the contamination of Cd and Hg was more serious than that of As, Cr, Cu, Ni, Pb, Sb, and Zn, whereas the presence of Co and V might be primarily from natural sources. The Igeo index for Cr and Ni might underestimate the degree of contamination, potentially as a result of high concentrations of these elements in the shale. The RI index was higher than 600, indicating a notably high ecological risk of sediment for the river. The average PECQ for As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn ranged from 1.4 to 4.1 for surface sediment and from 5.2 to 9.6 in the sediment cores, indicating a high potential for an adverse biological effect. It was concluded that the sediment in the Xi River was severely contaminated and should be remediated as a hazardous material.     

Speciation and assessment of heavy metals in surface sediments of Jinjiang River tidal reach, southeast of China

The concentration and speciation of heavy metals (Cr, Ni, Cu, Zn, Cd, Pb) in surface sediments (??≤ 63 μm) of Jinjiang River tidal reach are determined to evaluate the metal behavior. A modified BCR three-step sequential extraction procedure is carried out, and the residual fraction is undertaken by microwave-assisted acid digestion. The index of geo-accumulation indicates that Cd appeared highest among all these heavy metals in surface sediments, Cr, Cu, Zn lower, and Ni, Pb the least. The percentage of Zn, Cd is comparatively higher in the acid soluble fraction, Pb and Cu higher in the reductive fraction, indicating larger potential danger to the environment. So it is essential for developing the future remediation plans and pollution control strategies.     

Pollution in the urban soils of Lianyungang,China, evaluated using a pollution index,mobility of heavy metals,and enzymatic activities

Soil samples from 16 urban sites in Lianyungang, China were collected and analyzed. A pollution index was used to assess the potential ecological risk of heavy metals and a sequential extraction procedure was used to evaluate the relative distribution of Cu, Zn, Pb, Cd, Cr, and As in exchangeable, carbonate, Fe/Mn oxide, organic/sulfide, and residual fractions. The mobility of heavy metals and urease (URE) activity, alkaline phosphatase (ALP) activity, and invertase (INV) activity of soils was determined. The results showed that the average concentrations of Cu, Zn, Pb, Cd, Cr, and As in Lianyungang soils were much higher than those in the coastal city soil background values of Jiangsu and China. Among the five studied regions (utilities, commercial, industrial, tourism, and roadside), the industrial region had the highest metal concentrations demonstrating that land use had a significant impact on the accumulation of heavy metals in Lianyungang soils. Compared to the other metals, Cd showed the highest ecological risk. According to chemical partitioning, Cu was associated with the organic/sulfides and Pb and Zn were mainly in the carbonate and the Fe/Mn oxide phase. The greatest amounts of Cd were found in exchangeable and carbonate fractions, while Cr and As were mainly in the residual fraction. Cd had the highest mobility of all metals, and the order of mobility (highest to lowest) of heavy metals in Lianyungang soils was Cd > Zn > Pb > Cu > As > Cr. Soil urease activity, alkaline phosphatase activity, and invertase activity varied considerably in different pollution degree sites. Soil enzyme activities had the lowest levels in roadside and industrial regions. Across all the soil data in the five regions, the total Cu, Zn, Pb, Cd, Cr, and As level was negatively correlated with urease activity, alkaline phosphatase activity, and invertase activity, but the relationship was not significant. In the industrial region, alkaline phosphatase activity had significant negative correlations with total Cu, Pb, Cr, Zn, Cd, and heavy metal fractions. This showed that alkaline phosphatase activity was sensitive to heavy metals in heavily contaminated regions, whereas urease and invertase were less affected. The combination of the various methods may offer a powerful analytical technique in the study of heavy metal pollution in street soil.     

Assessment of metal enrichments in tsunamigenic sediments of Pichavaram mangroves, southeast coast of India

The 26 December 2004-Tsunami has deposited sediments in the Pichavaram mangrove ecosystem, east coast of India. Ten surface and three core sediment samples were collected within thirty days of the event. High concentrations of Cd, Cu, Cr, Pb, and Ni were observed in the tsunamigenic sediments. With respect to Fe, Zn, and Mn, there was little variation as compared to pre-tsunami values. The geo-accumulation index was calculated in order to assess the contamination of heavy metals in the sediments. The sediments were extremely contaminated with respect to Cd and they showed moderate to strong contamination with respect to Cr, Pb and Ni. The study highlighted the future risk of enhanced metal pollution in near future in this mangrove ecosystem.     

Heavy metal contamination in water, soil, and vegetables of the industrial areas in Dhaka, Bangladesh

Concentrations of Cu, Zn, Pb, Cr, Cd, Fe, and Ni have been estimated in soils and vegetables grown in and around an industrial area of Bangladesh. The order of metal contents was found to be Fe > Cu > Zn > Cr > Pb > Ni > Cd in contaminated irrigation water, and a similar pattern Fe > Zn > Ni > Cr > Pb > Cu > Cd was also observed in arable soils. Metal levels observed in different sources were compared with WHO, SEPA, and established permissible levels reported by different authors. Mean concentration of Cu, Fe, and Cd in irrigation water and Cd content in soil were much above the recommended level. Accumulation of the heavy metals in vegetables studied was lower than the recommended maximum tolerable levels proposed by the Joint FAO/WHO Expert Committee on Food Additives (1999), with the exception of Cd which exhibited elevated content. Uptake and translocation pattern of metal from soil to edible parts of vegetables were quite distinguished for almost all the elements examined.     

Contamination assessment of arsenic and heavy metals in a typical abandoned estuary wetland—a case study of the Yellow River Delta Natural Reserve

Coastal and estuarine areas are often polluted by heavy metals that result from industrial production and agricultural activities. In this study, we investigated the concentration trait and vertical pattern of trace elements, such as As, Cd, Ni, Zn, Pb, Cu, and Cr, and the relationship between those trace elements and the soil properties in coastal wetlands using 28 profiles that were surveyed across the Diaokouhe Nature Reserve (DKHNR). The goal of this study is to investigate profile distribution characteristics of heavy metals in different wetland types and their variations with the soil depth to assess heavy metal pollution using pollution indices and to identify the pollution sources using multivariate analysis and sediment quality guidelines. Principal component analysis, cluster analysis, and pollution level indices were applied to evaluate the contamination conditions due to wetland degradation. The findings indicated that the concentration of trace elements decreased with the soil depth, while Cd increases with soil depth. The As concentrations in reed swamps and Suaeda heteroptera surface layers were slightly higher than those in other land use types. All six heavy metals, i.e., Ni, Cu, As, Zn, Cr, and Pb, were strongly associated with PC1 (positive loading) and could reflect the contribution of natural geological sources of metals into the coastal sediments. PC2 is highly associated with Cd and could represent anthropogenic sources of metal pollution. Most of the heavy metals exhibited significant positive correlations with total concentrations; however, no significant correlations were observed between them and the soil salt and soil organic carbon. Soil organic carbon exhibited a positive linear relationship with Cu, Pb, and Zn in the first soil layer (0–20 cm); As, Cr, Cu, Ni, Pb, and Zn in the second layer (20–40 cm); and As, Cr, Cu, Ni, Pb, and Zn in the third layer (40–60 cm). Soil organic carbon exhibited only a negative correlation with Cd (P?I _geo values), which averaged less than 0 in the three soil layers, this finding indicates that the soils have remained unpolluted by these heavy metals. The mean concentrations of these trace elements were lower than Class I criteria. The degradation wetland restoration suggestions have also been provided in such a way as to restore the reserved flow path of the Yellow River. The results that are associated with trace element contamination would be helpful in providing scientific directions to restore wetlands across the world.     

Exploring the relationship between nitrogen dioxide and ground-level ozone by applying the joint multifractal analysis

The main goal of this study is to determine the present heavy metal pollution state in the two gulfs of the Aegean Sea; Saros and Gökova Gulfs. The surface sediments were collected from 11 and eight locations in the Saros and Gökova during May 2001, respectively. The results showed that the sediments of Saros and Gökova gulfs were polluted with Pb, Cr, Zn, Mn, and Ni and Pb, Cr, Ni, and Mn, respectively. For various metals the contamination factor (CF) has been calculated to assess the degree of pollution in sediments. The sediments were noted to be not contaminated with Hg, Cd, and Cu in all areas. Moderate contaminations were observed for Pb, Cr, and Zn in Saros Gulf. The CF was moderate and very high for Ni in the Saros and the Gökova Gulf, respectively.     

Geochemical fractionation of trace elements in sediments of Hugli River (Ganges) and Sundarban wetland (West Bengal, India)

A sequential extraction procedure was carried out to determinate the concentrations of 11 elements (Al, As, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Zn) in different geochemical phases of sediments collected along the Hugli (Ganges) River Estuary and in the Sundarban mangrove wetland, eastern coastal part of India. The chemical speciation of elements was determined using the three-step sequential extraction procedure described by the European Community Bureau of Reference. Total metal concentration was determined using a microwave-assisted acid digestion procedure. Metal concentrations were near the background level except for As for which a moderate pollution can be hypothesized. The mobility order of the metals was: Cd?>?Mn?>?Cu?>?Zn?>?As?>?Co?>?Pb?>?Ni?>?Fe?>?Cr?>?Al. The highest percentage of Cd (>60%) was found in the most labile phase. Residual fraction was prevailing for Fe, Cr and Al, while Pb was mainly associated with the reducible fraction. Data were compared with Sediment Quality Guidelines to estimate the relationship between element concentrations and adverse biological effects on benthic community, finding the possibility of some toxic effects due to the presence of As in the entire studied area and Cd, only in Calcutta.     

Spatial variation of salts in a Gyanpur canal command area

This study was aimed to establish background and reference values of total heavy metals in soils from a representative area of Albania (Tirana). Thirty-eight soil samples collected from genetic horizons of major soil types of Tirana were analyzed for important physicochemical properties by standard methods and for total contents of Cd, Cr, Ni, Pb, Zn, and Cu by atomic absorption spectrometer, after extraction with aqua regia. The results showed that the total contents of Cd, Cr, Ni, Pb, Zn, and Cu in surface horizons varied widely with respective mean values of 0.3 (??0.6), 174.2 (??63.7), 305.9 (??133.0), 19.7 (??12.4), 95.5 (??26.3), and 42.7 (??6.8) mg/kg. The highest metal contents were found in two soils developed in limestone. The depth distribution of metals showed a tendency for accumulation of Cd and Pb in the surface horizons of three soils, suggesting that these metals partially come from anthropogenic inputs. Correlation analysis indicated that the metal contents of soils were controlled by soil properties, including pH, CaCO₃, clay, organic matter, cation exchange capacity, and Fe oxides. The background values (given as the 90th percentile) were much higher than those reported in the literature, showing that the levels of respective metals were naturally higher. The total metal contents of some soils were above background levels, suggesting metal pollution. The reference values for all the analyzed metals were quite consistent with those of the Dutch system. The proposed background and reference values can be used to evaluate the soil pollution with these elements.     

Environmentally safe sewage sludge disposal: the impact of liming on the behaviour of Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn

Dewatered sewage sludge containing relatively high total concentrations of Cr (945 micrograms ml-1), Cu (523 micrograms ml-1), Ni (1186 micrograms ml-1) and Zn (2950 micrograms ml-1) was treated with quicklime and sawdust for sludge disinfection and post-stabilisation. The mobility of the heavy metals in the sludge samples was assessed by applying a modified five-step Tessier sequential extraction procedure. Water was added as a first step for estimation of the proportion of the easily soluble metal fractions. To check the precision of the analytical work the concentrations of heavy metals in steps 1-6 of the extraction procedure were summed and compared to the total metal concentrations. The mass balance agreed within +/- 3% for Cd, Cu, Cr, and Zn and within +/- 5% for Ni, Pb, Fe and Mn. Data from the partitioning study indicate that in the lime-treated sludge at a pH of 12 the mobility of Cu and Ni notably increased with the solubilisation of these metals from their organic and/or carbonate and Fe and Mn oxide and hydroxide fractions, respectively. Liming slightly decreased the proportion of other heavy metals in the easily soluble fractions while its impact on the partitioning between other sludge phases was almost insignificant. Due to the increased solubility of Ni and Cu as well as potential Cr oxidation at high pH, liming cannot be recommended for sludge disinfection. Addition of sawdust did not change the heavy metal partitioning.