Partitioning Of Heavy Metals Research Articles

Fixation and partitioning of heavy metals in slag after incineration of sewage sludge

Fixation of heavy metals in the slag produced during incineration of sewage sludge will reduce emission of the metals to the atmosphere and make the incineration process more environmentally friendly. The effects of incineration conditions (incineration temperature 500–1100°C, furnace residence time 0–60min, mass fraction of water in the sludge 0–75%) on the fixation rates and species partitioning of Cd, Pb, Cr, Cu, Zn, Mn and Ni in slag were investigated. When the incineration temperature was increased from 500 to 1100°C, the fixation rate of Cd decreased from 87% to 49%, while the fixation rates of Cu and Mn were stable. The maximum fixation rates for Pb and Zn and for Ni and Cr were reached at 900 and 1100°C, respectively. The fixation rates of Cu, Ni, Cd, Cr and Zn decreased as the residence time increased. With a 20min residence time, the fixation rates of Pb and Mn were low. The maximum fixation rates of Ni, Mn, Zn, Cu and Cr were achieved when the mass fraction of water in the sludge was 55%. The fixation rate of Cd decreased as the water mass fraction increased, while the fixation rate of Pb increased. Partitioning analysis of the metals contained in the slag showed that increasing the incineration temperature and residence time promoted complete oxidation of the metals. This reduced the non-residual fractions of the metals, which would lower the bioavailability of the metals. The mass fraction of water in the sludge had little effect on the partitioning of the metals. Correlation analysis indicated that the fixation rates of heavy metals in the sludge and the forms of heavy metals in the incinerator slag could be controlled by optimization of the incineration conditions. These results show how the bioavailability of the metals can be reduced for environmentally friendly disposal of the incinerator slag.

Heavy Metal Partitioning in Bottom Sediments of the Matanza-Riachuelo River and Main Tributary Streams

This study provides geochemical partitioning, potential bioavailability, and enrichment of Cd, Cu, Pb, and Zn in bottom sediments collected from the Matanza-Riachuelo River and its main tributary streams. A modified Tessier sequential extraction procedure, complemented with acid volatile sulfide (AVS) and simultaneous extracted metals (SEM) measurements, was applied to determine the partitioning of metals into four fractions (metals bound to amorphous sulfide, carbonate, and exchangeable), bound to Fe/Mn oxides (reducible), bound to organic matter/sulfide (oxidizable) and residual. Spatial and vertical distributions of metals were studied. The core sediments show a decreasing concentration of metals with depth. In top sediments, non-residual Cu was mainly associated with oxidizable phase, whereas Pb, Cd, and Zn were mainly associated with amorphous sulfide. Pb exhibited the highest enrichment in all sites. The ratio AVS/SEM was greater than one at sediment sections close to the water column, indicating that metals extracted with hydrochloric acid were mainly associated with the amorphous sulfide. The strong influence of amorphous sulfide in the retention of Cd, Pb, and Zn in anoxic sediments of Matanza-Riachuelo river system suggests that dredging and aeration could lead to the remobilization of metals from sediments to the water column, hence making the metals more available to the biota.

Quantification of uncertainty in modelled partitioning and removal of heavy metals (Cu, Zn) in a stormwater retention pond and a biofilter

Strategies for reduction of micropollutant (MP) discharges from stormwater drainage systems require accurate estimation of the potential MP removal in stormwater treatment systems. However, the high uncertainty commonly affecting stormwater runoff quality modelling also influences stormwater treatment models. This study identified the major sources of uncertainty when estimating the removal of copper and zinc in a retention pond and a biofilter by using a conceptual dynamic model which estimates MP partitioning between the dissolved and particulate phases as well as environmental fate based on substance-inherent properties. The two systems differ in their main removal processes (settling and filtration/sorption, respectively) and in the time resolution of the available measurements (composite samples and pollutographs). The most sensitive model factors, identified by using Global Sensitivity Analysis (GSA), were related to the physical characteristics of the simulated systems (flow and water losses) and to the fate processes related to Total Suspended Solids (TSS). The model prediction bounds were estimated by using the Generalized Likelihood Uncertainty Estimation (GLUE) technique. Composite samples and pollutographs produced similar prediction bounds for the pond and the biofilter, suggesting a limited influence of the temporal resolution of samples on the model prediction bounds. GLUE highlighted model structural uncertainty when modelling the biofilter, due to disregard of plant-driven evapotranspiration, underestimation of sorption and neglect of oversaturation with respect to minerals/salts. The results of this study however illustrate the potential for the application of conceptual dynamic fate models base on substance-inherent properties, in combination with available datasets and statistical methods, to estimate the MP removal in different stormwater treatment systems and compare with environmental quality standards targeting the dissolved MP fraction.

Study of heavy metal concentration and partitioning in the Estrela River: implications for the pollution in Guanabara Bay - SE Brazil

In this study, the geochemical analysis of ten sediment samples collected along the fluvial system of the Estrela River, which flows into the northern portion of Guanabara Bay, shows the presence of anthropogenic impacts in this area. Concentrations of Fe, Mn, Zn, Cu, Pb, Cr and Ni obtained were slightly higher, when compared with values found in natural environments. The particle size and organic matter content in most of the analyzed stations showed features not conducive to the accumulation of pollutants due to the low organic matter content and the strong presence of sand fraction. There was also the fractionation of heavy metals in sediments and it was found the prominence of residual and reducible phase, besides the significant occurrence of organic fractions in some analyzed stations. These factors, thus, highlight the potential risks of contamination, where the metals associated with the organic phase can become bioavailable in processes of dissolution, provided by physico-chemical changes that can occur in this aquatic environment.

Pollutant release from a disturbed urban snowpack in northern Sweden

Water and pollutant release from a disturbed urban snowpack was studied in an experimental plot encompassing a road section and the adjacent grassed boulevard in the city of Luleå, in northern Sweden. Winter road maintenance in this area includes snow ploughing and applications of grit without any road salts. During the study period, 18 snowmelt events were observed. Compared to rural areas and urban areas with extensive use of chloride in winter road maintenance, in the former case, the observed snowmelt quality differed by relatively high and uniform pH (7.7–8.1) and, in the latter case, by low chloride event-mean-concentrations (EMCs) (5.7–123.4 mg/L) and conductivity (11.6–60.7 mS/m). Total suspended solids (TSS) EMCs greatly exceeded those reported for rural snowmelt and urban rainfall runoff and contributed to the high pH buffering capacity of deposited snow. Observed concentrations of total and dissolved heavy metals were compared to water quality guidelines that suggested a high likelihood of biological effects. Chloride was the only pollutant that indicated an early release and all other constituents showed a uniform release with snowmelt from the snowpack. The partitioning of heavy metals between total and dissolved phases indicated the highest dissolved fractions for Cu, followed by Cd, Ni and Zn, and the lowest values were observed for Pb. The urban snowmelt characteristics substantially differed from those reported for undisturbed sites with respect to higher pollutant loads, high pH buffering capacity and a general absence of early or delayed pollutant release from the snowpack.

Speciation of heavy metals by modified BCR sequential extraction procedure in different depths of sediments from Sungai Buloh, Selangor, Malaysia

The sequential extraction procedure proposed by the European Standard, Measurements and Testing (SM&T) program, formerly the Community Bureau of Reference (BCR), was applied for partitioning of heavy metals (HMs) in river sediments collected along the course of Sungai Buloh and the Straits of Malacca in Selangor, Malaysia. Eight elements (V, Pb, Cd, Cr, Co, Ni, Cu and Zn) from seven stations (S1–S7) and at different depths were analyzed using the modified BCR Sequential Extraction Procedure (SEP) in combination with ICP-MS to obtain the metal distribution patterns in this region. The results showed that heavy metal contaminations at S2 and S3 was more severe than at other sampling sites, especially for Zn, Cu, Ni and Pb. Nevertheless, the element concentrations from top to bottom layers decreased predominantly. The samples from the Straits of Malacca (S4–S7) the highest contamination factors obtained were for Co, Zn and Pb while the lowest were found for V and Cr, similar to Sungai Buloh sediments. The sediments showed a low risk for V, Cr, Cu and Pb with RAC values of less than 10%, but medium risk for Co, Zn (except S3), Cd at S1 and S2 and Ni at S1, S3 and S5. Zn at S3 and Cd at S3–S7 showed high risk to our sediment samples. There is not any element of very high risk conditions in the selected samples.

Fractionation of heavy metals in sediment by using microwave assisted sequential extraction procedure and determination by inductively coupled plasma mass spectrometry

In this work, a fast microwave assisted extraction procedure was developed and optimized for the heavy metals (Cu, Ni, Cr, Pb and Cd) partitioning in the three-stage sequential extraction procedure proposed by the European Standards, Measurements and Testing (SM&T) Program, formerly the Community Bureau of Reference (BCR). The microwave oven procedure was optimized to obtain extraction efficiencies similar to the conventional BCR procedure, in less time, while using smaller volumes of reagents. In the optimization process, three variables (extraction time, ramping time and microwave power) were considered as factors and as a response the concentration of different metal ions in each individual BCR fraction. Interactions between analytical factors and their optimized levels were investigated using a central composite design. Extractable metals obtained by both comparable methodologies were measured by inductively coupled plasma mass spectrometry. With the use of optimal microwave conditions, steps 1–3 of the sequential extraction (including the hydrogen peroxide digestion in step 3) could be completed between 21 and 22 min. Detection limits were between 1 and 18 ng l − 1 . The accuracy of the proposed method was checked with a certified reference material (CRM) of Lake Sediment BCR 701. Values obtained were in accordance with those reported for the certified material with only a few exceptions. Different origin sediments (river and marine) were analyzed by both BCR and MW procedures, and the results obtained were comparable according to the t-paired-test for a 95% confidence level.

Accumulation and partitioning of heavy metals in mangrove rhizosphere sediments

A field study was conducted to clarify the effect of rhizosphere processes on the accumulation and partitioning of heavy metals (Pb, Zn, Cu, Cr, Cd and Ni) in mangrove sediments. Metals were fractionated by a sequential extraction procedure into three chemically distinct fractions: water soluble, exchangeable and carbonate bound (B1), Fe–Mn oxide bound (B2), and organic and sulfide bound (B3). Results indicate that rhizosphere processes tend to increase the metal concentrations in the rhizosphere sediments. However, plant uptake may result in the decrease of the metal concentrations in the rhizosphere sediments when the metal concentrations are relatively low in the bulk sediments. Compared with the bulk sediments, the rhizosphere sediments have low concentrations of heavy metals in the B1 and B2 fractions and high concentrations in the B3 fraction. Either an increase or decrease in the residual fraction of heavy metals in the rhizosphere sediments may appear, depending on whether the formation of the refractory metal-organic compounds or the activation of the residual fractions dominates. Results also indicate that mangrove plants absorb and store non-essential metals in the perennial tissues, thus reducing the export of non-essential metals via leaf litter transport. Mangrove plants are excellent candidates for phytostabilization of heavy metals in intertidal substrates.

Accumulation and Partitioning of Heavy Metals by Bacterial Cells and Associated Colloidal Minerals, with Alteration, Neoformation, and Selective Adsorption of Minerals by Bacteria, in Metal-Polluted Lake Sediment

Energy dispersive X-ray microanalysis and transmission electron microscopy were used to investigate heavy metal accumulation and partitioning by a statistically meaningful assortment of bacteria and colloidal minerals in metal-polluted lake sediment. Visually selected external and internal parts of bacterial cells were analysed individually. Variations in element distribution and relationships provided clues to small-scale biogeochemical processes and their implications for microbial ecology. Most bacteria had mineral coatings of varying composition and texture formed by adsorption of detrital clay and precipitation of authigenic oxides and clay attributable to Fe and Al complexing by cell walls and fibrils. Fe oxide precipitated abiotically and indiscriminately on bacteria and minerals, but Mn oxide was purely biogenic, precipitating only on certain bacteria. Cell walls also complexed Cu; formation of mineral coatings interfered with Cu binding, but the coatings themselves scavenged Cu. Cu and Zn were bound preferentially by oxides, but Ni was bound mainly by clay. Many bacteria accumulated metals preferentially on cell exteriors or in cytoplasmic inclusions, implying different mechanisms of bioaccumulation and detoxification, whose original purpose may have been to concentrate nutrient trace metals from dilute solution and regulate their proportions. Bacteria commonly employed both mechanisms, suggesting adaptation to different metal species. Preferential intake and exclusion of metals also occurred, and exterior-interior partition coefficients of metals in cells correlated with specific metal properties, revealing clues to the processes involved. In addition, bacteria were important agents of diagenesis. Besides precipitating oxides, they degraded adsorbed clay, synthesised intracellular and extracellular clay, and adsorbed clay minerals selectively.

Geochemical Partitioning of Heavy Metals in Roadside Surface Soils of Different Grain Size along Major Roads in Kano Metropolis, Nigeria

This study evaluates the effect of grain size on levels of metal in roadside surface soils collected along high traffic roads in Kano Metropolis as a consequence of increase in automobile over the years. Composite surface soil samples were collected along ten different roads. Samples were analysed for soil physicochemical parameters, heavy metals (Cd, Cr, Ni, Pb, Cu and Zn) content. On an average a six sequential extraction of roadside surface soils showed that Cd, Cr, Ni, Pb, Cu and Zn are predominantly occur in the Fe-Mn oxide, residual, residual, carbonate bound, organic and residual fractions respectively. It was found that concentrations in the water soluble and exchangeable fractions were generally low for most of the studied metals. Considering the proportion of metals bound to the water soluble to the exchangeable and the carbonate bound fractions, the comparative mobility of metals showed the order; Ni > Cd > Pb > Cr > Cu > Zn. Highest mobility factor (MF) for all studied metals was obtained in 150μm samples with exception of Ni, Pb and Cu where highest percentage MF was obtained in 1400μm samples and 355μm for Zn. This could indicate other sources than fine particulate emission form vehicles responsible. With toxicity it appears that Cd, Cr, Ni, Pb and Cu pollution along the roadside is of concern.

Distribution and removal efficiency of heavy metals in two constructed wetlands treating landfill leachate

The results of heavy metals (Fe, Mn, Zn, Ni, Cu, Cr, Pb, Cd) removal and partitioning between aqueous and solid phases at two treatment wetlands (TWs) treating municipal landfill leachates are presented. One of the TWs is a surface flow facility consisting of 10 ponds. The other TW is a newly constructed pilot-scale facility consisting of three beds with alternately vertical and horizontal subsurface flow. The metals concentrations were analysed in leachate (both TWs) and bottom sediments (surface flow TW). Very high (90.9-99.9%) removal rates of metals were observed in a mature surface flow TW. The effectiveness of metals removal in a newly constructed pilot-scale sub-surface flow wetland were considerably lower (range 0-73%). This is attributed to young age of the TW, different hydraulic conditions (sub-surface flow system with much shorter retention time, unoxic conditions) and presence of metallic complexes with refractory organic matter.

Distribution and chemical partitioning of heavy metals in marine near-shore sediment cores: a case study from the Xugou, Lianyungang, China

The concentrations and chemical partitioning of heavy metals (Co, Cr, Ni, Zn, Cu, and Pb) in the marine near-shore sediment cores were investigated. Typically, the mean concentrations from Core B sediment samples were 98.6, 21.1, 47.0, 46.4, 107.6, and 31.9 mg kg( - 1) for Cr, Co, Ni, Cu, Zn, and Pb, respectively. The heavy metal concentrations were normalized to commonly used reference elements Al, Li, Sc, and total organic carbon. Based on Pearson coefficients, Li was found to be a good normalizer for Co (r = 0.974), Cr (r = 0.967), Ni (r = 0.898), and Zn (r = 0.929) in 80 sediment samples from three sampling sites. However, the correlation coefficients between Li and Cu, and Li and Pb were relatively low. Multivariate statistic approaches (Principal Component Analysis and Cluster Analysis) were adopted for data treatment, allowing the identification of two main factors controlling the heavy metal variability in the sediments. Heavy metals in the enrichment sections were evaluated by a sequential extraction method for possible chemical forms in sediments. The results showed that the residual, Fe/Mn oxides and Organic/sulfide fractions were dominant geochemical phases in the enriched sections, indicating low bioavailability of heavy metals in sediments.

Elemental chemistry and geochemical partitioning of heavy metals in road dust from Dhanbad and Bokaro regions, India

Road dust collected from India’s richest and oldest coal mining belt of Dhanbad and Bokaro regions was analysed for particle size characteristics and elemental composition. The particle size distribution pattern shows dominance of 500–250 μm and 250–125 μm size fractions, constituting 45–58% of the mass size spectrum. Si is the most dominant element and its concentration varied between 29.3 and 36.4% with the average value 34.3%. Fe, Ti and Mn are the dominant heavy metals followed by Zn, Cr, Pb, Cu, Ni and Co. No significant differences concentration of metals between sampling sites was apparent; however, some sites tend to accommodate relatively higher metals due to its proximity to industrial and mining sites. In general, finer fraction (<63 μm) tend to contain 1–3 times higher metals as compared with the bulk composition. Except Pb and Mn all the measured metals are generally lie below grade zero, suggesting that there is no pollution threat with respect to these metals in roadway dust from the studied sites. Geochemical speciation study shows that the lithogenic phase is the major sink for heavy metals. Fe–Mn oxide and organic are the major non-lithogenic phases and Pb and Zn are the major elements of the non-lithogenic phase.

Comparison of sequential extraction and principal component analysis for determination of heavy metal partitioning in sediments: the case of protected Lagoon El Kelbia (Tunisia)

A sequential extraction procedure applied to surface sediments from El Kelbia Lagoon determined the partitioning of Ba, Co, Cr, Cu, Ni, Sr, V and Zn among evaporites, carbonates, Fe–Mn oxides, organic matter and silicates. To validate the procedure, the sequential extraction results (SER) were compared to principal components analysis (PCA) using major and trace element concentrations and mineralogical quantitative data of surface sediments. SER showed that a part of Sr was highly mobile; Cu, Sr, and Zn and a part of Co and Ni were mobile depending on pH conditions; Cr and V were strongly bound to silicate phases; Co and Ni were partitioned between carbonates, oxides and silicates, and a great part of Ba and Sr were bound to organic matter or sulfides. An agreement was found with PCA in terms of partitioning among minerals for most trace elements. Moreover, the absence of correlation between Ca concentrations and the abundances of calcite, gypsum or dolomite could be explained by an important fraction of Ca bound to organic matter. Also, unexpected negative correlations between abundances of smectite and illite could be explained by a transformation of illite into smectite. Thus, SER and PCA were mostly convergent, which enabled: (1) validation of the extraction procedure used, and (2) refinement of interpretations of the origin and relations between minerals.

Sediment geochemistry of streams draining abandoned lead/zinc mines in central Wales: the Afon Twymyn

Despite the decline of metal mining in the UK during the early 20th century, a substantial legacy of heavy metal contamination persists in river channel and floodplain sediments. Poor sediment quality is likely to impede the achievement of ‘good’ chemical and ecological status for surface waters under the European Union Water Framework Directive. This paper examines the environmental legacy of the Dylife lead/zinc mine in the central Wales mining district. Leachable heavy metal concentrations in the bed sediments of the Afon Twymyn are established and the geochemical partitioning, potential mobility and bioavailability of sediment-associated heavy metals are established. Sediment samples were collected from the river bed and dry-sieved into two size fractions (<63 and 64–2,000 µm). The fractionated samples were then subjected to a sequential extraction procedure to isolate heavy metals (Pb, Zn, Cu, Cd, Fe, Mn) in three different geochemical phases. Sediment samples were then analysed for heavy metals using Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES). The bed sediment of the Afon Twymyn is grossly polluted with heavy metals. Within the vicinity of the former mine, Pb concentrations are up to 100 times greater than levels reported to have deleterious impacts on aquatic ecology. Most heavy metals exist in the most mobile easily exchangeable and carbonate-bound geochemical phases, potentially posing serious threats to ecological integrity and constituting a significant, secondary, diffuse source of pollution. Metal concentrations decrease sharply downstream of the former mine, although there is a gradual increase in the proportion of readily extractable Zn and Cd. Implementation of sediment quality guidelines is important in order to achieve the aims of the Water Framework Directive. Assessments of sediment quality should include measurements of background metal concentrations, river water physico-chemistry and, most importantly, metal mobility and potential bioavailability. Uniformity of sediment guidelines throughout Europe and flexibility of targets with regard to the most heavily contaminated mine sites are recommended.

Comparison of two sequential extraction procedures for heavy metal partitioning in mine tailings

This study aimed at elucidating the fractionation of Cd, Zn and Pb in mine tailings and evaluating the extraction selectivity of different extractants – and thus the efficiency of two sequential extraction procedures. For the purpose of figuring out the applicability of different sequential extraction procedures (SEP’s) in Cd, Zn and Pb fractionation in mine tailings, two SEP’s (i) modified BCR and (ii) Tessier’s scheme were applied to mine tailings (new as well as old). To compare the results obtained by two methods having different number of fractions (four and five respectively), the fractions were rearranged into four “equivalent fractions” defined as acid soluble, reducible, oxidisable and residual. Systematic variations in the “reducible” fraction, i.e. the content of metal in the reducible fractions obtained by Tessier’s procedure were, in general, higher than those obtained by BCR scheme. This may be attributed to stronger conditions used in Tessier’s scheme to extract this fraction. This shows that the fractions are only empirically (operationally) defined and are not totally exclusive to the specified mineral phase. Percentages of Cd, Zn and Pb extracted in the organic fraction by modified BCR scheme were always higher than those obtained by Tessier’s scheme. Based on the fractionation results by both the schemes, it appears that as compared to Cd and Zn, Pb has lower extraction yield in old tailings as compared to new tailings in organic/sulphides bound fraction. This can be explained by the formation of secondary Pb minerals of low solubility, formed by the oxidation of sulphides in old tailings as a result of weathering. Speciation data indicate that Cd has the greatest affinity in the acid soluble fraction, Pb is associated with the reducible fraction and Zn is incorporated into the residual fraction (crystalline silicate matrices) irrespective of the solid matrix type. The metal associations in the oxidizable fraction appear to be matrix specific, i.e., Zn dominates this fraction in new tailings and Pb in old tailings.

Relationships between heavy metals in the catfish, &lt;i&gt;Chrysicthys nigrodigitatus&lt;/i&gt;, water column and sediments of taylor creek, southern Nigeria

Heavy metals in the aquatic environment have to date originated basically from naturally occurring geochemical resources. Nonetheless, this has been enhanced by anthropogenic activities resulting in pollution. Consequently, relationships and partitioning of heavy metals in the dissolved phase, suspended particulate matter (SPM), sediments and the catfish C. nigrodigitatus were investigated in five selected sites along Taylor creek, southern Nigeria. The degree of relationships between the various metals was dissimilar in each of the investigated matrices. In the matrices, not several significant relationships (PO.05) were obtained. Only Ni-Cd (r=0.95), Mn-Cd (r=0.63), Mn-Ni (r=0.64) were associated in the sediments and in SPM, Fe-Cr (r=0.54) and Zn-Ni (r=0.72), which suggests that the sources were not common for both matrices. In the dissolved phase, no strong relationships (PO.05) between the heavy metals were obvious. The best relationships were observed for Ni-Zn (r=0.72) and Cd-Pb (r=0.65). Partitioning coefficients (£d) of heavy metals between dissolved phase and SPM were generally low, which is typical for fresh water ecosystems and fairly stable over the creek all through the seasons. Furthermore, the bio-concentration factors (BCFs) of C. nigrodigitatus were low unlike those of other natural waters. Conversely, the state of the aquatic ecosystem indicates that the heavy metals could contribute to inferior biodiversity and shifts in community composition from sensitive to tolerant taxa that also signifies that the heavy metals in C. nigrodigitatus exceeded the Risk Based Consumption Limits, based on an adult body weight of 70 kg and 16 Fish Meals/Month, indicating that consumers of C. nigrodigitatus from the creek may be exposed to neurotoxins.Keywords: Cat fish, Chrysicthys nigrodigitatus, heavy metals, Nigeria

Distribution and Partitioning of Heavy Metals in Subtidal Sediments of the Arabian Gulf Coast of Saudi Arabia

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Partition of heavy metals (Hg, Cd, and Pb) between sphalerite and hydrothermal solution and the typomorphism of sphalerite surface: XPS, AES, and AFM data

Partition of heavy metals (Hg, Cd, and Pb) between sphalerite and hydrothermal solution and the typomorphism of sphalerite surface: XPS, AES, and AFM data

Investigation of heavy metal partitioning influenced by flue gas moisture and chlorine content during waste incineration

The impact of moisture on the partitioning of the heavy metals including Pb, Zn, Cu and Cd in municipal solid waste (MSW) was studied in a laboratory tubular furnace. A thermodynamic investigation using CHEMKIN software was performed to compare the experimental results. Simulated waste, representative of typical MSW with and without chlorine compounds, was burned at the background temperature of 700 and 950°C, respectively. In the absence of chlorine, the moisture content has no evident effect on the volatility of Pb, Zn and Cu at either 700 or 950°C, however, as flue gas moisture increasing the Cd distribution in the bottom ash increased at 700°C and reduced at 950°C, respectively. In the presence of chlorine, the flue gas moisture reduced the volatility of Pb, Zn and Cu due to the transformation of the more volatile metal chlorides into less volatile metal oxides, and the reduction became significant as chlorine content increase. For Cd, the chlorine promotes its volatility through the formation of more volatile CdCl 2. As a result, the increased moisture content increases the Pb, Zn, Cu and Cd concentrations in the bottom ash, which limits the utilization of the bottom ash as a construction material. Therefore, in order to accumulate heavy metals into the fly ash, MSW should be dried before incineration.