Inputs Of Zn Research Articles

Historical variation of heavy metals with respect to different chemical forms in recent sediments from Xianghai Wetlands, Northeast China

The major objective of this research is to determine whether pollution trends could be reconstructed from sediment records at the downstream wetlands of the Huolin River. Sediment cores, representing a range of watershed characteristics and anthropogenic impacts, were collected from two marshes at the Xianghai Wetlands in order to trace the historical variation of heavy metals, accumulation rates, and chemical forms. Cores were 210Pb-and 137Cs-dated, and these data were used to calculate sedimentation rates and sediment accumulation rates that were compared with environmental change. Ranges of dry mass accumulation rates and sedimentation rates were 0.27–0.96g/ cm2/yr and 0.27–0.90cm/yr. After normalization to Al, the anthropogenic enrichment of Cu, Zn, Cr, and Pb occurred in the uppep layer of sediments and indicated that heavy metal contamination coming from the hydrologic inputs primarily occurred after the 1980s. This result was consistent with two decades of surface coal-mining history within the upstream region of Huolin River. Sediment inputs of most heavy metals at Xianghai Wetlands began to increase over background levels at around 1885 and were generally consistent with the time of the Qing Dynasty’s immigration settlement. The anthropogenic inputs of Cu, Zn, Fe, Mn, Cr, and Pb have been 1.20–3.67 times greater than values of their natural inputs after the 1980s, which may be a result of increased input of heavy metal-rich alluvial deposits derived from surface coal-mining activities in the watershed. Sequential extraction was used to describe partitioning of heavy metals among different mineralogical components in sediments, and results showed that heavy metals in sediment cores were mostly associated with the lithogenic bonding forms (residual fraction) and least with the exchangeable fraction (except Pb). The major fraction of Pb was in the Fe−Mn oxide fraction (mean: 40.7–48.6%), indicating that Pb in these sediments had greater mobility and suggested that it might be primarily from anthropogenic sources.

Fifty-year sedimentary record of heavy metal pollution (Cd, Zn, Cu, Pb) in the Lot River reservoirs (France)

The Lot–Garonne fluvial system is known for its historic heavy metal pollution resulting from mining and smelting activities since the late 19th century. Here, we report 137Cs activities and heavy metal (Cd, Zn, Cu, Pb and V) concentration–depth profiles from sediment cores retrieved in 2001 from three reservoirs in the Lot River. High mean sedimentation rates of 2.4–2.8 cm a −1 are indicated by 137Cs dating. The reservoir sediments have recorded the heavy metal deposition and thus allow establishing a connection between the temporal evolution of the heavy metal pollution and historical changes in smelting and waste-treatment proceedings. Based on heavy metal concentrations in sediments upstream of the anthropogenic inputs and bottom-sediments of the furthest downstream core (interpreted as old soil or riverbed), concentrations of ∼17, ∼82, ∼0.33 and ∼28 mg kg −1 for Cu, Zn, Cd and Pb, respectively, are proposed as natural background values for the Lot fluvial system. The geoaccumulation index ( I geo [Müller, G., 1979. Schwermetalle in den Sedimenten des Rheins-Veränderungen seit. Umschav 79, 133–149.]) revealed that the Lot River sediments must be considered as “severely polluted” in Cd and Zn. Moreover, despite remediation efforts undertaken in the former smelting site, the Lot River is still “severely” ( I geo ∼ 4) and “moderately to severely” ( I geo > 2) impacted by Cd and Zn inputs, respectively.

Tire-wear particles as a source of zinc to the environment.

Tire-tread material has a zinc (Zn) content of about 1 wt %. The quantity of tread material lost to road surfaces by abrasion has not been well characterized. Two approaches were used to assess the magnitude of this nonpoint source of Zn in the U.S. for the period 1936-1999. In the first approach, tread-wear rates from the automotive engineering literature were used in conjunction with vehicle distance-driven data from the U.S. Department of Transportation to determine Zn releases. A second approach calculated this source term from the volume of tread lost during lifetime tire wear. These analyses showed that the quantity of Zn released by tire wear in the mid-1990s was of the same magnitude as that released from waste incineration. For 1999, the quantity of Zn released by tire wear in the U.S. is estimated to be 10 000-11 000 metric tons. A specific case study focused on Zn sources and sinks in an urban-suburban watershed (Lake Anne) in the Washington, DC, metropolitan area for a time period of the late 1990s. The atmospheric flux of total Zn (wet deposition) to the watershed was 2 microg/cm2/yr. The flux of Zn to the watershed estimated from tire wear was 42 microg/cm2/yr. The measured accumulation rate of total Zn in age-dated sediment cores from Lake Anne was 27 microg/cm2/yr. These data suggest that tire-wear Zn inputs to urban-suburban watersheds can be significantly greater than atmospheric inputs, although the watershed appears to retain appreciable quantities of vehicular Zn inputs.

Over one hundred years of trace metal fluxes in the sediments of the Pearl River Estuary, South China

The rapid economic development in the Pearl River Delta (PRD) region in South China in the last three decades has had a significant impact on the local environment. Estuarine sediment is a major sink for contaminants and nutrients in the surrounding ecosystem. The accumulation of trace metals in sediments may cause serious environmental problems in the aquatic system. Thirty sediment cores were collected in the Pearl River Estuary (PRE) in 2000 for a study on trace metal pollution in this region. Heavy metal concentrations and Pb isotopic compositions in the four 210Pb-dated sediment cores were determined to assess the fluxes in metal deposits over the last one hundred years. The concentrations of Cu, Pb and Zn in the surface sediment layers were generally elevated when compared with the sub-surface layers. There has been a significant increase in inputs of Cu, Pb and Zn in the PRE since the 1970s. The results also showed that different sampling locations in the estuary received slightly different types of inputs. Pb isotopic composition data indicated that the increased Pb in the recent sediments was of anthropogenic origin. The results of trace metal influxes showed that about 30% of total Pb and 15% of total Zn in the sediments in the 1990s were from anthropogenic sources. The combination of trace metal analysis, Pb isotopic composition and 210Pb dating in an estuary can provide vital information on the long-term accumulation of metals in sediments.

Metal uptake by young trees from dredged brackish sediment: limitations and possibilities for phytoextraction and phytostabilisation

Five tree species ( Acer pseudoplatanus L., Alnus glutinosa L. Gaertn., Fraxinus excelsior L., Populus alba L. and Robinia pseudoacacia L.) were planted on a mound constructed of dredged sediment. The sediment originated from a brackish river mouth and was slightly polluted with heavy metals. This preliminary study evaluated the use of trees for site reclamation by means of phytoextraction of metals or phytostabilisation. Although the brackish nature of the sediment caused slight salt damage, overall survival of the planted trees was satisfactory. Robinia and white poplar had the highest growth rates. Ash, maple and alder had the highest survival rates (>90%) but showed stunted growth. Ash, alder, maple and Robinia contained normal concentrations of Cd, Cu, Pb and Zn in their foliage. As a consequence these species reduce the risk of metal dispersal and are therefore suitable species for phytostabilisation under the given conditions. White poplar accumulated high concentrations of Cd (8.0 mg kg −1) and Zn (465 mg kg −1) in its leaves and might therefore cause a risk of Cd and Zn input into the ecosystem because of autumn litter fall. This species is thus unsuitable for phytostabilisation. Despite elevated metal concentrations in the leaves, phytoextraction of heavy metals from the soil by harvesting stem and/or leaf biomass of white poplar would not be a realistic option because it will require an excessive amount of time to be effective.

Land inputs of trace metals, major elements, particulate organic carbon and suspended solids to an industrial coastal bay of the NE Atlantic

Rivers, streams and municipal and industrial effluents flowing into the Ferrol Ria (NW Spain) were analyzed for dissolved and particulate trace elements (Cd, Cu, Pb, Zn), particulate major elements (Al, Fe, Si), particulate organic carbon and nitrogen (POC and PON), and total suspended solids. Trace metal clean techniques were applied. Mean annual fluxes of these components were calculated. Dissolved trace metal concentrations in the major freshwater inputs were found to be within typical values for uncontaminated rivers: Cd: 0.020–0.035 nM; Cu: 11.7–19.2 nM; Pb: 0.40–0.71 nM and Zn: 18–54 nM. Two sources of suspended particulate matter (SPM) were observed: (i) a detrital SPM, which becomes more important at high river discharges, with metal concentrations tending to lithogenic values; (ii) an organic- and metal-rich SPM, which becomes dominant at low discharges. Municipal and industrial effluents in the northern shore, despite of constitute a minor freshwater contribution to the bay, were responsible for more than 50% of total inputs of Cu, Cd, Pb, Zn, POC and PON. The fluxes of trace metals obtained for the Ferrol Ria are in the range of other inhabited world semi-enclosed embayments.

Geochemical variations of major and trace elements in recent sediments, off the Gulf of Mannar, the southeast coast of India

The Gulf of Mannar along the Tuticorin coast is a coral base of the southeast coast of India. To obtain a preliminary view of its environmental conditions, geochemical distribution of major elements (Si, Al, Fe, Ca, Mg, Na, K, P), trace elements (Mn, Cr, Cu, Ni, Co, Pb, Zn, Cd) and acid leachable elements (Fe, Mn, Cr, Cu, Ni, Co, Pb, Zn, Cd) were analyzed in surface sediment samples from two seasons. Geochemical fractionation confirmed the lithogenic origin of metals, which were mainly associated with the detrital phase. The sediments in the gulf are sandy with abundant calcareous debris, which controls the distribution of total and acid leachable elements. Enrichment factors relative to crust vary by a magnitude of two to three and the presence of trace metals indicates the input of Cr, Pb, Cd, Cu and Zn in both forms through industrial activities. Factor analysis supports the above observation with higher loadings on acid leachable elements and its association with CaCO3. The increase in concentration of trace metals (Cr, Pb, Cd, Cu, Co, Ni, Zn) along the Gulf of Mannar indicates that the area has been contaminated by the input from riverine sources and the industries nearby. The present study indicates that other sources should be evaluated in the long-term monitoring program.

Metal contents in Porites corals: Anthropogenic input of river run-off into a coral reef from an urbanized area, Okinawa

In order to monitor pollutants from urban areas to coral reefs, metal contents in Porites coral samples collected from the Hija River mouth and at nearby sites from the estuary were analyzed. The corals were cleaned by oxidative and reductive treatments to effectively eliminate detritus and organic materials. Metal-to-calcium (Me/Ca) ratios in the samples were determined by ICP-MS. Filtered samples of river water were also measured similarly for metal concentrations. The extent of anthropogenic contribution by riverine input was assessed by comparing the Me/Ca values in corals to those of Rukan-sho, an unpolluted coral reef. High riverine inputs of Mn, Cd, Zn and Ag were observed from Me/Ca values in the coral samples. Manganese in the coral samples showed strong dependence on salinity, varying inversely to the distance from terrestrial sources. Considering a lead background of 25.0 nmol/mol measured in the Rukan-sho corals, Pb/Ca in corals of the Hija River estuary that are two and three times higher may indicate lead enrichment in the river mouth. Because Pb is only moderately high in the Hija River water compared to its concentration in surface seawater, lead may have accumulated in the estuarine water and sediments, resulting in an elevated concentration of lead available for coral uptake.

Estimation of heavy metals (Cu, Zn, Pb) input into Punat Bay

The fate of heavy metals (Cu, Pb, Zn) from their sources to the final sink was analysed. Investigations included the identification of sources, the input from each source as well as transport towards their temporary (soil, vegetation, and marine water) and final sink (marine sediments). Research was conducted in the catchment area of Punat Bay on the island of Krk (Northern Adriatic, Croatia). Four sources were identified: long-range transport, traffic, antifouling paints and eroded material which annually introduced about 158 kg of Cu, 175 kg of Pb and 666 kg of Zn into the Bay. Antifouling paints were significant but not the main source of pollution in this area as was considered in previous investigations. Due to long-range transport, the input of Zn was almost four times greater, whereas the input of Pb was almost six times greater than the input from antifouling paints. Aerosols emitted from motor vehicles still represent the mayor source of Pb in this area. Cu originates mostly from antifouling paints and long-range transport. It was estimated that only around 30% of analysed elements introduced into the water column would be deposited in their final sink, i.e. marine sediments.

Distribution of soil fractions of zinc and its uptake by potatoes, maize, wheat and barley after soil amendment by sludge and inorganic Zn salt

Zinc distribution in the main soil fractions and zinc accumulation in potatoes, maize, wheat and barley after different soil treatments (basic sludge rate, triple sludge rate, NPK, NPK + inorganic Zn) were investigated in a field experiment conducted at five localities of the Czech Republic (Červený Újezd, Hněvčeves, Humpolec, Lukavec, Suchdol) with different soil and climatic conditions. Three soil types were investigated in the experiment: clay-loamy Chernozems, loamy Luvisols, clay-loamy Luvisols and two loamy Cambisols. Sequential analyses provided an overview of soil Zn distribution in the following fractions: exchangeable, Fe-Mn oxide, organic and residual ones. The sludge and inorganic Zn addition supported Zn mobility growth and higher Zn retention in Fe-Mn oxides in all tested soils. The influence of the above-mentioned treatments on higher Zn association with soil organic compounds was not explicitly found. Potatoes, wheat and barley accumulated more Zn after its addition into the soils by sludge and inorganic salt. By contrast, Zn content in maize decreased with higher input of Zn into the soil. The highest Zn concentrations were usually observed in plants grown on both Cambisols.

Surface runoff losses of copper and zinc in sandy soils.

Increased anthropogenic inputs of Cu and Zn in soils have caused considerable concern relative to their effect on water contamination. Copper and Zn contents in surface soil directly influence the movement of Cu and Zn. However, minimal information is available on runoff losses of Cu and Zn in agricultural soils, and soil-extractable Cu and Zn in relation to runoff water quality. Field experiments were conducted in 2001 to study dissolved Cu and Zn losses in runoff in Florida sandy soils under commercial citrus and vegetable production and the relationship between soil-extractable Cu and Zn forms and dissolved Cu and Zn concentrations in runoff water. Five extraction methods were compared for extracting soil available Cu and Zn. Concentrations of dissolved Cu and Zn in runoff were measured and runoff discharge was monitored. Mean dissolved Cu in field runoff water was significantly correlated with the extractable Cu obtained only by 0.01 mol L(-1) CaCl2, Mehlich 1, or DTPA-TEA methods. Dissolved Zn in runoff water was only significantly correlated with extractable Zn by 0.01 mol L(-1) CaCl2. The highest correlations to dissolved Cu in runoff were obtained when soil-available Cu was extracted by 0.01 mol L(-1) CaCl2. The results indicate that 0.01 mol L(-1) CaCl2-extractable Cu and Zn are the best soil indexes for predicting readily released Cu and Zn in the sandy soils. Both runoff discharge and 0.01 mol L(-1) CaCl2-extractable Cu and Zn levels had significant influences on Cu and Zn loads in surface runoff.

Surface Runoff Losses of Copper and Zinc in Sandy Soils

Increased anthropogenic inputs of Cu and Zn in soils have caused considerable concern relative to their effect on water contamination. Copper and Zn contents in surface soil directly influence the movement of Cu and Zn. However, minimal information is available on runoff losses of Cu and Zn in agricultural soils, and soil-extractable Cu and Zn in relation to runoff water quality. Field experiments were conducted in 2001 to study dissolved Cu and Zn losses in runoff in Florida sandy soils under commercial citrus and vegetable production and the relationship between soil-extractable Cu and Zn forms and dissolved Cu and Zn concentrations in runoff water. Five extraction methods were compared for extracting soil available Cu and Zn. Concentrations of dissolved Cu and Zn in runoff were measured and runoff discharge was monitored. Mean dissolved Cu in field runoff water was significantly correlated with the extractable Cu obtained only by 0.01 mol L−1 CaCl2, Mehlich 1, or DTPA–TEA methods. Dissolved Zn in runoff water was only significantly correlated with extractable Zn by 0.01 mol L−1 CaCl2 The highest correlations to dissolved Cu in runoff were obtained when soil-available Cu was extracted by 0.01 mol L−1 CaCl2 The results indicate that 0.01 mol L−1 CaCl2–extractable Cu and Zn are the best soil indexes for predicting readily released Cu and Zn in the sandy soils. Both runoff discharge and 0.01 mol L−1 CaCl2–extractable Cu and Zn levels had significant influences on Cu and Zn loads in surface runoff.

IMPROVING THE MICRONUTRIENT AVAILABILITY IN CALCAREOUS SOILS BY SEWAGE SLUDGE AMENDMENT

The pollution associated with non-essential heavy metals in sewage sludge is a hazard usually taken into consideration with land application of such biosolids. The risk of contamination may also be a factor for elements that are essential for plant growth because they are present in sewage sludge in very high concentrations. Calcareous soils, however, are often deficient in elements like Fe and Zn. In this experiment, we attempted to estimate the contribution of sewage sludge application to the input and availability of Fe, Mn, Cu, and Zn in amended soils. In order to study the dynamics of these essential elements, the experimental design was based on the incubation of two calcareous soils having different textures (sandy clay loam and clay loam) amended with composted and non-composted sewage sludge. Sewage sludge application rates to the soils were 30 and 50 g dry sludge kg−1 soil. Also, for each soil, a control treatment with no organic amendment was established. Seven samples were taken from each soil-sludge treatment combination at 0, 15, 30, 60, 90, 120 and 150 days after the start of the incubation. A significant increase in available Fe, Cu, Mn and Zn was observed. The application of increasing rates of sewage sludge slightly increased the available fraction of the micronutrients studied. The influence of soil texture was to increase the available fraction in the clay loamy soil compared to the sandy clay loamy soil. Availability of Fe, Cu, Mn and Zn was continued to increase throughout the incubation period.

Input of heavy metals to the forest floor as a result of Cracow urban pollution

The influence of Cracow's urban pollution on small forest ecosystems was studied during 1998–2000. Seven sites located at different distances from the Cracow conurbation and from busy road were selected. Two sites were situated 26 and 31 km from Cracow town along an eastern transect, the other five—3, 8, 14, 26 and 35 km respectively, from Cracow—along a southern transect. At the beginning of September, five litter traps were set at each site. The quantity of litter fall, along with percentage composition of each species, were estimated for an area of 1 m 2. The concentration of Cd, Pb, Cu, Zn and Fe in the litter fall and the input of these metals to the forest floor were determined. The input of cadmium ranged from 84 μg m −2 at Kornatka in 1998 to 382 μg m −2 at Bonarka in 2000. The input of lead was about 10 times higher than cadmium and varied from 406 μg m −2 at W e ̨ glówka in 1998 to 3717 μg m −2 at Bonarka in 2000. Input of Cu, Zn and Fe to the forest floor showed the similar tendency. During 1998–2000, the highest heavy metal concentrations in the litter fall and their impact on the forest floor were always found at sites close to the Cracow conurbation and, in the eastern transect, close to a steel works. Input of metals to the forest floor tended to decrease with increasing distance from the centre of Cracow.

Natural and Anthropogenic Heavy Metal Deposition to the Snow in King George Island, Antarctic Peninsula

Successive 24 snow samples, collected from a 1.2m snow pit at a site on the summit of Main Dome in King George Island, Antarctic Peninsula, were measured for heavy metals such as Pb, Cd, Cu, and Zn and other chemical species. The mean concentrations of heavy metals are 3.48pg/g for Pb, 0.10pg/g for Cd, 16.6 pg/g for Cu and 15.8 pg/g for Zn, respectively. Pb and Cd concentrations observed in our samples are very comparable to those reported for recent snow at other Antarctic sites, while Zn and Cu levels are much higher than those at other sites. The annual fallout fluxes of all heavy metals approximately calculated are, however, much greater in King George Island than at other sites. With respect to the estimates of natural contributions, sea salt spray is found to be a major contributor to Cd and Zn inputs to the snow and minor to Cu inputs. On the other hand, the anthropogenic input can account for a large part of Pb concentrations. A tentative estimate represents that local emissions could be responsible for more than half of the excess Pb flux to the snow in King George Island.

Atmospheric deposition of metallic pollutants over the Ligurian Sea: labile and residual inputs

Atmospheric fluxes of six trace metals (Cd, Cr, Cu, Ni, Pb and Zn) with Al as a crustal reference were measured at Cap Ferrat (French Riviera) between February 1997 and July 1998. An original sampling protocol enabled the separation of labile (seawater at pH 2) and residual fractions in the total atmospheric input. Median acid-labile fractions were 91%, 69%, 83%, 84%, 97% and 98% of the total for Cd, Cr, Cu, Ni, Pb and Zn, respectively. Under the conditions used, lability of individual metals is related to the anthropogenic component of the samples. Enrichment factors and anthropogenic fraction are estimated for each metal. Some interannual changes are investigated (Pb, Zn). The observed increase of Zn inputs may be linked to local input from the Nice district waste plant (commissioned in 1988), 6.5 km away.

Partitioning of Zn, Pb and Cd in river sediments from a lead and zinc mining area using the BCR three-step sequential extraction procedure.

The extent of pollution was investigated in sediments collected along the course of the river Meza and its tributaries in the lead and zinc mining area of the Mezica valley (Slovenia). In order to evaluate the heavy metal burden, total concentrations of Zn, Pb and Cd were determined and the partitioning of these metals between the easily and sparingly soluble sediment fractions was performed by the use of the slightly modified BCR sequential extraction procedure. The quality of analytical data was checked with Certified Reference Material CRM 601. Good agreement between the determined and certified or indicative metal concentrations was obtained. In order to estimate the natural and anthropogenic inputs of Zn, Pb and Cd in the sediments, normalisation to Al was applied. The results of the partitioning study indicate that Zn prevails in the most sparingly soluble fraction and is distributed between organic matter and sulfides, while a smaller proportion is found in the easily soluble fraction. Pb is distributed mainly between organic matter and sulfides, whereas Cd is predominantly associated with the most sparingly soluble fraction. Data from the normalisation procedure indicate that the anthropogenic inputs of Zn, Pb and Cd correlate with the very high total metal concentrations determined in sediments. The highest total Zn, Pb and Cd concentrations (16.3. 9.3 and 0.13 g kg(-1), respectively) were found in the sediment of the Helena rivulet, arising from former mining activities. In spite of the relatively low easily soluble metal fractions in the sediment, the concentrations of metals in these fractions are high, owing to the extremely high total metal concentrations. These data indicate severe pollution of the terrestrial and aquatic environment.

Heavy Metal Contamination and Mixing Processes in Sediments from the Humber Estuary, Eastern England

The geochemical properties of cores collected from mud flat and salt marsh environments in the Humber Estuary were investigated. A total of 10 cores were collected along a shore-normal transect on the northern bank of the estuary, near Skeffling. Major and trace element concentrations were determined for each core. The vertical distributions of210Pb and137Cs were also examined to provide a measure of the rate of sediment accumulation. Surface intertidal sediments show elevated concentrations of a range of trace and major elements, including Pb, Zn, Cu, Al, Mn and Fe. Concentrations were higher in the upper mud flats and salt marsh where sediment grain size is finer. Dating of salt marsh sediments indicated a local sediment accretion rate of 0·4cmyr−1. The early-diagenetic remobilization of heavy metals has apparently been limited, and the salt marsh sediments provide a (time-integrated) record of historical pollutant inputs. Heavy metal fluxes have been calculated from the salt marsh sediments and are broadly comparable with other industrialized and semi-industrialized estuaries. Cu, Pb and Zn inputs to the Skeffling area peaked in the mid-20th century, while Ti, Al and Fe, which are discharged into the Humber from two Tioxide-processing facilities, are only slightly enriched in these sediments. On the mud flats, local mixing, resuspension and erosion has resulted in correlatable sedimentary horizons interspersed with mixed sediment layers. Consequently, the vertical distribution of heavy metals in these mud flats is relatively erratic, and the mud flat sediments are unsuitable for studying historical pollution trends.

Dating and Heavy Metal Contents of Sediment Cores of a High-Alpine, Remote Lake: Jörisee (Switzerland)

Sediment cores were collected at the MOLAR (MOuntain LAke Research) site Jörisee. The goal of the analysis was to date the sediment cores in order to correlate actual input conditions of nutrients and pollutants at this high-alpine, remote site, to historical situations. The sediment cores were dated by determining gamma rays of Pb-210 and Cs-137. The calculated sedimentation rate is 0.1 cm/year. Leaching techniques were used to investigate redox sensitive species. The results give evidence for post depositional recycling in case of Fe and Mn. In contrast, the heavy metals Pb, Zn, Cr and Ni are not affected by existing redox gradients. Sediment samples were leached with diluted nitric acid to determine anthropogenic input of Pb, Zn, Cr and Ni. Concentrations of these heavy metals reflect changes in the input conditions since the beginning of industrialization, which is the examined time period.

Zinc and Lead Removal from Blast Furnace Sludge with a Hydrometallurgical Process

During the production of pig iron in a blast furnace, a Zn- and Pb-containing sludge is generated in the air pollution control system. This toxic waste can be landfilled after dewatering and pretreatment, which is very costly. The sludge particles contain large amounts of Fe and C that could be recycled in the furnace. However, the Zn content of the sludge is high, and the Zn input to the blast furnace must be limited, so Zn has to be removed. This paper describes a hydrometallurgical process whereby the sludge is leached under both acid (HCl) and oxidizing conditions. After the separation of the solids, which mainly contain C and Fe, from the leaching solution, the latter is passed through an anion exchanger to remove Zn and Pb and is recirculated to the reactor. Investigation of the leaching behavior showed that a pH below 1.5 and a redox potential above 650 mV are required to obtain high leaching efficiencies for Zn and Pb. Sequential extraction showed that the largest part of Zn and Pb is extracted in...