Modified BCR Sequential Extraction Procedure Research Articles

Evaluation of Total Concentrations and Extractable Fractionations of Cd, Co and Ni in Soils from Dumpsites across Rivers State, Nigeria

The mobility of trace metals in soils strongly depends on the forms in which the metals are bound to major soil components. This study aims to determine the total concentrations and extractable fractionations of Cd, Co and Ni in soil samples collected from dumpsites across Rivers State, Nigeria. Solar Thermo Elemental Atomic Absorption Spectrometer model (SG 71906) was used after mixed acid digestion (HCl: HNO3 in a ratio of 3:1 v/v) and modified BCR sequential extraction procedure. The concentration levels of Cd, Co and Ni in all the samples varied, with mean values of 13.48 11.85, 25.29 17.62 and 20.52 15.66 mg/kg, respectively. Using the Community Bureau of Reference (BCR) sequential extraction procedure, the elements recoveries were within the acceptable range varying between 92.10% and 98.33% for Co and Cd, respectively. Data from the BCR extraction procedure revealed that the majority of Cd fraction was associated with residual fraction, Co fraction bound to the exchangeable fraction, while Ni was found to be associated with oxidisable fraction. These results suggest that the trace elements in the soil were highly mobile and bioavailable for plant uptake. Results from the findings particularly correlation analysis is indicative of the fact that some of the contaminants may have anthropogenic and natural origin. Hence, these contaminants could pose significant threat to human health and the environment.

Effects of Biochars Derived from Sewage Sludge and Olive Tree Prunings on Cu Fractionation and Mobility in Vineyard Soils over Time

Copper-contained products that are widely employed yearly in viticulture for vine disease management, lead to Cu accumulation in topsoil creating an increased risk for land workers and for leaching and/or uptake of Cu by plants, especially in acidic soils where Cu mobility is higher. In this study, the impact of two biochar types on Cu distribution and redistribution in fractions was evaluated in four acidic vineyard soils in relation to incubation time. The two biochars were derived from sewage sludge (SG) and olive tree prunings (OL). Soils (control) and biochar-amended soils with application rate of 20 % (w/w) were spiked with CuCl2 (160 mg kg−1) and incubated in the laboratory at ambient temperature 22 ± 5 °C. After 1, 3, 7, 15, 36, and 90 days of incubation, modified BCR sequential extraction procedure was used to determine Cu distribution in the four soil chemical phases and to examine potential Cu redistribution between these fractions both in soils and in amended soils with biochars. Results show that biochar amendment affects Cu distribution in different soil fractions. In SG treatment, from the 1st and up to 36th incubation day, both exchangeable and reducible Cu fractions decreased, while oxidizable Cu increased, in relation to control soils. At 90th incubation day, a redistribution of Cu was observed, mainly from the oxidizable to the residual fraction. In OL treatment, during the first 36 incubation days exchangeable and oxidizable Cu slightly increased, while reducible Cu decreased. At the 90th incubation day the higher percentage of Cu was extracted from the residual fraction, but exchangeable Cu was present in remarkable quantities in the three of the four studies soils. SG application in the studied soils highly restricted the availability of added Cu promoting Cu-stable forms thus reducing the environmental risk while OL did not substantially reduce Cu available fraction over the experimental incubation period. Fourier transformation infrared analysis (FTIR) provided convincing explanations for the different behavior of the two biochar types.

Estimating remobilization of potentially toxic elements in soil and road dust of an industrialized urban environment.

The mobility of potentially toxic elements (PTEs) is of paramount concern in urban settings, particularly those affected by industrial activities. Here, contaminated soils and road dusts of the medium-size, industrialized city of Volos, Central Greece, were subjected to single-step extractions (0.43M HNO3 and 0.5M HCl) and the modified BCR sequential extraction procedure. This approach will allow for a better understanding of the geochemical phase partitioning of PTEs and associated risks in urban environmental matrices. Based on single extraction procedures, Pb and Zn exhibited the highest remobilization potential. Of the non-residual phases, the reducible was the most important for Pb, and the oxidizable for Cu and Zn in both media. On the other hand, mobility of Ni, Cr, and Fe was low, as inferred by their dominance into the residual fraction. Interestingly, we found a significant increase of the residual fraction in the road dust samples compared to soils. Carbonate content and organic matter controlled the extractabilities of PTEs in the soil samples. By contrast, for the road dust, magnetic susceptibility exerted the main control on the geochemical partitioning of PTEs. We suggest that anthropogenic particles emitted by heavy industries reside in the residual fraction of the SEP, raising concerns about the assessment of this fraction in terms of origin of PTEs and potential environmental risks. Conclusively, the application of sequential extraction procedures should be complemented with source identification of PTEs with the aim to better estimate the remobilization of PHEs in soil and road dust influenced by industrial emissions.

Fractionation, Mobility and Environmental Risk of Trace Metals in the Sediments from N’zi River, Côte d’Ivoire

Despite increasing human activities, such as agriculture, little information is available on the status of trace metals contamination in rivers in developing countries including Côte d’Ivoire (West Africa). The aim of this study was study chemical fractions of Cu, Pb, Zn, and Ni, to identify mobility, sources and to evaluate ecological risks of traces metal in sediment of N’zi River using modified BCR sequential extraction procedure. The results showed that all metal were dominated by residual fractions. Labile fractions of Pb accounted for 0.0 – 68% of total contents indicating significant anthropogenic sources for Pb, while for Cu, Ni and Zn results suggesting natural sources. The potential mobility of the metals manifested following order: Ni > Zn > Cu > Pb. Risk assessment code indicated low to medium risk for Pb and low risk for other metals in the sediments.
 Cluster analysis (CA) and Matrix correlation were used to detect the relationship between the studied sampling sites and to see if some of the parameters interrelated with each trace metal concentration in exchangeable fraction. Results indicated high anthropogenic contamination at stations near to urban and agricultural areas.

Sequential extraction studies on the river Tisa sediments for the assessment of the metal pollution

The sequential extraction procedure was applied for partitioning of metals in river sediments collected along the course of the river Tisa (Serbia). Eight elements (Sb, Sn, As, Cd, Cu, Hg, Pb and Zn) from twenty-one sampling site were analyzed using the modified BCR sequential extraction procedure in combination with ICP-OES. The results of sequential extraction, statistical analyses and calculation of EF and lithogenic and anthro?pogenic ratio of metals are similar. In the river Tisa sediments Sn, Cd, Hg, Pb and Zn are of anthropogenic origin, while As, Cu and Sb are of lithogenic and anthropogenic origin. The sediments from the river Tisa show high risk for Cd, medium risk for Hg and Zn, low risk for Sn, As, Cu and Pb, whereas Sb does not show the risk for the aquatic environment.

Waste management: impact on metal accumulation and speciation in Aba River channel, Nigeria

ABSTRACT The impact of indiscriminate disposal of waste materials on the quality of Aba River was examined in this research. Levels of Cd, Pb, Cu, Ni, Fe, Zn, Cr, and Mn were determined in water and sediments from Aba River. Modified BCR sequential extraction procedure was employed for the fractionation of metals in sediments. Levels of toxic metals in water (Cd, Pb, Ni, and Cr) were higher than their recommended limits for potable water. However, mean levels of all the metals except Fe were within their safe limits in sediment. Levels of all the metals in sediments were also higher than in water significantly at p < 0.05. Results showed that Cd, Pb, Ni, and Cr existed mostly in the non-residual fractions while essential elements (Cu, Fe, Zn, and Mn) existed mainly in the residual fraction. Consequently, toxic metals were more mobile and bio-available than the essential ones in Aba River. Cd, Pb, and Ni were metals with serious potential health risk to those exposed to the River. Principal component analysis revealed natural and anthropogenic factors as being responsible for the accumulation of metals in the studied Aba River.

Distribution and partitioning of heavy metals in large anthropogenically impacted river, the Pearl River, China

In order to evaluate the distribution and partitioning characteristics of heavy metals in the large anthropogenically impacted Pearl River Basin, the contents of “anthropophile” elements (Cr, Ni, Cu, Zn, Cd and Pb, which are clearly influenced by human activities) were determined, and their partitioning coefficients (Kd) between water and sediments and enrichment factors (EF) were calculated for samples collected at different locations along the Pearl River main stream. The modified BCR sequential extraction procedure (proposed by the European Community Bureau of Reference in 1993), which involves the successive extraction of metals in a decreasing order of reactivity, was applied. Sediment samples from the upper, middle, and lower reaches were included in this study. The results showed that the content of most metals in water and sediment samples gradually increases from upstream to downstream, suggesting a possible input from human activities as shown by their increasing high EF, ranged from 1.4 to 3.9 for Cu, from 1.4 to 6.7 for Zn, from 2.5 to 59.1 for Cd, and from 1.7 to 8.9 for Pb, respectively. The higher partition coefficients (Kd) for Cr, Zn, and Pb (105–106) indicated that they were mainly transported in solid phase, while parts of Ni, Cu, and Cd were transported in dissolved phase as they display relatively lower Kd in the range of 104–105. According to the results of the BCR leaching, the percentage of non-residual fraction of heavy metals in the sediments showed a decreasing order of Cd > Pb > Zn > Cu > Ni > Cr, implying that Cd and Pb were more active and bioavailable compared to the other four metals, and thus would be potentially more harmful to the watershed ecosystem.

Solid-phase distribution and mobility of thallium in mining-metallurgical residues: Environmental hazard implications

Thallium (Tl) and its compounds are non-essential and highly toxic for living organisms, even at low concentrations. In this paper, we analyzed the presence and geochemical distribution of Tl in different mining-metallurgical and sediment samples collected from several mining zones of Mexico. A modified BCR sequential extraction procedure was also applied to the samples to investigate the geochemical behavior and potential environmental risk of Tl according to types of ore deposit and mineral processing method applied. Results revealed the presence of Tl in the majority of the mining-metallurgical samples, with labile concentrations reaching up to values of 184.4 mg kg−1, well above the environmental standards. A comparison of Tl partitioning in different samples showed that Tl was usually found associated with labile fractions instead of entrapped in the environmentally-passive residual fraction. Specifically, high levels of Tl were extracted from the exchangeable/acid-extractable and poorly-crystalline reducible fractions, suggesting its association with both soluble and amorphous Fe-Mn oxyhydroxides, respectively. Besides, Tl was also frequently found associated with the crystalline reducible fraction, presumably bonded to manganese oxides and jarosite-like minerals. Lastly, little amounts of Tl were extracted from the oxidizable fraction. Considering the fractionation of Tl in these mining-metallurgical samples, they may pose a significant environmental hazard. This study provides useful insights into the potential sources of Tl pollution in Mexico and emphasizes the need for further research to determine the extent of its impact and to develop effective remediation protocols to protect the environment from Tl toxicity.

Relation between different metal pollution criteria in sediments and its contribution on assessing toxicity

Several tools have been developed and applied to evaluate the metal pollution status of sediments and predict their potential ecological risk assessment. To date, a comprehensive relationship between the information given by these sediment tools for predicting metal bioavailability and the effective toxicity observed is lacking. In this work, the possible inter-correlations between the data outcoming from using several qualitative evaluation tools of the sediment contamination (contamination factor, CF, the enrichment factor, EF, or the geoaccumulation index, Igeo), metal speciation on sediments (evaluated by the modified BCR sequential extraction procedure) and free metal concentrations in pore waters were studied. It was also our aim to evaluate if these assessment tools could be used for predicting the pore waters toxicity data as toxicity proxy. Principal component analysis and cluster analysis revealed that two quality indices used (CF and EF) were highly correlatable with the more labile fractions from BCR sediment speciation. However, neither of these parameters did correlate with the toxicity of pore waters measured by the chronic toxicity (72 h) in Pseudokirchneriella subcapitata. In contrast, the toxic effects of the given total metal load in sediments were better evaluated by using an additive metal approach using pore water free metal concentrations.

Speciation of heavy metals Cu, Ni and Zn by modified BCR sequential extraction procedure in sediments from Banten Bay, Banten Province, Indonesia

Banten Bay is categorized as a marine area that is busy with marine tourism activities, settlements and also industries. One potential impact of the condition is the occurrence of pollution from both industrial and domestic sources, erosion and sedimentation in the coastal environment. Samples were collected from 25 representative stations in April 2016. Chemical speciation of three heavy metals (Cu, Ni, and Zn) was studied using a modified sequential extraction procedure proposed by the European Standard, Measurements and Testing (SM&T) program, formerly the Community Bureau of Reference (BCR). The aims of this study are to determine geochemical speciation of 4 bounds of metal: acid-soluble, reducible, oxidizable and residual, and to assess their impacts in the sediments of Banten Bay, Indonesia. The result shows that the percentage of Copper (45.90-83.75%), Nickel (18.28-65.66%), and Zinc (30.45-79.51%) were mostly accumulated in residual fraction of the total concentrations. The Risk Assessment Code (RAC) reveals that about 0-7.07% of Copper and 1.11-24.35 % of Zinc at sites exist in exchangeable fraction and therefore, they are in low risk category. While 7.34-34.90 of Ni at sites exists in exchangeable fraction and therefore, it is in medium risk category to aquatic environment.

Risk assessment of toxic metals in marine sediments from the Arctic Ocean using a modified BCR sequential extraction procedure

ABSTRACTSurface sediment samples were collected from the Pacific sector of the Arctic Ocean during the 6th Chinese National Arctic Research Expedition (CHINARE), 2014. Concentrations and extractabilities of six toxic metals (Cd, Cr, Cu, Ni, Pb, and Zn) were determined using a modified sequential extraction procedure as described by the European Community Bureau of Reference (BCR). A new analytical hierarchy approach to risk assessment, involving sediment quality guidelines and risk-assessment codes, is described for metals in marine sediments from the Arctic Ocean. Results indicate a mobility order of Pb > Cd > Cu > Zn > Ni > Cr with mean liable fraction (F1+F2+F3) being 83.0%, 81.6%, 62.0%, 47.1%, 42.1%, and 15.6%, respectively. Ni presents the most serious ecological risk in the study area, with most samples (93.9%) indicating medium risk, followed by Cu (54.5%) and Zn (27.3%). For Ni and Zn, there are also samples showing high ecological risk (Ni at site NB02, northern Bering Sea; Zn at R07, northern Chukchi Sea). The ecological risk for Cr indicates low ecological risk (93.9%) and some medium risk (6.1%). All Cd assessments indicate low ecological risk, while most Pb assessments indicate zero (33.3%) to low risk. The new ecological risk assessment method improves on assessments based on metal mobility or concentration alone.

Fractionation of potentially toxic elements (PTE) in soils irrigated with wastewater using modified BCR sequential extraction procedure

Fractionation of potentially toxic elements (PTE) in soils irrigated with wastewater using modified BCR sequential extraction procedure

Combined bioremediation of soil co-contaminated with cadmium and endosulfan by Pleurotus eryngii and Coprinus comatus

The subjects of this study were to investigate the remediating potential of the co-cultivation of Pleurotus eryngii and Coprinus comatus on soil that is co-contaminated with heavy metal (cadmium (Cd)) and organic pollutant (endosulfan), and the effects of the co-cultivated mushrooms on soil biochemical indicators, such as laccase enzyme activity and bacterial counts. A pot experiment was conducted to investigate the combined bioremediation effects on co-contaminated soil. After the mature fruiting bodies were harvested from each pot, the biomass of mushrooms was recorded. In addition, bacterial counts and laccase enzyme activity in soil were determined. The content of Cd in mushrooms and soil was detected by the flame atomic absorption spectrometry (FAAS), and the variations of Cd fractions in soil were determined following the modified BCR sequential extraction procedure. Besides, the residual endosulfan in soil was detected by gas chromatography-mass spectrometry (GC-MS). The results indicated that co-cultivation of P. eryngii and C. comatus exerted the best remediation effect on the co-contaminated soil. The biomass of mushroom in the co-cultivated group (T group) was 1.57–13.20 and 19.75–56.64% higher than the group individually cultivated with P. eryngii (P group) or C. comatus (C group), respectively. The concentrations of Cd in the fruiting bodies of mushrooms were 1.83–3.06, 1.04–2.28, and 0.67–2.60 mg/kg in T, P, and C groups, respectively. Besides, the removal rates of endosulfan in all treatments exceeded 87%. The best bioremediation effect in T group might be caused by the mutual promotion of these two kinds of mushrooms. The biomass of mushroom, laccase activity, bacterial counts, and Cd content in mushrooms were significantly enhanced, and the dissipation effect of endosulfan was slightly higher in the co-cultivated group than in the individually cultivated groups. In this study, the effect of co-cultivated macro fungi P. eryngii and C. comatus on the remediation of Cd and endosulfan co-contaminated soil was firstly reported, and the results are important for a better understanding of the co-remediation for co-contaminated soil.

Redox-controlled release dynamics of thallium in periodically flooded arable soil

To our knowledge, this is the first work to mechanistically study the impact of the redox potential (EH) and principal factors, such as pH, iron (Fe), manganese (Mn), dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), chlorides (Cl−) and sulfates (SO42-), on the release dynamics of thallium (Tl) in periodically flooded soil. We simulated flooding using an automated biogeochemical microcosm system that allows for systematical control of pre-defined redox windows. The EH value was increased mechanistically at intervals of approximately 100 mV from reducing (−211 mV) to oxidizing (475 mV) conditions. Soluble Tl levels (0.02–0.28 μg L−1) increased significantly with increases in EH (r = 0.80, p < 0.01, n = 30). Thallium mobilization was found to be related to several simultaneous processes involving the gradual oxidation of Tl-bearing sulfides, reductive dissolution of Fe-Mn oxides and desorption from mineral sorbents. Manganese oxides did not appear to have a considerable effect on Tl retention under oxidizing conditions. Before conducting the microcosm experiment, Tl geochemical fractionation was assessed using the modified BCR sequential extraction procedure. The BCR revealed a majority of Tl in the residual fraction (77.7%), followed by reducible (13.3%) and oxidizable fractions (5.9%). By generating high levels of Tl toxicity at low doses, Tl released under oxidizing conditions may pose an environmental threat. In the future, similar studies should be conducted on various soils along with a determination of the Tl species and monitoring of the Tl content in plants to achieve more detailed insight into soluble Tl behavior.

Fraction Of Heavy Metals In Sludges From Typical Coking Wastewater Treatment Plants By Modified Bcr Sequential Extraction Procedure

Fraction Of Heavy Metals In Sludges From Typical Coking Wastewater Treatment Plants By Modified Bcr Sequential Extraction Procedure

Bioremediation of cadmium-dichlorophen co-contaminated soil by spent Lentinus edodes substrate and its effects on microbial activity and biochemical properties of soil

Soil contamination resulting from industrial and agricultural activities has caused high concerns in recent years. Compared with single pollutant, co-contaminants of heavy metal and organic pollutant in soil are quite complicated. The overall objective of this study was to evaluate the potential of spent Lentinus edodes substrate (SLS) as an organic amendment for bioremediation of cadmium (Cd) and dichlorophen (DCP) co-contaminated soil. Pot experiments were conducted to investigate the effect of SLS on the distribution of Cd and dissipation of DCP. The microbial counts and soil respiration rate were determined. The ligninolytic enzymes (manganese peroxidase and laccase) and soil enzymes (dehydrogenase, urease, and acid phosphatase) were analyzed. Variations of Cd fractions in soil were determined following the modified BCR sequential extraction procedure. DCP in soil was detected on a gas chromatography–mass spectrometry (Agilent 6890N GC–MS). Results showed that the addition of SLS or sterilized SLS (SSLS) could facilitate soil biological properties including microbial counts, respiration intensity, and soil enzyme activities compared to control soil. The HOAc extractable Cd decreased by 10.94–17.09 and 9.63–12.02 % in SLS and SSLS amended soil, respectively. As for the dissipation of DCP, the SSLS amended soil recorded 82.4–92.8 % while the SLS amended soil recorded 85.0–96.9 % compared to the non-amended soil (68.3–84.1 %). The presence of available residual nutrients in the substrate could promote the growth of indigenous microbes, which could contribute to the dissipation of DCP. This study investigated the potential of SLS on the bioremediation of sites co-contaminated with Cd and DCP. The SLS-facilitated removal of soil DCP was due to SLS-promoted soil biological properties including the microbial numbers and soil respiration as well as the ligninolytic enzymes. The addition of SSLS and SLS resulted in a decrease of Cd extractability in soil, and significantly facilitated the activities of dehydrogenase, urease, and acid phosphatase. The results demonstrated the potential of SLS in ex situ bioremediation of soil co-contaminated with Cd and DCP, providing an attractive reusing option of this organic waste.

Distribution, fractionation, and contamination assessment of heavy metals in offshore surface sediments from western Xiamen Bay, China

Surface sediment samples were collected at 21 offshore sites in western Xiamen Bay, Southeast China. Total concentrations of Li, V, Cr, Co, Ni, Cu, Zn, Sr, Mn, Pb, Ba, Fe, and Ti were determined by inductively coupled plasma-optical emission spectrometry; Hg was determined by atomic fluorescence spectrometry. A modified BCR sequential extraction procedure was used to extract fractions of the above elements. Concentrations of Pb, Cr, and Hg at most sites met the primary standard criteria of Marine Sediment Quality except site S12 for Pb and S7 for Cr, while concentrations of Zn at 17 sites and Cu at seven sites exceeded the criteria. The mean concentration of Hg was three times higher than the background, with a possible source being the Jiulong River. Fe, Ti, Ba, Co, V, and Li dominated the residual phase, mainly from terrestrial input. Ni, Cr, Pb, and Hg in the non-residual phase varied largely between sites. Sr, Mn, Cu, and Zn were mainly in the non-residual fraction. Most sites showed considerable ecological risk; exceptions were site S7 (very high) and sites S10, S11, and S14 (moderate). Cu showed moderate-to-high pollution and Pb exhibited no-to-low pollution, while other metals had a non-pollution status according to their ratios of secondary phase to primary phase (RSP). Results of two assessment methods showed moderate pollution and a very high ecological risk for Cu, Zn, Ni, and Cr at site S7, which might be due to the local sewage treatment plant.

Characteristics and phytotoxicity assay of biochars derived from a Zn-rich antibiotic residue

The disposal and utilization of antibiotic residues (ARs) are a serious concern and have been identified as “a hazardous material” in China because of the residual antibiotic. However, little attention was paid to the potential environmental risk of the persistence of toxic heavy metals in those residues. Pyrolysis is an effective technology that used to reduce solid waste. Thus, in order to systematically investigate the influence of pyrolysis temperature and residence time on physicochemical characteristics, heavy metal speciation and bioavaibility in ARs derived biochars, ARs was pyrolyzed at different temperatures (300–700°C) and residence time (1 and 2h). The residue and biochar characteristics were characterized with a thermogravimetric analyzer, element analyzer, scanning electron microscopy, and Brunauer–Emmerr–Teller (BET) methods. Zn species in the biochars were determined with modified BCR sequential extraction procedure. The bioavailability of Zn in biochars and the resulted phytotoxicity were measured through a phytotoxicity test. Results indicated that both temperature and residence time have effects on biochar physiochemical properties, Zn speciation and bioavailability. Residual antibiotic was eliminated, and Zn was enriched and stabilized through pyrolysis. Zn bioavailability and phytotoxicity decreased with the increasing temperature and residence time. A temperature at 500°C was optimal for this residue disposal. The results obtained in this study would enhance our knowledge on heavy metal transformation in pyrolysis and would be useful in designing an environment friendly approach to utilize this Zn-rich AR or other biowaste with similar characteristics.

Soil vanadium pollution and microbial response characteristics from stone coal smelting district

A field investigation was performed to study the content, speciation and mobility of vanadium, as well as microbial response in soil from a stone coal smelting district in Hunan province of China. The results showed that the contents of soil V ranged from 168 to 1538 mg/kg, which exceeded the maximum permissible value of Canadian soil quality for V. The mean soil V content from wasteland area reached 1421 mg/kg, and those from the areas related with slag heap, ore pile and smelting center were 380, 260 and 225 mg/kg, respectively. Based on the results of the modified BCR sequential extraction procedure, V contents in the mobile fractions varied from 19.2 to 637 mg/kg accounting for 7.4%–42.3% of total V, and those of V(+5) species were between 21.9 and 534.0 mg/kg. Soil enzyme activity and microbial basal respiration were adversely affected by high level of soil V. More attention should be paid to soil V pollution and potential hazardous surrounding the stone coal smelting district.

Geochemical speciation, anthropogenic contamination, risk assessment and source identification of selected metals in freshwater sediments—A case study from Mangla Lake, Pakistan

Geochemical speciation of selected metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sr and Zn) using modified BCR sequential extraction procedure was performed in the sediments collected from Mangla Lake, Pakistan. The extraction method was optimized using certified reference material (BCR-701) which showed significant recoveries (95–106%). Among the metals, Cd, Co, Ni, Pb and Sr exhibited relatively higher mobility and bioavailability, while Cu, Fe, Mn and Zn were found mainly in the residual fractions. Principal component analysis (PCA) revealed four groups of the metals in the sediments; I (Cd–Cr–Ni–Sr), II (Co–Pb), III (Fe–Zn), and IV (Mn–Cu); first two groups were mostly contributed by anthropogenic sources. The pollution indicators (individual contamination factor, enrichment factor and geoaccumulation index) revealed significant anthropogenic contamination of Cd, Co, Ni, Pb, Sr and Zn in the sediments. Risk assessment code (RAC) indicated medium risk for Co and Ni; high risk for Cd and Pb; and very high risk for Sr in the sediments. Cluster analysis (CA) and global contamination factor (GCF) were used to identify the pollution hotspots, which indicated more severe metal contamination at sites near to Mirpur city and other urban/semi-urban areas (S3–S5), especially for Cd, Co, Ni, Pb and Sr.