Metals In Stream Sediments Research Articles

Spatial distributions, potential sources, and ecological risks of heavy metals in stream sediments in Zambia

The ecological risk assessment and source identification of heavy metals (HMs) are significant for resource utilization and food security. This study aims to assess the spatial distributions, potential sources, and ecological risks of HMs in stream sediments in Zambia. Using 735 samples collected from stream sediments across the country and methods such as inductively coupled plasma mass spectrometry (ICP-MS), atomic fluorescence spectrometry (AFS), and X-ray fluorescence spectrometry (XRFS), this study determined the concentrations of the seven HMs, i.e., arsenic (As), chromium (Cr), copper (Cu), mercury (Hg), nickel (Ni), lead (Pb), and zinc (Zn). The spatial distributions of these HMs were determined using a Geographic Information System (GIS), and their ecological risks were accessed based on the analytical results of their potential sources. Additionally, this study explored the relationships between mining activities and regions with high heavy metal (HM) concentrations based on the statistical analysis of the HM concentrations and geology of the study area. The results indicate the stream sediments in Zambia exhibit average As, Cr, Cu, Hg, Ni, Pb, and Zn concentrations of 1.49 × 10−6, 19.34 × 10−6, 12.12 × 10−6, 12.70 × 10−9, 7.13 × 10−6, 12.52 × 10−6, and 16.30 × 10−6, respectively. The analytical results of the geoaccumulation index (Igeo) and potential ecological risk index (PERI) reveal the presence of relatively high As and Cu concentrations, especially in Copperbelt and North-Western provinces and areas surrounding Lusaka—the capital of Zambia. The HM contamination in stream sediments in Zambia is primarily caused by Cu and gold (Au) mining. This study exemplifies how to determine potential sources and ecological risks of HMs in stream sediments, holding important implications for nation-scale environmental contamination prevention and land utilization planning.

Assessment of ecological and health risk impact of heavy metals contamination in stream sediments in Itapaji-Ekiti, SW Nigeria

BackgroundHeavy metal contamination in aquatic ecosystems is a major environmental and health concern globally. This study assessed the ecological and health risks associated with heavy metal pollution in stream sediments in Itapaji-Ekiti, Southwest Nigeria. The study contributes collectively to a comprehensive understanding of the geochemical dynamics and contamination factors affecting the studied stream sediments. MethodsHeavy metals study was conducted on stream sediments within the geographical confines of sheet 244, Ado map. Seventeen stream sediment samples were obtained from various sites and subjected to analysis to determine the concentrations of heavy metals such as lead (Pb), copper (Cu), zinc (Zn), chromium (Cr), cadmium (Cd), barium (Ba), arsenic (As), nickel (Ni) and vanadium (V) using X-ray Fluorescence (XRF). The results showed that the concentrations of these metals exceeded permissible levels at most sampling sites, indicating significant contamination of the stream sediments. The concentrations and pollution levels of the heavy metals from selected sampling sites were documented for ecological and health risk evaluations. ResultThe findings revealed that the concentrations of these metals surpassed acceptable thresholds at the majority of sampling locations, indicating significant contamination of the stream sediments. The concentrations of heavy metals, specifically Cr and Cd, exhibit moderate contamination, while Pb and Ba demonstrates a significant contamination factor with moderate to extreme degree of contamination. Several ecological risk indices were calculated to evaluate the potential ecological risks. The results revealed that the stream sediments posed considerable to very high ecological risks at most sites based on the risk quotient, contamination factor and pollution load index. The non-carcinogenic and carcinogenic risk assessments for heavy metals in stream sediments exposed potential health risks, especially for children, indicating the need for protective measures. The cumulative cancer risk, particularly for adults, raised concerns about the overall health implications of prolonged exposure to the heavy metal concentrations in the streams. ConclusionThe study also evaluated ecological and health risks, revealing potential risks from heavy metals. Hazard and cancer risk assessments suggested the increasing potential of heavy metals to pose health risks, particularly for inhabitants of the area.

Contamination, Sources, Distribution and Risk Evaluation of Heavy Metals in Stream Sediments of Mewongo Gold District, Nyong Group, Cameroon

Contamination, Sources, Distribution and Risk Evaluation of Heavy Metals in Stream Sediments of Mewongo Gold District, Nyong Group, Cameroon

Geochemical evaluation and environmental risk assessment of heavy metals: A case study from Ireland using Tellus stream sediment data (2011–2017)

A comprehensive assessment of the distribution, spatial mapping and ecological risk of heavy metals in stream sediments of 17 counties of Ireland based on the Tellus geochemical survey programme in Ireland was carried out. Average trace metal concentrations of chromium (Cr), nickel (Ni), copper (Cu), lead (Pb), zinc (Zn), vanadium (V), cobalt (Co), arsenic (As), and major and minor oxides iron oxide (Fe2O3), manganese oxide (MnO) in the stream sediments were above the background values, but lower than Irish sediment quality guidelines for livestock and Canadian sediment quality guidelines (ISQG); threshold effect level (TEL) and probable effect level (PEL). 69.65% of Ni, 22.13% of Zn, and 96.7% of Pb samples exceeded the low-effect-range (ERL) values, whereas only 21%, 1.80% and 0.69% of the same elements exceeded the median effect range (ERM) values. Hotspots of Zn (>12000 mg kg−1), Pb (>10,000 mg kg−1), Fe2O3 (61.38%), MnO (26%), Cr (>2300 mg kg−1) and Ni (874.2 mg kg−1) were observed at Wicklow, Dublin, Mayo, Galway and Cavan counties. Catchment geochemistry was identified for the presence of heavy metals in the stream sediments. The geo-accumulation index (Igeo) indicated Kildare to be the least contaminated county with Igeo < 0 for Cr, Ni, Cu, Zn, Pb and As for 50% of the samples. The enrichment factor (EF) indicated that some sites located in Mayo and Donegal were highly contaminated. PInemerow followed the trend, Tipperary > Dublin > Waterford > Monaghan > Donegal > Wexford > Galway > Wicklow > Cavan > Meath > Kilkenny > Leitrim > Mayo > Louth > Sligo > Kildare > Carlow. Based on potential ecological risk index (PERI), 83.1% of the sites posed low ecological risk (PERI <150), 11.9% sites posed moderate risk (150 < RI < 300) and high ecological risk was posed by 0.3% (PERI >1200) of the sites. Lithology, topography and anthropogenic factors influenced the distribution and ecological risks of heavy metals. Non-carcinogenic and carcinogenic risk for adults and children were above the recommended value.

Contamination, sources and risk assessments of metals in stream sediments of Pouma area, Pan-African Fold Belt, Southern Cameroon

Contamination, sources and risk assessments of metals in stream sediments of Pouma area, Pan-African Fold Belt, Southern Cameroon

Assessing the Environmental Impact of Artisanal Gold Mining Activities on the Waters and Sediments Around Meli, Northwestern Tigray, Ethiopia

The paper presents the environmental impact of artisanal gold mining activities on the waters and sediments around Meli, northwestern Tigray, Ethiopia. Stream sediment, water, and tailing samples were collected in the dry season in January of 2019 and analyzed for heavy metals Cu, Zn, Pb, and As. The physicochemical parameters (pH, EC, major cations, and anions) of a few water samples were also measured. Flame atomic absorption spectrometry was used to determine the level of the metals in stream sediments. The results show that tailing has the highest concentration of metals followed by the stream sediments. The least concentrations are recorded in water for all metals. Pb has the highest mean concentration of all heavy metals in stream sediments, waters, and tailing samples. The mean Geo-accumulation Index (Igeo) and Contamination Factor (CF) suggest that the sediment represents uncontaminated to moderately contaminated classes. Concentrations of Cu and Zn in the water samples are generally within the maximum allowable concentration of the WHO, whereas concentrations of Pb and As are above the limit. Metal Index for surface and groundwater suggests that the area is polluted with heavy metals Pb and As. The main sources of the metals are assumed to be the sulfide ores facilitated by natural weathering processes and artisanal mining activities like excavations, crushing, grinding, and amalgamation processes. The Gibbs and Durov plots show that major hydrogeochemical processes controlling the water chemistry are water-rock interactions with considerable mixing of water types.&#x0D; &#x0D;

ASSESSMENT OF TEMPORAL VARIATION OF HEAVY METALS IN SEDIMENTS OF WARRI RIVER, SOUTHWESTERN NIGERIA

Contaminated sediment poses a serious environmental problem, therefore knowledge of the concentration of heavy metals in stream sediments is very important because of their significance to aquatic life and human health. The concentration of heavy metals (Cd, Pb, Cr, As, Ni, Zn, Fe and Cu), in stream sediments of some parts of Warri River, Southwestern Nigeria were examined during the rainy and dry seasons using Atomic Absorption Spectrophotometer, in order to assess their contamination levels using the environmental contamination indexes; Geoaccumulation Index, Enrichment Factor (EF), and Contamination Factor (CF). For both the rainy and dry seasons, the results revealed average heavy metal concentrations obtained in all samples in the study area in the order As&gt;Cd&gt;Pb&gt;Ni&gt;Cr&gt;Zn&gt;Cu&gt;Fe. The trend in mean Igeo values was as follows: As (-0.66) &gt; Zn (-4.93) &gt; Cu (-5.8) &gt; Fe (-5.31) &gt; Cd (5.76) &gt; Pb (-6.35) &gt; Ni (11.25), showing that River Warri’s sediments were not polluted by heavy metals. Cu= Zn (0.08), Cd (0.34), Pb (0.02), As (0.01), and Ni (0.00) were the mean CF values across all measured locations, indicating a low contamination factor. The average EFs for the sediments were As (1.09) &gt; Cd (1.10) &gt; Cu (1.46) &gt; Zn (1.61) &gt; Pb (1.09) &gt; Ni (1.09) &gt; Fe (0.83), showing low enrichment (&lt;2). Evaluation of enrichment factor, geo-accumulation index and contamination factor values showed that the stream sediments of the study area were unpolluted. Heavy metals in the sediments were found to be linked to anthropogenic activities in the study region, according to the results of the hierarchical cluster analysis (HCA). The metal concentrations in the sediment were found to be elevated at some sampled points, it is therefore recommended that annual monitoring of the stream sediments of the study area is undertaken. Also, sustainable practices should be employed in order to conserve the resources of the Warri River.

Relationship Between Metals In Ovacık Stream Sediment Samples

Ovacık Village is located in Balıkesir province and is 12 km away from Balıkesir Center. The GPS coordinates of Ovacık Village are 39° 43' 51'' North and 27° 47' 37'' East. The stream sediments in the study area consisted of the erosion of magmatic, metamorphic and volcanic rocks and surface waters and eroded rock particles along the stream bed. The relationship between metals in stream sediments has been investigated on the basis of geochemical properties. As, Cd, Cu, Mn, Ni, Pb and Zn element contents of 23 stream sediment samples were taken from different locations from Ovacık village and its surroundings. The minimum, maximum, medyan, median and standard deviation values of these metals in the stream sediments were calculated and it was observed that the mean values were higher than the standard deviation values. The minimum and maximum values (ppm) of the metals studied As: 7.7 - 51.3, Cd: 0.13 - 0.58, Cu: 25.2 - 70.6, Mn: 661 - 1135, Ni: 8.6 - 33.7, Pb: 12.3 - 57.7 and Zn: 59 - 220 According to the Spearman correlation coefficient values, a strong positive correlation was observed between As - Cu, Cd - Pb, Cd - Zn, Cu - Ni and Pb - Zn metal associations (p &amp;lt;0.01). Factor analysis was made with the obtained analysis results and 3 different factor values were created and analyzed. Factor 1: Cd - Pb - Zn association and 37.01% of the total variance; Factor 2: Cu - Mn - Ni association and 24.7% of the total variance; Factor 3: As and total variance was 18.4%, the total variance value was found to be 80.1%. The spatial distributions of the metals were analyzed using the Surfer 9.0 program in the creation of the distribution maps. As and Cu elements at locations 16 and 17; Mn and Ni elements at locations 3, 6 and 7; Cd, Pb and Zn elements have the highest values in locations 3, 12 and 20, they show a similar distribution.

Concentration, Spatial Distribution and Potential Ecological Risk of Heavy Metals in Stream Sediments of the Misiones Province, Argentina

One hundred and twenty-eight stream sediment samples were collected in the Misiones province of Argentina by the low-density geochemical mapping project of the China Geological Survey. The analyzed data were used to study the concentration, spatial distribution, local pollution level and potential ecological risk of eight heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb and Zn) by factor analysis, geoaccumulation index (Igeo), enrichment factor (EF) and the Hakanson’s potential ecological risk index (Eir and RI) methods. Results showed that the background values (median) of those elements were 2.97 ppm, 0.13 ppm, 212.60 ppm, 322.53 ppm, 0.013 ppm, 64.42 ppm, 12.58 ppm, and 198.85 ppm, respectively. Except for Hg, the contents of other elements were higher than the abundance of continental crust. The spatial distribution of Cu and Zn in stream sediments were consistent, while that of other elements were different. The factor analysis results implied that Cd, Cr, Cu, Ni and Zn were mainly affected by geological background and inherited the characteristics of regional parent rocks. Furthermore, Pb was not only controlled by natural conditions but also related to human activities, while As and Hg represented the anthropogenic sources, and their concentrations were affected by human activities. The results of Igeo and EF told us that Cu was heavily polluted in stream sediments; Pb and Zn were largely mildly polluted; As, Cr, Cd, Ni and Hg were mostly nonpolluted. The ecological risks were ordered as As &gt; Cu &gt; Cd &gt; Pb &gt; Hg &gt; Cr &gt; Ni &gt; Zn. In general, the potential ecological risk of heavy metals in the Misiones province was low, but As and Cu also have a high ecological risk at some sampling points, which should be considered.

Heavy Metal Pollution Assessment in Stream Sediments from Urban and Different Types of Industrial Areas in South Korea

ABSTRACT Stream sediments from heavily industrialized areas, including urban areas (SS), industrial complexes (US), petrochemical industries (PS), and the Onsan industrial complex (OS) in Korea, were studied to identify 19 heavy metals pollution status and the metal sources. The concentration of heavy metals, except for Li, Be, and Cs in the stream sediments from the Onsan industrial complex near the largest Cu/Zn/Pb smelting facilities, was 3 to 1,302 times higher than that in urban and other industrial areas. Moreover, owing to the smelting activity in the Onsan area, the degree of pollution by major metal products (e.g., Cu, Zn, Pb, Sn, Cd, Sb, Ag) and raw or additive materials (Cr, Ni, Mo, As, Hg) was significantly higher than that in other areas. Heavy metals in stream sediments near smelters greatly exceeded the screening levels (SEL), which could have adverse effects on the health of biota. These values also exceeded the cleanup screening levels of freshwater sediments in the USA. The highest pollution load index value of 47.8 was observed in the vicinity of the smelter (OS) and decreased in the following order: heavy industry (3.6, US) > petrochemical industry (2.4, PS) > urban streams (1.2, SS). Our results suggest that metal pollution in stream sediments might be caused by atmospheric dust generated during the smelting process, as well as sediment particles that accumulate and are washed off from impervious layers such as industrial facilities, raw material storage yards, and road surfaces.

Occurrence, behaviour and environmental risk assessment of trace metals in stream sediments from southwestern Burkina Faso, West Africa.

In this study, the influence of source area weathering and provenance on the stream sediment geochemistry as well as the environmental impacts of selected potentially toxic trace elements (PTE) were evaluated. Four components derived from the R-mode factor analysis of additive logratio-transformed data pointed to the combined influence of weathering of granitoids, sedimentary rocks and greenstone belts and gold mineralisation on the stream geochemistry. Although 13 PTE were enriched in the majority of the samples, only five elements (As, Cr, Cu, Pb and Ni) were likely to have adverse biological effects. Based on the geochemical maps, the areas susceptible to produce adverse biological effects due to As enrichments are solely drained by the greenstone belts, whereas enrichment of Pb was pronounced in areas of high population densities. The linear regression between enrichment factor (EF) and adverse effect indices (AEI) indicated that in order for Pb to pose threats to the benthic organisms, EF should be 4.5, whereas EF for sediment toxicity are 1 for Cu, Cr and Ni and 2 for As. Consequently, Cu, Cr, Ni, As and, to a lesser degree, Pb pose serious environmental threats to benthic organisms in southwestern Burkina Faso. The stream sediment geochemical data of this study constitute a baseline for assessing future environmental risks.

Distribution, Association, and Ecological Risk Evaluation of Heavy Metals and Influencing Factors in Major Industrial Stream Sediments of Chandrapur District, Central India

The accumulation of heavy metals in stream sediment depends on various influencing factors. Sediments are aggregation of number of species along with organic debris. Accretion of heavy metals on sediment is the outcome of absorption by fine-grain inorganic particles of clays, adsorption of hydrous ferric and clays, and complexation with natural organic matters. These processes are regulated by different influencing factors including TOC and pH. This study reveals the spatial distribution of potentially toxic heavy metals (Cd, Hg, Pb, Co, Cu, Cr, Ni, and Zn) and assessment of contamination levels to find out the role of TOC and pH in distribution of heavy metal contamination in major industrial stream sediment in Chandrapur district, Central India. The pollution indices and multivariate statistical analysis were carried out to identify the correlation between various parameters. The concentration of anthropological derived heavy metals is higher in TOC-rich area. PCA and HCA study reveals that heavy metals are significantly correlated with TOC of the sediments, while Ni is associated with pH. Chromium shows the ambiguous behavior towards association with pH and TOC. The study also reveals that there is urgent need for assessment of Wardha River and Erai River basins because there could be hotpots for heavy metal contamination.

Geochemistry, risk assessment, and Pb isotopic evidence for sources of heavy metals in stream sediments around the Ulukışla Basin, Niğde, southern Turkey

Concentrations of selected elements (Al, Fe, Mn, Mo, As, Cd, Cu, Cr, Ni, Co, Pb, Sb, and Zn) and Pb isotope ratios were determined in 53 sediments from Alihoca, Gümüş, Horoz, and Çakıt streams around the south-central Taurides (Ulukışla Basin), Niğde, which is a known mining province in Turkey. Several pollution and risk assessment indices were used to assess possible heavy metal pollution in the stream sediments and the associated potential ecological risks. Concentrations of As, Cd, Cu, Cr, Ni, Co, Pb, Sb, and Zn were elevated in the streams located near ancient mines, active mines, and slag piles in the area, suggesting an influence from mining activities. The pollution assessment indices indicated that the sediments were significantly polluted by As, Cd, Sb, Zn, and Pb and moderately polluted by Cu, Ni, Cr, and Co. The sediments show very high potential ecological risk with As, Cd, Sb, and Pb as the principal contributors. Ni, Cr, As, Pb, Zn, and Cd exceeded the probable effect concentrations in most of the samples implying that their concentrations may frequently affect sediment-dwelling organisms. Multivariate statistical analyses indicate that the accumulation of heavy metals in the stream sediments is due to an interplay of anthropogenic activities (mining and agrochemical application) and geogenic processes (weathering of bedrocks and supergene alteration of base metal-rich mineralization). Pb isotopic tracing indicates that total Pb in the sediments (206Pb/207Pb = 1.09–1.29) is primarily from weathering and dissolution of ultrapotassic rocks (206Pb/207Pb up to 1.20) and galena (206Pb/207Pb up to 1.21) from the Pb-Zn-Au deposits in the area with some anthropogenic input from mine slag piles (206Pb/207Pb = 1.10).

Effect Thresholds of Metals in Stream Sediments Based on In Situ Oligochaete Communities

Aquatic oligochaetes, comprising a large number of species showing various degrees of resistance to chemical pollution, are recognized as valuable bioindicators of sediments’ quality. In the Geneva area (Switzerland), oligochaete tools were previously tested for assessing the biological quality of stream sediments, and effect thresholds of combined metals (quotients) in sediments were defined. The aims of the present study were to update this previous work with new data acquired in different cantons of Switzerland and to establish effect thresholds on oligochaete communities for individual metals and for combined metals. The oligochaete metrics “Oligochaete index of sediment bioindication (IOBS)”, “oligochaete density” and “percentage of tubificids without hair setae” proved pertinent for assessing the effects of metals and organic matter in sediments. We established a threshold effect level (TELoligo) and probable effect level (PELoligo) for eight metals in sediments (Cr, Ni, Zn, Cu, Pb, Cd, Hg and As) as well as a probable effect level for these metals combined (mPELoligo-Q). These thresholds could be used directly to screen for alteration of in situ communities restricted to sediments and/or for establishing sediment quality standards based on a combination of different biological and ecotoxicological tools.

Environmental diagnosis of metals in streams near sugarcane cultivation areas: current and historical analysis in the central region of the State of São Paulo.

In Brazil, innumerable regions of native landcover have been removed and replaced by agricultural cultivation, especially of sugarcane. In this culture, the application of fertilizers containing metals has caused impacts on the water resources causing contamination of stream sediments and occasioning bioaccumulation of metals in aquatic invertebrates. In the year of 2006, an environmental diagnosis of metals in sediments of streams located near sugarcane cultivation areas and in streams located in preserved areas, was published. That study pointed to high concentrations of metals in stream sediments in agricultural areas. These streams have been monitored over the last 10 years conducting analyses of metals and monitoring possible changes in land use. In the present paper, a historical comparison of metals contamination in the sediments of the same streams is conducted, aiming to present a status of 10 years later, analyzing 5 metals (Zn, Cd, Mn, Cr and Fe) found in the sediments of 8 streams, five located in areas of sugarcane cultivation and three located in preserved areas. This study also shows that there is higher concentration of metals in the sediments of streams near sugarcane cultivation than in preserved areas. The temporal historical evaluation showed high concentrations of Cd in 2016 when compared to the year 2006 for streams near sugarcane cultivation.

Evaluation of Heavy Metals in Stream Sediments from Abakaliki Pb – Zn Ore Mining Areas of Ebonyi State, Nigeria

This research is an assessment of toxic metals in stream sediments from the Abakaliki Pb-Zn mine area of Ebonyi state. Heavy metals in stream sediment samples were analysed using Atomic Absorption Spectrometer (AAS). Physicochemical parameters were determined show that pH is generally low (3.65) resulting from the dissolution of the sulphide Ore. The heavy metal mean trend indicates that Fe &gt; Zn &gt;Pb&gt; Cr &gt;Cu &gt; Ni &gt; AS &gt; Cd in the stream sediment samples. Fe, Zn, Cu, Pb and Cr were observed to be high. The variations for the heavy metals suggest that mining operation is responsible for the distribution and redistribution of chemical elements. The values of contamination factor for the stream sediment indicate moderate contamination for Cd, As and Ni while Fe, Zn, Pb, Cu and Cr show very high contamination. The result of enrichment factor (EF) using Fe concentration as normalizing value show that Ni, Cd, Cr, As, and Cu have depletion to mineral enrichment while Pb and Zn show moderate enrichment. The result of the Correlation analysis and principal component analysis ( R- Mode and Q-mode) applied to the data analysis show that Zn, Pb, Cd, Cu, and Cr heavy metals originated from similar sources but may have been influenced by mining operation while Ni and As are attributed to a geogenic source. Proper sewage disposal practice and soil remediation are recommended.

Integrated Characterization of Toxicity Distribution of Selected Heavy Metals in Stream Sediments Around Itakpe Iron Ore Mines, North Central Nigeria

The results of the analysis were subjected to five (5) indices: contamination factor (CF); Ecological risk factor (Eri); Enrichment factor (EF); index of geo-accumulation (Igeo) and anthropogenic factor (AF). The CF results showed that the River PomPom dry and wet season sediments were collected in February and July respectively from 0cm to 10cm depth. Stainless steel spoon was used to collect the samples. The sediment samples were packaged, labeled and refrigerated for onward transportation to the laboratory. All samples were oven-dried (50oC) for about 24 hours, sieved through -80 mesh. About 1.0g of each sample was digested, filtered and the filtrates were ready for heavy metal analysis using Atomic sediments were most contaminated with Fe in both seasons, least contaminated with Cd at dry season and Zn in wet season. The Eri factor revealed pollution hazard level of middle during wet season and tiny in dry season. Pb and Ni showed strong and middle hazard level during wet season and Cu revealed middle level during dry season. The enrichment factor indicated extremely enriched for Fe in all locations in both seasons while most heavy metals showed depletion to minimal enrichment. The Igeo for both seasons showed that Fe was moderately to highly polluted in all locations. During dry season, other heavy metals showed moderately to unpolluted while in wet season Cd, Ni and Pb indicated moderately to very highly polluted. In both seasons, the % AF was very high for Fe, Cu, Pb. The AF% was very high for Ni and Cd in wet season. All sites in both seasons have experienced deterioration but more in the wet season. From these indices, the stream sediments have been significantly contaminated with Fe, Ni, Pb and Ni in most locations in both seasons.

Anthropogenic contamination and risk assessment of heavy metals in stream sediments influenced by acid mine drainage from a northeast coalfield, India

The total concentrations and chemical partitioning of heavy metals in streambed sediments, collected around the Jaintia Hills coal deposit of northeast India, were studied using pollution indices and multivariate techniques to evaluate the risk and contamination levels from heavy metals and their possible origins. Results show that sediments close to mining sites have low pH (<4), high organic carbon, and contain significant amounts of Fe-oxyhydroxide phases (mainly, goethite and schwertmannite), which implies direct impact of coal mine drainage. The average concentrations of Fe, Cu, Co, Cd, Cr, and Zn exceeded the World average, and in some cases, Cd, Cu, Ni, and Cr concentrations exceeded the threshold effects level, which suggests they will be toxic to aquatic biota. Contamination factors (CF) show that the sediments are low to highly contaminated with Cd, Cu, Mn, Pb, Fe, and Zn and low to moderately contaminated with Co, Cr and Ni. The pollution load index (PLI), degree of contamination index (C deg) and Nemerow integrated pollution index (NIPI) show that the sediments are moderately to highly contaminated, with the extent of pollution greatest nearest to the collieries. The potential ecological risk index (RI) shows low to considerable ecological risk from heavy metals in the sediments, with Cd having the high potential of risk, which also agrees with the risk assessment code (RAC). Multivariate statistical analysis suggests that the concentrations of the heavy metals in stream sediments are strongly influenced by Fe-oxyhydroxide phases and organic carbon derived from anthropogenic sources, mainly coal mining activities. Although a significant proportion of the Cd, Mn, and Ni in the sediments are partitioned into exchangeable and organic fractions, a sizable amount of metals are also found in the Fe–Mn fraction, suggesting that Fe-oxyhydroxides play a dominant role in controlling metal mobility in these stream sediments.

Mobility and Bioavailability of Metals in Stream Sediments Impacted by Mining Activities: the Jaralito and the Mexicana in Sonora, Mexico

This study aims at investigating heavy metal mobility and bioavailability in sediments from the Mexicana and Jaralito streams, Northern Mexico. A chemical partition analysis (sequential extraction) was performed to determine geochemical phases in which metals are found. Geoaccumulation index (Igeo) and enrichment factor values were obtained from analytical results and geochemical baseline data. Sediments showed high concentrations (mg/kg) of Cd (below detection limit, BDL-3.50), Cr (3–41), Cu (238–1090), Fe (41267–61033), Mn (678–1143), Ni (18–35), Pb (51–124), and Zn (116–356). Metal concentrations in geochemical phases exhibited the following order: residual > interchangeable > Fe/Mn oxide > carbonate >organic matter/sulfide. Both streams presented high degree of enrichment for Cu, Fe, Mn, Ni, Pb, and Zn, indicating anthropic origin of these metals. Metal mobilities in Jaralito and the Mexicana were Fe > Cu > Mn > Pb > Zn > Ni > Cr and Fe > Cu > Mn > Zn > Ni > Pb > Cr > Cd, respectively. Jaralito and the Mexicana sediments exhibit a mostly gravel-sandy texture with higher metal contents than in fine fractions. Sediment Geoaccumulation index values suggest that Jaralito features moderate to strong contamination by Ni, Pb, and Cu, whereas the Mexicana features strong contamination by Cd, Cu, Pb, and moderate contamination by Ni, Pb, and Zn. The quality criteria comparisons (LEL and SEL) indicate these areas are contaminated by metals and represent a substantial environmental risk because of high metal mobility and availability. Future studies on water chemistry and biota are needed to fully assess pollution impact in the Jaralito and Mexicana streams. The probability of adverse biological effects from high metal levels in those streams confirms the urgency of implementing effective environmental management practices.

Distribution of trace metals in stream sediments along the Trans-Amazonian Federal Highway, Pará State, Brazil

A total of 64 sediment samples were collected along a stretch of about 988 km of the Trans-Amazonian Federal Highway, between Marabá and Itaituba, Pará State, in order to characterize the distribution of metals and trace elements. Due to the lithological and geological diversity along this stretch of the Amazon, the study region was divided in three distinct tracks. Statistical data analysis (Spearman correlation and Principal Factor Analysis) shows strong signature and predominance of regional rocks chemistry, such as mafic-ultramafic-bearing elements (Ni and Cr) and hydrothermalism-bearing elements such as Cu and Pb. Enrichment factors were calculated for three different normalizer agents: 1) Fe and Mn, representing the Fe and Mn (hydr)oxides, 2) Al representing clay minerals, and 3) organic matter (OM). The Fe and Mn (hydr)oxides showed to be the most proficient metal carrier among the geological matrices, likely due to the larger lithological diversity. On the other hand, OM positively correlated to trace element distribution.