Metal Contamination In Sediments Research Articles

Heavy Metal in River Sediments of Huanghua City in Water Diversion Area from Yellow River, China: Contamination, Ecological Risks, and Sources

Determination of heavy metal (HM) contamination, ecological risks, and sources in river sediments are important to preventing and controlling environmental pollution. This study investigated the spatial distribution, potential ecological risks, and biological toxicity of five heavy metals in river sediments of Huanghua City in the water diversion area from the Yellow River, China. GIS, redundancy analysis (RDA), and the positive matrix factorization (PMF) model were used to accurately quantify the pollution sources and the spatial distribution of pollution sources. The results revealed that Cu had the highest degree of natural pollution, and the source mainly comes from traffic. Residential land (RL), population density (PD), GDP, and industrial construction (IC) make high contributions to traffic pollution; the highest level of potential ecological risk was Hg, and the source mainly comes from industrial wastewater discharges. IC makes a high contribution to industrial wastewater discharges pollution; the highest effect of bio-toxic risk was As, and the source mainly comes from farmland drainage water. Agricultural production potential (APP) and water area (WA) make high contributions to farmland drainage water pollution; Zn might be of natural origin, and woodlands (WLs) make high contribution to natural origin. This result provided a new idea for the system control of sediment heavy metal pollution in Huanghua City.

Promoting removal of copper from sediment and production of bioelectricity by sediment microbial fuel cells using tea extracts

In a sediment microbial fuel cell (SMFC) in which both the cathode and the anode are embedded in the sediment, copper is removed from the anode zone by its migration to the cathode. However, the removal of copper in an SMFC is often limited by poor mass transfer in the sediment environment. Tea extracts are rich in tea polyphenols, which are antioxidizing and transfer electrons. Adding tea extract to the electrodes of an SMFC can not only increase the efficiency of reduction of copper but also minimize the internal resistance of the SMFC, increasing its power output and the migration of copper. The results herein reveal that (1) the peak redox current of tea extract that was obtained using 50 % ethanol as the extractant was 60 μA, which was 1.39 and 1.69 times those obtained using DI water and 75 % ethanol, respectively; (2) adding tea extract reduced the internal resistance of the SMFC by 12.5 %; (3) the SMFC to whose anode tea extract was added removed 70.7 % of copper and had a maximum power density of 19.45 mW/m3, which was 1.66 times that of the SMFC without the tea extract. The SMFC with added tea extract can potentially be used to remediate heavy metal-contaminated sediment.

In Situ Remediation Technology for Heavy Metal Contaminated Sediment: A Review.

Sediment is an important part of the aquatic ecosystem, which involves material storage and energy exchange. However, heavy metal pollution in sediment is on the increase, becoming an important concern for the world. In this paper, the state-of-art in situ remediation technology for contaminated sediment was elaborated, including water diversion, capping, electrokinetic remediation, chemical amendments, bioremediation and combined remediation. The mechanisms for these techniques to reduce/immobilize heavy metals include physical, electrical, chemical and biological processes. Furthermore, application principle, efficiency and scope, advantages and disadvantages, as well as the latest research progress for each restoration technology, are systematically reviewed. This information will benefit in selecting appropriate and effective remediation techniques for heavy metal-contaminated sediment in specific scenarios.

Heavy metal contamination in surface sediments of the Upper Bhima Basin, Maharashtra, India

Heavy metal contamination in surface sediments of the Upper Bhima Basin, Maharashtra, India

Multi-index assessment of heavy metal contamination in surface sediments of the Pearl River estuary intertidal zone

Surface sediments from 21 stations within the Pearl River estuary (PRE) intertidal zone were sampled for heavy metal contamination analysis. Average heavy metal concentrations (mg/kg) in the PRE intertidal zone were 118.5 (Cr), 860.4 (Mn), 19.5 (Co), 72.5 (Ni), 128.1 (Cu), 198.5 (Zn), and 73.0 (Pb), with the concentrations of Mn, Co, Ni, Cu, and Zn being significantly higher than their corresponding background values. The enrichment factor (EF) and geo-accumulation index (Igeo) reveal the same contamination status, with Pb, Ni, Co, Mn, and Cu showing slight to moderate contamination. Overall, the combined heavy metal concentration in the PRE intertidal surface sediments had a 24.7 % probability of toxic effects on aquatic biota based on the joint probabilistic risk (JPR) approach. Principal component analysis (PCA) coupled with the correlation analysis (CA) revealed that the heavy metal contamination in the PRE intertidal zone might originate from natural and anthropogenic sources.

Heavy metal contamination, distribution and source apportionment in the sediments from Kavvayi Estuary, South-west coast of India

Heavy metal contamination in sediments poses serious threat to ecosystem and human health through food web. In this study, surface sediment samples from Kavvayi estuary were analyzed to understand the sources and pollution levels of heavy metals. The results revealed that the average contents (μg g−1) of eight selected heavy metals followed the order of Mn (65–795) > Cr (30–442) > Co (30–250) > Ni (15–175) > Zn (20–120) > Cu (5–55) > Pb (5–40). Enrichment factor (EF) and contamination factor (CF) analyses revealed that Pb, Ni and Cr shows moderate pollution levels, whereas Co indicates severe pollution levels. The rests of the heavy metals (Zn, Cu and Mn) were at no to low pollution levels. The correlation matrix combined with multivariate principal component analysis suggests the heavy metals, except for Co, mainly originated from natural weathering and erosion of rocks and soils in the catchment. The results of this study provide a comprehensive assessment of heavy metal contamination in the sediments of the Kavvayi region. The result can aid the development of effective remediation strategies and improve government decision-making and coastal management.

Contamination and health risks of trace metals in water and sediments of May Sieley stream, Ethiopia

The Stockholm Convention underpins the significance of monitoring the toxic trace metals in ecosystems. This study was conducted in May Sieley stream, North Ethiopia, in 2020. The main aim was to assess the spatial-temporal variation of trace metals in water and sediments using the ICP-OES technique and further evaluate their health risks. PCA and correlation analysis identified the sources of pollution, mutual dependence, and identical behavior of trace metals. Except for Hg, the Cu, Zn, Ni, As, Cr, Cd, and Pb were high in water during the post-rainy season. The trace metals concentrations were lower in dry season sediment than in post-rainy season except for Cu and Zn. The post-rainy season showed a higher upstream concentration than the rest. There was a strong positive correlation (0.84 < r < 0.93, p < 0.01) between Ni–Cr–Cd–Pb, suggesting that the same factors influenced these trace metals. Hg correlated negatively with all other trace metals suggesting that this trace metal tends to move in a different direction. The water's Cr, Cd, Pb, and As exceeded WHO standards during the post-rain season. However, Hg and As exceeded those standards in the dry season. Pb, As, Cd, and Hg showed unacceptable non-carcinogenic levels in both groups (Q > 1). All trace elements assessed displayed unacceptable carcinogenic risk levels in both groups. The findings are significant to the policymakers in framing water quality control strategies at the river basin level.

Comparing the applicability of ecological risk indices of metals based on PCA-APCS-MLR receptor models for ports surface sediments

This study collected surface sediments from seven ports in Taiwan and analyzed their characteristics along with 10 metals. Enrichment factor (EF), relative EF (REF), potential ecological risk index (PERI), and mean effect range median quotient (m-ERM-q) were used to evaluate the levels of metal contamination and ecological risks in sediments. Principal component analysis (PCA) and the absolute principal component score-multiple linear regression (APCS-MLR) model were applied to quantify the main factors affecting the variations in sediment metals. The different normalization techniques that vary between indexes significantly affect the estimates of risk levels for sediment metals. APCS-MLR model confirmed the significant difference among the sediment quality indices in the degree of anthropogenic pollution, ranging in the order of REF (normalized with reference site and Fe, 97.0 %), PERI (normalized with reference site, 85.5 %), EF (normalized with crust and Fe, 79.4 %), and m-ERM-q (not normalized, 56.6 %).

Evaluation of heavy metals contamination and pollution indices levels in surface sediments of the Bizerte coastal line, Tunisia

Heavy metal concentrations in surface sediments collected from 17 stations samples in Bizerte coastal line were determined in order to evaluate the contamination status in the region. Heavy metal concentrations (mg/kg) of Bizerte coast line followed the decreasing trend of Fe>Pb>Zn>Mn>Cu>Cr>Ni>Co>Cd. The pollution degree of the surface sediment collected from 17 samples station in Bizerte coast line by heavy metals was evaluated on the basis of pollution indices (EF, Igeo, CF, PLI and CD). Results of Igeo, EF, CF, PLI and DC demonstrated that pollution levels of Pb and Cd were moderate, which should require more attentiveness as main pollution factors. However, no pollution was found for Zn, Cu, Ni, Cr, Co and Mn. Hierarchical cluster analysis was used to identify the influence of anthropogenic activities on the surface sediment.

Preliminary environmental assessment of metal-contaminated sediment dredging in an Urban River, New Jersey, USA.

While several studies have reported success with remedial sediment dredging, the sustainability of these impacts remain unclear. This preliminary study aimed to investigate the short- and long-term effects of remedial dredging on metal contamination, dredging efficacy and ecological status of the Lower Passaic River. To accomplish this, pre- and post-dredging data were statistically analyzed and evaluated using geochemical indices. Short-term results showed effective heavy metal reduction although their concentrations became elevated in water column, increasing bioaccumulation risk in aquatic biota. On the long-term, metal concentrations increased in surface sediments. Ecological assessment revealed that Cu, Hg and Pb pose greater risks while Ag remained abundant despite dredging. Further investigation suggests that post-dredging residuals, surface runoff and sewage pollution may contribute significantly to recontamination and continued pollution. Depletion in long-term dredging efficacy from spring to summer suggest that season-influenced changes in temperature, algae growth and stormwater discharge may have played a role.

SEASONAL METAL POLLUTION LEVEL AND ECOLOGICAL RISKS OF THE SUPERFICIAL SEDIMENTS FROM A TROPICAL LAGOON AREA

The aim of this study was to the assessment of the seasonal level metal contamination of the superficial sediments from the lagoon area II and to deduce the likely seasonal ecological risks which results. This study were conducted during one year (from June 2020 to May 2021) and the concentration in eight trace metals (As, Cd, Cr, Cu, Hg, Pb, Ni and, Zn) of these substrates, obtained in this period, were used. Seven metal contamination indexes, six ecological risks indexes and, two sediment qualities guidelines were used for this purpose. The results highlighted the very severe contamination of these superficial sediments in all season by all these trace metals in the whole, especially by As, Cd and Hg. So, the seasonal ecological risks for its fauna, particularly for its benthic fauna, were very severe. The population of its benthic fauna threatened by this pollution was relatively important, to 21% in this period.

Assessing the ecological risk and ecotoxicity of the microbially mediated restoration of heavy metal-contaminated river sediment

Anthropogenic activities such as mining, smelting industries, and the application of pesticides in agriculture might result in contamination of multiple heavy metals in the environment. Heavy metal contamination of sediment is a serious environmental problem, and thus the remediation of contaminated sediment is a worldwide challenge. Several strategies have been developed for the remediation of contaminated sediment, however the ecological risk and ecotoxicity of the restored sediment have rarely been evaluated. We assessed whether river sediment highly contaminated with heavy metals could be restored using microbial bioleaching followed by evaluating the residual toxicity and ecological risk of the microbially remediated sediment. Sequential extraction revealed that the bioavailable levels of Cu, Ni, and Zn in the contaminated sediment exceeded sediment quality guideline (SQG) thresholds. It was consequently found that acidophilic sulfur-oxidizing Acidicaldus sp. SV5 effectively bioleached Cu, Ni, and Zn from the contaminated sediment, reducing the bioavailable fraction of these elements below SQG thresholds. The ecological risk assessment indicated that SV5-driven remediation significantly reduced the potential ecological risk of the contaminated sediment. The residual ecotoxicity of the microbially remediated sediment was also tested with the soil nematode Caenorhabditis elegans. There was a significant decrease in the body burden of Cu, Ni, and Zn in C. elegans and a reduction in the toxicological effect on survival, growth, and reproduction in the microbially remediated sediment. Our study suggests that a combination of chemical analysis, chemical-based ecological risk assessment, and ecotoxicity tests would be helpful for the development of efficient and eco-friendly strategies for the restoration of contaminated sediment, which could be incorporated into sediment quality management practices.

Exploring the impacts of physicochemical characteristics and heavy metals fractions on bacterial communities in four rivers

Heavy metals contamination in sediment poses serious threats to bacterial communities that play critical roles in sediment biogeochemical processes. However, the physicochemical factors and the major heavy metals fractions that affect sediment bacterial communities are still unclear. Here, we performed heatmap and redundancy analyses to examine the effects of physico-chemical characteristics and heavy metals fractions on the sediment bacterial community from rivers in the UK (River Tyne and Ouseburn) and India (River Ganga and Yamuna). The results revealed that physicochemical characteristics and heavy metals fractions altered the diversity, richness, and structures of the bacterial community. Moreover, the fractions of Co, Zn, Pb, Cr, and Cu played significant roles in shaping the bacterial community structure, and physicochemical variables, particularly NH4+-N and NO2−-N, also influenced the bacterial diversity and structure. Firmicutes showed strong associations with both physicochemical factors and heavy metals fractions. Chloroflexi and Actinobacteriota can be used as biomarkers for Zn contamination. Overall, our study identified the significance of sediment chemical characteristics and heavy metals fractions in determining the bacterial community structure as well as bioremediation and environmental management of metals contaminated sites.

Comprehensive Ecological Risk Assessment of Heavy Metals Based on Species Sensitivity Distribution in Aquatic of Coastal Areas in Hong Kong.

In recent decades, the ecological environment of some coastal areas in China has been seriously affected by terrestrial pollutants, and there is an urgent need for ecological risk assessment of China’s coastal environment. The assessment of heavy metal pollution in Hong Kong waters was carried out using different environmental and ecological indicators. The heavy metal contents (Cu, Pb, Zn, Cd, As, Cr, and Hg) in the near coast of Hong Kong were analyzed for two different seasons of the year 2018 (April—spring and September—autumn). We assessed the distribution and enrichment of heavy metals in the near coast of Hong Kong, and the potential biohazardous effects were assessed using the species sensitivity distribution method. The results showed that only Pb, Zn, and Hg in seawater exceeded the Class I standard. Pb, Zn, Cd, and As in organisms exceeded the standard, and no heavy metals exceeded the standard in sediments. The species sensitivity distribution method indicated that the biohazardous factor of heavy metals of the Hong Kong coast is higher in spring than in autumn, and the potential hazard ratio has the characteristics of high northwest and low southeast, which leads to its msPAF also having these characteristics. From the correlational analyses among heavy metals, we found that the pH change in seawater was related to the concentration of heavy metals, the concentration of heavy metals in seawater was proportional to the salinity of seawater, Pb and Cu were likely to have the same source, and Zn and Cd may not have the same emission sources as the other heavy metals. Overall, heavy metal contamination of seawater, sediments, and organisms near the Hong Kong coast was within acceptable limits, but the problem of heavy metal dispersion should be prevented.

Heavy metal distribution and contamination in wetland sediments: A review

Heavy metal distribution and contamination in wetland sediments: A review

Contamination and Health Risk Assessment of Heavy Metals in Soil and Ditch Sediments in Long-Term Mine Wastes Area.

The ecological and health risks posed by wastes discharged from mining areas to the environment and human health has aroused concern. 114 soil samples were collected from nine areas of long-term mine waste land in northwestern Yunnan to assess the pollution characteristics, ecological and health risks of heavy metals. The result revealed that the geo-accumulation indexes were Cd (4.00) > Pb (3.18) > Zn (1.87) > Cu (0.25). Semi-variance analysis revealed that Cd and Cu showed moderate spatial dependency, whereas Pb and Zn showed strong spatial dependency. Cd posed an extreme potential ecological risk. Slopes and ditches were extreme potential ecological risk areas. Non-carcinogenic risk to children from Pb and Carcinogenic risk to adult and children from Cd was non-negligible and direct ingestion was the major source. This study provided a scientific basis for policymakers in management and exposure reduction.

Metal contamination in sediments of dam reservoirs: A multi-facetted generic risk assessment

The quality of bottom sediments is a key factor for many functions of dam reservoirs, which include water supply, flood control and recreation. The aim of the study was to combine different pollution indices in a critical generic risk assessment of metal contamination of bottom sediments. Both geochemical and ecological indices reflected that sediment contamination was dominated by Zn, Pb and Cd. The ecological risk indices suggested a high riks for all three metals, whereas human health risks were high for Pb and Cd. An occasional local contamination of sediments with Cr and Ni was revealed, although at levels not expected to cause concerns about potential ecological or health risk. Sediments from the Rybnik reservoir for Cu only revealed a high potential ecological risk. EF turned to be as being the most useful, whereas TRI (∑TRI) was the most important ecological index. All multi-element indices suggested similar trends, indicating that Zn, Pb and Cd taken altogether had the greatest impact on the level of sediment contamination and posed the greatest potential ecological and health risks to organisms. The use of sequential BCR extraction and ecotoxicity analyses allowed for a multi-facetted generic risk assessment of metals in sediments of dam reservoirs.

Copper removal from sediment microbial fuel cells with cathode with added slow-release oxygen beads: Performance, power output and microbial communities

Sediment microbial fuel cells can generate electrons by degrading organic contaminants in a sediment environment, promoting the migration of copper ions from the sediment to the cathode. They can thus be used to remove copper ions from sediment. Biochar-based oxygen-releasing beads were developed and added to the cathode in sediment microbial fuel cells to treat copper-contaminated sediment. The slow release of O2 from the oxygen-releasing beads and the adsorption of copper ions by the biochar increased the output voltage, degradation of organic pollutants and removal of copper ions by the sediment microbial fuel cells. The power density of the sediment microbial fuel cell with 10 g beads at the cathode was 66.2 mW/m2, which is 2.3 times that of without oxygen-releasing beads. The recovery percentage of copper ions in sediment microbial fuel cells with oxygen-releasing beads was 51.2%, which is 1.4 times the value, 34.8%, for sediment microbial fuel cell without beads. Therefore, adding oxygen-releasing beads improved the voltage output of the sediment microbial fuel cell and accelerated the migration of copper ions, solving the problem of low mass transfer in the sediment. Accordingly, significant amounts of copper compounds are formed on the cathode and surfaces of biochar-based oxygen-releasing bead, confirming that this technology can be effectively used to remediate heavy metal-contaminated sediment and to generate electricity.

Heavy metal contamination in beach sediments as a result of sewage outlet and waste residue dumping in Qingdao, China.

Heavy metal pollution on beaches due to enhanced human activities has received attention. This study takes four beaches in China as examples to study the characteristics of heavy metal pollution. The results show that most beach sediments have a certain degree of heavy metal accumulation as a result of human activities, except for the sediments of No. 1 beach. The beaches in order of the degree of pollution were No. 3 beach > Shilaoren beach > No. 2 beach > No. 1 beach. Three of the four studied beaches show contamination with As, Cr, Fe, Ni, Pb and Zn. Sewage outlets are the main sources of these pollutants, but the high levels of Zn and Fe are caused by coal cinder dumping at one beach, and the high levels of Ni are due to the coating of fishing boats at another beach. Heavy metal pollution occurs in areas near pollutant sources or at the high or low tide lines due to waves and tides. Heavy metals also diffuse vertically, resulting in contamination at certain depths. The distribution of heavy metals over ten years showed that most of the pollutants on cape-bay beaches are difficult to diffuse outward, which indicates that a special pollutant management plan needs to be developed for such beaches.

Heavy Metal Contamination of Sediments from an Exoreic African Great Lakes’ Shores (Port Bell, Lake Victoria), Uganda

Lake Victoria (L. Victoria) is the largest African tropical and freshwater lake, with one of the highest pollution levels, globally. It is shared among Uganda, Kenya and Tanzania, but it is drained only by the river Nile, the longest river in Africa. Though environmental studies have been conducted in the lake, investigations of the heavy metals (HMs) contamination of sediments from fish landing sites and ports on the Ugandan portion of L. Victoria are limited. In this study, sediments of an urban, industrial and fish landing site (Port Bell) on L. Victoria, Uganda was investigated to establish its HMs pollution levels and potential health risks to humans and ecosystems. Sediment samples were collected in triplicate (n = 9) from three different points of Port Bell, digested and analyzed using atomic absorption spectrometry for the presence of these HMs: copper (Cu), lead (Pb), cadmium (Cd) and chromium (Cr). The average daily dose through dermal contact and hazard quotient (HQ) were calculated to assess the health risk that is associated with dredging works (lake sand mining). Four geochemical enrichment indices: contamination factor (CF), geo-accumulation index (Igeo), pollution load index (PLI) and potential ecological risk (PERI) were used to quantify the contamination of the HMs in the sediments. The results showed that the mean HM content of the samples ranged from: 6.111 ± 0.01 to 7.111 ± 0.002 mg/kg for Cu; from 40.222 ± 0.003 to 44.212 ± 0.002 mg/kg for Pb; from 0.352 ± 0.007 to 0.522 ± 0.010 mg/kg for Cr; from 3.002 ± 0.002 to 3.453 ± 0.003 mg/kg for Cd. Health risk assessments indicated that there are no discernible non-carcinogenic health risks that could arise from the dredging works that are conducted in the study area as the indices were all below one. The contamination factors that were obtained suggest that Cd has reached a state of severe enrichment in the sediments (CF &gt; 6). An assessment using Igeo established that the sediments were not contaminated with regards to Cu and Cr, but they exhibited low-to-median and median contamination with respect to Pb and Cd, respectively. Though the pollution load indices show that the contamination levels raise no serious concerns, the potential ecological risk indices show that there is considerable pollution of the Port Bell sediments, particularly with regard to Cd. Upon examination using multivariate statistical analyses, Cd and Cr showed a strong correlation which alluded to their introduction from anthropogenic sources. Based on the sedimentary HMs concentrations and the environmental indices that are employed in this study, it is recommended that the spatial variations in the concentrations of the HMs in water, sediments and biota should be monitored.