Cd In Sediments Research Articles

Heavy metals (Pb and Cd) contents in the seawater and sediment in Panjang and Pamujaan Besar Islands, Banten Bay, Indonesia

The industrial activities in the coastal area of Banten Bay harmed water quality and tourism aesthetics. This study aims to determine the accumulation of heavy metals Pb and Cd in the water and sediment, which was conducted for 3 months from May until July in 2019 in Pulau Panjang and Pamujaan Besar. Data were collected by using the purposive sampling method. The water samples were studied using Van Dorn Water Sampler, while sediment samples were undertaken using Peterson Grab. The concentration of Pb and Cd in water and sediment were analyzed at the Environmental Laboratory of the Department of Aquaculture. Those Concentrations in waters and sediments were the highest in June than in other months. In general, the water quality was still classified as normal because it was under the quality standards of the Decree of Ministry of Environment No. 51 of 2004. Heavy metal in Banten Bay fluctuated while Pb exceeded the quality standard in June and decreased in May and July. While Cd metal in May and June exceeded the quality standard and then declined in July. Those concentrations were still below the standard limits of the Canadian Council of Ministers of the Environment 2001.

DISTRIBUTION OF HEAVY METALS IN RESIDUAL SEDIMENTS FROM TIGRIS AND EUPHRATES AND SHATT AI- ARAB RIVER

Sediment samples were taken from six location in Tigris, Euphrates and Shatt AI-Arab River during 2021- 2022, sample were extracted to determine the heavy metals (Cd, Cu, Fe, Pb, Mn, Ni and Zn) in Residual sediment of these samples by using the inductively coupled plasma atomic emission spectrometer (ICP). The analysis was also determined percentage of total organic carbon and grain size. The results of the concentrations in the Residual phase as follows (Fe> Mn> Cu > Pb> Zn> Ni >Cd) was (811.71, 90.49, 72.47, 67.34, 64.44, 38.52,25.54) dry weight. The results showed that the concentrations of the Metals were high, except for nickel and cadmium, which were relatively few, as for of total organic carbon concentrations high value (TOC %) It was (7.2 µg/g) at the six station during winter while the lowest value was (2.0µg/g) at the first station during summer. The grain size analysis was mainly silt and clay are the most predominate in the study area. Geo Accumulation Index (I-geo) for heavy elements in the sediments was also determined, and it showed that the yearly rate of the concentrations of the metals varied between the lowest value (-6.895) of Iron and the maximum value (6.826) for cadmium. Additionally, it was determined the enrichment coefficient (EF) for the heavy elements in the sediments, where the annual rate of the metals ranged between the lowest value (3.26) for manganese and the highest value (10488.14) for cadmium, and was accounted the Contamination factor (CF)for the heavy metals in the sediments, where the annual average of the metals ranged between the lowest value (0.012) for Iron and the highest value (170.26) for cadmium. These results showed that organic matter pollution was mainly from direct discharge of domestic wastewater into Tigris, Euphrates, and Shatt al-Arab river.

Metal accumulation in two crab species from the Woji Creek (Nigeria) and human health risk assessment due to crab consumption: Callinectes sapidus and Cardisoma armatum

This study evaluates the concentrations of Cd, Cr, Pb, Ni, As and Cu in water, sediment and tissues (gill, muscle, hepatopancreas) of two crab species (Callinectes sapidus and Cardisoma armatum) collected from the Woji Creek in Niger Delta, Nigeria. As well as the health risk of consuming the crabs was determined. Mean values of metals in surface water revealed concentrations (mg/L) of a trend of Pb (3.252) > Cu (2.328) > Cr (1.590) > Cd (0.146) > Ni (0.109) and in sediments, the trend was in the order Pb (140.930) > Ni (37.481) > Cr (29.984) > Cu (21.001) > Cd (8.910). Hepatopancreas of the crabs accumulated higher concentrations of Cd and Pb; with mean concentrations of Cd and Pb of 0.110 ± 0.008 mg/kg and 1.364 ± 0.060 mg/kg in Callinectes amnicola, and 0.112 ± 0.008 mg/kg and 0.735 ± 0.026 mg/kg in Cardisoma armatum respectively. In the tissues of the three crab species, Pb and Cr were highest; while As was very low in the crab species. The HI was below 1 for males and females (adults and children) which indicates no risk to health from consumption of the edible crab species. Although the risk due to the consumption of these is low, they could be a dietary source of chronic doses of metals to humans.

Contamination by heavy metals from mining activities: An ecological impact assessment of Mura and Kimpulande Rivers, Democratic Republic of the Congo

The contamination levels and distribution of heavy metals were assessed in riverbed sediments and water column samples from Mura and Kimpulande Rivers, both impacted by copper-cobalt and gold mining activities. Analyses were performed using inductively coupled plasma-mass spectrometry (ICP-MS), atomic absorption spectrometry (AAS), and atomic fluorescence spectrometry (AFS). Results showed high concentrations of Ni, Cu, Zn, As, Cd, and Hg in water samples. The concentrations of As, Cd, and Hg in water from both rivers exceeded the limits set in Democratic Republic of the Congo (DRC) legislation on requirements for mine water discharges. High concentrations were found also for Cu, Cr, Zn, As, Cd, Pb, and Hg in river sediments and were assessed against sediment quality guidelines for the protection of aquatic life. The Enrichment factor (EF) and the Geoaccumulation index (Igeo) values revealed extremely severe enrichment of Cu, Co, As, and Cd and extreme pollution by Cu and Co in sediment samples demonstrating high contamination of these rivers. The results from calculated ecologic risk factors revealed that aquatic ecosystems in the investigated rivers are at risk. Therefore, a review of current mining practices is needed and the urgent enforcement of good practices is recommended in order to protect the environment and public health.

Distribution and contamination assessment of heavy metals in soils and sediments from the Fildes Peninsula and Ardley Island in King George Island, Antarctica

Concentrations of heavy metals (Cu, Pb, Zn, Cd and Cr) in surface soils and sediments collected in 2008 from 37 sampling sites in the Fildes Peninsula and Ardley Island were detected by atomic absorption spectrometry. The total contents of Cu, Pb, Zn, Cd and Cr ranged, respectively, from 61.36 to 562.2 mg/kg, 0.52 to 1.95 mg/kg, 54.61 to 577.9 mg/kg, 0.04 to 3.76 mg/kg and 6.83 to 25.9 mg/kg in soils and from 58.55 to 498.3 mg/kg, 0.60 to 2.51 mg/kg, 56.22 to 345.9 mg/kg, 0.07 to 5.77 mg/kg and 7.76 to 39.5 mg/kg in sediments. The geo-accumulation index and the pollution load index were calculated to evaluate the environmental effects of heavy metal pollutants, Cu, Zn and Cd, in the study area. Soils and sediments from Ardley Island were found to be moderately polluted with the studied metals. Pearson’s correlation analysis and principal component analysis were applied to assess the distribution pattern and potential source of heavy metals. The results suggest that Cu, Zn and Cd in the study area originated from both the lithogenic sources and penguin guano, while Pb and Cr were probably derived from lithogenic sources.

Distribution and ecological risk of heavy metal(loid)s in surface sediments of the Hai Phong coastal area, North Vietnam

ABSTRACT Surface sediment samples were collected from the Hai Phong coastal area, and grain size and heavy metal content were analyzed to estimate the effects of natural and anthropogenic activities. The area comprised five sediment types: fine sand, very fine sand, very coarse silt, coarse silt, and medium silt. Ten heavy metal(loid)s (Fe, Cu, Pb, Zn, Cd, As, Cr, Co, Mn, Mo) were assessed. The average concentration of followed the order of Fe > Mn > Zn > Pb > Cu > Cr > As > Co > Mo > Cd. Cu, Pb, and As were over Interim Sediment Quality Guideline (ISQGs), while Cr, Zn, and Cd were below ISQG levels. Three sediment groups with three levels of heavy metal(loid)s were identified: group 1 was distributed in the river and nearshore, with coarse silt and the highest heavy metal(loid) concentration; group 2 was distributed in the river, nearshore, and offshore, with very coarse silt and high heavy metal concentrations; and group 3 was distributed in the river and offshore, with very fine sand and the lowest heavy metal concentrations. Runoff from the mainland had a significant effect with a high contamination of As, Cu, and Pb in Hai Phong coastal area.

A Food-Safety Risk Assessment of Mercury, Lead and Cadmium in Fish Recreationally Caught from Three Lakes in Poland.

Simple SummaryThe research aimed to determine the content of lead (Pb), cadmium (Cd), and mercury (Hg) in water, sediment, and freshwater fish species roach (Rutilus rutilus), perch (Perca fluviatilis), and pike (Esox lucius) from the Dratów, Syczyńskie, and Czarne Sosnowickie lakes located on Polesie Lubelskie, Poland, as well as a food safety assessment for the consumer. Pb and Cd were measured by graphite furnace atomic absorption spectrometry, while Hg was measured by cold vapor atomic absorption spectrometry. The research results showed that both the waters and the sediments of the studied lakes are characterised by a low concentration of Pb, Cd, and Hg, which indicates the lack of a moderate influence of anthropopressure on these reservoirs. The range of heavy metal contents in the muscles of roach, pike, and perch for Pb was 0.0399–0.1595, 0.0305–0.0920, and 0.0296–0.1057 mg kg−1, respectively; for Cd 0.0014–0.0095, 0.0010–0.0015, and 0.0020 mg kg−1, respectively; and for Hg 0.0123–0.0499, 0.0185–0.0255, and 0.0216–0.0583 mg kg−1, respectively. The content of heavy metals in fish muscles was low and conformed to requirements as defined in the European Union (EU) food legislation. The health risk assessment with regard to the heavy metal contents in the muscles of fish confirmed the safety of this food for consumers.Heavy metals are introduced into water due to anthropogenic activities and can significantly affect an entire ecosystem. Due to their close integration with the water environment, fish are a sensitive indicator of contamination. In addition, fish is an important element in human diets, therefore, monitoring the concentrations of metallic contaminants in their meat is particularly important for food safety. This study aimed to assess the pollution of water ecosystems with selected toxic heavy metals in lakes Dratów, Czarne Sosnowickie, and Syczyńskie. The concentration of Pb, Cd, and Hg in water, sediment, and freshwater fish muscle tissue was determined, and a food safety assessment was performed. The analysis of water and sediments showed that the sediments were characterised by a significantly higher concentration of heavy metals. Presumably, this ecosystem element plays an important role in the uptake of heavy metal contaminants by fish whose levels were higher in planktonophagous and benthophagous fish species as compared to predatory fish. The food safety assessment showed that amounts of heavy metals in the muscle tissue posed no threat to the health of consumers ingesting that fish species, neither individually (THQ) nor collectively (TTHQ).

Fe oxides and fulvic acids together promoted the migration of Cd(II) to the root surface of Phragmites australis

Dissolved organic matter (DOM) or iron/manganese (hydro)oxides were important factors in the migration of Cd in sediments of wetlands. DOM and Fe oxides simultaneously affect the longitudinal and transverse migration of Cd in wetlands sediments of plants was still unclear. In this study, a 14-day rhizobox experiment was conducted and the result showed that the rhizosphere effect of Cd migration was only limited to the upper layer of sediments (− 2 to − 4 cm). Fe with fulvic acid (FA) simultaneously existed can precipitate Cd(II) from supernatant to sediments downward. Fe oxides at sediment concentration could effectively prevent Cd(II) from migrating to root surface (0.21 vs 0.02 at%). While Fe oxides with FA together at sediment concentration could effectively promoted the migration of Cd(II) to root surface (0.07 vs 0.08 at%). The formation of organo-metallic complexes of Fe in the presence of FA profoundly proved this finding (increased by ~33.0%). And the polysaccharides and aromatics in organic matter were the chief functional groups participating in the incorporation of Cd and Fe oxides. The findings reveal the migration rules of Cd(II) in sediments by FA and Fe oxides and give an insight into the mechanisms of Cd(II) migration to the root surface around wetland plants.

Water-sediment regulation scheme of the Xiaolangdi Dam influences redistribution and accumulation of heavy metals in sediments in the middle and lower reaches of the Yellow River

Water and sediment regulation by dams influence the erosion, deposition, and transport of sediments, which should cause the redistribution and accumulation of contaminants. In this study, we investigated the impacts of the water-sediment regulation scheme (WSRS) of the Xiaolangdi Dam (XLD) on the distribution and accumulation of six heavy metals (HMs) (Cr, Ni, Cu, Zn, Cd, and Pb) in sediments in the Yellow River. Our results showed that the concentrations of HMs were higher in sediments in the study area compared to background levels, and the accumulation of HMs mainly occurred in the downstream reaches during the WSRS. However, following the WSRS, the HMs were mainly distributed in the reservoir area. While not significantly different between the reservoir area and downstream reaches, HM concentrations varied spatially and were significantly different (p < 0.05) between seasons. Accumulation of HMs occurred in sediments in the study area, particularly Zn and Cd in the downstream reaches in post-WSRS seasons, and was driven by agricultural and urban industrial activities. The accumulation of Cd induced a very high contamination level and ecological risk of sediments, while Pb induced a considerable contamination and moderate ecological risk in the downstream reaches in the post-WSRS II season. In conclusion, the WSRS led to high HM concentrations in downstream reaches during the WSRS, whereas the XLD led to high HM concentrations in the reservoir area after the WSRS. These results are critical for better understanding the effects of the WSRS on contaminants and for informing the management and restoration of regulated rivers.

The role of Mineral Salts Company in pollution of Mighan playa sediments with heavy metals by contamination indices and multivariate analysis methods, Arak, Iran

Heavy metal concentrations were investigated for 30 sediments collected from different regions of Mighan playa/lake. The means of Cr, Cu, Ni, Pb, Zn and Cd in sediments of playa/lake were much lower than the soil guideline values of Iran and background values of region (BVR). However, the maximum concentrations of Cr, Cu, Ni, Pb, Zn and Cd were higher than BVR. Only 7% of Cr, Cu, Zn, 27% of Ni, 14% of Pb and 38% of Cd concentration exceeded the BVR. The heavy metal Cr, Zn, Ni and Cd are the most important metals in different land use. About 11% of the samples in the lake land use contain Cr, Ni, Pb and Zn has concentration higher than BVR. The concentration of Cu and Pb in 33% and 67% samples is exceeded the BVR in Tail of Mineral Salts Company. The spatial distribution patterns of Cr, Cu, Ni, Pb, Zn and Cd were generally similar and increase from Mighan playa/lake to the Arak city and mainly affected by anthropogenic sources. Among the six types of land use, the concentrations of Cr, Ni, Zn and Cd in the range land and wastewater sludge were significantly higher than those in the other land use (p <0.05). In factor analysis, Cr, Ni, Zn in factor1, Cd in factor2, Pb, Zn in factor3 were originated from the municipal sewage, industrial plants activities and Arak urban traffic.

Remediation of As and Cd contaminated sediment by biochars: Accompanied with the change of microbial community

As and Cd pollution in sediment has posed a potential threat to ecosystem owing to their high toxicity. Fixing heavy metals and transforming their speciation into stable forms can be a sustainable method. In this study, nine biomass feedstocks were pyrolyzed into biochars for immobilization of As and Cd in sediment, and the accompanied changes in the microbial community were analyzed to evaluate their effect on bioavailability. The heavy metal immobilization capacity of biochars in sediment were assessed by measuring the change of As and Cd concentrations in aqueous phases (overlying water (COW) and pore water (CPW)) and the leachate of Toxicity Characteristic Leaching Procedure (TCLP), and metal speciation after biochar treatment. The maximum reduction of As and Cd concentrations could reach 95% and 78% (COW), 73% and 59% (CPW), 81% and 37% (leachate), respectively, and the F1, F2, F3 fraction (bioavailable form) of As and Cd significantly decreased (up to 18.0%) in the biochar-treated sediments. The ACE (Abundance-based Coverage Estimator) and Shannon index results revealed that biochars efficiently enriched the microbial biodiversity and population in the sediment. Water hyacinths biochar (WHB) exhibited the better performance among all biochar samples mainly due to the abundant oxygen-containing functional groups on the surface and the higher O/C. The overall results highlighted the inhibition effects of biochar on heavy metal mobility and bioavailability, and helped to provide guidance for optimization of biochars for sediment remediation.

Environmental impact on the natural resources of an area affected by mining activity in Bolivia: a geochemical evaluation of soils and sediments

The current methods used in Bolivia to extract gold using the amalgamation process with mercury result in environmental contamination and a risk to human health. The objective of this study was to determine Hg, As, Cu, Cd, Pb and Zn concentrations in soils and sediments from three mining districts. Results showed As and Hg concentrations were higher in the topsoil than in the sub-surface soils in the Sunchullí-Viscachani area, indicating active As/Hg atmospheric deposition, where concentrations exceeded the threshold levels. In addition, concentrations of Cd and Zn largely exceeded the threshold levels in the Katantica and Sural mining districts. In addition, the Sunchullí and Viscachani lagoon sediments were contaminated by Hg, As, Cd, Zn and Cu, whilst Katantica lagoon showed high concentrations of Zn, Cd and Hg, and high levels of As, Zn and Cu were reported in the Sural lagoon. Our results showed that the Cu, Pb, As and Hg concentrations in sediments in the Sunchullí river; As, Hg and Cu in the Pelechuco river, and As and Hg in the Rayo Rojo river all come from direct mine discharges into the rivers. These high concentrations of metals and metalloids must cause an impact on the aquatic ecosystems and human health. Therefore, there is a need to study the availability and speciation of metals and metalloids in soils and sediments to better understand the cycling of these elements and their transfer to the food chain.

Assessment of heavy metals distribution in a coastal environment of Versova coast, Mumbai, India

The existence of heavy metals namely, copper, chromium, and cadmium was studied in coastal waters off Versova, Mumbai. Monthly sampling was carried out from October 2012 to March 2013 across 36 stations. Concentrations of Copper (Cu), Cadmium (Cd) and Chromium (Cr) were measured using the Atomic Absorption Spectrophotometry (AAS). The concentration of dissolved elements in surface water varied from 0.01 to 0.03 mg/l. Concentrations of dissolved elements in sub-surface waters were as follows: Cu (0.01 to 0.02 mg/l), Cd (0.02 to 0.03 mg/l) and Cr (0.02 to 0.03 mg/l). The concentrations of Cu, Cd and Cr in suspended solids of the surface water were 0.82 – 1.68, 5.22 – 10.24 and 3.26 – 16.03 mg/kg, respectively, while their concentrations in suspended solid obtained from the sub-surface water were 2.77 – 4.29, 3.24 – 10.10 and 1.91 – 5.67 mg/kg, respectively. The concentrations of Cu, Cd, and Cr in sediments were 74.52 – 112.81, 3.02 – 22.88 and 65.05 – 107.74 mg/kg, respectively. The physico-chemical parameters of water and sediment were analyzed to understand the temporal distribution of heavy metals.

Physicochemical properties, total hydrocarbon content, and trace metals of water and sediments from major River Estuaries within the Niger Delta Region of Nigeria

Water and sediment samples from Cross River, Imo River, and Qua Iboe River Estuaries were collected and treated using standard analytical procedures. The samples were analyzed for their physicochemical properties, total hydrocarbon content (THC), and trace metals. Results obtained revealed that, the mean levels of total suspended solids (TSS), total dissolved solids (TDS), turbidity, colour, biochemical oxygen demand (BOD), THC, cadmium (Cd), iron (Fe), nickel (Ni), lead (Pb), and zinc (Zn) in water were higher than their acceptable limits in Nigeria. Whereas, the mean levels water pH, electrical conductivity (EC), dissolved oxygen (DO), nitrate, sulphate, phosphate, and copper (Cu) were within their acceptable limits. The results obtained also revealed that, the mean levels of nitrate, THC, and Fe in sediments were higher than their recommended limits. While the levels of pH, EC, sulphate, phosphate, Cd, Cu, Ni, Pb, and Zn in sediments were within their recommended limits. This study indicated that the anthropogenic activities by oil and oil-related companies within the Niger Delta Region of Nigeria may have contributed significantly to the high level of toxic substances in the water channels within the zone. The results obtained revealed that, the direct or indirect exposure to untreated water from the studied water channels may result in serious health challenges. Hence, the environment should be closely monitored to forestall a devastating situation in the region.

Contamination and ecological risk assessment of heavy metals in water and sediment from hubs of fish resource river in a developing country

River water and sediment embody environmental characteristics that give valuable information about the eco-environment. Due to rapid unplanned urbanization and industrialization, the aquatic environment of any urban river can be seriously polluted by heavy metals. Four heavy metals (As, Cr, Cd, and Pb) were analyzed in surface sediments and water from the Kirtankhola River located in the coastal area of Bangladesh. The decreasing pattern of metals was observed as Cr > Pb > As > Cd in both water and sediment. The heavy metal ranges were 1.67–7.31, 12.64–45.69, 0.01–1.59, and 8.03–35.68 μg/L in the water and 2.09–6.89, 14.76–47.08, 0.01–1.77 and 6.37–41.43 mg/kg in sediments for As, Cr, Cd, and Pb. The number of metals tested in water samples surpassed the acceptable limits of drinking water quality, indicating that water from this river is not safe for drinking and cooking and could pose a risk to the riverine ecosystem. The pollution load index (PLI) values were close to one, indicating that the sediment of the study river was low contamination. Contamination factor (CF) has reported that As, Cd, and Pb have been moderate to extremely polluted by sediment samples and metals level implied that the condition is much alarming and probably severely affecting the aquatic ecology of this riverine ecosystem.

Effectively reducing the bioavailability of heavy metals in disturbed sediment with biochar: In-situ remediation

The effect of biochar, derived from Phyllostachys pubescens (PP), on the bioavailability and release fluxes of Cd, Cu, and Zn in disturbed sediments was investigated. The content of Cd, Cu, and Zn in overlying water and pore water sharply increased after sediment disturbance. When biochar dose exceeded 2.96 kg/m2, the maximum amount of Cd, Cu, and Zn in the overlying water was significantly decreased, and a 5 cm biochar layer was formed. Release fluxes of Cd2+, Cu2+, and Zn2+ at the new sediment-water interface were negative diffusion fluxes, which reached maximum values of −0.61, −8.31 and −93.57 μg∙(m2d)−1, respectively. The bioavailability of Cd, Cu, and Zn, measured by diffusive gradients in thin film (DGT) probes, reached 0.92, 5.28 and 34.71 μg∙L−1 in sediment when the biochar dose was 14.78 kg∙m−2, which led to a reduction in [Cd]-DGT, [Cu]-DGT, and [Zn]-DGT by 46.51%, 71.54%, and 61.38%, respectively, compared with blank. Bacterial community analysis showed that low dose treatment(2.96–5.91 kg∙m−2) increased the Chao1 and Shannon of bacterial communities, while high dose treatment (8.87–14.78 kg∙m−2) showed negative effect. Overall, the PP biochar can be used to immobilize heavy metals in disturbed sediments as an economically and feasible method in field.

Speciation and mobility of heavy metals in the Yundang Lagoon catchment surface sediments after 30 years of continuous remediation and management at Xiamen in China

ABSTRACT The present study emphasised the speciation and mobility of heavy metals (Cr, Mn, Ni, Cu, Zn, As, Cd, and Pb) in sediments of the Yundang Lagoon catchment (YLC) at Xiamen in China. The maximum total metals concentrations of Cr, Cu, Zn, Cd, and Pb were higher than the class I pollution level of China Marine Sediment Quality values. Average total metals concentrations of Cu, Zn, Cd, and Pb were greater than world average shale values. The highest average percentages of Cr (68.01%), Mn (39.14%), Ni (61.32%), and As (74.09%) were found in the residual fraction, while Cu (50.69%) was the highest in the oxidisable fraction. Furthermore, the greater percentages of Zn (37.65%), Cd (48.98%), and Pb (47.52%) were bound in the reducible forms in YLC sediment. Total organic carbon (TOC) showed a strong correlation with heavy metal fractions, suggesting that TOC could be a carrier of heavy metals within alkaline urban sediment. The risk assessment code values for Cd, Mn, and Zn indicate that these metals could pose a medium to a high potential risk to the aquatic organisms. However, the present remediation strategy should be continued with more focus on reducing urban runoff and domestic discharge into the lagoon.

Pollution and Risk Assessment of Heavy Metals in the Sediments and Soils around Tiegelongnan Copper Deposit, Northern Tibet, China

The surface sediments of the Rongna River and the surface soils around the Tiegelongnan copper deposit were collected, and the heavy metals Cu, Zn, Pb, Cr, Cd, As, Hg, and Ni were measured for their concentrations and health risk assessment. When the Rongna River passed through the Cu deposit area, the concentrations of Cu, Zn, As, Cd, Ni, and Hg in the surface sediments increased significantly, and the concentrations of Cu, Zn, and As exceeded the corresponding Grade II environmental quality standard. The heavy metals in the soil of the mining area were greater than the background value of the soil in Tibet. The geoaccumulation index indicated that the sediments of the river entering the mining area were very highly polluted by Cu and moderately polluted by Cd and Zn, and the soils in the mining area were moderately polluted by Cu. The potential ecological risk (PER) indices revealed that the sediments of the river entering the mining area had significantly high ecological risks, while the PER of the sediments away from the river section of the mining area was low, and the PER of the soils around the Cu deposit was moderate. The results of the health risk assessment indicated that the noncarcinogenic risks of heavy metals in sediments and soil of the mining area were within the acceptable range for adults and children. However, the carcinogenic risk of As and Cd in the sediment and As in the soil exceeds the relevant national standards, which may pose a certain risk to human health.

Ecological risks associated to trace metals of contaminated sediments from a densely urbanized tropical eutrophic estuary.

The sediment contamination by trace metals in coastal aquatic ecosystems is a worldwide environmental problem, since metals can be toxic, persistent, and bioaccumulated. In case of natural events, such as storms, or anthropogenic activities, like dredging, the sediment resuspension to the water column occurs and can solubilize metals, probably increasing their bioavailability and consequently the risk to aquatic life. This study evaluated the bioavailability on reactive trace metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in estuarine sediments from Iguaçu and Meriti Rivers, both in the drainage basin of Guanabara Bay (Rio de Janeiro, Brazil). Additionally, a discussion about the anthropogenic interference throughout time of six short sediments cores, calculating three different indexes (contamination factors, CF; potential ecological risk index for a single heavy metal, Eif for short; potential ecological risk, PERI) was performed. It was considered as reactive phase, the metal concentrations obtained using a weak acid extraction (in HCl 1mol L-1 solution). Zn presented high concentrations after resuspension, being above effect range medium (ERM) (52.81 to 1337.4mgkg-1). The CF indicated very high contamination degree for Cu (14.62 to 17.96) and Zn (27.80 to 35.85) for both rivers. The Eif for short presented higher risk to Cu and Zn for Iguaçu and Meriti rivers. PERI index classified Meriti River samples as severely contaminated (238.10 to 351.62).

Cadmium concentration in water and sediment from lake Lau Kawar, North Sumatra

Heavy metals are easy to bind organic matter and settle to the bottom of the waters and unite with sediments, which is cadmium. Cadmium (Cd) is found from volcanic eruptions, from various human activities, and is carcinogenic. This study aims to analyze the concentration of cadmium in water and sediment in Lake Lau Kawar. Water samples were collected by purposive sampling at three stations using Horizontal Bottle samples. Sediment samples were collected compositely using an Eckmann grab then analyzed by the Atomic Absorption Spectrophotometer method. Descriptive data analysis used comparative quantitative methods, namely comparing the level of cadmium in water and sediment in Lau Kawar Lake with the quality standards set by WHO and IADC/CEDA. The water quality in Lake Lau Kawar is in good condition. The concentration of heavy metal Cd in water and sediment still meets the established water quality standard criteria. The source of Cd contamination in the lake, which comes from the volcanic ash of Mount Sinabung, is only carried in low quantities. The largest source of contamination comes from the activities of residents as fertilizers and pesticides used on agricultural land.