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The quality of sediments in the mixing zone of river freshwater and marine saline water as an important geochemical barrier for potentially toxic elements (PTEs) remains poorly understood. This study aims to analyze the current pollution with PTEs and associated ecological risks in sediments of the Don River delta and the surrounding area of the Taganrog Bay of the Sea of Azov (Russia). The PTE content was determined in fifty-four collected samples using the WDXRF and assessed using geochemical and ecotoxicological indicators. The source of Cr, Mn, Ni and Pb is mainly river runoff, and Cu, Zn and Cd are from a variety of anthropogenic sources. As shown by the assessment of the geoaccumulation index (Igeo), single pollution index (PI) and contamination factor (CF), these elements are the priority pollutants. According to these estimates, high and very high contamination of sediments in the estuarine zone of the Don River with Cd and Pb was detected in 72–94% and 2–57% of samples, respectively. However, environmental risks are determined almost exclusively by the level of Cd. Total contamination as assessed by the Nemerow pollution index (NPI), modified degree of contamination (mCd) and metal pollution index (MPI) is of concern in 83–98% of the samples studied. The most heavily polluted sediments are in the vicinity of residential areas of the Taganrog Bay. Despite the lower average pollution levels of deltaic sediments, freshwater biota are exposed to higher potential toxic risks of adverse effects by PTE, particularly from Ni and Pb. Thus, the complex hydrological regime and uneven anthropogenic impact predetermine the geochemical state of the sediments of the estuarine zone of the Don River. [ABSTRACT FROM AUTHOR]

Baiyangdian Lake, recognized as the largest freshwater body in northern China, plays a vital role in maintaining the regional eco-environment. Prior studies have pointed out the contamination of sediments with heavy metals, raising concerns about eco-environmental challenges. Therefore, it is imperative to evaluate the current pollution levels and ecological threats related to heavy metals found in the sediments of Baiyangdian Lake as well as in its inflow rivers. In May 2022, surface sediments with a depth of less than 20 cm were analyzed for Cu, Zn, Pb, Cr, Ni, As, Cd, and Hg to determine the pollution status, identify sources of pollution, and evaluate potential ecological risks. A range of evaluation methods used by predecessors such as geo-accumulation index (Igeo), enrichment factor (EF), ecological risk index (RI), sediment quality guidelines (SQGs), positive matrix factorization (PMF), absolute principal component score-multiple linear regression model (APCS-MLR), chemical mass balance (CMB), and UNMIX model were analyzed. After comparison, multi-methods including the geo-accumulation index (Igeo), absolute principal component score-multiple linear regression model (APCS-MLR), ecological risk index (RI), and sediment quality guidelines (SQGs) were utilized this time, leading to a better result. Findings reveal that pollution levels are generally low or non-existent, with only 1.64% of sampling sites showing close to moderate pollution levels for Cu, Pb, and Zn, and 4.92% and 1.64% of sites exhibiting close to moderate and moderate pollution levels for Cd, respectively. The main contributors to heavy metal presence are pinpointed as industrial wastewater discharge, particularly Cu, Zn, Pb, Cd, and Hg. The ecological risks are also relatively low, with 4.92%, 1.64%, and 1.64% of sampling sites demonstrating close to moderate, moderate, and strong risks in the inflow rivers, respectively. Additionally, only one site shows moderate potential biological toxicity, while the rest display non-toxicity. These findings will update our cognition and offer a scientific basis for pollution treatment and ecosystem enhancement for government management. [ABSTRACT FROM AUTHOR]

Lake Tanganyika, the second deepest lake in Africa, has a unique ecosystem that provides rich fish proteins for populations along the lake basin. With socioeconomic development and rapid population growth, Lake Tanganyika is threatened by environmental pollution. In this study, the concentrations of heavy metals, including Cr, Ni, Cu, Zn, Cd, Pb, Fe, and Mn, in the surface sediments of the inflow rivers in northeastern quadrant of Lake Tanganyika were characterized. The geoaccumulation index (Igeo) and enrichment factor (EF) were employed for heavy metal assessment. The results showed that heavy metal concentrations in the surface sediments of the inflow rivers in northeastern quadrant of Lake Tanganyika exhibited significant spatial variations. The concentration of heavy metals was the highest near urban areas, followed by the estuarine wetland and forest grassland. This indicated that heavy metal content was closely related to human activities. The concentrations of Zn, Cd, and Pb were defined as unpolluted, and the concentrations of Pb, and Fe were only slightly enriched. Principal component analysis and cluster analysis demonstrated that the heavy metals Cr, Zn, Cd, and Pb may originate from a mixture of natural sources and anthropogenic inputs, including agricultural and industrial inputs. Ni, Fe, and Mn were principally from natural sources, and Cu primarily originated from anthropogenic inputs such as vanadium iron ore mining and iron and steel smelting. These results are important for understanding the nonpoint sources of heavy metal pollution in the Lake Tanganyika Basin. [ABSTRACT FROM AUTHOR]

This study assessed the accumulation levels and ecological risks associated with seven heavy metals (As, Pb, Cd, Hg, Cu, Cr, Zn) in the surface sediments of the Bong Mieu River in Quang Nam Province, Vietnam. The sampling encompassed 10 locations (S1–S10), considering areas both impacted and less impacted by gold mining activities. The findings revealed elevated levels of heavy metal pollution and associated ecological risks attributable to gold mining. Heavy metal content varied within specific ranges: As (70.6–341.2 mg/kg), Pb (216.3–504.1 mg/kg), Hg (0.138–0.252 mg/kg), Cd (0.91–1.51mg/kg), Cu (18.3–45.5 mg/kg), Cr (10.5–19.1 mg/kg), and Zn (49.3–84.1 mg/kg). Among these elements, Hg, Cu, Cr, Zn, and Cd adhered to the acceptable limits of VNTR 43:2017/MONRE (VNTR 43:2017/MONRE: National Technical Regulation/Ministry of Natural Resources and Environment of Vietnam). However, As and Pb content at all locations exceeded these limits significantly, with As being 4.1–20 times higher and Pb 2.3–5.5 times higher. The pollution of Pb and As was attributed to waste discharge from gold mining activities, which carry substantial amounts of these metals in various forms. The Igeo indicated heavy pollution of As and Pb in the sediments. Ecological risk factors were ranked as follows: E r i (As) > E r i (Pb) > E r i (Hg) > E r i (Cd) > E r i (Cu) > E r i (Cr) > E r i (Zn). The potential ecological risk (RI) due to combined heavy metal impact varied across locations, with S2 > S8 > S9 > S6 > S7 > S10 > S1 > S3 > S4 > S5, exhibiting low to moderate risk (RI values ranging from 73.4 to 252.8). The study area demonstrated high contamination levels for As and Pb, coupled with low to moderate potential ecological risks. [ABSTRACT FROM AUTHOR]

Nutrients, organic matter (OM), and heavy metals (HMs) in lake sediments are critical elements contributing to water pollution. In April 2019, surface sediments from Wanghu Lake were collected, and the nutrient, organic matter, and heavy metal content of the sediments were determined. We mainly evaluated the sediment pollutants through four evaluation methods to assess pollution and provide a reference for pollution control in Wanghu Lake. The results indicated that the averages of total phosphorus (TP) and total nitrogen (TN) were (1045.74 ± 190.17) mg/kg, (945.27 ± 203.56) mg/kg; most of them showed serious pollution and moderate pollution, respectively. OM was (32.31 ± 5.11) g/kg. Among them, TP and OM in the northwestern Wanghu Lake were significantly higher than those in the eastern lake (p < 0.05). It shows that nutrients are greatly affected by historical aquaculture and urban human activities. TP was the most serious in the center of the lake, and the source of pollution was mainly the historical deposition. The average of Cd, Cr, Cu, Ni, Pb, Zn, Hg, and As in the sediments were 2.15, 1.09, 1.93, 1.37, 1.28, 1.49, 2.60, 1.77 times that of the soil background values of Hubei Province, respectively. Hg and Cd were the main factors contributing to the surface sediments, with levels at considerable and moderate risks, respectively. [ABSTRACT FROM AUTHOR]

The Inner Ambon Bay (IAB) is an important area for the economic development of the city of Ambon, one of only a few urban areas in eastern Indonesia. This study is intended to monitor the anthropogenic impact on IAB by employing combined rock magnetic and geochemical analyses on 20 samples collected from IAB and the surrounding rivers. Magnetic susceptibility values of samples in the IAB averaged 26.37× 10−8 m3/kg, which is relatively high and comparable to that of contaminated coastal environments. Magnetic susceptibility correlated positively with certain metals such as Cr, Co, Ni, and Mn but negatively with Hg. Geochemical analyses showed that Hg and Ag contents were relatively high but pose only moderate risk to the environment based on the geo-accumulation index. Furthermore, the potential ecological risk index (PERI) showed that there were two points that showed moderate ecological risk. Multivariate statistical analysis (principal component analysis (PCA), Pearson's correlation coefficient (PCC), and hierarchical cluster analysis (HCA)) outlined that the metallic accumulation in the sediments of IAB was related to lithological, geological, and anthropogenic impacts. Therefore, oil spills and household waste are likely major reasons for anthropogenic pollution in the sediments of the IAB.

The presence of heavy metals in rivers in the Niger Delta region has become a source of concern due to its associated health challenges. The present study was conducted to assess the risk of heavy metal accumulation in surface sediments obtained from creeks and dredged tributaries of the River Ethiope, Delta State, South-South, Nigeria. Heavy metals in the sediments were extracted using the three-step sequential extraction method of the European Commission Standard Measurement and Testing Program. The heavy metals; magnesium (Mn), iron (Fe), zinc (Zn), lead (Pb), copper (Cu), cobalt (Co), arsenic (As), chromium (Cr), cadmium (Cd) and barium (Ba) were quantified by employing inductively coupled plasma-mass spectrometry (ICP-MS). Assessment of the extent of sediment contamination was carried out by determining the contamination factor (CF), degree of contamination (Cd), modified degree of contamination (mCd), pollution load index (PLI), ecological risk factor (Er), potential ecological risk index (PI) and geo accumulation index (1 geo). Pearson's correlation coefficient and principal component analysis (PCA) were used to determine the sources and the relationship between pollutants across sediments. The values of heavy metals ranged from 12.5 mg kg-1-116 mg kg-1 and 21.6 mg kg-1-71.1 mg kg-1 in the wet and dry seasons, respectively. The trend of heavy metals for risk index (RI) in this study is Cd > Pb > Cr > Co > Zn > Cu > Mn (wet season) and Cu > Cd > Pb > Zn > Cr > Mn > Co = As (dry season). It showed that heavy metal pollution was a result of Cd for extreme contamination, while moderate to high contamination levels were due to Pb and Cu. The Pearson's correlation coefficient analysis and PCA displayed strong positive loadings for Mn, Fe, Zn, Pb, Cu and Cd across seasons as a result of high contamination levels in the study sites. The pollution load index revealed that the sediments were polluted by the metals, and the mean and median analyses revealed that the metals datasets were normally distributed, except for Cu with an irregular distribution. [ABSTRACT FROM AUTHOR]

The operation of cascade reservoir systems has altered river hydrology and sediment distribution patterns. In this study, 31 surface water and sediment samples were collected from the Heihe River from July to August in 2019 and 2020 to investigate the spatial distribution and sources of heavy metals and assess their ecological risks. The results revealed that the concentrations of heavy metals in surface water were much lower than the quality standards for surface water in China, and there were no significant differences in the natural reaches, center and tail of the reservoir. Cd in surface sediments was at a heavy contamination and high risk level, and the heavy metal pollution levels in the main streams and tributaries differed greatly, especially in the graded reservoirs with a gradual accumulation trend. This may be related to the fact that there were many fine-grained sediments in the reservoir center near the dam. Factor analysis-multiple linear regression (FA-MLR) revealed that heavy metals mainly come from natural factors and anthropogenic input, with anthropogenic inputs mainly coming from mining activities in the tributaries and industrial and agricultural activities in the main stream. HIGHLIGHTS The effects of cascade dam construction on the spatial distribution of heavy metals in surface water and sediments of Heihe River in China were systematically studied.; The operation of cascade dams has a significant effect on the spatial distribution of heavy metals in surface sediments.; Heavy metals pollution and ecological risk of surface sediments were mainly concentrated for natural river sections in tributaries.;

Article highlights Five heavy metals concentrations displayed a wide seasonal and spatial variation. The mean concentration was Cr ˃ Zn ˃ Cu ˃ Pb ˃ Cd in winter and Zn ˃ Cu ˃ Cr ˃ Pb ˃ Cd in summer. The average CF value was Cd ˃ Cr ˃ Pb ˃ Cu ˃ Zn in winter and Cd ˃ Cu ˃ Zn ˃ Pb ˃ Cr in summer, respectively. The average EF value was Cd, followed by Cu, Pb, Cr, and Zn in winter and Cd, Zn, Cu, Pb, and Cr in summer, from highest to lowest, respectively. Contamination caused by Cd was more severe than for other heavy metals in both winter and summer. Cd was the major contributor to the potential ecological risk in the study region. Multivariate statistical analyses results showed Cd and Cr was more distinct from other element in winter and summer, indicate that Cd and Cr have a mixed source include both anthropogenic and lithogenic sources.

Urmia Lake, in the northwest of Iran, is the largest body of saline water in the Middle East, which has been desiccated in recent decades. To investigate the pollution status and ecological-health risks of heavy metals and metalloids in the surface sediments of this lake, 26 sediment samples were collected along the salt marshes of the lake and were analyzed for heavy metals and metalloid concentrations. The potential ecological risk assessment was carried out using enrichment factor (EF), geo-accumulation index (Igeo), contamination factor (CF), and potential ecological risk (Eri) standard indices. The average concentrations (mg kg−1) of heavy metals and metalloids were as follows: Fe (11,714) > Sr (320.8) > Mn (274.3) > V (28.5) > Cu (24.7) > Zn (21.2) > As (17.3) > Ni (14.8) > Cr (12.6) > Pb (11) > Co (4.0) > U (1.7), Hg (0.6) > Mo (0.36). The concentrations of As, Hg, and Sr in lake sediments were higher than geochemical background values. The non-carcinogenic risks caused by heavy metals and metalloids were insignificant regarding health risks. Levels of carcinogenic risk for metal(loid)s were in the acceptable ranges (10−6–10−4). The ecological risk was low, except for As, Sr, and Hg which showed moderate to significant EF, Igeo, and CF values. Arsenic and Sr were enriched in the surface sediments in desiccated parts of the lake due to complete lake water evaporation. It seems that further drying of the lake increases the potential ecological risk of heavy metals and metalloids in the surface sediments of Urmia Lake. [ABSTRACT FROM AUTHOR]

Environmental magnetism parameters have become a useful tool in addressing environmental issues. Due to the rapid, sensitive, economical and non-destructive characteristics of environmental magnetism, the present contribution focuses on magnetism parameters as proxy for heavy metal pollution, especially from their relationship with contents of heavy metal. We evaluated heavy metals pollution and examined environmental magnetism in the Dexing section of the Le'an River. The pollution load index (PLI) of Cr, Pb, As, Cu and Zn, as well as the concentration of other heavy metals, were analyzed, and the magnetic indexes of various sediments were analyzed. The results showed that the concentrations of all heavy metals far exceeded the local background values, and that the average contamination factor of Cu was as high as 22.88, making it the element of most serious contamination. The problem of heavy metal pollution near the mine is very serious. The content of magnetic minerals in sediments of Le'an River is relatively high and the composition of magnetic minerals is relatively stable. The stable-single domin (SSD) content is high at S1 and S10, indicating that ferromagnetic mineral content is relatively rich here, which dominates the magnetic characteristics of the sample. In general, it was found that environmental magnetism indicators did not exist in the Dexing section of the Le'an River that could clearly indicate the concentration of heavy metal pollution. Only a few heavy metals can be effectively indicated by magnetic parameters. IRM-20mT and S-ratio can be used as indicators of Cr, Pb, As, Cu and Zn, but they are not accurate. The correlation between Sr and magnetic indexes IRM200mT, IRM300mT, SIRM, IRM-300mT and HIRM is significant, which can be used as an indicator of Sr concentration. IRM20mT can also be used as an indicator of Hg concentration. [ABSTRACT FROM AUTHOR]

The present study evaluated the potentials of phytoremediation and the biomonitoring of potentially toxic metals (PTMs) (Zn, Ni, Fe, Pb, and Cu) in the mangrove leaves of Rhizophora apiculata from the tropical mangrove ecosystem in the Sepang Besar River and Lukut River, Peninsular Malaysia. Overall, the present studies concluded that (a) the levels of essential Fe, Cu, and Zn in lamina are significantly (p < 0.05) higher than in MP, (b) the levels of Pb and Ni in MP are significantly (p < 0.05) higher than in lamina, (c) the lamina has better potential as a phytoremediator of Cu, Zn, and Fe, while MP is a better potential phytoremediator of Pb and Ni, (d) lamina is a potential biomonitoring agent of potentially toxic metals based on better correlation coefficients with the surface sedimentary geochemical fractions, and (e) metal uptake in the mangrove leaves and comparative levels of metals is low with reported studies. Specifically, based on bioconcentration factors (BCF), their most obtained values were considered low (<1), suggesting that R. apiculata can be considered as a low-efficiency plant for the bioaccumulation of PTM. However, the present findings also suggested that R. apiculata may be classified as a potential phytoremediator for Zn, Cu, Pb, and Ni in the leaves, as indicated by higher metal accumulation in the MP, with BCFEFLE values > 1.0; BCFAR > 1.0 for Cu, Pb, and Ni. The mangrove leaves are potential biomonitors of PTMs since positive correlations of PTMs were found between the leaves and their habitat surface sediments. Having been identified as a potential phytoremediator and biomonitor of PTMs, the present study emphasized the possibility of establishing a framework for managing the coastal aquatic ecosystems along the mangrove ecosystems of Sepang and Lukut. [ABSTRACT FROM AUTHOR]

It is of great significance to study the distribution characteristics and transport of heavy metals in complex sedimentary environments and areas with intensive human activities. This study analyzed sediment size, heavy metal contents (Cu, Zn, Cd, Cr, and Pb), organic carbon content, and sulfide content in surface sediments collected from 27 sites in Chengbei Sea. The main controlling factors of the distribution and transport of heavy metals were discussed from the perspective of sediment dynamics. The concentrations of Cu, Zn, Cd, Cr, and Pb in surface sediments were 7.9–20.5 mg/kg, 33.8–94.6 mg/kg, 0.08–0.26 mg/kg, 6.3–62.3 mg/kg, and 3–13.4 mg/kg, respectively. According to the geoaccumulation index, the study area was not polluted by the heavy metals, except for Cd, which did not pollute only areas with relatively coarse-grained sediments. Combining the results of correlation analysis, tidal residual current analysis, sediment transport trend analysis, and principal component analysis confirmed that Cu, Zn, and Cd originate from natural sources, and their distribution characteristics are mainly controlled by the grain size of surface sediments. Cr and Pb could be attributed to human activities, such as oil exploration, and their distribution characteristics were affected by sediment transport and tidal residual current. Zonation of the sedimentary dynamic environment also provided reference for the relationship between the distribution of heavy metals in surface sediments and sedimentary environments. [ABSTRACT FROM AUTHOR]

In order to strengthen the environmental control of Minjiang River Basin and support the management and control of heavy metal pollution in Minjiang Estuary, based on the measured data of 14 sampling stations in Minjiang Estuary, this paper systematically evaluated the distribution of heavy metals and their potential ecological risks in surface sediments of Minjiang Estuary by using the methods of correlation analysis, principal component analysis and potential ecological risk index. The results showed that there were significant differences in the content of heavy metals in the surface sediments of Minjiang Estuary. Except for Zn and Hg at individual stations, the concentrations of other heavy metals were accorded with first class of the national marine sediment quality. The main factor affecting the distribution of lead was industrial sewage, while the main factors affecting the distribution of other heavy metals were organic matter and sedimentary environment. The proportion of low risk and medium risk of potential ecological risk of heavy metals in surface sediments of Minjiang Estuary was 71.43% and 28.57%, respectively. Among them, the east and south of Langqi Island were medium risk areas, and the north and northeast of Langqi Island and the outside of Chuanshi waterway were low risk areas. Cd and Hg were the main heavy metal elements with potential ecological risks, which had reached a high risk level, and risk monitoring work should be strengthened.

The epicontinental seas to the east of China have become highly anthropogenically impacted due to rapid economic development in recent decades, resulting in various environmental problems, including heavy metal pollution. The Bohai Strait, as a key junction connecting the material-energy exchange between the Bohai and Yellow Seas, is extremely critical in regional pollution prevention and control. To ascertain the spatial distribution and contamination levels of heavy metals in the surface sediments of the northern Bohai Strait, a systematic investigation was conducted. Geochemical analysis revealed that the concentrations (in ppm) of heavy metal elements in surface sediments vary in the range of 4.19–77.6 for As, 0.04–0.21 for Cd, 5.1–65.7 for Pb, 0.30–39.40 for Cu, 7.77–46.50 for Ni, 1.50–86.60 for Cr, 11.70–91.80 for Zn, and 0.005–0.038 for Hg. Ecological statistics indicate that the northern Bohai Strait suffers from prominent heavy metal pollution primarily induced by As, Cd, and Pb, accompanied by relatively weak pollution of Cu and Ni. Sediments collected from the submarine depressions and the southeast region exhibit higher heavy metal concentrations, and as a consequence, more serious ecological risk. Correlation analysis indicated that the accumulations of Hg, Cr, and Zn were associated with the deposition of organic matter. Preliminary provenance discrimination suggested that the pollutants were mainly derived from the eastern parts of the North Yellow Sea, rather than the Bohai region. [ABSTRACT FROM AUTHOR]

In order to study the speciation, contamination statues, and distribution characteristic of heavy metals in the surface sediments of cascading dams, the reservoir regions of Manwan and Dachaoshan cascading dams were sampled and investigated. The speciation and its contents of heavy metals (As, Cd, Cr, Cu, Pb, and Zn) were analyzed by the modified European Community Bureau of Reference (BCR) sequential method. The ecological risk assessment of heavy metals was performed by the ratio of secondary phase and primary phase (RSP) method. The source identification of heavy metals was performed by correlation analysis (CA) and principal component analysis (PCA). The results indicated that the values of RSPcd were from heavy pollution (IV level), and those of RSPZn were from light pollution (II level) to moderate pollution (III level) in the lacustrine zone of the upper-stream Manwan dam. The values of the RSP were no pollution (I level) in the downstream of the Dachaoshan dam. The ecological risk assessment of heavy metals (Cd, Zn, and As) at the upper stream of the Manwan dam was generally higher than that at the downstream Dachaoshan dam. Cascading dams operation showed significant accumulation effects on heavy metals in surface sediments. The source identification of heavy metals showed that Cd and Zn were mainly from anthropogenic activities; As, Cu, and Pb were affected by both natural processes and anthropogenic activities; and Cr was mainly from natural processes. [ABSTRACT FROM AUTHOR]

BACKGROUND Anning is an important industrial and mining city in the upper reaches of the Yangtze River Economic Belt. It is a fulcrum for economic development and ecological civilization construction in the Central Yunnan New Area. The investigation of geochemical water system sediments and hydrogeology in the Anning area was last performed in the 1970s and the 1980s. In recent years, the impact of human production and life on the ecological environment remains unclear. OBJECTIVES Surface sediment samples from the Anning area were investigated to reveal their pollution status, spatial distribution characteristics, and potential ecological risks of river sediments. METHODS X-ray fluorescence spectroscopy, inductively coupled plasma optical mass spectrometry, gas chromatography-mass spectrometry, and other methods were used to systematically analyze the contents and distribution characteristics of major elements, trace elements, and 16 priority-controlled PAHs. Geoaccumulation index, Hankanson ecological risk index, and sediment quality criteria were used to assess the ecological risk of eight typical heavy metals (As, Cd, Cr, Cu, Ni, Zn, Pb, and Hg) and PAHs. RESULTS Results showed that the heavy metal content in the river sediments from the Anning area was higher than the background values of the national and southern rivers. The spatial distributions of the heavy metals were highly variable and uneven. Additionally, Cd, Hg, and Ad showed medium to severe potential ecological risks. The average content of ∑PAHs was 20856ng/g, and the detection rate of the 16 monomers was ~100%. The overall ecological risk of PAHs was low, and their main sources were petrochemical industry and combustion of petroleum fuels. The major risks of pollutants in the river sediments of the Anning area were mainly concentrated in the vicinity of steel plants and chemical factories in the Tanglangchuan River. CONCLUSIONS This research provides a scientific basis for local governments to strengthen key industrial point source pollution control, and reduce and control industrial sewage discharge.

Sediment samples collected from the river Shitalakhya, Bangladesh, were analyzed using atomic absorption spectroscopy (AAS) to investigate site-to-site (spatial) and seasonal (i.e., dry, pre-monsoon, post-monsoon) variation of Cr, Mn, Ni, Cu and Zn. The mean concentrations of Cr, Mn, Ni, Cu and Zn were 22.37 ± 6.09, 612.59 ± 160.08, 54.11 ± 11.21, 50.36 ± 9.40 and 103.62 ± 62.74 mg/kg in the dry, 31.58 ± 5.22, 569.71 ± 112.16, 58.35 ± 7.82, 49.93 ± 17.36 and 110.88 ± 95.83 mg/kg in the pre-monsoon and 18.09± 6.32, 567.02 ± 115.55, 50.89 ± 6.58, 39.75 ± 4.56 and 55.22 ± 11.33 mg/kg in the post-monsoon, respectively. Based on the metals’ concentrations, no considerable difference was observed among the three seasons, but the concentrations were slightly elevated in the dry and pre-monsoon compared to that in the post-monsoon with respect to site-to-site variation. Among the metals examined, concentrations of Ni and Cu were elevated because of the use of oxides of these heavy metals as catalysts in the ammonia plant. The following statistical indices i.e., Pearson correlation matrix, geo-accumulation index (Igeo), contamination factor (Cf), degree of contamination (Cd), pollution load index (PLI) and ecological risk potential (RI) factors were taken into account to assess the heavy metals contamination of the sediments. According to the values of the statistical indices for Cr, Mn, Ni, Cu and Zn, it is concluded that the study area was with low contamination while concentrations of Ni and Cu were higher than the Threshold Effect Level (TEL) and Toxicity Reference Value (TRV) values suggesting unsafe to use the sediments for vegetation and other uses.

Background: Heavy metals due to their ecological risks and high toxicity to living organisms are considered as one of the most dangerous pollutants. Therefore, the present study was conducted to investigate the level of pollution, toxicity and the ecological risks of heavy metals in the coastal surface sediments of Bushehr province using systematic review. Methods: To conduct this review study, the concentration level of heavy metals in the surface sediments of Bushehr coastal was obtained by searching for published studies during the 9 years (2012-2020) through databases (Springer, Google Scholar, ProQuest, Web of Science, SID, Magiran). Finally, a comprehensive description of heavy metal pollution, toxicity and risks in coastal sediments was investigated using various indicators. Results: As a result of reviewing the extracted studies from the databases, 24 papers were selected. The survey results showed that the order of mean concentration of heavy metals in sediments was as Zn>Ni>Cr>Cu>Pb>Cd, and the amount of metals Pollution load index in different coastal sediments ranged from 0.15 to 1.99. The order of ecological risks for metals was observed as Cd>Pb>Ni>Cu>Cr>Zn, and the potential ecological risks for metals was obtained in the range of 3.76-257.38. In addition, the results of Toxic unit analysis and modified Hazard quotient of metals showed that the degree of toxicity and risk of contamination varies from very low to severely contaminated. Conclusion: Based on the findings from the perspective of toxicity control and ecological risks of metals, it is necessary to prevent the transfer of heavy metals, especially Cd, Pb and Ni due to dominant human activities in the coastal areas of Bushehr. Also, due to the maximum pollution load and ecological risks in Bidkhon (Assaluyeh) coasts, pollution sources should be determined to effectively control and manage the entry of pollutants in this area.

Heavy metals contamination in sediments may endanger ecosystems and human health via the food chain. In fact, there is little to no understanding about heavy metal accumulation in surface sediment of one of the most economically important marine bodies for Vietnam, the Thai Binh Coast, where five large rivers co-discharge into the Gulf of Tonkin. Twenty-seven surface sediment samples were collected from the intertidal regions and analyzed for: arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), mercury (Hg), nickel (Ni), and zinc (Zn) using inductively coupled plasma mass spectroscopy (ICP-MS). The studied area exhibited a large spatial variation in the concentration of heavy metals, e.g., the dry sediment concentration of Cd was the least (0.05–0.49 mg.kg−1), whereas that of Zn was the greatest (45.4–252 mg.kg−1). Based on the geoaccumulation index ( I geo ), most of the studied heavy metals were accumulated at low pollution levels, except four locations exhibited moderately and highly polluted levels of Hg with I geo Hg values from 1.92 to 2.66. However, the high contamination factor value implicated that not only Hg but also all other detected heavy metals in this area resulted from anthropogenic activities along the coast and the river upstream. This implied the need for quick action from the government. In addition, numerous analytical methods were used to see the association between metals, total organic carbon (TOC), and particle size distribution, including Pearson correlation coefficient (P) and principal component analysis (PCA). Hg demonstrates lowest connection with TOC (PHg-TOC ~ 0) but individual heavy metal correlations are largely positive, with many reaching 1.0 (e.g., PNi-Cr = 0.89, PCd-As = 0.72, PNi-Cu = 0.76, and PCu-Cr = 0.72). From the PCA diagram, we can observe that those sampling points in the positive direction of PC1 were expected to have a high concentration of Cu, Zn, As, Ni while having extremely little sand content. [ABSTRACT FROM AUTHOR]

BACKGROUND: Anning is an important industrial and mining city in the upper reaches of the Yangtze River Economic Belt. It is a fulcrum for economic development and ecological civilization construction in the Central Yunnan New Area. The investigation of geochemical water system sediments and hydrogeology in the Anning area was last performed in the 1970s and the 1980s. In recent years, the impact of human production and life on the ecological environment remains unclear. OBJECTIVES: Surface sediment samples from the Anning area were investigated to reveal their pollution status, spatial distribution characteristics, and potential ecological risks of river sediments. METHODS: X-ray fluorescence spectroscopy, inductively coupled plasma optical mass spectrometry, gas chromatography - mass spectrometry, and other methods were used to systematically analyze the contents and distribution characteristics of major elements, trace elements, and 16 priority - controlled PAHs. Geoaccumulation index, Hankanson ecological risk index, and sediment quality criteria were used to assess the ecological risk of eight typical heavy metals (As, Cd, Cr, Cu, Ni, Zn, Pb, and Hg) and PAHs. RESULTS: Results showed that the heavy metal content in the river sediments from the Anning area was higher than the background values of the national and southern rivers. The spatial distributions of the heavy metals were highly variable and uneven. Additionally, Cd, Hg, and Ad showed medium to severe potential ecological risks. The average content of ∑ PAHs was 20856ng/g, and the detection rate of the 16 monomers was -100%. The overall ecological risk of PAHs was low, and their main sources were petrochemical industry and combustion of petroleum fuels. The major risks of pollutants in the river sediments of the Anning area were mainly concentrated in the vicinity of steel plants and chemical factories in the Tanglangchuan River. CONCLUSIONS: This research provides a scientific basis for local governments to strengthen key industrial point source pollution control, and reduce and control industrial sewage discharge. [ABSTRACT FROM AUTHOR]

The Ledong Sea Area is located on the southwest side of Hainan Island. In recent years, with the development of industrialization and urbanization, the problem of heavy metals in marine sediments has gradually become a global problem, and research on this topic is of great significance for nearshore environmental protection and coastal management. This paper analysed the heavy metal content of 97 surface sediments in the Ledong Sea, indicating unpolluted to moderately polluted and low to moderate risk. Cu, Zn, Hg, Pb, Cr, and Cd are highly correlated, with similar origins, and originate from rivers carrying industrial wastewater, domestic sewage, and weathered material from the parent rocks, which are subsequently redistributed under the action of ocean dynamics. The distribution of Hg is mainly influenced by feed and biological metabolites during the farming process. As originates from rivers carrying large amounts of agricultural pesticide and fertilizer residues. • The ocean hydrodynamics can redistribute heavy metal elements imported from rivers. • Coastal aquaculture is one of the main causes of heavy metal enrichment. • The study of heavy metal transport process is very important for pollution control measures. • The concentrations of heavy metals in the Ledong Sea area had little risk to Marine organisms. [ABSTRACT FROM AUTHOR]

Sediment samples collected from the river Shitalakhya, Bangladesh, were analyzed using atomic absorption spectroscopy (AAS) to investigate site-to-site (spatial) and seasonal (i.e., dry, premonsoon, post-monsoon) variation of Cr, Mn, Ni, Cu and Zn. The mean concentrations of Cr, Mn, Ni, Cu and Zn were 22.37 ± 6.09, 612.59 ± 160.08, 54.11 ± 11.21, 50.36 ± 9.40 and 103.62 ± 62.74 mg/kg in the dry, 31.58 ± 5.22, 569.71 ± 112.16, 58.35 ± 7.82, 49.93 ± 17.36 and 110.88 ± 95.83 mg/kg in the pre-monsoon and 18.09± 6.32, 567.02 ± 115.55, 50.89 ± 6.58, 39.75 ± 4.56 and 55.22 ± 11.33 mg/kg in the post-monsoon, respectively. Based on the metals' concentrations, no considerable difference was observed among the three seasons, but the concentrations were slightly elevated in the dry and pre-monsoon compared to that in the post-monsoon with respect to site-to-site variation. Among the metals examined, concentrations of Ni and Cu were elevated because of the use of oxides of these heavy metals as catalysts in the ammonia plant. The following statistical indices i.e., Pearson correlation matrix, geo-accumulation index (Igeo), contamination factor (Cf), degree of contamination (Cd), pollution load index (PLI) and ecological risk potential (RI) factors were taken into account to assess the heavy metals contamination of the sediments. According to the values of the statistical indices for Cr, Mn, Ni, Cu and Zn, it is concluded that the study area was with low contamination while concentrations of Ni and Cu were higher than the Threshold Effect Level (TEL) and Toxicity Reference Value (TRV) values suggesting unsafe to use the sediments for vegetation and other uses. [ABSTRACT FROM AUTHOR]

Forty-three surface sediment samples were collected in September 2019 from Tasaul Lake (Black Sea coast, Romania) to examine the metal distribution patterns, assess the level of metal contamination, and identify the pollutant sources. The determined mean metal concentrations were as follows: Al 49,772 mg/kg, Zn 84.40 mg/kg, Cr 83.70 mg/kg, V 76.45 mg/kg, Ni 42.53 mg/kg, Cu 34.27 mg/kg, Pb 26.30 mg/kg, As 12.49 mg/kg, and Hg 0.06 mg/kg. The metals in the surface sediments of Tasaul Lake displayed moderate spatial variation, with higher metal concentrations mainly occurring in the south and southeast (As, Pb, and Hg), southwest (Cu and Zn), and west of the lake (Cr, Ni, and V). Heavy metal contamination in sediments is assessed using pollution indices such as enrichment factor, contamination factor, and pollution load index. The highest CFs and EFs were determined for As (moderate to high pollution), followed by Pb (low to moderate pollution). The Cu, Zn, and Hg pollution indices showed values corresponding to low pollution levels, while Ni, Cr, and V presented the lowest indices, suggesting unpolluted sediments. Multivariate statistical analyses were performed to identify the origin of the analyzed heavy metals. Cr was predominantly sourced from lithogenic components, Ni and V originated from both natural and anthropogenic sources, and As, Cu, Zn, Pb, and Hg showed mainly anthropogenic sources such as agricultural runoff, domestic and industrial wastewater discharges, and quarrying activities. [ABSTRACT FROM AUTHOR]

One hundred and twenty topsoil (0–20 cm layer) samples and 45 surface sediment samples were collected from the riparian area and bottom of Qinggeda Lake. The content of Pb, Cu, Cr, Ni, Zn, Mn, V, and As were determined to reveal the distribution characteristics and explore the spatial dependency relationship between environmental factors (pH, conductivity, and organic matter) and heavy metals using Kriging interpolation and the geographical weighted regression model. Results showed as follows: (1) The average contents of Pb, Cu, Cr, Ni, Zn, V, and As did not exceed the Standard of National Soil Environmental Quality. However, Cu, Cr, and V were higher than the Xinjiang soil background. (2) The target elements in the surface sediments of the lake showed a decreasing trend from the center of the lake to the shore. Also, the heavy metal concentrations in the eastern part of the lake shore were significantly higher than those in other areas, and the highest concentrations appeared in the paddy field. (3) The effects of the eight heavy metals on pH, conductivity, and organic matter displayed significant spatial nonstationary characteristics. Cr, As, Cu, and Zn are the primary factors that affect environmental characteristics such as pH, conductivity, and organic matter content. [ABSTRACT FROM AUTHOR]

The sediment acts as not only sink but also source of heavy metals in aquatic environment, which may cause the endogenous pollution in drinking water reservoirs. In this work, we collected the surface sediments from Qingcaosha Reservoir, the largest river-embedded reservoir in China, and investigated the spatial distribution, risk, and sources of heavy metals in four seasons. Significant spatial and seasonal heterogeneity could be found in the distribution of five heavy metals (Cr, Cu, Mn, Zn, and Ni) in the surface sediments. The highest concentrations of the five metals were detected in the sediments from the reservoir downstream, especially in summer and next spring. The geo-accumulation index (Igeo) and enrichment factor (EF) suggest that the sediment pollution caused by single metal was heavier in summer than in other seasons. Also, the Nemerow pollution index (PIN) manifests that the synergetic pollution induced by five metals was most serious in summer, followed by next spring. However, the potential ecological risk index (PERI) indicates that none of these metals caused potential ecological risk in four seasons. Comprehensive analysis demonstrates that the sediment pollution gradually increased from autumn to winter and then to next spring. Principal component analysis shows that the main pollution source of five heavy metals may come from industrial wastewater and domestic sewage, which was almost independent of seasons. This work can provide data support for the subsequent seasonal optimization of drinking water quality and reservoir management. [ABSTRACT FROM AUTHOR]

Heavy metals (Sc, Cr, Co, Ni, Cu, Ga, Ge, Nb, Mo, Cd, In, Hf, Ta, W, Tl, Pb, Bi, Th, and U) in the surface sediments of the Ganges-Brahmaputra-Meghna (GBM) river system of the Bengal Basin (BB) were measured to evaluate the heavy metal contamination and anthropogenic influence. The average concentration levels of most of the heavy metals (except Mo and Tl) were above the average crustal and shale values. Contamination indices, including the contamination factor, pollution load index, enrichment factor, and geo-accumulation index, and multivariate statistical analyses indicated that the GBM is slightly polluted by heavy metals with some considerable pollution from Bi, Th, Ta, Cd, Nb, Pb, In, and U. Among the four individual rivers, the Brahmaputra River and Ganges-Brahmaputra (GB) confluence river sediments contain higher heavy metal concentrations than do the Ganges and Meghna Rivers, which may be caused by the effects of local municipal discharge, industrial or urban wastes, and ferry crossing activities. [ABSTRACT FROM AUTHOR]

The article shows the results of research on heavy metals (Cr, Zn, Ni, Cu, Pb, Cd) content in bottom sediments of two small storage reservoirs located in the south-eastern part of Poland. The analyses covered the top 10 cm layer of sediment samples taken in transects perpendicular to the shoreline, located in upper, central and lower sections of the studied reservoirs. The ordinary kriging method was applied to interpolate spatial distribution of heavy metals content in the sediments. The assessment of surface sediment contamination with heavy metals was based on a threshold effect level and probable effect level methods. In addition, the ecological risk was assessed on the basis of the indices: potential ecological risk index and toxic risk index. Moreover, the principal component analysis was carried out to find determinants for the distribution of the analyzed trace elements in reservoirs. The results of the completed analysis have proven that the highest concentrations of heavy metals (HM) are found in the vicinity of dams in both reservoirs. Calculated probable effects level values indicate a negative impact of Pb– Bliżyn Reservoir (BR) and Cd– Małoszówka Reservoir (MR) on aquatic biota. The analysis of heavy metal content and their interrelationships in surface sediments proves that Pb, Cu and Zn in the BR and Cd and Cr in the MR have anthropogenic origins. Moreover, the main determinants for HM distribution in the reservoir are hydromorphological parameters, which determine sediment grading and organic matter transport. [ABSTRACT FROM AUTHOR]

Sediment quality is an important indicator in establishing the ecological status of aquatic ecosystems. Heavy metals are considered toxic and persistent substances that accumulate in the biotic and abiotic components of aquatic ecosystems, especially in sediments. This study presents research on the spatial distribution of 5 heavy metals (Cr, Ni, Cu, Zn, Pb) measured in the Lower Danube surface sediments on the adjacent segment of Tulcea County in the summer of 2019. Moreover, the statistical relationship between the heavy metals mentioned above was studied using preliminary statistical analysis methods, namely Pearson Correlation matrix and Cluster Analysis. Concentrations of the five heavy metals studied were determined using the X-ray fluorescence (XRF) technique. The results of this study indicated the following falling trend of average heavy metal concentrations Cr>Zn>Ni>Cu>Pb. Positive correlations were found between Cu-Ni (r = 0,89), Zn-Ni (r = 0,80), Zn-Cu (r = 0,90), Pb-Ni (r = 0,88), Pb-Cu (r= 0,76), Pb-Zn (r = 0,82) pairs. [ABSTRACT FROM AUTHOR]

Eighteen surface sediment samples collected from the Rongcheng offshore area of China in 2021 were analyzed for heavy metal concentrations, sources, and pollution status. The Cu, Zn, Cr, Cd, As, and total organic carbon (TOC) distributions were similar. In contrast, the distributions of Pb and Hg were irregular, and high concentrations appeared in two or several areas. Occasional adverse effects were observed from pollution caused by Cu, Pb, and As, and none of the heavy metal concentrations exceeded the probable effect level (PEL). The Pearson's correlation coefficient, geoaccumulation index, and principal component analysis were used to distinguish the sources and assess the pollution risk of heavy metals. The results showed that heavy metals did not pollute the surface sediments in the Rongcheng offshore area and that the metals were mainly derived from natural sources. • Spatial distributions and pollution status of seven heavy metals were determined. • Multiple indices of heavy metals suggested their natural sources. • There was no heavy metal pollution in Rongcheng offshore area. [ABSTRACT FROM AUTHOR]

To comprehend the contamination levels of heavy metals in surface sediments of Shaying River (Anhui Section, China), samples of sediments were collected using grab samplers in 14 sampling sites in the river. Chromium (Cr), cadmium (Cd), copper (Cu), and lead (Pb) in sediments were monitored via flame atomic absorption spectroscopy, and arsenic (As) via atomic fluorescence spectroscopy. The geo-accumulation index (Igeo), pollution load index (PLI), and potential ecological risk index (RI) were applied to evaluate the sediment pollution of the five heavy metals. The results indicate that the mean concentration levels (range) of Cr, Cd, Cu, Pb, and As in sediments were 58.38 (29.89-116.66), 5.41 (3.14-10.93), 38.51 (23.77-60.83), 35.10 (19.28-82.21), and 0.44 (0.13-1.46) mg/kg, respectively. The mean Igeo values of Cr, Cd, Cu, Pb, and As were -0.69, 5.41, 0.36, -0.13, and -4.84, respectively. The average potential ecological coefficients (Eri) of Cr, Cd, Cu, Pb, and As were 1.95, 324.70, 6.42, 7.02, and 0.29, respectively. The RI values of the five heavy metals ranged from 197.65 to 687.24, and the mean was 340.38. Among the studied heavy metals, Cd was the highest contaminating element, whereas As was the lowest. Especially Cd was the main contributor to RI in all the sampling sites. Moreover, Cr, Cd, Pb, and As might have similar sources of contamination based on the Pearson correlation matrix of analysis. [ABSTRACT FROM AUTHOR]

Background and Aim:This research was conducted of determining and comparing the heavy metals of zinc, iron, manganese, copper, nickel and vanadium in summer in waters and sediments of Naseri wetland in Khuzestan province, 2017. Material and Methods:Sampling of water and sediments from three areas of north, central and southern Naseri wetland was carried out in summer. In order to measure heavy elements, the ICP-OES model Varian 710-ES was used to measure the induction plasma (ICP) and its composition by mass spectrometry (ICP-MS). Results:The average concentration of heavy metals in Naseri wetland water was obtained at station 3 above the first and second stations. Zinc, iron, copper and vanadium were lower in the wetland water than national and international standards, but higher levels of manganese and nickel were obtained. The average of the concentrations of the studied metals except the nickel in the surface sediments of the wetland in the second station was higher than the first and third stations. Ni was found higher in the sediments of the third station. Conclusion:The results of calculating the contamination factor showed that heavy metals were zinc, iron, manganese, nickel, vanadium and copper in low pollution levels. The degree of contamination of the studied metals also showed that pollution of Nasseri wetland sediments was low. The degree of contamination of modified heavy metals indicates very low contamination of sediments of Naseri wetland. The ecological risk of zinc, iron, manganese, nickel, vanadium, and copper was in the low-risk category. The total ecological risk of heavy metals at the stations was also classified as low risk. [ABSTRACT FROM AUTHOR]

Abstract The aim of this study is to investigate the distribution, ecological risk and quantitative source apportionment of seven heavy metals in surface sediments along a partially mixed estuary (Modaomen, China). The study area was divided into three regions based on salt-freshwater mixing: a tidal river channel, weakly mixed zone and strongly mixed zone. The concentrations of Cu, Zn, Pb, Cd, Cr and Ni were significantly higher in the weakly mixed zone, while a higher Co content was found in the tidal river channel. From enrichment factor (EF) analyses, Cd was moderate to extreme severely enriched at most stations, and other heavy metals were minor enrichments. Adverse effects on aquatic biota may occur occasionally for all seven heavy metals based on the sediment quality guidelines (SQGs). The correlations between Al and heavy metals suggested that metals in sediments were mainly attributed to anthropogenic sources. Then Positive matrix factorization (PMF) and Geostatistic method were used to quantify the heavy metal sources and determine impacted regions. A mixed source from the inner Lingding Bay and West River contributed approximately 50% of the Cu, Zn, Pb, Cr and Ni. The electroplating industry accounted for about 57% of the Cd content, and the major contaminated area was concentrated at the confluence of the West River and its tributaries. The alloy industry contributed approximately 65% of the Co, most of which was near an industrial park. Highlights • The concentrations of heavy metals were significantly higher in the weakly mixed zone. • Heavy metals occasionally have adverse effects on aquatic biota. • PMF was combined with GIS to determine the regions impacted by the sources and further interpret the source types. [ABSTRACT FROM AUTHOR]

Abstract Heavy metals, pharmaceuticals, and other wastes released into the environment can significantly influence environmental antibiotic resistance. We investigated the occurrence of 22 antimicrobial resistance genes (ARGs) and 10 heavy metal concentrations, and the relationship between ARGs and heavy metals in surface sediment from seven sites of Lake Taihu. The results showed significant correlations (p < 0.05) between sediment ARG levels, especially for tetracycline and sulfonamides (e.g., tet (A), tet (D), tet (E), tet (O), sul1, sul2 and int-1) and specific heavy metals (Fe, Mn, Cr, Cu, Zn, among others) in the Lake. In the surface sediments, heavy metals showed an interaction with resistance genes, but the strength of interaction was diminished with increasing depth. For most of the heavy metals, the concentration of elements in the top sediments was higher than that in other depths. Tetracycline resistance genes (tet (A), tet (B), tet (D), tet (E) and tet (O), β-lactam resistance genes (SHV , TEM , CTX , OXA and OXY) and sulfonamide resistance genes (sulA, sul1 , sul2 , sul3 and int-1) were detected. They showed a trend which inferred a statistically significant increase followed by decreases in the relative abundance of these ARGs (normalized to 16S rRNA genes) with increasing depth. This study revealed that tet (A), tet (O), TEM, OXY, int-1 , s ul1 and sul3 were widespread in surface sediments with high abundance, indicating that these genes deserve more attention in future work. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]

The aquatic ecosystem pollution by heavy metals is a real problem for the environment biotic components due to their toxic properties. Through the self-cleaning capacity of the Danube water, all heavy metals tend to accumulate in aquatic organisms, in vegetation and especially in surface sediments. The aim of this paper is to analyze the spatial distribution of heavy metals during 2019, in the Danube surface sediments, near the Galați city. The samples were collected from 5 stations, along the Danube river, between Km 160 and Km 117. The following 7 heavy metals were determined and analyzed using the X-ray fluorescence (XRF) technique: Fe, Mn, Cr, Ni, Zn, Cu and Pb. The result showed that the concentrations of Ni, Cr and Cu exceeded the permissible limit imposed by Romanian Order 161/2006, in certain sampling stations. [ABSTRACT FROM AUTHOR]

The status and ecological impacts of sedimentary elements of the marginal seas of Arctic and Northern Pacific Oceans was investigated during 2016 to 2018 by using inductively coupled plasma mass spectrometry. Industrial (0.006 mg kg−1–64.6 g kg−1), precious (0.003–43.8 mg kg−1), rare earth (0.006–112.9 mg kg−1), and heavy metal (0.009–398.9 mg kg−1) elements showed spatial variation, and temporal uniformity. The results indicated ΣREEs and light REEs enrichment compared to chondrite and heavy REEs, respectively, while nonsignificant positive and negative δCe and δEu anomalies existed, respectively. High contamination and extreme enrichment of priority control, industrial (As, Mo, Re, Sb), precious (Au, Ir, Pd, Pt, and Ru) and RE elements indicated potential moderate to high ecological and biological risks. The study highlighted the ecological importance and fragile nature of these ecosystems and calls for an urgent action to ensure sustainability of these ecosystems. [Display omitted] • Major and trace elements were detected in the ocean sediments of Artic region. • Highest heavy metal concentration in Alpha-Mendeleev Ridge (0.009 - 398.9 mg Kg-1). • Precious elements span 0.003 to 43.8 mg Kg-1, with notable spatial differences. • Heavy metal (loids) & REEs posed low, while As and Cd posed moderate risks to biota. • Low and high risks to biota displayed by heavy metals/REEs and As/Cd, respectively. [ABSTRACT FROM AUTHOR]

A total of 25 surface sediment samples collected from Laoshan Bay, China, during 2018, were analyzed for heavy metal concentrations, sources, and pollution status. The Cu, Zn, and Cr distributions were similar, whereas the distributions of other metals and the total organic carbon (TOC) content were irregular, and high concentrations appeared in one or two areas. Pearson's correlation coefficient, the geoaccumulation index, and principal component analysis were used to distinguish the sources and assess the pollution risk of heavy metals. The results showed that the surface sediments in Laoshan Bay were not polluted by Cu, Zn, Cr, or As, but were unpolluted to strongly polluted with Pb, Cd, and Hg. Cu, Zn, Cr, and As were mainly derived from natural sources; Pb and Cd were mainly derived from anthropogenic sources; and Hg may have had compound sources. • Spatial distributions and pollution status of seven heavy metals were assessed. • Multiple indices of Cu, Zn, Cr, and As suggested their natural sources. • High I geo values for Pb, Cd, and Hg indicated their anthropogenic sources. [ABSTRACT FROM AUTHOR]

Abstract This study analyzes the distribution and transportation of heavy metals in surface sediments by determining the concentrations of 6 heavy metals (Cr, Zn, Ni, Pb, Cu, and Cd) based on 164 surface sediments collected from the East China Sea (ECS). The results indicated that concentrations of heavy metals were higher in the south than the north with a clear boundary near 30° N. The distributions of the six heavy metals could be divided into four groups that corresponded well with different sediment components, suggesting that hydrodynamic sorting processes play an important role in the selective transportation of sedimentary heavy metals. In addition, the spatial distributions of heavy metals were more consistent with fine-grained sediments having a grain size lower than 32 μm. Heavy metal concentrations were slightly higher than found in previous studies conducted from 2002 to 2010. In addition, their spatial patterns have changed drastically compared to data from 2006, suggesting that intensive inland human activities have had a profound impact on heavy metal transportation and distribution in the estuarine & inner-shelf regions of the ECS. Graphical abstract Unlabelled Image Highlights • Distribution patterns of heavy metals in the East China Sea are depicted. • Hydrodynamics and sediment properties are the main factors affecting heavy metal distribution. • Spatial patterns have drastically changed in the context of intensive human activities. [ABSTRACT FROM AUTHOR]

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We determined the heavy metal concentrations and evaluated the pollution status of 213 surface sediment samples collected from the nearshore zone of southern Jiangsu Province, China. The distributions of lead (Pb) and zinc (Zn) were similar, and their concentrations were highest in tidal creeks dominated by fine-grained sediments, such as the Dawanhong and Wangcanghong creeks and the outer part of Lanshayang Creek. The spatial distributions of chromium (Cr) and cadmium (Cd) were similar, with high concentrations south of Yangkou Port and Haozhi Port. Copper (Cu) concentrations were high off the coast of Rudong. The sediments were not polluted by Cu, but were weakly polluted by Cd, Cr, Pb, and Zn. The results of principal component analysis indicated that Pb and Zn were mainly from natural sources, Cd and Cr were from anthropogenic sources, and Cu was from a mixture of natural and anthropogenic sources. [ABSTRACT FROM AUTHOR]

The distribution, sources, and risk assessment of eight quinotone antibiotics (QNs) in the surface sediments from the wetland in Jiaozhou Bay were investigated. The results showed that QNs were detected in all samples, and the total concentrations of QNs in the sediments ranged from 0.276 to 5.229 ng/g. The highest concentration occurred at the entrance to the Yang River wetland. Principal component analysis suggested that the QNs mainly originated from sewage discharges from hospitals, human and aquaculture industries. Risk assessment, based on risk quotients, indicated the current ofloxacin level might be a medium risk level, while other QNs were all low risk. Nevertheless, there should still be concerns due to high consumption of QNs by human beings, animals, and aquatic organisms in the wetland. This investigation provides baseline data that the government can use as a reference guide to control QNs residues in Jiaozhou Bay wetland. [ABSTRACT FROM AUTHOR]

Heavy metal contamination in the surface sediments of large shallow lakes in China is becoming increasingly serious. However, more attention has been paid to the human health risk of heavy metals in the past, while little consideration has been given to aquatic organisms. Taking Taihu Lake as an example, we explored the spatial and temporal heterogeneity of the potential ecological risks of seven heavy metals (Cd, As, Cu, Pb, Cr, Ni, and Zn) to species at different taxonomic scales using an improved species sensitivity distribution (SSD) method. The results showed that all six heavy metals, except Cr, were exceeded to some extent compared to background levels, with Cd being the most severe exceedance. Based on the hazardous concentration for 5% of the species (HC 5), Cd had the lowest HC 5 value, implying the highest ecological risk of toxicity. Ni and Pb had the highest HC 5 values and the lowest risk. Cu, Cr, As and Zn were at a relatively moderate levels. For the different groups of aquatic organisms, the ecological risk of most heavy metals was generally lower for vertebrates than for the whole species. The risk for invertebrates and algae was higher than that for all species. Zn and Cu had the highest potentially affected fractions (PAFs) for all classification cases, with mean PAFs of 30.25% and 47.2%, respectively. Spatially, the high ecological risk of sediment heavy metals was significantly related to the spatial characteristics of the type and intensity of human activities in the catchment. Administratively, the environmental quality standards for freshwater sediments proposed by America and Canada are insufficient to protected against the ecological risks of heavy metals in Taihu Lake. In the absence of such standards, China urgently needs to establish an approptiate system of environmental quality standards for heavy metals in lake sediments. [Display omitted] • Cd poses the highest eco-risk to aquatic organisms, with 95% of species protected. • Invertebrates and algae in shallow lakes are at higher eco-risk of heavy metal. • Zn and Cu have the highest potentially affected fractions on aquatic organisms. • The eco-risk of heavy metals is spatially linked to coastal human activities. • Existing enviro criteria are of limited use in preventing eco-risks of heavy metals. [ABSTRACT FROM AUTHOR]

In this study, 30 surface sediment samples were collected from Zhifu Bay in northern China and analyzed for heavy metals; in addition, their concentrations and pollution status were evaluated. The distributions of Cu and Zn were similar and mainly dominated by fine-grained sediments, whereas the other heavy metal distributions were not very regular. Al was positively correlated with Cu and Zn, and weakly correlated with Pb, As, and Hg. Except for some stations that showed minor enrichment and were unpolluted to moderately polluted by Cr, Cd, and Hg, the overall quality of sediments in the study area was good. Three principal components with eigenvalues >1 were estimated, accounting for 72.06 % of the total variability and representing natural sources, natural and anthropogenic, and anthropogenic sources, respectively. • Spatial distributions and pollution status of seven heavy metals were determined. • Except for Cr, Cd and Hg, the overall quality of sediments was good. • Except for Cd and Hg, other metals were mainly derived from natural source. [ABSTRACT FROM AUTHOR]

To assess the sources and pollution status of heavy metals, surface sediments from the Old Yellow River estuary were systematically sampled and analyzed to determine the concentrations of seven heavy metals. The Pearson's correlation coefficient, enrichment factor, geoaccumulation index, and principal component analysis were used to distinguish the sources and assess the pollution risk of heavy metals. The results showed that the distributions of Al, Fe, Cu, Pb, Zn, Cr, and As were similar and mainly dominated by fine-grained sediments, whereas the distributions of Cd and Hg were irregular. Al was strongly correlated with Fe, Cu, Pb, Zn, As, and Mz, and positively correlated with Cr. Except for Cr, Cd, and Hg, all the other elements were positively correlated with Mz. Multiple indicators indicated that Cu, Pb, Zn, Cr, and As were mainly derived from natural sources, whereas Hg and Cd were derived from anthropogenic sources. • Spatial distributions and pollution status of seven heavy metals were determined. • The distributions of Al, Fe, Cu, Pb, Zn, Cr, and As were similar. • Except for Cd and Hg, other metals were mainly derived from natural source. [ABSTRACT FROM AUTHOR]