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This paper provides a detailed description of the findings and methodology related to the monitoring of microplastics in three lakes and one river of the Akmola Region in Kazakhstan. The concentration of microplastic particles and the analysis of water and sediment quality of the Yesil River and Kopa, Zerendinskoye, and Borovoe lakes have been analyzed. A total of 64 water samples were collected across the spring, summer, and autumn seasons, with subsequent analysis revealing a seasonal increase in microplastic concentrations. The average microplastic content ranged from 1.2 × 10−1 particles/dm3 in spring to 4.5 × 10−1 particles/dm3 in autumn. Lakes exhibited higher concentrations compared to the Yesil River. Correlation analysis highlighted a connection between microplastic content and turbidity, particularly notable during the spring season. Analysis of sediments revealed a decrease in microplastic concentrations from the coastal zone toward open waters sediments. Microplastic fibers were predominant in sediments (69.6%), followed by fragments (19.1%), films (7.4%), and granules (3.9%). Larger particles (>500 µm) were found in beach sediments, constituting an average of 40.5% of the total plastics found. This study contributes valuable insights into the spatial and temporal distribution of microplastics, emphasizing the need for ongoing monitoring and management strategies to address this environmental concern. [ABSTRACT FROM AUTHOR]

Introduction. The aquatic ecosystem as the final recipient of waste produced by anthropogenic and natural processes is a growing pollution problem on our planet and currently the presence of heavy metals, they present is an alarming index. This research is important because the Ite district uses river water as an elemental liquid for its daily activities and consumption. The Locumba River sub-basin is located within the Ite district and is characterized by mining and agricultural activities. Objective. Determine the quality of the river sediments through the concentrations of heavy metals (As, B, Cd, Cr, Cu, Fe, Mn and Pb) in the upper area of the Locumba river. Materials and methods. In the months of January and March, sampling was carried out in an altitudinal range between 350 and 800 meters above sea level, in the dry and rainy season. The guide for sediment sampling (LSASDPROC- 200-R4), USEPA quality standards, was used. The analyzes were performed by ICPOES Plasma Spectroscopy. Results. The concentration levels show us that heavy metals are present as; Arsenic exceeded standards of 58 ppm on average, Boron with 8.2 ppm, Copper with 372 ppm and Lead with 121 ppm. Conclusions. The sediment quality of the Locumba River due to the presence of heavy metals is not adequate and brings with it environmental risks, affecting the biota and ecosystems. [ABSTRACT FROM AUTHOR]

BACKGROUND AND OBJECTIVES: Heavy metals are categorized as hazardous pollutants due to their incapability in decomposing and undergoing bioaccumulation and biomagnification. Heavy metal pollution is a global issue, particularly in emerging nations such as Indonesia. In this case, sediments contribute to pollution dispersion because they can transport, mobilize, and redistribute toxic compounds. The Cisadane river is one of 15 watersheds in Indonesia with the highest restoration priority. Therefore, it is essential to conduct study on the sediment quality of this river. This investigation aimed to evaluate the levels of cadmium, chromium, and lead in the sediments to assess the conditions of the Cisadane River. METHODS: At eight stations (representing the midstream and downstream region), surface sediment samples were collected using a van Veen sediment grab based on the hypothesis that heavy metal pollution originated from land-based activities and migrated down river estuaries. The Thermo Scientific iCAP 7400 was utilized to assess heavy metals (cadmium, chromium, and lead) by adopting prior research methodologies and method guidelines. FINDINGS: Except for lead, which surpassed the interim sediment quality standard, the levels of heavy metals observed in the midstream and downstream sections of the Cisadane River were found to be well below the guideline level. In this case, lead was the metal with the highest concentration in the sediments of the Cisadane River, followed by chromium and cadmium. The enrichment of heavy metals in river sediments was most likely caused by soil leaching, municipal and industrial sewage, as well as land waste disposal. After the landfill area, there were two areas with the highest concentration. Therefore, this investigation indicated the existence of landfills as point sources of heavy metals. Regarding specifics, two sites following the landfill constitute the apex of heavy metal amplification. CONCLUSION: This analysis shows that the sediment's cadmium, chromium, and lead contents are below the standards' threshold and safe for the habitat. Cadmium, chromium and lead exceed sediment quality requirements in sample sites after landfills, assumed to be due to leachate discharge and landfill activities. This study further also reveals that landfills are point sources of heavy metals. In this case, the heavy metals are two to four times higher in one kilometer from the landfill's leachate discharge. Therefore, the Enforcement of the Indonesia Waste Law Number 18 Year 2008 would have replaced unsanitary dumping including implementation of physicochemical, biological, and combination remediation techniques, with a vastly superior waste management system. [ABSTRACT FROM AUTHOR]

The study was conducted in Lake Rinconada, a glacial lake affected by artisanal and small-scale gold mining activities in the southern Andes in Peru. The objectives of the study were to investigate the spatial distribution of heavy metals (As, Cu, Hg, Pb and Zn) in water and sediments and to assess the degree of metal pollution and ecological risk using the geoaccumulation and potential ecological risk indexes. The concentrations of As and Hg in sediments from Lake Rinconada exceeded the Canadian sediment quality regulations, whereas the concentrations of As, Hg and Pb in water and sediments from the mining-affected tributary, Lunar de Oro River exceeded the Peruvian and Canadian guidelines for water and sediments quality respectively. According to the geoaccumulation and potential ecological risk indexes, Lake Rinconada is extremely polluted by As and Hg, and the pollution is mostly concentrated in the northern part of the lake, where the mining-affected Lunar de Oro River flows into the lake. Concentrations of Pb are also high in the northern part of the lake, suggesting that the nearby gold mining town is a source of pollution. The results of this study allows to report that Lake Rinconada is completely deteriorated. [ABSTRACT FROM AUTHOR]

Heavy metals (HM) contamination in freshwater sediments is a matter of serious concern. This concern is further aggregated in developing countries like Pakistan due to their high population growth and low economy. This study aimed to determine the quality of sediments in the Indus River and its tributaries. For this purpose, the available data on HM concentration published in last three decades (1992-2021) on freshwater sediments were collected. HM concentrations data was used for the geospatial distribution, pollution quantification factors, and ecological risk index. Among HM, iron (Fe) showed the highest concentration, while the silver (Ag) showed the lowest. This study revealed that HM mean concentration in the sediments exceeded the sediment quality guidelines. Ravi River a tributary of Indus River showed higher values of pollution quantification factors and potential ecological risk index and was categorized as significantly polluted. This study will provide a comprehensive assessment of HM pollution in river sediments all over Pakistan. [ABSTRACT FROM AUTHOR]

Riverine surface sediments are known to be important sources and sinks for different variables like metals, organic carbon and nutrients. This paper presents the surface sediment quality of the Red River which was monitored for nine trace metal elements, total organic carbon and nutrients (nitrogen, phosphorus and silica) during four sampling campaigns in 2019. The results showed that Fe and As concentrations were higher than the allowed values of the Vietnam National technical regulation on the surface sediment quality QCVN 43:2017/BTNMT. Trace metal element concentrations were, from highest to lowest, Fe > Mn > Cu > Zn > Pb > Cr > As > Cd > Hg. The geoaccumulation index and the enrichment factor values revealed that the Red River sediments were polluted by As; moderately polluted by Cu, Pb, Cd, and Hg; and uncontaminated by other metals (Mn, Cr and Zn). For other variables, total organic carbon (0.43 ± 0.31%), total nitrogen (0.09 ± 0.04%), and total phosphorus (0.060 ± 0.018%) were low in comparison with other urban rivers, whereas total silica (29.93 ± 4.52%) seemed to be high. Spatially, the lowest values of most variables were observed at the Hoa Binh site, where human population and activities are lowest and when discharge was highest. In contrast, most variables were highest at the Ba Lat site where the human activities clearly impacted on the Red River. These results indicate that the Red River sediment is affected by a combination of natural characteristics and human activities in the basin. [ABSTRACT FROM AUTHOR]

A heavily impacted river basin (Caudal River, NW Spain) by Hg and Cu mining activities, abandoned decades ago, was used to evaluate the environmental quality of their river sediments. The obtained results compared with reference values established by the US EPA and the Canadian Council of Ministers of the Environment for river sediments, have shown that the main elements of environmental concern are arsenic (As), mercury (Hg) and, to a lesser extent, copper (Cu), which reach concentrations up to 1080, 80 and 54 mg kg−1, respectively. To understand the role that river sediments play in terms of risk to ecosystem health, a comparison has been made between the total content of metal(oid)s in the sediments and the bioavailable contents of the same elements in pore water, passive DGT (Diffusive Gradients in Thin films) samplers and the sediment extractant using acetic acid. A good correlation between the As and Cu contents in the DGTs and the pore water was found, resulting in a transfer from the pore water to the DGT of at least 47 % of the Cu and more than 75 % of the As when the concentrations were low, with a deployment time of 4 days. When As and Cu concentrations were higher, their transfer was not so high (above 23.6 % for As and 19.3 % for Cu). The transfer of Hg from the pore water to the DGT was practically nil and does not seem to depend on the content of this metal. The fraction extracted with acetic acid, conventionally accepted as bioavailable, was clearly lower than that captured by DGTs for As and Cu (≤5 % and ≤8.5 % of the total amount, respectively), while it was similar for Hg (0.2 %). • Three methods for determining the bioavailable fraction in sediments are compared. • Passive DGT (Diffusive Gradients in Thin films) samplers seem to be advantageous. • The methodology is applied in a river basin with anthropic impacts. [ABSTRACT FROM AUTHOR]

A revised environmental licence that authorises the disposal of coal mine effluent has reduced the severity and spatial extent of water pollution and associated ecological impairment of a high conservation-value river flowing into and within the Greater Blue Mountains World Heritage Area. This study investigated water quality and the ecological condition of the Wollangambe River above and below a colliery effluent outfall and assessed the longitudinal impact 22 km downstream. Results are compared to a previous study conducted in 2012/2013 when the environmental licence allowed hazardous pollutant discharges (zinc, nickel) from the colliery. The current study revealed that water quality and river sediment at sampling sites in close proximity (< 2 km) to the effluent outfall continues to contribute ecologically hazardous concentrations of metals and river macroinvertebrates reflect diminished ecological health. However, further downstream monitoring has revealed a significant improvement in ecological condition that can be directly attributed to the revised pollution licence. We hypothesise that the ecological recovery of the most contaminated reaches of the river that lies proximate to the discharge point is constrained by four decades of accumulated zinc and nickel within river sediments. Nickel (978 mg/kg) and zinc (2080 mg/kg) exceeded ecosystem protection guidelines by 45 and 10 times, respectively. The study highlights the importance of appropriate and site-specific environmental licencing to protect riverine ecosystems of conservation significance from long-term contamination. [ABSTRACT FROM AUTHOR]

Mangrove sediment acts as a natural accumulator of potentially toxic metals (PTMs). Here, we have investigated the efficiency of mangrove species, e.g., Sonneratia caseolaris and Avicennia officinalis phytoremediation potential in a globally significant vulnerable river. The lower pH and anoxic conditions facilitate the elevated accumulation of PTMs in river Hooghly. The presence of PTMs in fine sediment fraction in greater proportion indicates a larger role of fine-grained silt and clay particles in the accumulation process. The estimated sediment quality indices indicate no significant change in the last 30 years. However, the ecotoxicological indices suggest a low level of ecological risks but can turn toxic because of the gradual accumulation of metals. The accumulations of PTMs in mangroves are regulated by the metal bio-availability. The result emphasizes mangrove pneumatophores, as a greater accumulator of PTMs than mangrove leaves. Higher translocation factors also indicate the applicability of mangroves as a phytoremediator of contaminated sediment. [ABSTRACT FROM AUTHOR]

Purpose: The spatial distribution and potential ecological risks of potentially toxic elements (PTEs) such as Sb, As, Cu, Zn, Pb, and Cr in sediment samples from the Qingfeng River were evaluated. This study aims to reveal the current status of sediment quality in the Qingfeng River and provide a scientific basis for its remediation and further comprehensive management. Materials and methods: Descriptive analysis and inverse distance weighted method were used to investigate the concentration and spatial distribution of PTEs in sediments. The geoaccumulation index evaluation (Igeo), Nemerow index (NI), and potential ecological risk index (RI) were used to evaluate the pollution degree of PTEs. Multivariate statistical techniques, such as cluster analysis, correlation analysis, and principal component analysis, were used to identify the sources of PTEs. Results and discussion: The results showed that the river sediments were mainly polluted by Sb (concentration range: 69–11,900 mg kg−1) and As (concentration range: 8–607 mg kg−1) and that the average concentrations were 4.3 and 553 times those of the background values, respectively. Based on the spatial distribution and pollution risks of PTEs, the study area was divided into three river sections, and the pollution risks were decreased in the order of upstream > midstream > downstream. The geoaccumulation index evaluation showed that the hierarchy of PTE pollutant concentration was as follows: Sb > As > Cu > Zn > Cr > Pb. The Nemerow indexes and potential ecological risk indexes all indicated that a very high potential risk exhibited in the study area, while the potential ecological risk of Sb was significantly higher than that of the other PTEs. Correlation analysis and principal component analysis indicated that Pb, As, and Sb were mainly derived from industrial activities, and Cu, Cr, and Zn were mainly derived from agricultural activities. Conclusions: The results showed that a very high potential risk existed in the study area. Sb was the main pollution factor of the surface sediments of the Qingfeng River and posed a very high potential ecological risk, while Cu, Cr, Zn, and Pb had low ecological risks. The results also determined that the sources of PTEs in the sediments could be mainly attributed to human activities. Substantial measures should be taken to control and resolve the PTE pollution in the Qingfeng River at the source. [ABSTRACT FROM AUTHOR]

Surface sediment quality of potential rivers in Peru was evaluated using indicators of contamination, accumulation and ecological risk of heavy metals and As. Surface sediment samples were collected at 54 sampling sites in the Tishgo and Chia rivers during 2018. The determination of Cu, Pb, Zn and As was performed by flame atomic absorption spectrophotometry. The results revealed the decreasing order of the mean concentrations of heavy metals and As in the Chia River of Zn > Cu > As > Pb and Tishgo of Zn > Pb > As > Cu. The PLI for the Tishgo River were greater than one (PLI > 1) denoting the deterioration it has been experiencing. In the Chia River, 60% of the sampling sites indicated no appreciable contamination by these elements (PLI < 1). The Igeo values of As in both rivers showed a state of contamination, from moderately to severely contaminated. In the Tishgo River the potential ecological risk varied from low to moderate and in the Chia River from low to considerable. Finally, this study reveals the applicability of the evaluation indexes of contamination, accumulation and potential ecological risk of toxic metals so that special control measures can be adopted. [ABSTRACT FROM AUTHOR]

Emet River Basin is a worldwide significant mining area and contains the most important boron and chromium deposits of Turkey. In this study, water and sediment quality of Emet River Basin was evaluated using some toxic element risk assessment indices. Samples were collected seasonally from 8 locations and nickel (Ni), chromium (Cr), arsenic (As), zinc (Zn), lead (Pb), copper (Cu) and cadmium (Cd) accumulations in water and sediment were analysed using an ICP-OES. Water Quality Index (WQI), Heavy Metal Pollution Index (HPI), Heavy Metal Evaluation Index (HEI) and Degree of Contamination Index (Cdeg) were applied to the data for assessing the water quality and Biological Risk Index (BRI), Potential Ecological Risk Index (PERI), Geo-Accumulation Index (Igeo), Contamination Factor (CF) and Pollution Load Index (PLI) were applied to the data for assessing the sediment quality. According to the results of WQI, HPI, HEI and Cdeg, As and Cr were recorded as the most dangerous toxicants; according to the results of BRI, Igeo, CF and PLI, Cd, As and Pb were recorded as the most dangerous toxicants; and according to the results of PERI, Ni and Cr were recorded as the most dangerous toxicants among the investigated elements. The seasonal average values of applied ecological indices for the water of the basin ranged 71.41–888.29 for WQI, 85.97–915.76 for HPI, 4.04–49.80 for HEI and − 2.95–42.80 for Cdeg. The seasonal average values of applied ecological indices for the sediment of the basin ranged 33.72–130.56 for PERI, 0.14–0.93 for BRI, − 3.92–5.99 for Igeo and 0.45–1.20 for PLI. In addition to the intensive agricultural applications around the region, the geological structure of the watershed was considered as the main cause of the high heavy metal accumulations in basin waters and sediments. [ABSTRACT FROM AUTHOR]

Approximately 200 million m3 of sediments are dredged every year in the United States. Of this amount, 2.3–9 million m3 are contaminated to the extent that they require special, and often costly, handling. Therefore, there is a pressing need to develop appropriate technology for the safe utilization of these sediments, especially in the case of the Hudson River, which is well known to demonstrate significant polychlorinated biphenyls (PCBs) contamination. Hence, the aim of the present study was to examine the influence of different doses of Hudson River sediments (10%, 25%, 50%, 75% and 100% admixtures) on soil quality and on the biochemical and growth response of cucumber (Cucumis sativus L. cv 'Wisconsin SMR 58'), used as potential phytoremediation tool for sediment-borne PCBs. A sediment/soil admixture was found to significantly decrease the nitrogen (N) content in the substratum; in addition, phosphorus (P) content was significantly increased by 50–100% sediment, while potassium (K) content was significantly increased by 10% sediment, and significantly decreased by >50% sediment. Although sediment treatment resulted in a gradual increase in PCB content in the soil-sediment substratum, exceeding the threshold effect concentration (TEC) for the ≥50% sediment admixture, the Microtox assay did not suggest toxicity to microorganisms. The results demonstrated also that admixture of 10–25% Hudson River sediment increased cucumber growth; however, higher doses led to growth inhibition, manifested as lower biomass and smaller leaves. Also, chlorophyll a and b content decreased with increasing doses of sediment. Phenylpropanoid and flavonol contents were significantly higher in plants grown in soil amended with 10% of sediment, but significantly lower in soil treated with a 100% sediment admixture. The anthocyanin content in plants was lower at admixtures of 50% and higher. The obtained results corresponded with the decreasing content of N and K. [ABSTRACT FROM AUTHOR]

Quality is one of the most important risk indicators in river basins. Therefore, monitoring and evaluating water and sediment quality has a very important role in process of risk management. The aim of the monitoring is provide for the sustainability of water bodies and these results are the basis for the risk management in the river catchment area. Hornad, Laborec and Poprad are the rivers in Eastern Slovakia. Hornad and Laborec belongs to basin of Danube and Poprad belongs to basin of Vistula. Sediment sampling was carried out according to ISO 5667-6. Monitoring was carried out in the spring on 2017-2018. The chemical composition of sediments was determined by means of X-ray fluorescence (XRF) using SPECTRO iQ II (Ametek, Germany, 2000). The results of sediment quality evaluated by method PERI revealed that the quality of sediment in 2018 was better than 2017. Results of XRF analysis of sediments were compared with the limited values according to the Slovak Act 188/2003 Coll. of Laws on the application of treated sludge and bottom sediments to fields. It can be state that limit values comparing with Slovak legislation were not exceeding in all sediment samples in rivers in Eastern Slovakia. Based on the monitoring data of sediment quality in the study area, a quantitative analysis of heavy-metal pollution in sediment was conducted using the method of potential ecological risk index (PERI) which is method for evaluate the potential ecological risk of heavy metals. It is based exclusively on chemical parameters of sediments because sediment data show mean integrated values in time, with higher stability than water column parameters; sediments are easily sampled at field work; sediment samples are more representative for time and space scales and analytical data are easily obtained, especially because sediments present high concentrations of contaminants, decreasing the possible errors due to detection limits of the applied analytical method. This method comprehensively considers the synergy, toxic level, concentration of the heavy metals and ecological sensitivity of heavy metals. Potential ecological risk index can be obtained using three basic modules: degree of contamination (CD), toxic-response factor (TR) and potential ecological risk factor (ER). The results show on the basis on potential ecological risk index that the quality of sediment in 2018 is better than 2017. The worst result shows Hornad in 2017. Significant improvement occurred at the sampling point S2 in Hornad in 2018. The best results show Laborec in 2018. The results show on the basis on potential ecological risk index that quality of sediment in 2018 is better than 2017. [ABSTRACT FROM AUTHOR]

This study focussed on a comprehensive investigation on the state of pollution and identification of potential sources of contamination of some river sediments in Serbia by polycyclic aromatic hydrocarbons (PAHs), and is the basis for setting up further monitoring programs. The sediment quality of the Danube River (km 1433-845) and its tributaries in Serbia, including the Sava River (km 202-1), were analysed with respect to PAHs and total organic carbon (TOC). We found that total PAH concentration in the sediments from the Danube and its tributaries (10.0-4140 μg kg-1) was lower than total PAH concentration in Sava River sediments (265.1-11272 μg kg-1). Principal component analysis showed that concentrations of benzo[a]anthracene, chrysene, pyrene, fluoranthene, indeno[1,2,3-cd]pyrene, benzo[a] pyrene, benzo[b]fluoranthene and benzo[k]fluoranthene in the sediments were correlated with TOC. The diagnostic ratios anthracene/(anthracene+phenanthrene) and fluoranthene/(fluoranthene+pyrene) were calculated to evaluate the emission sources of the PAHs. Therefore, these ratios indicated the predominantly pyrogenic source of the PAHs in the sediments. Results have also shown that river sediments in the Danube and Sava rivers and their tributaries were not recently polluted with PAHs, excluding only one location – S4, downstream of Šabac and characterized by heavily polluted sediment. [ABSTRACT FROM AUTHOR]

The objective of the present study was to assess the status of surface sediments from Funa River. Sediment samples were characterized for physicochemical parameters, including grain size, organic matter and toxic metals. The result revealed high metal concentrations in river sediments, reaching values of 154.19, 186.00, 1105.34, 3.69, 548.02 and 5.45 mg/kg for Cr, Cu, Zn, Cd, Pb and Hg, respectively. A strong correlation was observed between analysed metals and organic matter suggesting that these contaminants could have originated from common sources with a similar transport pathway. Based on the Sediment Quality Guidelines for the Protection of Aquatic Life, Funa River is considered as highly polluted with toxic metals indicating the potential environmental and human health risk. The results of this research represent a useful tool to assess the sediment quality of urban river receiving system which can be applied to similar environment. [ABSTRACT FROM AUTHOR]

Zayandeh-Rud River is the only permanent river in the central plateau of Iran. This river has been subject to an extensive discharge of wastewater and effluents from several point and nonpoint pollution sources. Accordingly, sediment quality of Zayandeh-Rud River in Varzaneh region, were studied. Algae and the sediment were sampled through 3 replications at 6 stations in the downstream after crossing through the Isfahan city and reaching Gavkhuni international wetland. Chlorophyll content and As, Pb, and Cd concentrations were measured in each sample Cladophora sp. and Oscillatoria sp. were identified using standard identification keys. The mean concentrations of metals in all stations exceeded background levels. Mean concentration of arsenic (162.9 mg/kg) in the sediment is about 31 times more than the ISQG standard (5.9 mg/kg) and considerably higher than the similar studies in Iran and other regions of the world. The mean concentration of As in algae samples is higher than the most polluted areas of the world. The mean concentration of Pb in the sediment (19.69 mg/kg) is lower than the ISQGs standard (35 mg/kg) and most of the studied river in north of Iran such as Chalous, Baboul-Rud, Gorgan-Rud (North), Khiav (North West), and Anzali wetland. The mean concentration of Cd in the sediment (2.11 mg/kg) is significantly higher than ISQG standard (0.6 mg/kg and some north highly polluted wetlands of Iran such as Anzali. There is a significant positive correlation between the mean concentrations of As and Pb in the sediment and Cladophora sp. tissue, and a negative one between the mean concentration of Pb in the sediment and chlorophyll b/a. There are significant negative correlations between the mean concentration of As in the sediment and chlorophyll a, and the total chlorophyll concentration in Oscillatoria sp. The results of Muller index indicate that the concentrations of Pb, Cd, and As in all stations occur in the Unpolluted, Moderate/Heavy, and Heavy/Extreme groups, respectively. Degree of contamination and modified degree of contamination show very high degree of pollution in the studied area. RI in all the stations showed very high ecological risk. The bioaccumulation factor for all metals in both algae is less than one. So, these two species may not be described as heavy metal accumulators. This study is an alarm for the Zayandeh-Rud River as the most important freshwater source for the Iranian Plateau. [ABSTRACT FROM AUTHOR]

Representative sampling of suspended particulate matter is fundamental for assessing river sediment quality, including the distribution and physicochemical characterisation of particles at different hydrological events. This study compares time-integrated samplers and discrete sampling methods, focusing on (a) the representativeness of the different methods and (b) the comparability between the various sampling techniques. The study investigates whether different sampling devices used under the same conditions can reproduce the annual mean. Two time-integrated sampling techniques (Binnensammler floating collector (BS); self-constructed Phillips sampler (PS)) and two discrete sampling systems (continuous-flow centrifuge (CFC); hydrocyclone (HC)) were compared. The monitoring program (August 2013 to August 2014) was conducted using a 4-week sampling frequency at two different monitoring stations in the Rhine river basin. The analysis of physicochemical parameters included total organic carbon (TOC), particulate phosphorus (PP), grain size distribution (GSD), metals, and organic pollutants (PCBs, HCB, PAH). A nested analysis of variance (ANOVA) was used to evaluate the dependence of suspended matter quality parameters on the sampling method, the sampling device, and the sampling station. According to ANOVA, physical and chemical parameters as well as persistent organic pollutants are homogenous for the time-integrated samplers PS and BS. Comparing PS and the reference technique CFC, only the mean annual concentration of TOC is significantly higher for CFC (5.91%; PS, 4.53%) due to degradation processes. With the exception of TOC, Ni, and GSD, data of BS was comparable with that of CFC. Comparing CFC and HC, there are significant differences for GSD, Zn, and Ni. An analysis of the time series of GSD < 63 μm and sum of PAHs confirms the findings of the nested ANOVA, showing that HC time series display significant differences compared with the other samplers. [ABSTRACT FROM AUTHOR]

The study was performed to examine the occurrence of endocrine disrupting chemicals (EDCs), including four steroid estrogens, one plasticizer, and three preservatives in the Mahakam River, Indonesia. The physicochemical analysis of river water and sediment quality parameters were determined as well as the concentration of EDCs. The range of values for pH, total dissolved solids (TDS), dissolved oxygen (DO), biochemical oxygen demand (BOD), total suspended solids (TSS), nitrate, ammonium, phosphate, and oil/grease in river water and sediment were higher than recommended limits prescribed by the World Health Organization's Guidelines for Drinking-water Quality (GDWQ). Bisphenol A (BPA) was the most widely found EDC with the highest concentration level at 652 ng/L (mean 134 ng/L) in the river water and ranged from ND (not detected) to 952 ng/L (mean 275 ng/L) in the sediment. Correlation analysis to investigate the relationship between the EDCs' concentrations in water and sediment also revealed a significant correlation (R² = 0.93) between the EDCs' concentrations. High concentrations of EDCs are found in urban and residential areas because these compounds are commonly found in both human and animal bodies, resulting in the disposal of EDCs into canals and rivers in urban and suburban areas, as well as livestock manure and waste that is generated from intensive livestock farming around the suburban area. [ABSTRACT FROM AUTHOR]

Well-designed monitoring approaches are needed to assess effects of industrial development on downstream aquatic environments and guide environmental stewardship. Here, we develop and apply a monitoring approach to detect potential enrichment of metals concentrations in surficial lake sediments of the Peace-Athabasca Delta (PAD), northern Alberta, Canada. Since the ecological integrity of the PAD is strongly tied to river floodwaters that replenish lakes in the delta, and the PAD is located downstream of the Alberta oil sands, concerns have been raised over the potential transport of industry-supplied metals to the PAD via the Athabasca River. Surface sediment samples were collected in September 2017 from 61 lakes across the delta, and again in July 2018 from 20 of the same lakes that had received river floodwaters 2 months earlier, to provide snapshots of metals concentrations (Be, Cd, Cr, Cu, Ni, Pb, V, and Zn) that have recently accumulated in these lakes. To assess for anthropogenic enrichment, surficial sediment metals concentrations were normalized to aluminum and compared to pre-industrial baseline (i.e., reference) metal-aluminum linear relations for the Athabasca and Peace sectors of the PAD developed from pre-1920 measurements in lake sediment cores. Numerical analysis demonstrates no marked enrichment of these metals concentrations above pre-1920 baselines despite strong ability (> 99% power) to detect enrichment of 10%. Measurements of river sediment collected by the Regional Aquatics- and Oil Sands-Monitoring Programs (RAMP/OSM) also did not exceed pre-1920 concentrations. Thus, results presented here show no evidence of substantial oil sands-derived metals enrichment of sediment supplied by the Athabasca River to lakes in the PAD and demonstrate the usefulness of these methods as a monitoring framework. [ABSTRACT FROM AUTHOR]

Though more large tropical reservoirs are being constructed to meet the increasing energy demand, knowledge on the impact of damming a tropical river and the differences along the river after its impoundment is scarce. Thus, the present study aimed to increase our understanding of such differences both longitudinally and vertically. Water and sediment samples were collected at three different functional zones in the Murum River basin 10 months after impoundment began. Results show that the impoundment has an impact on both the water and sediment. Longitudinal variations of water and sediment characteristics were observed at different functional zones. The upstream riverine zone subjected to anthropogenic activities serves as the main input of suspended solids and nutrients to the reservoir. The nitrogen changed from a high nitrate and low ammonia condition prior to impoundment to a low nitrate and high ammonia condition due to the accumulation of organic matter and slow nitrification rate after impoundment. In the transitional and lacustrine zones, vertical stratifications of dissolved oxygen and temperature were observed. The thickness of a well-oxygenated column for sensitive aquatic organisms was only 2 m at some stations. Water quality in all zones showed impairment during the filling phase as compared to the good water quality index before impoundment. The reduction of suspended solids in the surface water column in the transitional and lacustrine zones is a positive change for aquatic organisms. Sediment characteristics were found to be distinct in the transitional zone, where it was lower in sand and higher in silt, clay, organic carbon and nutrients in contrast to the riverine zone. Clay increased in all zones after the impoundment. There is an urgent need to reduce the pollutants input from the upstream riverine zone. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Sediment quality status was assessed in tropical Marine Protected Areas (MPAs). • Chemical profiles of surface sediments of estuarine protected areas are provided. • Acute and chronic toxicity was associated with moderate to low levels of contamination. • Ecological-disturbance indicator species were reported in impacted sites of MPAs. • Integrated approach can assist in formulating management plans for MPAs. Abstract Marine Protected Areas (MPAs) represent a tool for conservation that is intended to protect marine and estuarine habitats, biodiversity, and ecological processes. Many MPAs, some of which include estuarine zones, are affected by contamination sources; the discharge of chemicals into aquatic systems results in sediment contamination, risks to benthic systems, and consequent negative effects on ecological function. This study evaluated sediment quality in estuaries located within the Mosaic of Marine Protected Areas of São Paulo State, Brazil (MMPASP) in austral winter and summer: the Verde River (RV), the Una do Prelado River (BU), the Guaraú River (GU), the Preto River (RP), and the Itanhaém River (ITA). Data on sediment chemistry (major and trace metals, as well as hydrocarbons) and whole-sediment toxicity in copepods and amphipods were associated with ecological indices of macrobenthic infaunal organisms in a weight-of-evidence approach meant to estimate the effects at the community level. Results revealed low-to-moderate levels of contamination, with higher concentrations detected at sites influenced by domestic effluent discharges (RP, ITA). Site-specific chemical contamination guidelines were in accordance with biological responses than threshold levels from international benchmarks, indicating a failure of these international criteria to predict effects. Sediments were toxic, and benthic descriptors corroborated these findings. The results reflected a pattern of environmental quality that ranged from relatively good conditions (RV, BU, GU) to poor environmental quality (RP, ITA). We concluded that benthic environments in the estuaries of the Central Shore Marine Protected Area (APAMLC) exhibit a good ecological status in general, but some sites are directly impacted by human activities and exhibit contamination levels associated with biological effects, thereby showing that some portions of these MPAs may be damaged by contamination. Environmental assessments based on the sediment quality triad (SQT) method provide suitable and reliable information on pollution within MPAs and can assist in establishing additional policies to control pollution sources and achieve conservation goals. [ABSTRACT FROM AUTHOR]

We investigated eight heavy metals (Cr, Cd, Cu, Ni, Pb, Zn, Mn, and Fe) in water and bed sediment at 9 study sites along with 2320 km stretch of the Ganga River. Principal component analysis (PCA) and indices such as geo-accumulation index (Igeo), contamination factor (CF), enrichment factor (EF), pollution indices, and sediment quality guidelines were used to assess source apportionment and magnitude of contamination. Concentrations of Cr, Cd, Pb, Ni, Cu, and Fe in water have exceeded their respective standards in the middle and lower reaches of the river. Sediment Cr and Ni have reached probable effective concentration (PEC) at Kannauj, imposing likely threats to sediment dwellers. Highest Igeo values were recorded for Cr, Cd, and Pb at Kannauj, Rajghat, and Howrah. We further tested ecological risks (Er) and potential ecological risks (PERI) to assess individual and cumulative effects and found the Kannauj, Rajghat, and Howrah sites under the high-risk category. The modified pollution index (MPI) and the modified degree of contamination (mCd) also revealed the middle and lower river reaches under moderately to the heavily polluted category. Our study provides the first detailed watershed-scale database on heavy metal concentration in water and bed sediment, the magnitude of contamination, and likely ecological risks to aquatic organisms in the Ganga River. Given that the Ganga water is used for drinking and irrigation and the river harbors a diversity of habitats for fisheries, the study merits attention from a human health perspective as well. [ABSTRACT FROM AUTHOR]

In the present study, the environmental changes over the past 100 years in the Cambé River watershed in Southern Brazil were investigated. For this, a sediment core was collected to examine the distribution of metals, polycyclic aromatic hydrocarbons (PAHs), and ecotoxicological markers. The core corresponds from 1914 to 2012, which was obtained by the decay of 210Pb. Changes in the study area also were examined by: Geoaccumulation index (Igeo) and enrichment factor (EF), sediment quality guidelines (SGQs), and ethoxyresorufin-O-deethylase (EROD) activity in Poeciliopsis lucida hepatocellular carcinoma (PLHC-1) cells line. The Σ16 PAHs ranged from 242.6 to 40,775 ng g−1, with pyrogenic source at the beginning of the core, which likely corresponds to the burning of forests to establish the city and the later use of fossil fuels from 1960 to 2012. In the 1930s, most of metals presented a concentration below the background. After the 1930s, high concentrations can be associated with the intense use of fertilizers (Cd, Cu, Zn, Hg) and increases in urban traffic (Zn and Pb). Igeo showed that the distribution of Cu is considered moderately to strongly polluted, and the EF of Pb was considered as moderately polluted. Statistical analyses showed a strong relation between the presence of the ANP, FLU, PHE, BaP, IND, and Bghi compounds and the induction of EROD activity, and no correlation with heavy metals. A prediction model for the linear regression was obtained between the ANP and BaP concentrations and the EROD activity, with an accuracy of 99%. [ABSTRACT FROM AUTHOR]

In this study, laboratory-scale green (e.g. living) roof platforms were established to assess the potential use of polluted river sediment in their substrate mixture. The mean runoff retention of the green roof platforms, which contained peat and/or river sediment, after 11 artificial rainfall events was >72%, significantly higher than traditional roofs. However, green roof platforms that had been filled with peat soil showed chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) leaching. Green roofs that had used river sediment showed good leaching control for COD, TN and TP. The cumulative leaching masses from the green roofs contained 30% (COD), 42% (TN) and 47% (TP) as much as the total leaching mass from traditional roofs, and the Cu, Zn, Cd and Pb leaching risk from green roofs when river sediments are used as part of a substrate mixture was relatively low. Despite some nutrient leaching in the initial phase of runoff from the green roofs, river sediment has the potential to be used as a substrate for extensive green roofs. [ABSTRACT FROM AUTHOR]

Abstract The effects of land use and connectivity on the characteristics of aquatic ecosystems are thought to be scale-dependent. This study aimed to evaluate the relationships between land use and reservoir characteristics at two spatial scales, after controlling for spatial processes. Water and surface sediment samples were collected from 31 sites (7 reservoirs) in the Paiva Castro and Piracicaba River basins (Cantareira System, São Paulo State, Brazil), during austral summer and winter. The dataset included 15 water quality variables and 6 surface sediment variables. Land use variables (natural areas, pasture, agriculture and urban areas) were obtained at two spatial scales (buffer and watershed) in each reservoir. Spatial variables were calculated using Moran's Eigenvectors Maps and Asymmetric Eigenvector Maps. The strengths of the relationships between land use and sediment variables were stronger than those between land use and water quality variables. The strengths of some of the relationships were scale-dependent. Finally, spatial processes, mostly hydrological connectivity, play an important role in water-sediment quality and should be considered in landscape management programs. Graphical abstract Unlabelled Image Highlights • Land uses have effects in water and sediment quality in tropical reservoirs. • Different land uses have different relationships with water/sediment variables. • Effects of land use vary between buffer zone and watershed scale. • Connectivity can explain some of variation of water and sediment characteristics. • Sediments are an effective tool to assess reservoir quality. [ABSTRACT FROM AUTHOR]

In river valleys, sediment moves between active river channels, near-channel deposits including bars and floodplains, and upland environments such as terraces and aeolian dunefields. Sediment availability is a prerequisite for the sustained transfer of material between these areas, and for the eco-geomorphic functioning of river networks in general. However, the difficulty of monitoring sediment availability and movement at the reach or corridor scale has hindered our ability to quantify and forecast the response of sediment transfer to hydrologic or land cover alterations. Here we leverage spatiotemporally extensive datasets quantifying sediment areal coverage along a 28 km reach of the Colorado River in Grand Canyon, southwestern USA. In concert with information on hydrologic alteration and vegetation encroachment resulting from the operation of Glen Canyon Dam (constructed in 1963) upstream of our study reach, we model the relative and combined influence of changes in (a) flow and (b) riparian vegetation extent on the areal extent of sediment available for transport in the river valley over the period from 1921 to 2016. In addition, we use projections of future streamflow and vegetation encroachment to forecast sediment availability over the 20 year period from 2016 to 2036. We find that hydrologic alteration has reduced the areal extent of bare sediment by 9% from the pre- to post-dam periods, whereas vegetation encroachment further reduced bare sediment extent by 45%. Over the next 20 years, the extent of bare sediment is forecast to be reduced by an additional 12%. Our results demonstrate the impact of river regulation, specifically the loss of annual low flows and associated vegetation encroachment, on reducing the sediment available for transfer within river valleys. This work provides an extendable framework for using high-resolution data on streamflow and land cover to assess and forecast the impact of watershed perturbation (e.g. river regulation, land cover shifts, climate change) on sediment connectivity at the corridor scale. [ABSTRACT FROM AUTHOR]

Abstract An approach pooling geochemical analyses and ecotoxicological tests has been applied to assess the sediment quality of the Capibaribe River Estuary, Brazil. Toxicity tests were performed to compare a well-established, labor-intensive protocol using ovigerous females to a new, easier and faster protocol using nauplii of the epibenthic marine copepod Tisbe biminiensis. The endpoints of the nauplii toxicity test were comparable to those of the female test. Nauplii proved to be more sensitive than females as a biological model for indicating sediment toxicity. All sediments collected had at least one contaminant above the threshold effects level (TEL) proposed in the literature. Furthermore, more than one-third of samples exhibited contaminants above the probable effects level (PEL). The PCA revealed that nauplii mortality was associated with metals in October 2014, which was confirmed by the Spearman correlation factor. In contrast, no strong association among contaminants and toxicological endpoints in May 2015 was found. Graphical abstract Unlabelled Image Highlights • A new protocol has been established for assessing sediment toxicity. • Nauplius of Tisbe biminiensis is more sensitive to xenobiotics than adult female. • Endpoints of the nauplii test were strongly correlated with toxic chemicals. • Sediments of the Capibaribe estuary are impacted by PAHs, organochlorines and metals. [ABSTRACT FROM AUTHOR]

Within the Oil-Sands industry in Alberta, Canada, tailings ponds are used as water recycling and tailings storage facilities (TSF) for mining activities. However, there could be possible circumstances under which a sudden breach of an embankment confining one of the TSFs may occur. Such a tailings pond breach would result in a sudden release of a huge volume of Oil Sands process-affected water (OSPW) and sediment slurry containing substantial amount of chemical constituents that would follow the downstream drainage paths and subsequently enter into the Lower Athabasca River (LAR). This study investigates the implications of OS tailings release on the water and sediment quality of the LAR by simulating the fate of sediment and associated chemicals corresponding to a hypothetical breach and release scenarios from a select set of tailings ponds using a two-dimensional hydrodynamic and constituent transport model. After predicting the total volume, time evolution and concentration of sediment and associated chemicals (metals, polycyclic aromatic hydrocarbons (PAHs) and naphthenic acids (NAs)) reaching the LAR, the transport and deposition of these materials within the study reach is simulated. The results show that, depending on tailings release locations, between 40 and 70% of the sediment and associated chemicals get deposited onto the river bed of the 160 km study reach while the rest leaves the study domain during the first three days following the release event. These sediment/chemicals deposited during the initial spill may also have long-term effects on the water quality and aquatic ecosystem of the river and the downstream delta. However, care has to be taken in interpreting the results as further analysis has shown that the outcomes of such model simulations are very sensitive to the various underlying assumptions as well as the values assigned to some model parameters representing the physical properties of the tailings material. [ABSTRACT FROM AUTHOR]

Artificial sand replenishments are globally used as innovative coastal protection measures. In these replenishments elevated porewater concentrations of trace elements are found. The present study investigated possible ecotoxicological risks at 2 intertidal depositional sites, the Sand Engine as a recent innovative Dutch coastal management project and a semiartificial tidal flat. Using the sediment quality triad approach, we considered 3 major lines of evidence: geochemical characterization, toxicity characterization using bioassays with the estuarine amphipod Corophium volutator, and ecological field survey. In both depositional areas C. volutator is at risk: moderate (Sand Engine) and low (tidal flat). For tidal flat, the bioavailability of trace elements differs between the field site and the laboratory. Contamination from arsenic and copper is present, but the low survival rate of C. volutator from the bioassay suggests the presence of additional contaminations. The highly morphological dynamic environment of Sand Engine creates a less favorable habitat for C. volutator, where local spots with stagnant water can temporarily create hypoxic conditions and sulfate becomes reduced. The dynamic system mobilizes especially arsenic, triggering adverse ecotoxic effects at low original sediment concentrations. To conclude, the sediment quality triad approach shows that a semiartificial tidal flat is preferred over a highly dynamic coastal management project like the Sand Engine. The Sand Engine concept does not provide suitable conditions for macrobenthos species like C. volutator; therefore, limiting the nature development goal set together with the coastal protection goal. Assessing each line of evidence from the approach together with additional measurements established more precise and realistic conclusions, showing that evaluating the contributions of this method is necessary to understand the causes of risk in a site‐specific manner. Environ Toxicol Chem 2018;37:2933–2946. © 2018 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC. [ABSTRACT FROM AUTHOR]

This study was made to determine the pollution status and potential ecological risk of heavy metals in sediment of Persian Gulf. Surface sediments were collected seasonally by Peterson grab, and the concentrations of heavy metals were measured by using inductively coupled plasma-optical emission spectrometry (ICP-OES). The range concentrations obtained in mg/kg were 10,800-22,400 for Fe, 5.32-10.12 for Pb, 24.63-42.38 for Ni, 22.52-39.46 for Cu, and 31.64-47.20 for Cr. The concentrations of Pb, Ni, Cu, and Cr have been found lower than the Interim Sediment Quality Guidelines and probable effect level values suggesting that heavy metal contents in sediments from area of study would not be expected to cause adverse biological effects on the biota. The obtained enrichment factor values for various metals were between minimal enrichment (Pb = 0.5) and extremely enrichment (Cu = 3.11). The values of Igeo for Pb, Ni, Cu, and Cr were characterized under no pollution (0). The highest value of potential ecological risk index (RI) (8.36) was observed at St. 4 while the lowest value (5.25) was detected at station 6. Based on potential ecological RI, the Persian Gulf had low ecological risk. [ABSTRACT FROM AUTHOR]

Microorganisms in sediments play an important role in C-, N- and S-cycles by regulating forms and contents of these elements. The coupled system or synergistic reaction among three elemental cycles can effectively alleviate the pollution of C, N, and S in sediments. However, ecological processes coupling C-, N- and S-cycles in sediments are still poorly understood. In order to understand the ecological processes mediated by microorganisms living in river sediments, a total of 135 sediment samples were collected from Huaihe River and its branches located in the Northern of Anhui Province, the abundance of functional marker genes (mcrA, pmoA, cmo, amoA, hzo, nirK, nirS, nosZ, dsrB, aprA), involving in C-, N- and S-transformation, were determined by qPCR. The correlation among functional genes from 135 river sediment samples was calculated. We supposed that the correlationship among functional genes could be used as a reference index speculating the coupled systems of C-N-S in this reasearch, then the distinct coupling relation of C-N-S was revealed, and probable genetic mechanisms were also expounded based on the hypothesis. The study found that amoA-AOA and dsrB possibly played a secondary role, while S-functional gene (aprA), C-functional gene (mcrA) and N-functional gene (hzo) were the key functional genes that participate in the coupled processes in the elemental biogeochemical cycle. The results also demonstrated that C, N might have combined effects on the coupling of carbon, nitrogen and sulphur transformation. [ABSTRACT FROM AUTHOR]

Vegetated filter strips (VFSs) are a best management practice (BMP) commonly implemented adjacent to row-cropped fields to trap overland transport of sediment and other constituents present in agricultural runoff. Although they have been widely adopted, insufficient data exist to understand their short and long-term effectiveness. High inter-event variability in performance has been observed, yet the majority of studies report average removal efficiencies over observed or simulated events, ignoring the disproportional effects of loads into and out of VFSs over longer periods of time. We argue that due to positively correlated sediment concentration-discharge relationships, disproportional contribution of runoff events transporting sediment over the course of a year (i.e., temporal inequality), decreased performance with increasing flow rates, and effects of antecedent moisture condition, VFS removal efficiencies over annual time scales may be significantly lower than reported per-event averages. By applying a stochastic approach, we investigated the extent of disparity between reporting average efficiencies from each runoff event over the course of 1 year versus the total annual load reduction. Additionally, we examined the effects of soil texture, concentration-discharge relationship, and VFS slope in contributing to this disparity, with the goal of revealing potential errors that may be incurred by ignoring the effects of temporal inequality in quantifying VFS performance. Simulation results suggest that ignoring temporal inequality can lead to overestimation of annual performance by as little as < 2% and to as much as > 20%, with the greatest disparities observed for soils with high clay content. [ABSTRACT FROM AUTHOR]

Soil contamination enters aquatic ecosystems affecting sediment quality. The region studied is the Taquari River, Brazil, close to a site contaminated by wood preservatives, with a runoff route into the river. The first stage of the remediation process (In this article, the terms intervention and remediation have been used with slightly different meanings. We consider intervention to be the first phase of the remediation process, which aims to remove active sources) was an intervention to remove the main active sources. The Salmonella/microsome assay and polycyclic aromatic hydrocarbons (PAHs) were used to assess sediment quality in organic extracts during different intervention phases. The strains used were TA98, TA97a, and TA100 with and without S9mix (±S9). The results indicated the presence of pro‐mutagens at site Ta010 (closest to the contaminated site) in all samplings, and the highest result occurred before intervention for TA100 + S9 (1,672 ± 215.9 rev/g). These values decreased during (83 ± 23.6 rev/g) and after this process (403 ± 105.9 rev/g), although the PAHs concentrations increased. Samples from this site presented PAHs with a carcinogenic potential during the assessed periods. After intervention, Ta006 (4 km downstream from Ta010) showed the most significant mutagenesis for TA100 + S9 (764 ± 230.2 rev/g) and, although the total PAHs values were lower, the species considered carcinogenic had higher concentrations. Mutagenesis predicted values of PAHs confirmed that carcinogenic species were predominantly detected by TA100, and the other PAHs by TA97a strains. Marked contaminant release to the river was observed, mainly in Ta010 at different periods. Mutagenicity and PAHs values in an internal stream, upstream from Ta010, showed a dispersion route of these agents. Thus, contamination in Ta010 and possible contribution to Ta006, after intervention, provides a warning regarding environmental quality in the region. Environ. Mol. Mutagen. 59:625–638, 2018. © 2018 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

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ABSTRACT Sim B.-R.; Kim H.C.; Kim C.-S.; Hwang D.-W.; Park J.-H.; Cho Y.-S.; Hong S., and Lee W.-C., 2018. Spatio-temporal changes of sediment environment in the Taehwa river estuary, Ulsan of Korea. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 41–45. Coconut Creek (Florida), ISSN 0749-0208. The Taehwa River is a successful case for restoration of ecological system in Korea through the restoration project conducted during 1995–2005. To sustain this restored ecosystem, seasonal surveys for surface sediment quality were conducted in the entire area of the river estuary during the year 2012. It is noteworthy that the areas with pollutant source inflow exhibited higher organic carbon and acid volatile sulphide concentrations than the pollutant standard indices (20 mg C·g−1 and 0.2 mg S·g−1) in the spring and summer. Trace metal concentrations (As: 13.2; Cu: 64.2; Zn: 185.7; and Pb: 48.3; mg·kg−1) also showed a considerable increment from their respective Effect Range Low standards. The observed sediment oxygen demand (avg. 41.13 mmol O2m−2·d−1) in the prime habitat of Ruditapes philippinarum was substantially higher in this study than the average value (16 ± 6 mmol O2m−2·d−1) in Southern coastal area of Korea. The results from materials flux study suggest that high phosphate release from sediment into water column in summer and low sedimentation rate of nitrogenous nutrients during fall season could influence prolonging algal blooms in the Taehwa estuary. A further study is needed for a long-term of sediment monitoring on environment quality changes to maintain the restored ecological system and a safe consume of seafood. [ABSTRACT FROM AUTHOR]

Coal mining activities in the Sydney basin have been historically associated with significant environmental impacts. The region is facing more recent coal seam gas extraction activities and the synergetic environmental impacts of the new mining activities are still largely unknown. The aim of this study was to provide environmental assessment of river sediments comparing upstream to downstream areas relative to industrial-discharge sites associated with coal and coal-seam-gas extraction within the Sydney basin. Various contaminants were measured to determine the sediment quality according to the Australian and New Zealand Environment and Conservation Council (ANZECC) guidelines. Arsenic, nickel and zinc were the main sediment contaminants in downstream samples exceeding the ANZECC guidelines. Degree of contamination (C d ), geoaccumulation index (I geo ), enrichment factor (EF), pollution load index (PLI) and sediment environmental toxicity quotients' increment in downstream sediment were estimated for the studied areas. Toxicology indices of metals present in the sediments near industrial discharge sites were used as an additional tool to compare the level of environmental effects with their increment. The study revealed that the sediments from coal mining sites were highly affected by increased concentrations of manganese, zinc, cobalt, nickel and barium. The sediments associated with coal mining activities were found to be substantially more affected than the sediments near coal seam gas production sites, mainly attributed to the different wastewater discharge licencing requirements. The approach applied in this study can be used as an additional model to assess the contribution of industrial and mining activities on aquatic environments. [ABSTRACT FROM AUTHOR]

Porsuk Stream Basin is a significant aquatic habitat located in the middle of the Aegean and Central Anatolian Regions of Turkey. Similar to may aquatic habitats, it is exposed to intensive agricultural, domestic, and industrial pollution. The aim of this study was to determine the toxic element levels in Porsuk Stream Basin sediment and evaluate the detected data using a multi-statistical technique. For this purpose, sediment samples were collected from 18 stations selected on the basin (three of them located on Porsuk Dam Lake) in summer 2015, and zinc, copper, lead, cadmium, nickel, and chromium accumulations in sediment samples were determined. All the detected data were compared with the consensus-based threshold effect concentrations (TEC), and factor analysis (FA) also was applied to detected data in order to evaluate the contamination grades in the basin. According to detected data, although Cu, Pb, and Cd concentrations were detected below the limit values, Zn, Cr, and Ni concentrations exceeded the limit values in general. According to results of FA, 3 factors - industrial, agricultural, and lead - explained 81.56% of the total variance. [ABSTRACT FROM AUTHOR]

The present study focuses on the evaluation of metal (chromium, copper, and lead), arsenic, and pesticide (atrazine and endosulfan) contamination in freshwater streams of one of the most important agricultural and industrial areas of central-eastern Argentina, which has not been reported earlier. The environmental fate of inorganic microcontaminants and pesticides was assessed. Samples were collected monthly for a year. Pesticide concentrations were measured in water; metal and arsenic concentrations were measured in water and sediments, and physicochemical variables were analyzed. In most cases, metals and arsenic in water exceeded the established guideline levels for the protection of aquatic biota: 98 and 56.25% of the samples showed higher levels of Cr and Pb, while 81.25 and 85% of the samples presented higher values for Cu and As, respectively. Cr, Pb, Cu, and As exceeded 181.5 times, 41.6 times, 57.5 times, and 12.9 times, respectively, the guideline level values. In sediment samples, permitted levels were also surpassed by 40% for Pb, 15% for As, 4% for Cu, and 2% for Cr. Geoaccumulation Index (Igeo) demonstrated that most of the sediment samples were highly polluted by Cr and Cu and very seriously polluted by Pb, which indicates progressive deterioration of the sediment quality. Atrazine never exceeded them, but 27% of the 48 water samples contained total endosulfan that surpassed the guidelines. The findings of this study suggest risk to the freshwater biota over prolong periods and possible risk to humans if such type of contaminated water is employed for recreation or human use. Improper disposal of industrial effluents and agricultural runoffs need to be controlled, and proper treatment should be done before disposal to avoid further deterioration of the aquifers of this area. [ABSTRACT FROM AUTHOR]

In Switzerland, surface waters are protected by the Swiss Water Protection Ordinance (OEaux; OFEV 1998), which stipulates that the water quality shall be such that the water, suspended matter, and sediments contain no persistent synthetic substances to ensure the protection of aquatic life. Local agencies are in charge of water quality monitoring, using a set of validated methods. Several lists of priority substances have been developed for aquatic microcontaminants for surface water monitoring but not for sediments. Some local agencies have established sediment monitoring programs, but to date, there exists no harmonized methodology for sediment quality assessment in Switzerland. Within the main goal of developing and providing methodologies for monitoring sediment quality in Switzerland, a screening was performed to help prioritize sediment-relevant microcontaminants. The screening approach was largely based on the NORMAN (network of reference laboratories, research centers, and related organizations for monitoring emerging environmental substances) system and was carried out in four steps: (1) identification of candidate substances, (2) selection of sediment relevant substances, (3) classification of substances into different categories based on identified data gaps and envisaged actions, and (4) ranking within each action category. This paper describes the methodology used in the prioritization process for sediment-relevant substances and provides recommendations for monitoring strategies in Switzerland. [ABSTRACT FROM AUTHOR]

Al-Arbaeen and Al-Shabab are two highly polluted lagoons lying along the Jeddah Coast. Surface sediments were collected from both lagoons to assess the levels and spatial distribution of polycyclic aromatic hydrocarbons (PAHs), as well as study the effect of environmental conditions on PAH concentrations. The concentration ranges for S38-PAHs in Al-Arbaeen and Al-Shabab lagoons were 5.4-5,372 ng/g (mean 1,637 ng/g) and 60-7,927 ng/g (mean 1,323 ng/g), respectively. Pollution levels in both lagoons were in the low-very high range with dominance by three- and four-ring congeners. Pyrene was the dominant congener, while benzo (a) pyrene represented the dominant carcinogenic congener in the study area. The disappearance of most of the low molecular weight congeners may be attributed to temperature and microbial activity. Carcinogenic PAHs contributed 59.9 and 23.6% for Al-Arbaeen and Al-Shabab lagoons, respectively. The diagnostic ratios revealed that the source of PAHs are of mixed origin and site specific. The probable toxic effects on organisms were examined for total and individual PAHs with sediment quality guidelines (ERL-ERM). The detected PAHs levels in the present study were compared with reported levels for coastal worldwide lagoons. [ABSTRACT FROM AUTHOR]

The contamination of riverine sediments and suspended matter with hydrophobic pollutants is typically associated with urban land use. However, it is rarely related to the sediment supply of the watershed, because sediment yield data are often missing. We show for a suite of watersheds in two regions of Germany with contrasting land use and geology that the contamination of suspended particles with polycyclic aromatic hydrocarbons (PAH) can be explained by the ratio of inhabitants residing within the watershed and the watershed's sediment yield. The modeling of sediment yields is based on the Revised Universal Soil Loss Equation (RUSLE2015, Panagos et al., 2015) and the sediment delivery ratio (SDR). The applicability of this approach is demonstrated for watersheds ranging in size from 1.4 to 3000 km 2 . The approach implies that the loading of particles with PAH can be assumed as time invariant. This is indicated by additional long-term measurements from sub-watersheds of the upper River Neckar basin, Germany. The parsimonious conceptual approach allows for reasonable predictions of the PAH loading of suspended sediments especially at larger scales. Our findings may easily be used to estimate the vulnerability of river systems to particle-associated urban pollutants with similar input pathways as the PAH or to indicate if contaminant point sources such as sites of legacy pollution exist in a river basin. [ABSTRACT FROM AUTHOR]

Solomon Islands is rapidly developing its natural resource exploitation sector, but data needed to assess consequent environmental impacts are scarce. We assessed catchments surrounding the Gold Ridge gold mine (Guadalcanal, Solomon Islands) and found that extensive changes in river course, and water and sediment quality have occurred downstream of the gold mine since its development. Sediment run-off from exposed areas associated with the mine pit has increased, elevating turbidity (up to 2450 NTU) and metal and arsenic levels, with levels of the latter being up to 0.141 mg/L in surface waters and 265 mg/kg in sediments. An overfull, inoperative tailings storage facility associated with the currently inactive gold mine with fluctuating arsenic levels (up to 0.087 mg/L in the water; 377 mg/kg in the sediment) presents an ongoing threat to the environment. Arsenic, due to its toxicity, appears to be the greatest threat, with sediment and water guideline levels in rivers exceeded 10-fold and exceeded nearly 20-fold in the tailings dam sediments. Despite elevated metal and arsenic content in the area, no toxic inorganic arsenic was found to have bioaccumulated in locally harvested food. In summary, the natural environment surrounding the Gold Ridge mine has been modified substantially and requires an ongoing monitoring program to ensure the ecosystem services of food and water for the local communities continue to be safe. This study informs not only the local area but also provides a microcosm of the broader global challenges facing the regulation of extractive industries in proximity to subsistence communities. [ABSTRACT FROM AUTHOR]

Houjing River, located in Kaohsiung City, is one of the most seriously contaminated rivers in Taiwan. This study analyzed the concentrations of heavy metals (As, Cd, Cr, Cu, Pb, Ni, Zn and Hg) in sediments and water samples collected from this river. Analysis of contamination factor ( C f i ) and potential ecological risk factor ( E f i ) of heavy metals in water showed that there were low grades of contamination and potential ecological risk for all heavy metals, suggesting that heavy metals in water were less likely to pose risks to the ecosystem. However, sentiment samples were found to have severe contamination levels based on ranges found in sediment quality guidelines (SQG). The average Cu concentration was almost twice as high as the upper standard values in all the guidelines. Multi-element indices were used to evaluate the synergistic effects of different metals at the sampling sites. The calculated results of different indices, the modified degree of contamination ( mC d ), Nemerow pollution index ( P N ) and potential ecological risk index ( RI ), were in good accordance. ‘Heavy’ contamination and ‘severe’ ecological risk were found at three sites, Demin, Zhuwai and Renwu. Cadmium and copper contributed the highest to the ecological risk there. Results of positive matrix factorization modeling identified four sources of heavy metal pollution in both sediments and water. Heavy metal contamination in the Houjing River is attributed to companies carrying out various industrial processes along the riverbank, including traditional metal-plating, plastic manufacture and semi-conductor packaging. Therefore, future pollution control and management plans should emphasize the strict regulation of discharge from these industrial activities. [ABSTRACT FROM AUTHOR]

Across the circumpolar world, intensive anthropogenic activities in the southern reaches of many large, northward-flowing rivers can cause sediment contamination in the downstream depositional environment. The influence of ice cover on concentrations of inorganic contaminants in bed sediment (i.e., sediment quality) is unknown in these rivers, where winter is the dominant season. A geomorphic response unit approach was used to select hydraulically diverse sampling sites across a northern test-case system, the Slave River and delta (Northwest Territories, Canada). Surface sediment samples (top 1 cm) were collected from 6 predefined geomorphic response units (12 sites) to assess the relationships between bed sediment physicochemistry (particle size distribution and total organic carbon content) and trace element content (mercury and 18 other trace elements) during open-water conditions. A subset of sites was resampled under-ice to assess the influence of season on these relationships and on total trace element content. Concentrations of the majority of trace elements were strongly correlated with percent fines and proxies for grain size (aluminum and iron), with similar trace element grain size/grain size proxy relationships between seasons. However, finer materials were deposited under ice with associated increases in sediment total organic carbon content and the concentrations of most trace elements investigated. The geomorphic response unit approach was effective at identifying diverse hydrological environments for sampling prior to field operations. Our data demonstrate the need for under-ice sampling to confirm year-round consistency in trace element-geochemical relationships in fluvial systems and to define the upper extremes of these relationships. Whether contaminated or not, under-ice bed sediment can represent a 'worst-case' scenario in terms of trace element concentrations and exposure for sediment-associated organisms in northern fluvial systems. Environ Toxicol Chem 2017;36:2916-2924. © 2017 SETAC [ABSTRACT FROM AUTHOR]

This study focuses on a heavily polluted effluent-dominated stream that passes through an industrialized region near Izmir, Turkey. The intermittent creek receives domestic and industrial discharges of Kemalpaşa District Center and its neighborhoods and more than 180 factories of the organized industrial zone. A monitoring campaign was conducted on the creek and samples were taken in two different seasons with distinct hydrological characteristics from 20 stations along the creek to quantify the quality status of water and sediment columns. A number of physicochemical parameters, heavy metals, and trace elements were measured by field and laboratory techniques to assess the status of creek's water and sediment quality. The spatial and temporal variations were determined, and statistical tools were used to conduct an environmental forensic overview along the creek. A geo-accumulation index and a modified heavy metal pollution index were calculated to cumulatively assess the quality of sediment and water columns, respectively. The results revealed that the creek was under significant pollution load from the industrial zone where metal processing, food and beverage production, marble and natural stone manufacturing, and paper production are made. In particular, elements such as Co, Cu, Cd, Mn, Ni, Pb, Zn, and Zr were found to be above the surface water quality standard values. Similarly, B, Cr, Ni, Cu, Zn, and Sn were determined to be in extreme levels in the sediment column with values exceeding the probable effect concentrations. [ABSTRACT FROM AUTHOR]