Book

Use of Sediment Quality Guidelines & Related Tools for the Assessment of Contaminated Sediments

Authors:
  • Commonwealth Scientific and Industrial Research Organisation, CSIRO
... Although agriculture is critically important in supporting a growing human population, it is also important to maintain the environmental integrity of downstream aquatic systems. Understanding the extent and impact of agricultural contaminants in river and stream sediments is a valuable step in finding mitigation strategies that effectively improve and/or maintain aquatic ecosystem services [2][3][4]. ...
... Twenty-eight-day whole surface sediment toxicity bioassays using H. azteca were conducted per 1 L sample according to modified USEPA protocols [4,15]. Bioassays were comprised of treatments of sieved sediment from three habitats (upstream, midstream, downstream) within each bayou (Cow Oak, Howden, Roundaway) collected seasonally (winter, spring, summer, fall) during three-year study period. ...
... Overlying water quality parameters associated with a 28-day amphipod sediment bioassay were within acceptable limits as prescribed by USEPA protocol [4,15]. Measured water quality data, mean and ranges, were as follows. ...
Article
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Agricultural activity enhances topsoil erosion and facilitates the transport of pesticides that alter watershed sediment quality. Agricultural stream (bayou) sediment quality in Mississippi, USA, was evaluated across three bayous, habitats (upstream, midstream, downstream), and seasonally from 2011 to 2014 for pesticide contamination, effects, and bioavailability to Hyalella azteca. Four-week (28-day) H. azteca sediment bioassays were conducted to assess survival and growth and tissue residues. Fourteen pesticides were detected in at least one sediment sample and nine pesticides were detected in H. azteca tissues. Sediment pesticides p,p’-DDT and p,p’-DDE were greatest in Cow Oak Bayou and heptachlor and bifenthrin were greatest in Howden Lake Bayou. Seasonally, λ-cyhalothrin and p,p’-DDT were greatest in winter while trifluralin, atrazine, and clomazone were greatest in the fall. H. azteca survival and growth ranged from 0 to 100% and 0.8–4.1 mg, respectively, with Cow Oak, downstream habitats, and spring samples having the greatest survival and growth. Greatest tissue pesticide residues were atrazine (1271 µg/kg), p,p’-DDT (1,093 µg/kg), and β-cyfluthrin (1003 µg/kg). Tissue pesticide residues were influenced primarily by p,p’-DDT with Cow Oak and fall tissue samples having the lowest residues. H. azteca tissue p,p’-DDT residues contributed to biological impairment. Although banned in the USA for 40 years, p,p’-DDT continues to impact sediment quality.
... Historically, sediments have been sampled to assess the occurrence within a hydrologic system of particulate-associated contaminants such as legacy organochlorine (OC) insecticides, polychlorinated biphenyls (PCB), polycyclic aromatic hydrocarbons (PAH), and metals. To assess the biological significance of such residues, both empirical and theoretically based benchmarks for these traditional sediment contaminants have been used for decades (e.g., MacDonald et al., 2000;U.S. Environmental Protection Agency, 2004;Wenning et al., 2005). However, a number of currently used pesticides also are hydrophobic (e.g., fipronil and pyrethroid insecticides), and have been analyzed in sediment in recent monitoring and research studies (e.g., Ding et al., 2010;Gan et al., 2012;Hintzen et al., 2009;Hladik and Kuivila, 2012;Nowell et al., 2013;Phillips et al., 2012;Phillips et al., 2014). ...
... Sediment-quality benchmarks have been developed in the past for legacy OC pesticides using both empirical and mechanistic methods (Wenning et al., 2005), but existing benchmarks for currently used pesticides are rare (Section 2.1.2). Common methods for deriving benchmarks for hydrophobic organic contaminants-biological effects correlation, equilibrium partitioning, and spiked-sediment toxicity approaches-differ in their advantages and limitations regarding applicability towards currently used pesticides. ...
... Empirical benchmarks are based on empirical associations between chemical contamination and biological effects, and do not indicate a direct cause-and-effect relationship. This approach may overestimate toxicity due to one particular chemical with benchmark exceedances because the empirical benchmarks are based on associations with toxicity in field sediment samples that often contain mixtures of chemical contaminants (Wenning et al., 2005). These benchmarks also assume that the influence of the chemical contaminant(s) is greater than the influence of environmental conditions (Long and Morgan, 1991). ...
Article
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Sediment-toxicity benchmarks are needed to interpret the biological significance of currently used pesticides detected in whole sediments. Two types of freshwater sediment benchmarks for pesticides were developed using spiked-sediment bioassay (SSB) data from the literature. These benchmarks can be used to interpret sediment-toxicity data or to assess the potential toxicity of pesticides in whole sediment. The Likely Effect Benchmark (LEB) defines a pesticide concentration in whole sediment above which there is a high probability of adverse effects on benthic invertebrates, and the Threshold Effect Benchmark (TEB) defines a concentration below which adverse effects are unlikely. For compounds without available SSBs, benchmarks were estimated using equilibrium partitioning (EqP). When a sediment sample contains a pesticide mixture, benchmark quotients can be summed for all detected pesticides to produce an indicator of potential toxicity for that mixture. Benchmarks were developed for 48 pesticide compounds using SSB data and 81 compounds using the EqP approach. In an example application, data for pesticides measured in sediment from 197 streams across the United States were evaluated using these benchmarks, and compared to measured toxicity from whole-sediment toxicity tests conducted with the amphipod Hyalella azteca (28-d exposures) and the midge Chironomus dilutus (10-d exposures). Amphipod survival, weight, and biomass were significantly and inversely related to summed benchmark quotients, whereas midge survival, weight, and biomass showed no relationship to benchmarks. Samples with LEB exceedances were rare (n = 3), but all were toxic to amphipods (i.e., significantly different from control). Significant toxicity to amphipods was observed for 72% of samples exceeding one or more TEBs, compared to 18% of samples below all TEBs. Factors affecting toxicity below TEBs may include the presence of contaminants other than pesticides, physical/chemical characteristics of sediment, and uncertainty in TEB values. Additional evaluations of benchmarks in relation to sediment chemistry and toxicity are ongoing.
... Contaminated sediments pose large problems for coastal waters in need of constant dredging; their management is controlled by the London Convention and various national legislation. The science of evaluating sediment-bound contaminants is described in Dickson et al. (1987), National Research Council (1989b, Baudo et al. (1990), Burton (1992), Ingersoll et al. (1997), Stolzenbach and Adams (1998) and Wenning (2005), among others. After many conferences and discussion, there is general agreement about the choice and application of the suites of bioassay tests to use, for both freshwater and marine environments. ...
... Much of the work is conducted on sediments contaminated by oil spills, polluted harbours and pulp-mill discharges. The uptake of sediment-borne contaminants, influence on bioavailability of influencing factors, relationships between sediment contamination and toxicity and the standardization and quality control of methods have received considerable attention (Power and Chapman, 1992;Lamberson et al., 1992;Wenning, 2005). ...
Chapter
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Contents: A Short History of Aquatic Toxicology The Aquatic Environment Factors that Affect the Environmental Concentration of Chemicals Basic Toxicological Concepts and Principles Factors that Influence Toxicity Toxic Agents and Their Effects Examination of Concentration-Response Relationships Toxicity Testing Interpreting Toxicity Test Data Biomonitoring Toxicity Dada and Environmental Regulations
... SQGs were reviewed in the derivation of screening values for Hong Kong (Chapman et al., 1999a(Chapman et al., , 1999b and in the implementation of equilibrium partitioning by the US EPA (McCauley et al., 2000). Workshops to review SQGs were conducted in 2000 (GIPME, 2000) and 2005 (Wenning et al., 2005) amongst others. Methods, advantages, assumptions and limitations in the use of SQGs for chemical mixtures were provided by Long et al. (2006) and SQGs were reviewed for global use by Burton (2002). ...
... A variety of sediment chemistry-based approaches has been developed from empirical and mechanistic relationships (Wenning et al., 2005;OSPAR, 2008) to assess risk of adverse effects to benthic communities. In the current work, schemes based on matching chemical and biological data are grouped into Empirical (correlative) Approaches, while Mechanistic Approaches, founded on equilibrium partitioning (EqP), address factors controlling bioavailability, chemical uptake and toxicity, i. e. provide a theoretical basis for an understanding of cause and effect. ...
Article
This review of 19 chemical approaches used in assessing sediment quality are classified into empirical, mechanistic and sediment quality indices (SQI) groups. Empirical sediment quality guidelines (SQGs), based on matching chemical and biological-effects data and the mechanistic techniques, founded on equilibrium partitioning principals (EqP), are well established and most used. Empirical SQGs provide a useful screening tool to initially identify locations and chemicals of most concern, but are not regulatory criteria. The EqP approach is causally linked however, the scheme assumes porewater chemistry largely controls sediment toxicity. SQIs are not based on matching chemical-biological data and combine schemes with multiple narrative intents. The 41 SQGs reviewed show a considerable range in upper and lower guideline values. Grain size and organic content should be included into SQGs, however inclusion of suspended sediment into SQGs raises concerns. SQGs are built into decision-tree schemes with other lines-of-evidence and evaluated in a weight-of-evidence framework.
... Originally, they provided the information on SQGs compared with a reference or background concentration of analysed substances [76]. After the 1980s, SQGs were developed to evaluate sediment quality where harm to aquatic organisms and the environment was observed [77]. In general, SQG approaches that use different criteria and factors are divided into two main categories [76]: ...
... Sediment quality guidelines (SEQs) for TMs and metalloid in mg/kg d.w. that reflect threshold effect concentration (TEC) and probable effect concentration (PEC)[77][78][79][80][81][82].Empirical SQGs with TEC and PEC in mg/kg·d.w. ...
Article
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This paper provides an overview of different methods of assessing the trace metal (TM) contamination status of sediments affected by anthropogenic interference. The geochemical background determination methods are also described. A total of 25 papers covering rivers, lakes, and retention tanks sediments in areas subjected to anthropogenic pressure from the last three years (2019, 2020, and 2021) were analysed to support our examination of the assessment measures. Geochemical and ecotoxicological classifications are presented that may prove useful for sediment evaluation. Among the geochemical indices, several individual pollution indices (CF, Igeo, EF, Pi (SPI), PTT), complex pollution indices (PLI, Cdeg, mCdeg, Pisum, PIAvg, PIaAvg, PIN, PIProd, PIapProd, PIvectorM, PINemerow, IntPI, MPI), and geochemical classifications are compared. The ecotoxicological assessment includes an overview of Sediment Quality Guidelines (SQG) and classifications introduced nationally (as LAWA or modified LAWA). The ecotoxicological indices presented in this review cover individual (ERi) and complex indices (CSI, SPI, RAC, PERI, MERMQ). Biomonitoring of contaminated sites based on plant bioindicators is extensively explored as an indirect method for evaluating pollution sites. The most commonly used indices in the reviewed papers were Igeo, EF, and CF. Many authors referred to ecotoxicological assessment via SQG. Moreover, PERI, which includes the toxic response index, was just as popular. The most recognised bioindicators include the Phragmites and Salix species. Phragmites can be considered for Fe, Cu, Cd, and Ni bioindication in sites, while Salix hybrid cultivars such as Klara may be considered for phytostabilisation and rhizofiltration due to higher Cu, Zn, and Ni accumulation in roots. Vetiveria zizanoides demonstrated resistance to As stress and feasibility for the remediation of As. Moreover, bioindicators offer a feasible tool for recovering valuable elements for the development of a circular economy (e.g., rare earth elements).
... This paper contends that the relative influences of true effects, random variation, and confounding may go unrecognized, unseparated in the derivation of benchmarks, or may not be adequately communicated to users. The evaluation of sample size on the reliability of empirical benchmarks complements the findings from a Society of Environmental Toxicology and Chemistry (SETAC) Pellston Workshop on Use of Sediment Quality Guidelines and Related Tools for the Assessment of Contaminated Sediments (Wenning et al., 2005). Fifty-five experts from North America, Europe, and Australia met for six days to review existing guidelines (or benchmarks) from around the world, assess strengths and limitations, and provide recommendations on framework and approaches that incorporate predictive and empirically derived concentration values in sediment. ...
... Threshold calculation methods like ERL try to isolate components of these mixtures and draw causal inferences about the individual components, but those components were not sampled in isolation or controlled in a laboratory experiment, and they are present in different sample sizes across mixture components. This is currently well understood as a limitation of such guidelines (Wenning et al., 2005). What has not been explored are the possible magnitudes of error associated with the derived values and the possibility that less toxic chemicals can be found to be toxic by association with other stressors in the sample. ...
Article
Tabulations of numerical concentration-based environmental benchmarks are commonly used to inform decisions on managing chemical exposures. Benchmarks are usually set at levels below which there is a low likelihood of adverse effects. Given the widespread use of tables of benchmarks, it is reasonable to expect that they are adequately reliable and fit for purpose. The degree to which a derived benchmark reflects an actual effect level or statistical randomness is critically important for the reliability of a numerical benchmark value. These expectations may not be met for commonly-used benchmarks examined in this study. Computer simulations of field sampling and toxicity testing reveal that small sample size and confounding from uncontrolled factors that affect the interpretation of toxic effects contribute to uncertainties that might go unrecognized when deriving benchmarks from data sets. The simulations of field data show that it is possible to derive a benchmark even when no toxicity is present. When toxicity is explicitly included in simulations, imposed effect threshold levels could not always be accurately determined. Simulations were also used to examine the influence of mixtures of chemicals on the determination of toxicity thresholds of chemicals within the mixtures. The simulations showed that data sets that appear large and robust can contain many smaller data sets associated with specific biota or chemicals. The sub-sets of data with small sample sizes can contribute to considerable statistical uncertainty in the determination of effects thresholds and can indicate that effects are present when they are absent. The simulations also show that less toxic chemicals may appear toxic when they are present in mixtures with more toxic chemicals. Because of confounding in the assignment of toxicity to individuals chemicals within mixtures, simulations showed that derived toxicity thresholds can be less than the actual toxicity thresholds. A set of best practices is put forward to guard against the potential problems identified by this work. These include conducting an adequate process of determining and implementing Data Quality Objectives (DQOs), evaluating implications of sample size, designing appropriate sampling and evaluation programs based on this information, using an appropriate tiered evaluation strategy that considers the uncertainties, and employing a weight of evidence approach to narrow the uncertainties to manageable and identified levels. The work underscores the importance of communicating the uncertainties associated with numerical values commonly included in tables for screening and risk assessment purposes to better inform decisions.
... However, overall sediment pass/fail outcomes using different AL sets with the same narrative intent (e.g., AL1, AL2) do not differ nearly as much as outcomes using different chemical action lists and decision rules (Apitz et al., 2007, Apitz, 2008, 2011Wenning et al., 2005;Apitz and Agius, 2013). The "Consensus" AL1 values used here provide a consistent set of hypothetical ALs for the full suite of contaminants in this study; they should not be regarded as regulatory proposals. ...
... This assumption is necessary to provide some basis of comparison, but the toxicity measures themselves contain uncertainty. Bioassessment can be subject to a range of confounding factors, and may be sensitive to unmeasured contaminants in the sediments; errors or mis-classifications can occur in any measurement (Apitz 2011;Wenning et al. 2005). Scenarios using mHQ filters to evaluate the possibility that sediments failing a single sub-lethal assessment (not described here but results in Table S1-3) suggest that some proportion of sediments classified as sub-lethally toxic (i.e., failing one sub-lethal test) could be the result of confounding factors (the authors were able to confirm that hydrogen sulphide toxicity, which has a strong confounding effect in Microtox™ bioassays done using solvent extracts, was unlikely to be the culprit since standard procedures used in the National Status and Trends Program require the removal of hydrogen sulphide prior to solvent extraction (Long et al., 1999). ...
Article
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The effects of possible changes to the Canadian two tiered assessment framework for dredged material based on outcomes of the 2006 Contaminated Dredged Material Management Decisions Workshop (CDMMD) are evaluated. Expanding on the "data mining" approach described in Apitz and Agius, 2013, which focused solely on chemical lines of evidence, the efficacy of Tier 1 approaches (increases to the number of chemical analytes, use of mean hazard quotients and the use of a screening bioassay) in predicting toxicity are evaluated. Results suggest value in additional work to evaluate the following areas: a) further expanding minimum chemical requirements, b) using more advanced approaches for chemical interpretation, and c) using a screening level bioassay (e.g. Canadian solid-phase photo-luminescent bacteria test) to determine whether it would complement Tier 1 chemistry as well as or better than the solvent-based Microtox(TM) test method evaluated in this study. This article is protected by copyright. All rights reserved.
... The concentrations of Mn in both the banks of the river were below their background value (i.e., 460 mg/kg) and showed no significant increase in concentration from the right to left banks of the river. Similarly, the concentration of Zn, Cu, and Fe is found below the maximum admissible concentrations as recommended by (Wenning et al. 2002;USEPA 2009) and also lower than average shale, threshold effect level (TEL), and portable effect level (PEL) values (Table 1). Relatively, narrow dispersion of these metals was noted in sediments among both banks (left and right) of the river. ...
... The results of Mn, Fe, Zn, and Cu in the study area are consistent with those reported by Nazeer et al. (2014) in the Soan River. In the study area, Pb content in sediment samples of the left bank of the river was slightly higher than regulatory limits of interim sediment quality guideline (ISQG) (Wenning et al. 2002;USEPA 2009), i.e., 35.8 mg/kg. The maximum concentration (72.0 mg/kg) of Pb was found in the samples collected from the left bank on the downstream of the river. ...
Article
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To assess the trace metal pollution in the Siran River, sediments were collected from 12 sites, from the left and right banks of the river in 2013. The concentrations, accumulation, distribution pattern, and pollution status of heavy metals in sediments were investigated using geoaccumulation index (Igeo) and enrichment factor (EF). The toxic risk of heavy metals was assessed using interim sediment quality guidelines (ISQGs), portable effect level (PEL), threshold effect level (TEL), and toxic effect threshold (TET). Igeo and EF values showed that sediments were loaded with Ni, Cd, Pb, and Co and no obvious variations were found among the left and right banks of the river. The EF and Igeo values were found in order of Co > Pb > Ni > As > Cd > Cu > Zn > Fe and Cd > Co > Pb > Ni > As > Fe > Zn > Cu > Mn, respectively. Furthermore, multivariate statistical analysis like inter-metal correlation, cluster analysis (CA), and principal component analysis (PCA) results revealed that geogenic and anthropogenic activities were major sources of sediment contamination in the study area. These results indicated that more attention should be paid to the inner loads of sediment in order to achieve improvements in reservoir water quality after the control of external pollution.
... This subsequently makes it difficult to detect, quantify or pin-point a specific pollutant at a given contamination site. Challenge is therefore to accurately assess the impacts of the pollutants as well as the remediation measures undertaken (Burton Jr, 1991;Wenning et al., 2005). The use of sediment cores for sample collection has been commonly practiced for analyzing contamination in streambeds Van Metre et al., 2003;Brinkmeyer et al., 2015). ...
Article
Streambeds are an integral part of the river ecosystems. They provide habitat to a vast array of aquatic and benthic organisms as well as facilitate the bio-degradation and transformation of organic matter and vital nutrients. Increasing anthropogenic influence introduces multiple stressors to the stream networks resulting in pollution of streambeds, which in turn, have detrimental effects on the overall stream ecosystem health. There is a huge gap in the current understanding of streambed pollution and its impacts, and the widely practiced streambed pollution mitigation strategies lack a holistic approach. In this comprehensive review, we first synthesize the state-of-the-art knowledge of conventional and emerging forms of contaminants, their overall impacts on stream ecosystem functions, and present future directions to comprehend the problem of streambed pollution. We highlight that fine sediments and plastics (found especially in urban streambeds) are among the major physical pollutants causing streambed pollution and the chemical pollutants generally comprise hydrophobic compounds including various legacy contaminants such as polychlorinated biphenyl (PCB), dichlorodiphenyltrichloroethane (DDT), a wide range of pesticides and a variety of heavy metals. Moreover, in recent years, highly polar and hydrophilic emerging contaminants such as micro-plastics, pharmaceutical waste and personal care products have been identified in riverbeds and streambeds across the world. We stress that the impacts of streambed pollution have been largely studied with discipline-driven perspectives amongst which the ecological impacts have received a lot of attention in the past. To present a comprehensive outlook, this review also synthesizes and discusses some of the understudied hydrological, geomorphological and biochemical impacts of different forms of streambed pollution. Subsequently, we also present a global inventory by compiling information from the published literature to highlight the status of streambed pollution around the globe. In the end, we endorse the positive and negative aspects of the current impact assessment methodologies and also highlight various physical, chemical and biological remediation measures that could be applied to alleviate streambed pollution.
... The derivation of guideline values for sediments is a more recent problem, but nonetheless one that is in need of harmonization. International approaches all predominantly rely on effects data or, in some instances, mechanistic guidelines based on equilibrium partitioning (Batley et al. 2005). The values derived by various jurisdictions are quite variable (Buchman 2008), although an analysis of the causes of this variation has not been conducted. ...
... Sediment quality guidelines (SQGs) are tools which use a variety of methods and assumptions related to concentrations of contaminants in sediments to predict the intensity of biological effects (MacDonald et al. 2000;Wenning 2005). In this study, concentrations of eight heavy metals in sediments from the East Dongting Lake and Honghu Lake were evaluated in the screening levels of ecological risk based on two sets of SQGs for freshwater ecosystems: The effect range low (ERL), effect range median (ERM), the threshold effect concentration (TEC), and probable effect concentration (PEC) values were applied. ...
Article
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Eight heavy metals including Cr, Ni, Cu, Zn, As, Cd, Hg, and Pb were investigated in surface water and sediments from a river-connected and a river-disconnected lakes (East Dongting Lake and the Honghu Lake, respectively). Zn had the highest mean concentrations in surface water in both lakes. Pearson’s correlation, principal component analysis, and hierarchical cluster analysis revealed that the distributions of Zn, Pb, and As in the East Dongting Lake and Zn, Cd, and As in the Honghu Lake were associated with anthropogenic activities. Nickel and Cr were associated with natural sources, while Cu and Hg originated from both anthropogenic and natural sources. Sediment quality guidelines revealed that both As and Hg could probably have adverse effects in the East Dongting Lake, whereas all detected heavy metals probably could not lead to adverse effects in the Honghu Lake. Potential ecological risks indices (RIs) of heavy metals in two lakes were 999.4 and 151.45, respectively, indicating greater pollution of heavy metals with high risk in the East Dongting Lake as compared to the Honghu Lake with low to moderate risk.
... Thus, responses observed in the laboratory may not occur or be as pronounced in natural systems. Higher weighting for biological LOE based on field observations is consistent with higher weighting of field-based effect studies than laboratory and chemistry-based analyses (Chapman and Anderson 2005; Wenning et al. 2005 ...
Weight of evidence (WOE) frameworks integrate environmental assessment data to reach conclusions regarding relative certainty of adverse environmental effects due to stressors, possible causation, and key uncertainties. Such studies can be investigative (i.e., determining whether adverse impact is occurring to identify a need for management) or retrospective (i.e., determining the cause of a detected impact such that management efforts focus on the correct stressor). WOE assessments do not themselves definitively establish causation; they provide the basis for subsequent follow-up studies to further investigate causation. We propose a modified investigative WOE framework that includes an additional weighting step, which we term "direction weighting". This additional step allows for the examination of alternative hypotheses, and provides improved certainty regarding possible causation. To our knowledge, this approach has not been previously applied in investigative ecological WOE assessments. We provide a generic example of two conflicting hypotheses related to a mine discharging treated effluent to a freshwater lake: chemical toxicity versus nutrient enrichment. This article is protected by copyright. All rights reserved.
... The x-axis and y-axis stand for decimal longitude and latitude, respectively. and consequently the PAH bioavailability, into account in the sediment matrices, PAH concentrations were normalized to 1% of TOC (Burgess et al., 2000;Wenning, 2005). PAH isomeric ratios (or diagnostic ratios), Phenanthrene/Anthracene (P/A) and Fluoranthene/Pyrene (F/P) were calculated in order to determine the bulk origin of the PAH contamination in sediment samples. ...
Article
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Benthic microorganisms are key players in the recycling of organic matter and recalcitrant compounds such as polyaromatic hydrocarbons (PAHs) in coastal sediments. Despite their ecological importance, the response of microbial communities to chronic PAH pollution, one of the major threats to coastal ecosystems, has received very little attention. In one of the largest surveys performed so far on coastal sediments, the diversity and composition of microbial communities inhabiting both chronically contaminated and non-contaminated coastal sediments were investigated using highthroughput sequencing on the 18S and 16S rRNA genes. Prokaryotic alpha-diversity showed significant association with salinity, temperature, and organic carbon content. The effect of particle size distribution was strong on eukaryotic diversity. Similarly to alpha-diversity, beta-diversity patterns were strongly influenced by the environmental filter, while PAHs had no influence on the prokaryotic community structure and a weak impact on the eukaryotic community structure at the continental scale. However, at the regional scale, PAHs became the main driver shaping the structure of bacterial and eukaryotic communities. These patterns were not found for PICRUSt predicted prokaryotic functions, thus indicating some degree of functional redundancy. Eukaryotes presented a greater potential for their use as PAH contamination biomarkers, owing to their stronger response at both regional and continental scales.
... Mahdollisia lähteitä (Sediment Quality Guidelines) ovat Yhdysvaltain (US EPA) ja Ruotsin (Swedish EPA 2000) ympäristönsuojelutoimiston, Australian ympäristömyrkkyjen tutkimuskeskuksen (Simpson et al. 2005) ja Kanadan hallituksen ohjeet (Canadian Council of Ministers of the Environment 1995). Hyvä yleisesitys sedimentin laatunormikäytänteistä eri maissa löytyy SETAC-järjestön julkaisusta (Wenning et al. 2005) sekä tämän hetken tilanne sedimenttien riskinarvioinnissa Euroopan kemikaaliviraston sivuilta (www.echa.europa.eu). ...
Technical Report
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The Ministry of Employment and the Economy (TEM) has recently published a guide on the environmental impact assessment (EIA) procedure for mining projects in Finland. The TEM guide focuses on the process of EIA application to mining projects. The current report was planned to provide supporting material for the TEM guide, and is a review of good practices for the predictive assessment of environmental impacts related to mining projects. This report presents good practices and approaches to early-phase EIA for mining projects in general, but is also within the context of the formal EIA process that is guided by EIA legislation. It addresses the EIA process objective of comparing major impacts of project alternatives, while providing consideration for the often limited data available in the early phases of the project. This report discusses the typical environmental impacts of mining, different mining processes, methods to characterize emissions from these processes, studies to define the baseline conditions of the planned mine site, and approaches for the actual assessment of various mining impacts. The final sections of the report review methods to determine the significance of the impacts and to compare project alternatives. This report differs from most industry-specific EIA guides in that it concentrates on the actual assessment of impacts. For instance, the sections dealing with health, social and economic impacts are quite extensive. The report also presents human rights-based approaches to impact assessment which is new to EIA. The aim of the report was to cover a wide variety of impacts. Subsequently, all of the listed impacts will not be an issue at any single mine, but every mining project can benefit from something in the report. The report as a whole also serves as a checklist for possible environmental impacts from mining projects. However, the report is not an exhaustive treatment of the topic and it should not be applied as an official guidance document. The report has been compiled by a large team of experts from the Geological Survey of Finland, Finnish Environment Institute, National Institute for Health and Welfare, University of Helsinki, FIANT Consulting Oy, Ramboll Finland Oy, Pöyry Finland Oy, and Ahma Environment Ltd. The authors are responsible for the content of their texts.
... Sediment samples for this study were collected from Hecklinger pond at the headwaters of Duck Creek, a fourmile stream that flows directly into the Maumee River and then into Lake Erie (Fig. 1). The pond has a surface area of approximately 3.32 ha with a steep concentration gradient of PCBs and PAHs as well as various heavy metal contaminants within its sediments, exceeding both the Ecological Reference and/or Human Health Reference Limits [30,31] [32,33] shortly before sample collection occurred. PCB Aroclors 1254 and 1260 in polluted sediments were detected at a concentration of 0.195 and 0.145 mg kg −1 of sediments, respectively, whereas total PCBs from the unpolluted location were undetectable. ...
Article
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Biphenyl dioxygenases, encoded by the bphA gene, initiate the oxidation of polychlorinated biphenyls (PCBs) and specify the substrate range of PCB congeners metabolized by bacteria. Increased bphA gene diversity within microbial communities may allow a broader range of PCB congeners to be catabolized, thus resulting in greater PCB degradation. To assess the role of PCBs in modulating bphA gene diversity, 16S ribosomal RNA (rRNA) gene and bphA environmental DNA libraries were generated from bacterial communities in sediments with a steep gradient of PCB contamination. Multiple measures of sequence diversity revealed greater heterogeneity of bphA sequences in polluted compared to unpolluted locations. Codon-based signatures of selection in bphA sequences provided evidence of purifying selection. Unifrac analysis of 16S rRNA sequences revealed independent taxonomic lineages from polluted and unpolluted locations, consistent with the presence of locally adapted bacterial communities. Phylogenetic analysis of bphA sequences indicated that dioxygenases from sediments were closely related to previously characterized dioxygenases that metabolize PCBs and polynuclear aromatic hydrocarbons (PAHs), consistent with high levels of these contaminants within the studied sediments. Structural analyses indicated that the BphA protein of Rhodococcus jostii, capable of metabolizing both PCBs and PAHs, provided a more optimal modeling template for bphA sequences reported in this study than a BphA homologue with more restricted substrate specificity. Results from this study suggest that PCBs and PAHs may drive local adaptation of microbial communities by acting as strong selective agents for biphenyl dioxygenases capable of metabolizing a wide range of congeners.
... Aujourd'hui, l'approche la plus utilisée en biosurveillance repose sur l'évaluation intégrée de la qualité des sédiments à partir d'une triade basée sur une approche chimique, écotoxicologique et biologique. Ce concept de base repose sur l'utilisation d'outils de laboratoire et d'observations in situ, permettant à la fois de renseigner sur l'exposition aux contaminants présents et sur les effets mesurés à différents niveaux d'organisation biologique jusqu'aux communautés (Chapman 1990 ;Wenning et al. 2005). ...
Article
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Les oligochètes sont utilisés en Suisse dans certains cantons pour évaluer la qualité biologique des cours d’eau et des lacs. L’indice oligochètes de bioindication des sédiments (IOBS) permet d’évaluer la qualité des sédiments fins/sableux de cours d’eau et la méthode des Traits fonctionnels (TRF) d’évaluer la qualité des sédiments grossiers superficiels et du milieu hyporhéique ainsi que de connaître la dynamique des échanges hydrologiques entre les eaux de surface et les eaux souterraines. L’IOBS a été appliqué en routine dans la région genevoise de 2008 à 2013 (92 relevés) et la méthode TRF y a été testée en 2012 et 2013. L’IOBS s’est révélé un bon bioindicateur de la qualité chimique des sédiments. Des seuils de toxicité des métaux des sédiments ont été établis et proposés. L’application de l’IOBS en complément de l’Indice biotique suisse (IBCH) a permis d’affiner les diagnostics écologiques. L’approche TRF s’est révélée d’un grand intérêt pour évaluer simultanément la qualité biologique des habitats grossiers et les échanges hydriques verticaux. L’IOBS et la méthode TRF devraient davantage être intégrés dans les programmes de surveillance de la qualité des cours d’eau. Le développement actuellement en cours de méthodes basées sur l’identification des oligochètes à l’aide de code-barres génétiques pourrait permettre de résoudre les problèmes liés à l’identification morphologique des espèces et une plus large utilisation des oligochètes comme bioindicateurs.
... The estimation of chemical contamination e ects on sediment quality requires consideration of a number of issues, due to the laborious comprehension of the biological availability of chemicals in sediments. Usually, the chemicals are present in the form of mixed chemical compounds so, their cumulative e ects on sediment are di cult to anticipate [21]. Aquatic ecosystems must be investigated in a holistic and integrated manner for water and sediment quality assessment. ...
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The aim of the study was to evaluate the impact of potential pollution sources, mainly from the upstream anthropogenic sources and port-related activities. The in-vestigated area covered a wide range of anthropogenic im-pacts (e.g., industrial wastes, storm water runoff, acciden-tal oil spills, intentional discharges and shipping activities). The quality of water and Sediments was assessed us-ing Standard methods, as physical-chemical parameters, chemistry and biology (microbiology, ecotoxicology) aim-ing to figure the level of pollution and the effect of port-related activities. Seawater quality results agreed generally with environmental Standards. Though, in some samples the concentrations of sulphates (mg/1) and heavy metals (μg/1), as B, As and Se exceeded the recommended lim-its, without posing a serious environmental concern. Most of the surface sediment samples contain critical levels of hydrocarbons (C>12), (mg/kg), polycyclic aromatic hydrocarbons (ng/g) and polychlorobiphenyls (ng/g). For some heavy metals (mg/kg), exchangeable concentrations were found to be very close or above the regulations. The signifi-cance of this study is incontestable taking into account the lack of previous relevant historical data of this area. In this sense, it was possible to indicate, in general, good environmental conditions, despite the industrial and concentrated local port-related activities in the investigated area.
... Sediment quality guidelines (SQGs) are useful to screen sediment contamination by comparing sediment contaminant concentration with the corresponding quality guidelines (Caeiro et al., 2005). These guidelines evaluate the degree to which the concentrations of contaminants in the sediments might adversely affect aquatic organisms and are designed to assist the interpretation of sediment quality (Wenning et al., 2005). Two types of SQGs developed for freshwater ecosystems (MacDonald et al., 2000) were applied in the present study: ...
Article
In this study the level of toxic metals (Mn, Zn, Pb, Cd, Co, Cu) was determined in sediment samples from the Chenab River, Pakistan. The potential toxicity of studied metals was determined by evaluating enrichment factor (EF), geo-accumulation index (Igeo) and metal pollution index (MPI). Considering the spatial distributional patterns, the metal concentrations were higher at Trimmu Headwork site followed by Pujnad, Khanki, Marala and Qadirabad Headwork sites. Unusual higher concentrations in the deeper sediments were observed, suggesting a historical deposition of the investigated metals in the area. The Igeo and EF values revealed that sediments in this study were considerably polluted by Cd and Pb and moderately polluted by other metals. Evaluation of metal toxicity based on mean probable effect concentration PEC quotient confirmed that the Chenab River is seriously contaminated with Cd and Pb. Results of the spatial distribution pattern revealed that rapid industrialization and urbanization nearby the study area were probable sources of metal pollution. Proper measures should be taken by industrial units to ensure appropriate treatment of wastewater before disposing the toxic effluents into nearby tributaries. Government authorities must ensure strict enforcement of the National Environmental Quality (NEQ) standards of municipal and industrial effluents to save the Chenab River from further degradation.
... The various lines of evidence were weighed based on the order of priority outlined by the Ontario Ministry of the Environment [9]. In agreement with the guidance of Wenning et al. [18], chemical lines of evidence received less weight than biological lines of evidence. Further, lines of evidence that involve individual organisms (e.g., laboratory toxicity tests) received less weight than lines of evidence that involve resident natural populations and communities (e.g., in-river benthic invertebrate surveys). ...
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Canadian Nuclear Laboratories’ Chalk River Laboratories (CRL) site is situated on the banks of the Ottawa River, about 180 km northwest of the City of Ottawa. Since 1947, the Ottawa River has received effluent from CRL's operations. Since this time, and in particular during the operation of the national research experimental research reactor (1947–1992), radionuclides (mainly 60Co and 137Cs) and mercury released in effluents have accumulated in deep-water sediments downstream of CRL. In the following, we present a holistic summary of characterization of the historical contamination and ecological risk assessment work completed to date. The evaluation included (i) comparisons of recommended benchmark dose and screening levels with concentrations in water and sediment, (ii) determination of relevant exposure pathways and biological receptors, (iii) measured and (or) modelled contaminant exposure to benthic receptors and trophic transfer of contaminants to upper trophic level receptors, (iv) whole-sediment laboratory toxicity tests using benthic invertebrates and fish, and (v) field studies assessing possible intermediate or long-term effects on aquatic biota at the population and community levels. The ecological risk related to the contaminated sediment site was assessed using multiple lines of evidence and a weight-of-evidence approach. Despite concentrations of anthropogenic radionuclides and mercury above screening levels in Ottawa River sediments near CRL, the laboratory toxicity tests, radiological dose and mercury bioaccumulation modelling, and biological surveys of benthic invertebrates and fish indicated no significant adverse effects. Ecological risk to Ottawa River benthic invertebrates, fish, fish-eating birds and mammals from historical sediment contamination near CRL is low-to-negligible, and levels of risk will continue to decline as sediment-bound radionuclides decay and contamination is buried by new sediment.
... At present, weight-of-evidence approaches, such as the sediment quality triad [16,17], are widely accepted to assess the ecological risk of sediment-bound contaminants, but the setting of environmental quality standards as done for surface water is still in its early stages. Over the years, research has demonstrated that sediments exceeding sediment quality guidelines do not always result in toxic effects on benthic organisms, and sometimes, even the opposite has been observed, probably due to the different bioavailability of contaminants [18]. In addition to chemical analysis and in situ benthic community assessment, ecotoxicity testing with single species could therefore be particularly useful. ...
Article
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Within the context of the Water Framework Directive, the need to identify new monitoring tools in support of the traditional chemical monitoring process is emerging. Chemical characterization by itself does not provide specific biological information about potential hazards to organisms, in particular when facing cocktails of contaminants. Therefore, ecotoxicity tests can represent a useful tool supporting the chemical information. In the present work, the value of ecotoxicity tests as an effect-based tool for monitoring freshwater and sediment quality of the south-western basin of Lake Como (Northern Italy) was evaluated, assessing the potential risk of pollutants. Results obtained from D. magna toxicity tests showed a temporal variation of toxic response in relation to the variability of organic micropollutant load characteristics of urban rivers. Sediment ecotoxicity test data showed the spatial variability of the sediments’ contamination within the lake, confirmed by chemical analysis of two classes of pollutants (dichlorodiphenyltrichloroethane (DDT) and polychlorobiphenyls (PCB)). The observed effects on organisms in laboratory tests caused by a mixture of almost unknown chemicals underline the importance of integrating effect-based tools into monitoring efforts.
... Especially through the activities of SETAC North America (Wenning et al. 2005; and the European SedNet network (Salomons and Brils 2004;SedNet 2004) sediment related issues were given increasing attention in both science and the public. While water quality has notably improved over the past three decades, the sediments in many European river basins still retain the toxic heritage from the past era of uncontrolled industrial production, and which will continue to influence the quality of waters significantly for many years to come (Salomons and Brils 2004;SedNet 2004). ...
... Although data from multiple metrics would best depict the condition of a restoration project, monitoring metrics must also reflect available funding. Selection should rely on the literature and knowledge of reference areas with an additional eye toward critical species, their habitats, and biotic and abiotic criteria such as organism abundance and water and/or soil chemistry ( Meador et al. 2002;Cacela et al. 2005;Gouguet 2005;Wang et al. 2013). As the restoration matures, monitoring efforts concentrate on metrics that help define limiting factors and instruct ongoing restoration activities. ...
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Ecological restorations of contaminated sites balance the human and ecological risks of residual contamination with the benefits of ecological recovery and the return of lost ecological function and ecosystem services. Risk and recovery are interrelated dynamic conditions, changing as remediation and restoration activities progress through implementation into long-term management and ecosystem maturation. Monitoring restoration progress provides data critical to minimizing residual contaminant risk and uncertainty, while measuring ecological advancement toward recovery goals. Effective monitoring plans are designed concurrently with restoration plan development and implementation and are focused on assessing the effectiveness of activities performed in support of restoration goals for the site. Physical, chemical and biotic measures characterize progress toward desired structural and functional ecosystem components of the goals. Structural metrics, linked to ecosystem functions and services, inform restoration practitioners of work plan modifications or more substantial adaptive management actions necessary to maintain desired recovery. Monitoring frequency, duration and scale depend on specific attributes and goals of the restoration project. Often tied to restoration milestones, critical assessment of monitoring metrics ensures attainment of risk minimization and ecosystem recovery. Finally, interpretation and communication of monitoring findings inform and engage regulators, other stakeholders, the scientific community and the public. Since restoration activities will likely cease prior to full ecosystem recovery, monitoring endpoints should demonstrate risk reduction and a successional trajectory toward the condition established in the restoration goals. A detailed assessment of the completed project's achievements, as well as unrealized objectives, attained through project monitoring, will determine if contaminant risk has been minimized, if injured resources have recovered and if ecosystem services have been returned. Such retrospective analysis will allow better planning for future restoration goals and strengthen the evidence base for quantifying injuries and damages at other sites in the future. This article is protected by copyright. All rights reserved.
... The routine analysis of these compounds in monitoring programs together with ecotoxicological and ecological indicators has helped the process of developing and validating SQGs around the world for many of these substances. Over the past few decades, SQGs have been developed for Btraditional^sediment contaminants including PCBs, PAHs, and organochlorine pesticides (Wenning et al. 2005;de Deckere et al. 2011). Lindane, endosulfan, and heptachlor, all of them phased out organochlorine insecticides, appear most often at concentrations below SQGs and may be recommended for reduced routine monitoring in the absence of other evidence (category 5). ...
Article
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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.
... Traditional approaches for assessment of contaminated sediments and verification of remedial measures generally rely on laboratory-based exposures for toxicity and bioaccumulation coupled with bulk sediment chemical characterization and benthic community structure characterization [21]. While these laboratory methods provide a high degree of experimental control, often times this comes with a significant loss of representativeness due to excessive manipulation and loss of the natural conditions and integrity of the samples and exposures [22]. ...
... Chemistry, toxicity and bioaccumulation tests are frequently used to evaluate risks of contaminated sediments to environmental receptors (USEPA, 2005). Whereas chemistry measurements can provide quantitative information on contaminants, toxicity tests provides direct measures of biological impacts (ASTM, 2009).A combination of these approaches through comparison of chemistry data to toxicity effect-based sediment quality guidelines can be used to evaluate the severity of sediment contamination (Wenning et al., 2005). The ERL for Cr, Cu, Pb, and Zn in the scheme proposed by MacDonald et al. (2000) are 80, 70, 35, and 120µg/g whereas ERM for Cr, Cu, Pb, and Zn are 145, 390, 110, and 270µg/g. ...
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Sediment core samples from seven stations in three Kenyan estuaries were analysed for Al, Ni, Zn, Cu, Cr, Mn and Pb by atomic absorption spectrophotometry to determine the spatial contamination (vertical and horizontal) and to identify any potential ecological risks. Samples were analysed for total metal concentration and data normalised using regression model of metal/Ni. The data was further compared to toxicity based Sediments Quality Guidelines (SQG) [Effects Range Low (ERL) and Effect Range Median (ERM)] giving an indication of potential ecological risks.There was a general reduction in metals input into the Kenya estuaries as evident from depletion of a number of metals in surface samples as compared to the subsurface samples. Enrichment Factors (EF) ranged from 0.1-92.9 indicating low to extreme contamination. Low contribution of anthropogenic sources of metal and the existence of metals in acceptable risk levels in most of the sites was also observed. However, some sites had a few samples with moderate to significant anthropogenic contribution of metals with the associated moderate to significant potential risk to biota. This study recommends a site-specific evaluation of these sites in order to quantify the level of risk, identifysource of contamination and suggest relevant management and mitigation measures.
... Hence, it is important to protect sediments from the impacts of contamination to preserve functional ecosystems. The intent of most Sediment Quality Guideline Values (SQGVs) is to provide a concentration below which the risk of adverse effects to aquatic organisms will be negligible (Wenning et al., 2005;Simpson and Batley, 2016). Many SQGVs used globally have been derived using a similar approach, i.e., using relationships between contaminant concentrations in field-collected sediments and observations of differences in ecology (e.g. ...
Article
The derivation of sediment quality guideline values (SQGVs) presents significant challenges. Arguably the most important challenge is to conduct toxicity tests using contaminated sediments with physico-chemistry that represents real-world scenarios. We used a novel metal spiking method for an experiment that ultimately aims to derive a uranium SQGV. Two pilot studies were conducted to inform the final spiking design, i.e. percolating a uranyl sulfate solution through natural wetland sediments. An initial pilot study that used extended mixing equilibration phases produced hardened sediments not representative of natural sediments. A subsequent percolation method produced sediment with similar texture to natural sediment and was used as the method for spiking the sediments. The range of total recoverable uranium (TR-U) concentrations achieved was 8–3200 mg/kg. This reflected the concentrations found in natural wetlands and water management ponds found on a uranium mine-site and was above natural levels. Dilute-acid extractable uranium (AE-U) concentrations were >80% of total concentrations, indicating that much of the uranium in the spiked sediment was labile and potentially bioavailable. The portion of TR-U extractable as AE-U was similar at the start and end of the 4.5-month field-deployment. Pore-water uranium (PW–U) analyses indicated that partition coefficients (Kd) were 2000–20,000 L/kg, and PW-U was greater in post-than pre-field-deployed samples when TR-U was ≤1500 mg/kg, indicating the binding became weaker during the field-deployment period. At higher spiked-U concentrations, the PW-U was lower post-field-deployment. Comparing the physico-chemical data of the spiked sediments with environmental monitoring data from sediments in the vicinity of a uranium mining operation indicated that they were representative of sediments contaminated by mining and that the U-spiked sediments had a clear U concentration gradient. This confirmed the suitability of the spiking procedure for preparing sediments that were suitable for deriving a SQGV for uranium.
... Sediment quality guidelines (SQGs) are useful to screen sediment contamination by comparing sediment contaminant concentration with the corresponding quality guidelines (Caeiro et al., 2005), which evaluate the degree to which the sediments associated chemical status might adversely affect aquatic organisms and are designed to assist the interpretation of sediment quality (Wenning et al., 2005). Threshold effect level (TEL) refers to the concentration below which adverse biological effects are expected to occur rarely, and Probable effect level (PEL) indicates the concentration above which adverse effects are expected to occur frequently (Long and Morgan, 1990). ...
Article
Heavy metal pollution in sediment resources may pose serious threat to ecosystem and human health through food web. In this study, surface sediment samples of 10 stations along the Feni River estuary were analyzed to profile the accumulation, sources and pollution levels of heavy metals. The results revealed that the average contents (μg g-1) of eight selected heavy metals followed the order of Mn (37.85) > Cr (35.28) > Ni (33.27) > Co (31.02) > Pb (6.47) > Ag (1.09) > As (0.85) > Hg (0.71), and the concentrations varied spatially and seasonally with relatively higher levels at upward stations and during the rainy season. According to sediment quality guidelines (SQGs), the sediment samples were heavily contaminated with Ag and Hg, and moderately with Co. Threshold effect concentration (TEC) and probable effect concentration (PEC) values indicated that the concentration of only Ni and Cr were likely to occasionally exhibit adverse effects on the ecosystem. Enrichment factor (EF), geo-accumulation index (Igeo) and contamination factor (CF) analyses revealed that Ag, Co and Hg were at moderate to high pollution levels and the rests (As, Cr, Ni, Pb and Mn) were at no to low pollution levels. Potential ecological risk index (PERI) also showed that Ag, Co and Hg were the most potential ecological risk factor being determined in this studied area. Correlation matrix combined with multivariate principal component analysis and cluster analysis suggest that Ag, Co, Ni and Hg originated from anthropogenic sources (agrochemicals, silver nanoparticles anti-microbial agent, silver plating), whereas As, Cr, Pb and Mn primarily originated from natural geological background.
... In the present work, the total chemical analysis of the sediment fine fraction smaller than 63 µm was considered to be an adequate estimate of exposure. Adjustments to account for bioavailability or chemical speciation can improve exposure estimates (Wenning et al. 2005;Alvarez-Guerra et al. 2010;Lécrivain et al. 2018). To determine the potential mobility, bioavailability and toxicity of the elements examined, more extensive studies including the analysis of element speciation, as well as the temporal variability in the sediments' characteristics, are proposed. ...
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Purpose The Limoncocha lagoon, inside a Ramsar site in the Ecuadorian Amazon, increasingly hosts ecotourism and energy development activities. This work estimates the local sediments’ baseline of As, Ba, Cd, Co, Cr, Cu, Mo, Ni, Pb, V and Zn using four methods. This makes it possible to apply single and integrated pollution indices to estimate the contamination level and the ecological risk of the sediments. Methods Seven sites were analysed for metal(oid)s by ICP-MS. The local baseline was estimated using the relative cumulative frequency method, the iterative 2σ- and 4σ-outlier-techniques and the normalisation method to a “conservative” element. Combinations of single Cf and Ef and integrated indices (NPI, mNPI, mCd, MEQ, RI, mPELq, mERMq and TRI) were applied. Results The relative cumulative frequency method had the best performance for the geochemical baselines. Cf and Ef indices classify sediments from a “low contamination” remote site to the “moderate contamination” and “minor enrichment” of the remaining sites due to As, Cd and Zn concentrations. The overall analysis of the integrated indices results in Ni, Zn and Cu being identified as priority pollutants because they have occasionally been associated with adverse biological effects in the centre of the lagoon and in the most anthropised areas. These are classified as moderately polluted with a medium–low priority risk level. Conclusions This work provides sediment baseline and contamination indicators for pollutants, which could be incorporated into the sediment quality assessment and monitoring programme of the Limoncocha lagoon. Ni, Cd and Cr due to the high baseline values in comparison with SQGs, and Cu and Zn due to their potential risk, should be of special attention. Graphical abstract
... Il apparaît donc fondamental d aborder la gestion des sédiments suivant une approche durable, ce qui n est pas le cas pour la plupart des projets de gestion actuels (Apitz, 2012 (Wenning et al., 2005;Flück et al., 2012). Ces critères ont vocation à définir des concentrations problématiques en contaminants, classer des échantillons de sédiments selon leur potentiel toxique, prioriser les sites à protéger/dépolluer. ...
Thesis
Les enjeux écologiques, réglementaires et économiques imposent que des méthodologies robustes d'évaluation des risques environnementaux des sédiments contaminés soient proposées aux gestionnaires et autres parties prenantes. Il importe par ailleurs que ces méthodologies soient organisées selon une approche graduée, qui permette de hiérarchiser et proportionner les efforts mis en oeuvre pour l'évaluation, selon les risques potentiels sur les écosystèmes. Ce travail de thèse vise donc au développement d'un outil biologique pour l'évaluation du danger toxique lié à la contamination des sédiments d'eau douce, intégrables dans une démarche d'évaluation du risque. Il s'agit de mesurer la toxicité des sédiments naturels contaminés par des polluants chimiques, via la mesure des perturbations biologiques provoquées par l'exposition d'organismes au laboratoire. Ainsi une batterie de bioessais, composée de trois espèces phylogénétiquement différentes (G. fossarum arthropode crustacé ; P. antipodarum mollusque gastéropode et C. riparius arthropode insecte), a été mise en place. Le développement de la batterie s'est déroulé en deux étapes principales. La première a porté sur l'évaluation de la variabilité des traits de vie des organismes exposés à une série de sédiments de qualité acceptable, et couvrant une gamme la plus large possible de granulométrie et de quantité de matière organique. La réalisation de cette étape a permis de proposer, pour chaque espèce et chacun des traits considérés, une gamme de réponse considérée comme normale, en dehors de laquelle un effet toxique chimique du sédiment est significativement mis en évidence. La seconde étape consistait à comparer les réponses des traits de vie en conditions contaminées à la gamme de réponses en conditions pas / peu contaminées préalablement définie. Ainsi, la capacité à caractériser des sédiments contaminés a été évaluée pour chaque trait de vie de chaque organisme. Les résultats obtenus montrent que certains traits ont un potentiel de discrimination fort (ex : taux d'alimentation de G. fossarum) alors qu'il est très faible pour d'autres (ex : production d'embryons de P. antipodarum). Les traits au potentiel de discrimination "intermédiaire" sont traités au cas par cas. Ils peuvent en effet être moyennement sensibles à un ensemble de contaminants, ou présenter des sensibilités spécifiques (ex : la croissance de C. riparius n'a répondu qu'aux sédiments présentant une contamination aux pesticides). L'exploitation des résultats a permis d'aboutir à la définition de référentiels de réponse pour chaque trait de vie testé pour les trois espèces et à des recommandations d'utilisation des tests mis en place (quels espèces / traits conserver, comment les combiner, que faudrait-il faire pour perfectionner la batterie ?)
... Ecological risk indices are being a major screening tool to potentially identify, rank, and prioritize significant toxic metals or contaminants in a system. There are several geo-chemistry-based empirical and mechanistic approaches to evaluate the potential risk of benthic sediment dwellers (Wenning, 2005;Birch, 2018). But, when indices are applied, the role of individual metals or contaminants to the overall risks was reduced because the approaches average the multiple toxic concentrations. ...
Article
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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 thirty 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.
... This subsequently makes it diffi-cult to detect, quantify or pin-point a specific pollutant at a given contamination site. Challenge is therefore to accurately assess the impacts of the pollutants as well as the remediation measures undertaken [187,188]. The use of sediment cores for sample collection has been commonly practiced to analyze the streambed pollution [38,42]. ...
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Streambeds are among the important components of stream ecosystems and support several critical ecosystem services such as transformation of organic matter and nutrients and provide habitat for aquatic organisms. Increasing anthropogenic influence introduces multiple stressors to the stream networks resulting in pollution of streambeds, which in turn, could have detrimental effects on overall stream ecosystem health. However, there are gaps in the current understanding of the impacts of streambed pollution and the mitigation strategies lack holistic approach. In this review, we first present a global inventory to highlight the status of streambed pollution around the globe. Next, we synthesize the state-of-art knowledge of conventional and emerging forms of contaminants, their overall impacts on stream ecosystem functions, and finally present future directions to comprehend the problem of streambed pollution. We highlight that fine sediments and plastics (found especially in urban streambeds) are among the major physical pollutants of streambed pollution and the chemical pollutants generally comprise of hydrophobic compounds including various legacy contaminants such as polychlorinated biphenyl (PCB), dichlorodiphenyltrichloroethane (DDT), a wide range of pesticides and a variety of heavy metals. Further, in recent years, highly polar and hydrophilic emerging contaminants such as micro-plastics, pharmaceutical waste and personal care products have been identified in rivers around the world. We stress that the impacts of streambed pollution have been largely studied with discipline-driven perspectives amongst which the ecological impacts have received a lot of attention in the past. To present a comprehensive outlook, this review also synthesizes the hydrological, geomorphological and biochemical impacts of different forms of streambed pollutants. In the end, we endorse the positive and negative aspects of the current impact assessment methodologies and also highlight various physical, chemical and biological remediation measures that could be applied to alleviate streambed pollution.
... Sediment characteristics influence the effectiveness of treatment technologies (US EPA, 1994;Vallero, 2010). Specific chemical and physical properties are used to describe a sediment sample: grain size, grain density, water content, total organic matter (TOM), buffering capacity, carbonates, geotechnical and agronomic properties (Batley et al, 2005). Water content, TOM content, dry bulk density and porosity affect basic sediment characteristics such as diffusion properties and mechanical properties, as well as the microbial metabolic rates (Avnimelech et al, 2001). ...
... SQGs were often employed to assess the intensity of biological effects of heavy metals in sediments. In SQGs, adverse biological effects of heavy metals are unlikely to happen when the heavy metal concentrations are lower than the threshold effect concentrations (TEC), while adverse biological effects are expected to happen when the heavy metal concentrations are higher than the probable effect concentrations (PEC) (MacDonald et al., 2000;Wenning et al., 2005). ...
Article
The surface sediment concentrations of heavy metals (Cu, Zn, Pb, Cd, Cr, Hg, and As), major metals (Fe and Mn), and the nutrient concentrations in the interstitial water of Lake Houguan, a large eutrophic shallow lake, were surveyed for three years. The results showed that Cu, Zn, and Fe were significantly higher in the east lake parts, and Cd in November was significantly higher than April. 19% of Hg and all of As were larger than the probable effect concentrations (PECs) according to the consensus-based sediment quality guidelines (SQGs), and the geo-accumulation index (Igeo) indicated As, Hg, and Cd were slightly polluted to severely polluted. The RI value (average 704.2) of the potential ecological risk index (PERI) suggested that heavy metals posed very high ecological risks with most of the contributions induced by Cd and Hg. The consequence of hierarchical clustering analysis (HCA) and principle component analysis (PCA) identified Cd, As, and Pb might originate from urbanization, industrial pollution, and agricultural activity; Hg might be from atmospheric deposition and anthropogenic sources above; Cu, Zn, Cr, Fe, and Mn might be from both natural and anthropogenic sources. The Spearman correlation analysis indicated Pb and As were significantly positively correlated with total nitrogen, while Cd significantly negatively correlated with sulfate; As was significantly correlated with ammonia, sulfate, and nitrate in the interstitial water. These results suggested eutrophication might affect sedimental heavy metals by increasing organic matter or influencing the redox potentials in the sediment.
... Owing to the lack of reference values for assessing environmental status in anthropized marine coastal areas, with the only exception of the Environmental Quality Standards (EQS) for sediments (D.M. 56/09, D.M. 260/10), as defined by the Italian Government according to 2000/60/CE, but not applicable for impacted areas, ICRAM defined site-specific "action levels" according to the current scientific literature (Burton, 2002;Wenning et al., 2005;den Besten, 2007) and the main approaches already applied by the USA (U. S. Environmental Protection Agency, 1996Agency, , 1997, Canada (CCME, 2001;Macfarlane and MacDonald, 2002), and Europe (van de Meent et al., 1990;Ospar Commission, 2004a,b), taking into account the peculiar geochemical characteristics along the Italian coast. ...
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In the first decades of 2000s, several Italian sites affected by strong anthropogenic impact were recognized as Sites of National Interest (SINs) for a successive reclamation project, some of which also including marine sectors. These coastal areas are characterized by high complexity and diversity as regards the natural setting as well as for extent, history, type, and degree of contamination. For this, the Italian Ministry of Environment charged its scientific research Institute (earlier ICRAM, now ISPRA) with planning a flexible, adaptable, and large-scale environmental characterization. In this context, the investigation of marine sediments was identified as the primary target to assess the environmental status, because of their conservative capacity with respect to contaminants and their role in the exchange processes with other environmental matrices, such as water column and aquatic organisms. A multidisciplinary, chemical-physical, and ecotoxicological survey was identified as the most appropriate and objective criterion for assessing the sediment quality associated, when necessary, with integrative studies. The results derived from this multidisciplinary approach highlighted the main sources of contamination, together with size and extent of the environmental impact on the coastal marine areas, strictly correlated with the kind of anthropogenic activities and coastal morphology. In order to underline how the different environmental setting influences the degree of anthropogenic impact, four different case studies, selected among the more complex by geochemical and geomorphological viewpoints and more extensively studied, were considered. A comprehensive evaluation of these case studies allowed to deduce some general principles concerning the effects of anthropogenic impact, which can be applicable to other transitional and marine coastal areas.
... For example, the interactions between the sediment and the overlying water affect the contaminants' mobility, and the effects of the contaminant might be affected by an unknown mixture of additional contaminants and conditions (Apitz 2005;Bridges et al. 2006). Therefore, it is suggested that SQG can be used to indicate very low or very high risks of toxicity to organisms but not to state whether toxicity is possible or impossible (Wenning et al. 2002;O'Connor 2004). The complexity of assessing contaminated sediments might warrant several LOEs to assess the ecological implications of the contaminants of concern. ...
Article
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Several countries currently lack common recommendations specific to Ecological Risk Assessment (ERA) of contaminated sediments and stakeholders report inconsistencies between currently used approaches. The objective of this study was to provide an increased understanding of how ERAs of contaminated sediments are conducted in comparison to established guidelines. For this, we use Sweden as a case study and compare seven ERAs with four internationally established strategies. Our results indicate that contaminant concentrations receive a comparatively high weight, despite a lack of appropriate benchmarks; toxicity measurements are uncommon, while routine in established strategies; and the integration and interpretation of results lack transparency. We identify three areas that may help improve the practice of ERAs: a common approach to benchmarks, recommendations for how to assess toxic effects, and a common approach for integrating and interpreting results.
... The element concentrations were compared with the sediment quality guidelines (SQGs) (McCauley et al. 2000). Effects range low (ERL), effects range median (ERM), threshold effects level (TRL), and probable effects level (PEL) are commonly used to evaluate the sediment quality and its effect on the biological community (Macdonald et al. 1996;Wenning 2005). The elements having concentrations below ERL and TEL values suggest rare or occasional adverse biological effects on the biota, while above ERM and PEL suggest frequent adverse effects on biota (Zahra et al. 2014;Sarkar 2018). ...
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... DelValls et al. (2004) have reviewed SQGs from different European countries and have shown that they differ by two orders of magnitude for some substances (e.g., As, Cu, and seven PCBs). Most of the limitations listed and discussed at the Pellston Workshop on "use of sediment quality guidelines and related tools for the assessment of contaminated sediments" in 2002 have not been addressed to date for existing SQGs; e.g., they deliver no or limited information on the ecologically important aspects of chronic toxicity to sediment-dwelling organisms and causeeffect relationships, in addition to the questionable transferability of SQGs, derived from one endpoint in the laboratory, to, e.g., effects on organisms in the environment (Wenning et al. 2005). Moreover, existing SQGs cover tens of substances at best, and therefore substances of emerging concern cannot be reliably assessed with this tool. ...
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