contaminated sediment risk Articles
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Passive sampling methods for contaminated sediments: Risk assessment and management
This paper details how activity‐based passive sampling methods (PSMs), which provide information on bioavailability in terms of freely dissolved contaminant concentrations (Cfree), can be used to better inform risk management decision‐making at multiple points in the process of assessing and managing contaminated sediment sites. Because Cfree is a better predictor of bioavailability than total ...
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Converting the dreaded PCBs into useful commodities
For decades polychlorinated biphenyls (PCBs) have been high on the list of toxins the public fears. A new vitrification technology is claimed to be able to completely destroy PCBs and other toxins in contaminated sediment by meltingit into a glass aggregate product that can be used in the construction industry. This process, developed by Minergy Corp., costs about as much as landfilling, without ...
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Effects‐based marine ecological risk assessment at a polychlorinated biphenyl‐contaminated site in Saglek, Labrador, Canada
Although the presence and distribution of polychlorinated biphenyls (PCBs) in Arctic marine environments has been well documented, the implications for the health of biota are poorly understood. In the present study, multiple lines of evidence, including site‐specific effects data, were used to assess PCB‐related risks to marine biota at a contaminated military site in Saglek Bay, Labrador, ...
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Passive sampling methods for contaminated sediments: Practical guidance for selection, calibration, and implementation
This manuscript provides practical guidance on the use of passive sampling methods (PSMs) that target the freely dissolved concentration (Cfree) for improved exposure assessment of hydrophobic organic chemicals in sediments. Primary considerations for selecting a PSM for a specific application include clear delineation of measurement goals for Cfree, whether laboratory‐based “ex‐situ” and/or ...
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A tiered assessment framework to evaluate human health risk of contaminated sediment
For sediment contaminated with bioaccumulative pollutants (e.g., PCBs and organochorine pesticides), human consumption of seafood that have bioaccumulated sediment‐derived contaminants is a well‐established exposure pathway. Historically, regulation and management of this bioaccumulation pathway has focused on site‐specific risk assessment. The state of California (USA) is supporting the ...
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Copper and nickel partitioning with nanoscale goethite under variable aquatic conditions
Metal contaminated sediments can be toxic to aquatic organisms and are common in human‐dominated ecosystems, which results in metals being a leading cause of ecosystem impairment. Bioavailability of metals is influenced by their affinity for dissolved and solid‐phase ligands, including iron (Fe) oxyhydroxides that have been hypothesized to reduce metal toxicity in sediments. We examined the ...
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Passive sampling in contaminated sediment assessment: Building consensus to improve decision‐making
Contaminated sediments pose an on‐going, pervasive, global challenge to environmental managers as sediments can reflect a legacy of pollution that can impair the beneficial uses of water bodies. A formidable challenge in assessing the risks of contaminated sediments has been elucidation and measurement of contaminant bioavailability, expressed as the freely dissolved concentration (Cfree) in ...
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Pacific lamprey ammocoetes (Entosphenus tridentatus) exposed to contaminated Portland Harbor sediments: Method development and effects on survival, growth, and behavior
Many anthropogenic disturbances have contributed to the decline of Pacific lamprey (Entosphenus tridentatus), but potential negative effects of contaminants on lamprey are unclear. Lamprey ammocoetes are the only detritivorous fish in the Lower Willamette River, Oregon and have been observed in Portland Harbor sediments. Their long benthic larval stage places them at risk from the effects of ...
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Mechanistic sediment quality guidelines based on contaminant bioavailability: Equilibrium partitioning sediment benchmarks
Globally, estimated costs to manage (i.e., remediate and monitor) contaminated sediments are in the billions of U.S. dollars. Biologically based approaches for assessing the contaminated sediments which pose the greatest ecological risk range from toxicity testing to benthic community analysis. In addition, chemically based sediment quality guidelines (SQGs) provide a relatively inexpensive ...
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Bioavailability‐based chronic toxicity measurements of permethrin to Chironomus dilutus
Compared to acute toxicity, chronic exposures to low levels of contaminants are more environmentally relevant but less data are available. Sediment toxicity of the pyrethoid permethrin to Chironomus dilutus was determined. The whole life cycle toxicity testing was conducted with the endpoints covering survival, growth, emergence and reproduction. Permethrin caused 50% lethality in C. dilutus at ...
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Accelerating progress at contaminated sediment sites: Moving from guidance to practice
Contaminated sediments are a pervasive problem in the United States. Significant economic, ecological, and social issues are intertwined in addressing the nation's contaminated sediment problem. Managing contaminated sediments has become increasingly resource intensive, with some investigations costing tens of millions of dollars and the majority of remediation projects proceeding at a slow pace. ...
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Extraction of sediment‐associated polycyclic aromatic hydrocarbons with granular activated carbon
Addition of activated carbon (AC) to sediments has been proposed as a method to reduce ecotoxicological risks of sediment‐bound contaminants. The present study explores the effectiveness of granular AC (GAC) in extracting polycyclic aromatic hydrocarbon (PAH) from highly contaminated sediments. Four candidate GAC materials were screened in terms of PAH extraction efficiency using single‐step ...
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Sorption and resistant desorption of Atrazine in typical Chinese soils
Atrazine is one of the most commonly used herbicides and is produced and used in large quantity worldwide. In the present study, the sorption and desorption of atrazine in five typical Chinese soils were examined. The sorption of atrazine followed the conventional linear isotherm reasonably well, indicating that sorption was driven largely by hydrophobic partitioning into soil organic matter. ...
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Critical perspectives on mercury toxicity reference values for protection of fish
Environmental management decisions at mercury‐contaminated sediment sites are predicated on the understanding of risks to various receptors, including fish. Toxicity reference values (TRVs) for interpreting risks to fish have been developed to assess mercury concentrations in fish or fish prey. These TRVs were systematically evaluated based on several lines of evidence. First, their conceptual ...
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Critical review of mercury SQVs for the protection of benthic invertebrates
Sediment Quality Values (SQVs) are commonly used – and misused – to characterize the need for investigation, understand causes of observed effects, and derive management strategies to protect benthic invertebrates from direct toxic effects. We compiled > 40 SQVs for mercury, nearly all of which are “co‐occurrence” SQVs derived from databases of paired chemistry and benthic invertebrate effects ...
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Passive sampling methods for contaminated sediments: Scientific rationale supporting use of freely dissolved concentrations
Passive sampling methods (PSMs) allow the quantification of the freely dissolved concentration (Cfree) of an organic contaminant even in complex matrices such as sediments. Cfree is directly related to a contaminant's chemical activity, which drives spontaneous processes including diffusive uptake into benthic organisms and exchange with the overlying water column. Consequently, Cfree provides ...
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Biocatalysed acidification and metal leaching processes in sediments of polluted urban streams
Sediments of fluvial streams are a sink for pollutants such as heavy metals and organic recalcitrant compounds. In anoxic conditions, sulphide generation and alkalinisation cause precipitation of heavy metals. The redox potential of the system could change to higher values, mainly owing to oxygen exposition generated by anthropogenic disturbances of the sediment such as dredging operations. ...
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Sediment dioxin levels as the basis for risk assessment and human health criteria
Methods for assessing human health risks and establishing water quality criteria under the Clean Water Act are based on the assumption that fish accumulation of dioxin is correlated with the dissolved phase of the dioxin in the water column by a water-to-fish predictive factor called a bioconcentration factor. However, dioxin does not remain dissolved in the water column to any significant ...
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Remedial strategy at superfund site calls for organophylic clay sediment cap case study
Project: Port of Portland Nearshore Cap Location: Portland. OR Products: Bulk Organoclay Background: U.S. EPA and the Port of Portland signed a legal agreement to assess and clean up contaminated river sediment at the Port's marine Terminal 4. This agreement authorizes the first early action cleanup project in the Portland Harbor Superfund Site and reflects the Port's commitment to accelerate ...
By CETCO
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Confined disposal facilities: History and trends
ABSTRACT Confined disposal facilities with filter layers have been used for disposal of dredged sediments for decades. Recent assessment of the environmental risk of contaminants in sediments has resulted in the use of lined confined disposal facilities. A case history outlines a contaminated sediment disposal facility designed with geosynthetics. Trends indicate more stringent requirements for ...
By CETCO
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