The management of surface waters and sediments is one of several activities at commercial and ind... more The management of surface waters and sediments is one of several activities at commercial and industrial shipping ports and harbors critical to maintaining environmental quality that safeguards surrounding communities and the environment. This chapter discusses a possible framework for assessing and managing risks to the aquatic environment, focusing primarily on sediments. Risk assessment provides a useful foundation for understanding the environmental benefits, residual hazards, and engineering limitations of different management strategies, as well as identifying and ranking management options. Understanding the important pathways for contaminant exposure, the human and wildlife populations potentially at risk, and the possible hazards associated with the implementation of different engineering options contributes to informed risk management decision making with regard to short- and long-term effectiveness and implementability of different sediment management strategies.
This paper briefly reviews the complex issues associated with remedy identification, screening, a... more This paper briefly reviews the complex issues associated with remedy identification, screening, and selection at contaminated sediment sites in North America. We present two case studies illustrating approaches used by stakeholders to arrive at remedy decisions. These approaches include watershed-level thinking and net environmental benefit analysis (NEBA), both of which recognize the influences of chemical and non-chemical, natural and anthropogenic Stressors, and their respective influences on the integrity of the aquatic ecosystem. In the absence of a sitewide human health or ecological risk assessment, and in the absence of a watershed-level approach that balances potential risks and benefits against implementation risks to human health and the environment, site managers typically are ill-equipped to effectively select environmentally appropriate and protective remedies for contaminated sediment sites. The U.S. Environmental Protection Agency (USEPA) Superfund feasibility study process, and a variety of innovative multi-criteria decision frameworks provide sound frameworks for remedy assessment and selection. Omitting these approaches can result in the selection of a remedy in which the environmental harm caused by the remedy can outweigh its perceived benefits. Two case studies are presented that involve distinct, but mutually supporting, approaches to remedy decision making that reflect unique outcomes in terms of the goals of ecological and human health risk reduction, environmental protection, and watershed improvement. Combined, these case studies evaluate a range of Stressors and compare net environmental benefits of each remedy alternative. Outcomes include meaningful risk reductions and minimal adverse impacts to the environment, workers and the local community residents.
Archives of Environmental Contamination and Toxicology, 2007
Total and hexavalent chromium [Cr(VI)] were measured in sediment and sediment porewater in the lo... more Total and hexavalent chromium [Cr(VI)] were measured in sediment and sediment porewater in the lower Hackensack River (NJ) to assess the relationship between sediment geochemistry and chromium speciation, which in turn controls the mobility, bioavailability, and toxicity of chromium. Between 2003 and 2005, >100 surface (0 to 15 cm) sediment samples were tested for total chromium and Cr(VI), acid-volatile sulfides (AVS), ferrous iron (Fe(II)), divalent manganese (Mn(II)), ammonia, and organic carbon. Sediment porewater samples were collected by centrifugation or using in situ samplers colocated with the collection of sediments. In whole sediments, total chromium and Cr(VI) concentrations ranged from 5 to 9190 mg/kg dry weight (dw) and from <0.47 to 31 mg/kg dw, respectively. Sediment porewater concentrations ranged from <10 to 83 µg/l for total chromium; Cr(VI) was not detected in sediment porewater (n = 78). Concentrations of AVS (ranging between <10.6 to 4178 mg/kg) and other geochemistry measurements indicated anoxic, reducing conditions in the majority of sediment samples. In polychaetes (Nereis virens) and clams (Macoma nasuta) exposed in the laboratory for 28 days to sediments contained between 135 and 1780 mg/kg dw total chromium, concentrations in whole tissues after 24-hour depuration ranged between 1.2 and 14.8 mg/kg wet weight (ww; median 1.6 mg/kg ww) total chromium. In whole tissues of indigenous polychaetes collected from the sediment, tissue concentrations of total chromium ranged between 1.0 and 37.5 mg/kg ww (median = 2.1 mg/kg ww). Chromium concentrations in whole tissues of animals exposed in the field or in the laboratory showed no relationship with total chromium or Cr(VI) concentrations in the sediment. There were no statistical differences among animals exposed to sediments from site and reference locations. The results of this study are consistent with sediment studies conducted elsewhere indicating low chromium bioavailability in sediment under reducing conditions. This study also highlights the importance of sediment geochemistry and in situ porewater measurements to understand the ecological significance of chromium in sediment and the potential for human health and ecological exposures.
Results from the field testing of some innovative sampling methods developed to evaluate risk man... more Results from the field testing of some innovative sampling methods developed to evaluate risk management strategies for polychlorinated biphenyl (PCB) contaminated sediments are presented. Semipermeable membrane devices (SPMDs) were combined with novel deployment methods to quantify the availability of PCBs at the Sangamo-Weston Lake Hartwell Superfund Site in SC. Three locations in Lake Hartwell were examined: a background site (BKG) with little detectable contamination and two contaminated sites (T-M/N and T-O). PCB availability was quantified using sediment surface samplers designed to hold SPMDs in contact with surface sediments, benthic dome samplers designed to enclose and suspend SPMDs at the sediment-water interface, and commercially obtained SPMD cages suspended in the water column. A two-way analysis of variance showed significant effects by sampler type (P < 0.0001) and site (P < 0.0001) for mean time-weighted average (TWA) total PCBs (t-PCBs). Regardless of the SPMD sampler used, mean TWA t-PCBs were directly proportional to the level of contamination present (BKG < T-M/N < T-O). Water column and surface sediment sampler t-PCB uptake patterns were described by a significant linear fit of the data (r2 = 0.9625, p < 0.0001, and r2 = 0.8188, p < 0.0001, respectively). Dome and sediment surface SPMD samples had a higher percentage of higher chlorinated PCBs compared to water column samples.
Purpose This study characterized the chemical transport potential of polycyclic aromatic hydrocar... more Purpose This study characterized the chemical transport potential of polycyclic aromatic hydrocarbons (PAHs) and total petroleum hydrocarbons (TPH) in the vicinity of a sand cap placed in the nearshore zone of a tidal marine embayment. Materials and methods Groundwater seepage was investigated along the perimeter and within the footprint of the sand cap, with results verifying the presence of significant freshwater upwelling shoreward of the sand cap boundary. The depth distribution of PAHs and TPH was assessed in sediment cores collected from within the cap area footprint. Results and discussion The depth distribution of PAHs and TPH demonstrated a spatial pattern of elevated chemical concentrations in the shoreward zone of the capped area, consistent with the spatial pattern of elevated freshwater flux. Visual inspection of recovered cores confirmed the presence of a fine-grained, low-conductivity sediment layer underlying the sand cap, with material properties of this layer potentially suggesting compaction following placement of the sand cap. This fine-grained sediment layer was not evident in the shoreward zone of the capped area. Conclusions The presence of the aquitard under the sand cap, coupled with the apparent erosion of this fine-grained layer in the higher energy shoreward zone, suggests the potential for enhanced groundwater seepage in the shoreward zone of the sand cap. It is hypothesized that enhanced groundwater flux is responsible for the elevated concentrations of PAH and TPH observed in core profiles collected from the zone characterized by elevated freshwater seepage and tidal pumping and that the fine-grained sediment layer that serves as an aquitard impedes groundwater flux within the cap area footprint. In effect, the absence of groundwater seepage observed for those stations within the footprint of the sand cap has likely resulted from compaction of the native sediment strata, whether or not compaction resulted directly from cap placement.
The present study evaluated sorbent amendments for in situ remediation of sediments contaminated ... more The present study evaluated sorbent amendments for in situ remediation of sediments contaminated with two divalent metals. A literature review screening was performed to identify low-cost natural mineral-based metal sorbents and high-performance commercial sorbents that were carried forward into laboratory experiments. Aqueous phase metal sorptivity of the selected sorbents was evaluated because dissolved metals in sediment porewater constitute an important route of exposure to benthic organisms. Based on pH-edge sorption test results, natural sorbents were eliminated due to inferior performance. The potential as in situ sediment amendment was explored by comparing the sorption properties of the engineered amendments in freshwater and saltwater (10 PPT salinity estuarine water) matrices. Self-assembled monolayers on mesoporous supports with thiols (Thiol-SAMMS) and a titanosilicate mineral (ATS) demonstrated the highest sorption capacity for cadmium (Cd) and lead (Pb), respectively. Sequential extraction tests conducted after mixing engineered sorbents with contaminated sediment demonstrated transfer of metal contaminants from a weakly bound state to a more strongly bound state. Biouptake of Cd in a freshwater oligochaete was reduced by 98% after 5-d contact of sediment with 4% Thiol-SAMMS and sorbed Cd was not bioavailable. While treatment with ATS reduced the small easily extractable portion of Pb in the sediment, the change in biouptake of Pb was not significant because most of the native lead was strongly bound. The selected sorbents added to sediments at a dose of 5% were mostly nontoxic to a range of sensitive freshwater and estuarine benthic organisms. Metal sorbent amendments in conjunction with activated carbon have the potential to simultaneously reduce metal and hydrophobic contaminant bioavailability in sediments.
Dechlorination studies were conducted using microbial cultures developed in a fluidized-bed react... more Dechlorination studies were conducted using microbial cultures developed in a fluidized-bed reactor (FBR) that dechlorinates pentachlorophenol (PCP) to 3,4-dichlorophenol (3,4-DCP) and 4-monochlorophenol (4-MCP). Electron donor experiments demonstrated that lactate, propionate, and H2 can serve as electron donors for chlorophenol (CP) dechlorination in mixed, anaerobic, PCP-enriched cultures. Dechlorination did not proceed in the absence of an electron donor. Acetate, which resulted in little H2 production, was a poor electron donor. The results of inhibition studies using vancomycin and 2-bromoethanesulfonic acid implicate members of the domain bacteria in the dechlorination of CPs, whereas methanogens do not appear to be involved in dechlorination. Brief heat treatment (80°C for 90 min) of the FBR enrichment cultures implicated endospore formers in the dechlorination of CPs, primarily at the ortho position, where PCP was dechlorinated to 3,4,5-trichlorophenol (3,4,5-TCP) (the sole TCP detected) and subsequently to 3,4-DCP. Both lactate and H2 served as electron donors in the heat-and oxygen-treated cultures. In contrast, a lactate-fed anaerobic spread-plate enrichment culture exhibited solely meta-dechlorination, where PCP dechlorinated solely to 2,4,6-TCP. The separation of ortho- and meta-specific dechlorination reactions provides evidence that PCP dechlorination in the FBR enrichment culture was catalyzed by at least the following two separate groups of CP-dechlorinating bacteria: one meta-dechlorinating group and one primarily ortho-dechlorinating group.
Elevated levels of chromium, partly attributable to historical disposal of chromite ore processin... more Elevated levels of chromium, partly attributable to historical disposal of chromite ore processing residue, are present in sediment along the eastern shore of the lower Hackensack River near the confluence with Newark Bay. Due to anaerobic conditions in the sediment, the chromium is in the form of Cr(III), which poses no unacceptable risks to human health or to the river ecology. However, as water quality conditions have improved since the 1970s, aerobic conditions have become increasingly prevalent in the overlying water column. If these conditions result in oxidation of Cr(III) to Cr(VI), either under quiescent conditions or during severe weather or anthropogenic scouring events, the potential for adverse ecological effects due to biological exposures to Cr(VI) is possible, though the reaction kinetics associated with oxidation of Cr(III) to Cr(VI) are unfavorable. To investigate the stability of Cr(III) in Hackensack River sediments exposed to oxic conditions, sediment suspension and oxidation experiments and intertidal sediment exposure experiments that exposed the sediments to oxic conditions were conducted. Results revealed no detectable concentrations of Cr(VI), and thus no measurable potential for total chromium oxidation to Cr(VI). Furthermore, total chromium released from sediment to elutriate water in the oxidation and suspension experiments ranged from below detection (&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.01 mg/L) to 0.18 mg/L, below the freshwater National Recommended Water Quality Criteria (NRWQC) of 0.57 mg/L for Cr(III). These results support conclusions of a stable, in situ geochemical environment in sediments in the lower Hackensack River with respect to chromium. Results showed that chemicals other than Cr(VI), including copper, lead, mercury, zinc, and PCBs, were released at levels that may pose a potential for adverse ecological effects.
... Victor S. Magar M.ASCE, Kristen Hartzell, Christy Burton, James T. Gibbs M.ASCE, Thomas L. Ma... more ... Victor S. Magar M.ASCE, Kristen Hartzell, Christy Burton, James T. Gibbs M.ASCE, Thomas L. Macchiarella, Jr. Abstract. ... 6, Battelle, Columbus, Ohio, 155162. Salanitro, JP, Diaz, LA, Williams, MP, and Wisniewski, HL (1994). ...
NATO Science for Peace and Security Series This Series presents the results of scientific meetings... more NATO Science for Peace and Security Series This Series presents the results of scientific meetings supported under the NATO Programme: Science for Peace and Security (SPS). The NATO SPS Programme supports meetings in the following Key Priority areas:(1) Defence Against ...
... Terrence Lyons, Jennifer A. Ickes, Victor S. Magar, M.ASCE, Carl S. Albro, Lydia Cumming, Bre... more ... Terrence Lyons, Jennifer A. Ickes, Victor S. Magar, M.ASCE, Carl S. Albro, Lydia Cumming, Brenda Bachman, Thomas Fredette, Tommy Myers, Mike Keegan, Ken ... Sediments placed in these CAD cells were typically 85100% silt/clay with in situ solids ranging from 30 to 55% (). ...
The management of surface waters and sediments is one of several activities at commercial and ind... more The management of surface waters and sediments is one of several activities at commercial and industrial shipping ports and harbors critical to maintaining environmental quality that safeguards surrounding communities and the environment. This chapter discusses a possible framework for assessing and managing risks to the aquatic environment, focusing primarily on sediments. Risk assessment provides a useful foundation for understanding the environmental benefits, residual hazards, and engineering limitations of different management strategies, as well as identifying and ranking management options. Understanding the important pathways for contaminant exposure, the human and wildlife populations potentially at risk, and the possible hazards associated with the implementation of different engineering options contributes to informed risk management decision making with regard to short- and long-term effectiveness and implementability of different sediment management strategies.
This paper briefly reviews the complex issues associated with remedy identification, screening, a... more This paper briefly reviews the complex issues associated with remedy identification, screening, and selection at contaminated sediment sites in North America. We present two case studies illustrating approaches used by stakeholders to arrive at remedy decisions. These approaches include watershed-level thinking and net environmental benefit analysis (NEBA), both of which recognize the influences of chemical and non-chemical, natural and anthropogenic Stressors, and their respective influences on the integrity of the aquatic ecosystem. In the absence of a sitewide human health or ecological risk assessment, and in the absence of a watershed-level approach that balances potential risks and benefits against implementation risks to human health and the environment, site managers typically are ill-equipped to effectively select environmentally appropriate and protective remedies for contaminated sediment sites. The U.S. Environmental Protection Agency (USEPA) Superfund feasibility study process, and a variety of innovative multi-criteria decision frameworks provide sound frameworks for remedy assessment and selection. Omitting these approaches can result in the selection of a remedy in which the environmental harm caused by the remedy can outweigh its perceived benefits. Two case studies are presented that involve distinct, but mutually supporting, approaches to remedy decision making that reflect unique outcomes in terms of the goals of ecological and human health risk reduction, environmental protection, and watershed improvement. Combined, these case studies evaluate a range of Stressors and compare net environmental benefits of each remedy alternative. Outcomes include meaningful risk reductions and minimal adverse impacts to the environment, workers and the local community residents.
Archives of Environmental Contamination and Toxicology, 2007
Total and hexavalent chromium [Cr(VI)] were measured in sediment and sediment porewater in the lo... more Total and hexavalent chromium [Cr(VI)] were measured in sediment and sediment porewater in the lower Hackensack River (NJ) to assess the relationship between sediment geochemistry and chromium speciation, which in turn controls the mobility, bioavailability, and toxicity of chromium. Between 2003 and 2005, >100 surface (0 to 15 cm) sediment samples were tested for total chromium and Cr(VI), acid-volatile sulfides (AVS), ferrous iron (Fe(II)), divalent manganese (Mn(II)), ammonia, and organic carbon. Sediment porewater samples were collected by centrifugation or using in situ samplers colocated with the collection of sediments. In whole sediments, total chromium and Cr(VI) concentrations ranged from 5 to 9190 mg/kg dry weight (dw) and from <0.47 to 31 mg/kg dw, respectively. Sediment porewater concentrations ranged from <10 to 83 µg/l for total chromium; Cr(VI) was not detected in sediment porewater (n = 78). Concentrations of AVS (ranging between <10.6 to 4178 mg/kg) and other geochemistry measurements indicated anoxic, reducing conditions in the majority of sediment samples. In polychaetes (Nereis virens) and clams (Macoma nasuta) exposed in the laboratory for 28 days to sediments contained between 135 and 1780 mg/kg dw total chromium, concentrations in whole tissues after 24-hour depuration ranged between 1.2 and 14.8 mg/kg wet weight (ww; median 1.6 mg/kg ww) total chromium. In whole tissues of indigenous polychaetes collected from the sediment, tissue concentrations of total chromium ranged between 1.0 and 37.5 mg/kg ww (median = 2.1 mg/kg ww). Chromium concentrations in whole tissues of animals exposed in the field or in the laboratory showed no relationship with total chromium or Cr(VI) concentrations in the sediment. There were no statistical differences among animals exposed to sediments from site and reference locations. The results of this study are consistent with sediment studies conducted elsewhere indicating low chromium bioavailability in sediment under reducing conditions. This study also highlights the importance of sediment geochemistry and in situ porewater measurements to understand the ecological significance of chromium in sediment and the potential for human health and ecological exposures.
Results from the field testing of some innovative sampling methods developed to evaluate risk man... more Results from the field testing of some innovative sampling methods developed to evaluate risk management strategies for polychlorinated biphenyl (PCB) contaminated sediments are presented. Semipermeable membrane devices (SPMDs) were combined with novel deployment methods to quantify the availability of PCBs at the Sangamo-Weston Lake Hartwell Superfund Site in SC. Three locations in Lake Hartwell were examined: a background site (BKG) with little detectable contamination and two contaminated sites (T-M/N and T-O). PCB availability was quantified using sediment surface samplers designed to hold SPMDs in contact with surface sediments, benthic dome samplers designed to enclose and suspend SPMDs at the sediment-water interface, and commercially obtained SPMD cages suspended in the water column. A two-way analysis of variance showed significant effects by sampler type (P < 0.0001) and site (P < 0.0001) for mean time-weighted average (TWA) total PCBs (t-PCBs). Regardless of the SPMD sampler used, mean TWA t-PCBs were directly proportional to the level of contamination present (BKG < T-M/N < T-O). Water column and surface sediment sampler t-PCB uptake patterns were described by a significant linear fit of the data (r2 = 0.9625, p < 0.0001, and r2 = 0.8188, p < 0.0001, respectively). Dome and sediment surface SPMD samples had a higher percentage of higher chlorinated PCBs compared to water column samples.
Purpose This study characterized the chemical transport potential of polycyclic aromatic hydrocar... more Purpose This study characterized the chemical transport potential of polycyclic aromatic hydrocarbons (PAHs) and total petroleum hydrocarbons (TPH) in the vicinity of a sand cap placed in the nearshore zone of a tidal marine embayment. Materials and methods Groundwater seepage was investigated along the perimeter and within the footprint of the sand cap, with results verifying the presence of significant freshwater upwelling shoreward of the sand cap boundary. The depth distribution of PAHs and TPH was assessed in sediment cores collected from within the cap area footprint. Results and discussion The depth distribution of PAHs and TPH demonstrated a spatial pattern of elevated chemical concentrations in the shoreward zone of the capped area, consistent with the spatial pattern of elevated freshwater flux. Visual inspection of recovered cores confirmed the presence of a fine-grained, low-conductivity sediment layer underlying the sand cap, with material properties of this layer potentially suggesting compaction following placement of the sand cap. This fine-grained sediment layer was not evident in the shoreward zone of the capped area. Conclusions The presence of the aquitard under the sand cap, coupled with the apparent erosion of this fine-grained layer in the higher energy shoreward zone, suggests the potential for enhanced groundwater seepage in the shoreward zone of the sand cap. It is hypothesized that enhanced groundwater flux is responsible for the elevated concentrations of PAH and TPH observed in core profiles collected from the zone characterized by elevated freshwater seepage and tidal pumping and that the fine-grained sediment layer that serves as an aquitard impedes groundwater flux within the cap area footprint. In effect, the absence of groundwater seepage observed for those stations within the footprint of the sand cap has likely resulted from compaction of the native sediment strata, whether or not compaction resulted directly from cap placement.
The present study evaluated sorbent amendments for in situ remediation of sediments contaminated ... more The present study evaluated sorbent amendments for in situ remediation of sediments contaminated with two divalent metals. A literature review screening was performed to identify low-cost natural mineral-based metal sorbents and high-performance commercial sorbents that were carried forward into laboratory experiments. Aqueous phase metal sorptivity of the selected sorbents was evaluated because dissolved metals in sediment porewater constitute an important route of exposure to benthic organisms. Based on pH-edge sorption test results, natural sorbents were eliminated due to inferior performance. The potential as in situ sediment amendment was explored by comparing the sorption properties of the engineered amendments in freshwater and saltwater (10 PPT salinity estuarine water) matrices. Self-assembled monolayers on mesoporous supports with thiols (Thiol-SAMMS) and a titanosilicate mineral (ATS) demonstrated the highest sorption capacity for cadmium (Cd) and lead (Pb), respectively. Sequential extraction tests conducted after mixing engineered sorbents with contaminated sediment demonstrated transfer of metal contaminants from a weakly bound state to a more strongly bound state. Biouptake of Cd in a freshwater oligochaete was reduced by 98% after 5-d contact of sediment with 4% Thiol-SAMMS and sorbed Cd was not bioavailable. While treatment with ATS reduced the small easily extractable portion of Pb in the sediment, the change in biouptake of Pb was not significant because most of the native lead was strongly bound. The selected sorbents added to sediments at a dose of 5% were mostly nontoxic to a range of sensitive freshwater and estuarine benthic organisms. Metal sorbent amendments in conjunction with activated carbon have the potential to simultaneously reduce metal and hydrophobic contaminant bioavailability in sediments.
Dechlorination studies were conducted using microbial cultures developed in a fluidized-bed react... more Dechlorination studies were conducted using microbial cultures developed in a fluidized-bed reactor (FBR) that dechlorinates pentachlorophenol (PCP) to 3,4-dichlorophenol (3,4-DCP) and 4-monochlorophenol (4-MCP). Electron donor experiments demonstrated that lactate, propionate, and H2 can serve as electron donors for chlorophenol (CP) dechlorination in mixed, anaerobic, PCP-enriched cultures. Dechlorination did not proceed in the absence of an electron donor. Acetate, which resulted in little H2 production, was a poor electron donor. The results of inhibition studies using vancomycin and 2-bromoethanesulfonic acid implicate members of the domain bacteria in the dechlorination of CPs, whereas methanogens do not appear to be involved in dechlorination. Brief heat treatment (80°C for 90 min) of the FBR enrichment cultures implicated endospore formers in the dechlorination of CPs, primarily at the ortho position, where PCP was dechlorinated to 3,4,5-trichlorophenol (3,4,5-TCP) (the sole TCP detected) and subsequently to 3,4-DCP. Both lactate and H2 served as electron donors in the heat-and oxygen-treated cultures. In contrast, a lactate-fed anaerobic spread-plate enrichment culture exhibited solely meta-dechlorination, where PCP dechlorinated solely to 2,4,6-TCP. The separation of ortho- and meta-specific dechlorination reactions provides evidence that PCP dechlorination in the FBR enrichment culture was catalyzed by at least the following two separate groups of CP-dechlorinating bacteria: one meta-dechlorinating group and one primarily ortho-dechlorinating group.
Elevated levels of chromium, partly attributable to historical disposal of chromite ore processin... more Elevated levels of chromium, partly attributable to historical disposal of chromite ore processing residue, are present in sediment along the eastern shore of the lower Hackensack River near the confluence with Newark Bay. Due to anaerobic conditions in the sediment, the chromium is in the form of Cr(III), which poses no unacceptable risks to human health or to the river ecology. However, as water quality conditions have improved since the 1970s, aerobic conditions have become increasingly prevalent in the overlying water column. If these conditions result in oxidation of Cr(III) to Cr(VI), either under quiescent conditions or during severe weather or anthropogenic scouring events, the potential for adverse ecological effects due to biological exposures to Cr(VI) is possible, though the reaction kinetics associated with oxidation of Cr(III) to Cr(VI) are unfavorable. To investigate the stability of Cr(III) in Hackensack River sediments exposed to oxic conditions, sediment suspension and oxidation experiments and intertidal sediment exposure experiments that exposed the sediments to oxic conditions were conducted. Results revealed no detectable concentrations of Cr(VI), and thus no measurable potential for total chromium oxidation to Cr(VI). Furthermore, total chromium released from sediment to elutriate water in the oxidation and suspension experiments ranged from below detection (&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.01 mg/L) to 0.18 mg/L, below the freshwater National Recommended Water Quality Criteria (NRWQC) of 0.57 mg/L for Cr(III). These results support conclusions of a stable, in situ geochemical environment in sediments in the lower Hackensack River with respect to chromium. Results showed that chemicals other than Cr(VI), including copper, lead, mercury, zinc, and PCBs, were released at levels that may pose a potential for adverse ecological effects.
... Victor S. Magar M.ASCE, Kristen Hartzell, Christy Burton, James T. Gibbs M.ASCE, Thomas L. Ma... more ... Victor S. Magar M.ASCE, Kristen Hartzell, Christy Burton, James T. Gibbs M.ASCE, Thomas L. Macchiarella, Jr. Abstract. ... 6, Battelle, Columbus, Ohio, 155162. Salanitro, JP, Diaz, LA, Williams, MP, and Wisniewski, HL (1994). ...
NATO Science for Peace and Security Series This Series presents the results of scientific meetings... more NATO Science for Peace and Security Series This Series presents the results of scientific meetings supported under the NATO Programme: Science for Peace and Security (SPS). The NATO SPS Programme supports meetings in the following Key Priority areas:(1) Defence Against ...
... Terrence Lyons, Jennifer A. Ickes, Victor S. Magar, M.ASCE, Carl S. Albro, Lydia Cumming, Bre... more ... Terrence Lyons, Jennifer A. Ickes, Victor S. Magar, M.ASCE, Carl S. Albro, Lydia Cumming, Brenda Bachman, Thomas Fredette, Tommy Myers, Mike Keegan, Ken ... Sediments placed in these CAD cells were typically 85100% silt/clay with in situ solids ranging from 30 to 55% (). ...
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