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Gidley PT, Lotufo GR, Schmidt SN, Mayer P, Burgess RM. Quantitative thermodynamic exposure assessment of PCBs available to sandworms ( Alitta virens) in activated carbon remediated sediment during ongoing sediment deposition. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2024; 26:814-823. [PMID: 38345076 PMCID: PMC11179148 DOI: 10.1039/d3em00405h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2024]
Abstract
Marine mesoscale studies with sandworms (Alitta virens) were conducted to isolate important processes governing the exposure and bioaccumulation of polychlorinated biphenyls (PCBs) at contaminated sediment sites. Ex situ equilibrium sampling with silicone-coated jars, and in situ passive sampling with low-density polyethylene (LDPE) were used to determine the performance of an activated carbon (AC) amendment remedy applied to the bed sediment. A quantitative thermodynamic exposure assessment ('QTEA') was performed, showing that PCB concentrations in polymers at equilibrium with the surficial sediment were suited to measure and assess the remedy effectiveness with regard to PCB bioaccumulation in worms. In practice, monitoring the performance of sediment remedies should utilize a consistent and predictive form of polymeric sampling of the sediment. The present study found that ex situ equilibrium sampling of the surficial sediment was the most useful for understanding changes in bioaccumulation potential as a result of the applied remedy, during bioturbation and ongoing sediment and contaminant influx processes. The ultrathin silicone coatings of the ex situ sampling provided fast equilibration of PCBs between the sediment interstitial water and the polymer, and the multiple coating thicknesses were applied to confirm equilibrium and the absence of surface sorption artifacts. Overall, ex situ equilibrium sampling of surficial sediment could fit into existing frameworks as a robust and cost-effective tool for contaminated sediment site assessment.
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Affiliation(s)
- Philip T Gidley
- US Army Corps of Engineers, Engineer Research and Development Center, Vicksburg, MS, USA.
| | - Guilherme R Lotufo
- US Army Corps of Engineers, Engineer Research and Development Center, Vicksburg, MS, USA.
| | - Stine N Schmidt
- Technical University of Denmark, Department of Environmental & Resource Engineering, Kgs. Lyngby, Denmark
| | - Philipp Mayer
- Technical University of Denmark, Department of Environmental & Resource Engineering, Kgs. Lyngby, Denmark
| | - Robert M Burgess
- US Environmental Protection Agency, ORD/NHEERL/Atlantic Ecology Division, Narragansett, RI, USA
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Grundy JS, Lambert MK, Burgess RM. Passive Sampling-Based versus Conventional-Based Metrics for Evaluating Remediation Efficacy at Contaminated Sediment Sites: A Review. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:10151-10172. [PMID: 37364241 PMCID: PMC10404352 DOI: 10.1021/acs.est.3c00232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/28/2023]
Abstract
Passive sampling devices (PSDs) are increasingly used at contaminated sites to improve the characterization of contaminant transport and assessment of ecological and human health risk at sediment sites and to evaluate the effectiveness of remedial actions. The use of PSDs after full-scale remediation remains limited, however, in favor of evaluation based on conventional metrics, such as bulk sediment concentrations or bioaccumulation. This review has three overall aims: (1) identify sites where PSDs have been used to support cleanup efforts, (2) assess how PSD-derived remedial end points compare to conventional metrics, and (3) perform broad semiquantitative and selective quantitative concurrence analyses to evaluate the magnitude of agreement between metrics. Contaminated sediment remedies evaluated included capping, in situ amendment, dredging and monitored natural recovery (MNR). We identify and discuss 102 sites globally where PSDs were used to determine remedial efficacy resulting in over 130 peer-reviewed scientific publications and numerous technical reports and conference proceedings. The most common conventional metrics assessed alongside PSDs in the peer-reviewed literature were bioaccumulation (39%), bulk sediments (40%), toxicity (14%), porewater grab samples (16%), and water column grab samples (16%), while about 25% of studies used PSDs as the sole metric. In a semiquantitative concurrence analysis, the PSD-based metrics agreed with conventional metrics in about 68% of remedy assessments. A more quantitative analysis of reductions in bioaccumulation after remediation (i.e., remediation was successful) showed that decreases in uptake into PSDs agreed with decreases in bioaccumulation (within a factor of 2) 61% of the time. Given the relatively good agreement between conventional and PSD-based metrics, we propose several practices and areas for further study to enhance the utilization of PSDs throughout the remediation of contaminated sediment sites.
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Affiliation(s)
- James S Grundy
- Oak Ridge Institute for Science and Education c/o U.S. Environmental Protection Agency, ORD/CEMM, Atlantic Coastal Environmental Sciences Division, Narragansett, Rhode Island 02882, United States
- U.S. Environmental Protection Agency, OLEM, Office of Superfund Remediation and Technology Innovation, Edison, New Jersey 08837, United States
| | - Matthew K Lambert
- U.S. Environmental Protection Agency, OLEM, Office of Superfund Remediation and Technology Innovation, Washington, District of Columbia 20460, United States
| | - Robert M Burgess
- U.S. Environmental Protection Agency, ORD/CEMM, Atlantic Coastal Environmental Sciences Division, Narragansett, Rhode Island 02882, United States
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Garza-Rubalcava U, Smith AV, Thomas C, Mills MA, Jackson WA, Reible DD. Long-term monitoring and modeling of PAHs in capped sediments at the Grand Calumet River. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 328:121633. [PMID: 37075922 DOI: 10.1016/j.envpol.2023.121633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 04/10/2023] [Accepted: 04/11/2023] [Indexed: 05/03/2023]
Abstract
The assessment of a cap for remediation of sediments requires long-term monitoring because of the slow migration of contaminants in porous media. In this study, coring and passive sampling tools were used to assess the transport and degradation of polycyclic aromatic hydrocarbons (PAHs) in an amended cap (sand + Organoclay® PM-199) in the Grand Calumet River (Indiana, USA) during four sampling events from 2012 to 2019. Measurements of three PAHs (phenanthrene (Phe), pyrene (Pyr) and benzo[a]pyrene (BaP), representing low, medium, and high molecular weight compounds, respectively) showed a difference of at least two orders of magnitude between bulk concentrations in the native sediments and the remediation cap. Averages of pore water measurements also showed lower levels in the cap respective to the native sediments by a factor of at least 7 for Phe and 3 for Pyr. In addition, between the baseline (BL), which corresponds to observations from 2012 to 2014, and the measurements in 2019, there was a decrease in depth-averaged pore water concentrations of Phe (C2019/CBL=0.20-0.07+0.12 in sediments and 0.27-0.10+0.15 in cap) and Pyr (C2019/CBL=0.47-0.12+0.16 in sediments and 0.71-0.20+0.28 in the cap). In the case of BaP in pore water, no change was observed in native sediments (C2019/CBL=1.0-0.24+0.32) and there was an increase in the cap (C2019/CBL=2.0-0.54+0.72). Inorganic anions and estimates of pore water velocity along with measurements of PAHs were used to model the fate and transport of contaminants. The modeling suggested that degradation of Phe (t1/2=1.12-0.11+0.16 years) and Pyr (t1/2=5.34-1.8+5.3 years) in the cap is faster than migration, thus the cap is expected to be protective of the sediment-water interface indefinitely for these constituents. No degradation was noted in BaP and the contaminant is expected to reach equilibrium in the capping layer over approximately 100 years if there exists sufficient mass of BaP in the sediments and there is no deposition of clean sediment at the surface.
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Affiliation(s)
| | - Alex V Smith
- Department of Civil, Environmental and Construction Engineering, Texas Tech University, USA
| | | | | | - W Andrew Jackson
- Department of Civil, Environmental and Construction Engineering, Texas Tech University, USA
| | - Danny D Reible
- Department of Chemical Engineering, Texas Tech University, USA; Department of Civil, Environmental and Construction Engineering, Texas Tech University, USA.
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Wang S, Lao W, Li H, Guo L, You J. Assessing bioaccumulation potential of sediment associated fipronil degradates in oligochaete Lumbriculus variegatus based on passive sampler measured bioavailable concentration. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 863:160514. [PMID: 36442630 DOI: 10.1016/j.scitotenv.2022.160514] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 11/20/2022] [Accepted: 11/22/2022] [Indexed: 06/16/2023]
Abstract
The degradates of fipronil have equivalent or even more toxicity to non-target aquatic invertebrates. To assess their environmental risks, information of bioaccumulation is required. Currently, little is known about the bioaccumulative property of fipronil degradates in sediment, while it is well known that passive sampler may measure bioavailable concentration (Cfree) which links with the environmental effect more tightly than the total environment concentration. The goal of the present study was to characterize bioaccumulation potential in oligochaete Lumbriculus variegatus for a fipronil degradate sulfide. The sediment organic carbon-water partition coefficient (KOC) was measured with polymethyl methacrylate (PMMA) film passive sampler, and KOC was used to bridge the gap between biota-sediment accumulation factor (BSAF) and bioconcentration factor (BCF). The bioavailable concentration (Cfree)-based KOC values were 5371 ± 152 and 5013 ± 152 (mL/g OC) for fipronil sulfide (FSI) and sulfone (FSO), respectively. Since the two fipronil degradates were produced continuously in sediment by the parent compound, the time-weighted-average (TWA) concentration of FSI in the sediment was estimated from a bioassay with L. variegatus to calculate BSAF value (0.581 ± 0.211 g OC/g lipid) and BCF (3046 ± 1103 or log 3.48 ± 0.16 mL/g). This approach is able to estimate the Cfree-based KOC and BCF values of fipronil degradate in sediment with ongoing degradation of the parent compound.
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Affiliation(s)
- Shunhui Wang
- School of Environment and Guangdong Key Laboratory of Environmental Pollution and Health, Jinan University, Guangzhou, China, 511443; State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu, China, 610500.
| | - Wenjian Lao
- Southern California Coast Water Research Project Authority, Costa Mesa, California, United States, 92626
| | - Huizhen Li
- School of Environment and Guangdong Key Laboratory of Environmental Pollution and Health, Jinan University, Guangzhou, China, 511443.
| | - Liang Guo
- State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, School of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu, China, 610500
| | - Jing You
- School of Environment and Guangdong Key Laboratory of Environmental Pollution and Health, Jinan University, Guangzhou, China, 511443
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Lombard NJ, Bokare M, Harrison R, Yonkos L, Pinkney A, Murali D, Ghosh U. Codeployment of Passive Samplers and Mussels Reveals Major Source of Ongoing PCB Inputs to the Anacostia River in Washington, DC. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:1320-1331. [PMID: 36622805 DOI: 10.1021/acs.est.2c06646] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Remedial investigations of sites contaminated with legacy pollutants like polychlorinated biphenyls (PCBs) have traditionally focused on mapping sediment contamination to develop a site conceptual model and select remedy options. Ignoring dissolved concentrations that drive transport and bioaccumulation often leads to an incomplete assessment of ongoing inputs to the water column and overestimation of potential effectiveness of sediment remediation. Here, we demonstrate the utility of codeployment of passive equilibrium samplers and freshwater mussels as dual lines of evidence to identify ongoing sources of PCBs from eight main tributaries of the Anacostia River in Washington, DC, that has been historically polluted from industrial and other human activities. The freely dissolved PCB concentrations measured using passive samplers tracked well with the accumulation in mussels and allowed predictions of biouptake within a factor of 2 for total PCBs and a factor of 4 for most congeners. One tributary was identified as the primary source of PCBs to the water column and became a focus of additional ongoing investigations. Codeployment of passive samplers and mussels provides strong lines of evidence to refine site conceptual models and identify ongoing sources critical to control to achieve river water quality standards and reduce bioaccumulation in the aquatic food web.
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Affiliation(s)
- Nathalie J Lombard
- Department of Chemical, Biochemical, and Environmental Engineering, University of Maryland, Baltimore County, Baltimore, Maryland21250, United States
| | - Mandar Bokare
- Department of Chemical, Biochemical, and Environmental Engineering, University of Maryland, Baltimore County, Baltimore, Maryland21250, United States
| | - Rachel Harrison
- Department of Environmental Science and Technology, University of Maryland, College Park, Maryland20740, United States
| | - Lance Yonkos
- Department of Environmental Science and Technology, University of Maryland, College Park, Maryland20740, United States
| | - Alfred Pinkney
- United States Fish and Wildlife Service, Chesapeake Bay Field Office, Annapolis, Maryland21401, United States
| | - Dev Murali
- District of Columbia Department of Energy and Environment, Washington, District of Columbia20002, United States
| | - Upal Ghosh
- Department of Chemical, Biochemical, and Environmental Engineering, University of Maryland, Baltimore County, Baltimore, Maryland21250, United States
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Wu R, Zhang S, Wang S. Development and microbial characterization of Bio-RD-PAOP for effective remediation of polychlorinated biphenyls. JOURNAL OF HAZARDOUS MATERIALS 2022; 436:129190. [PMID: 35739720 DOI: 10.1016/j.jhazmat.2022.129190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 05/02/2022] [Accepted: 05/17/2022] [Indexed: 06/15/2023]
Abstract
Polychlorinated biphenyls (PCBs) as typical halogenated persistent organic pollutants are widely distributed in natural environments, and can be enriched and magnified in organisms via food webs. It is consequently urgent and necessary to develop techniques to completely remove these persistent organohalides. In this study, we developed a process (Bio-RD-PAOP) by integrating microbial reductive dechlorination (Bio-RD) with subsequent persulfate activation and oxidation process (PAOP) for effective remediation of PCBs. Results showed the synergistic combination of advantages of Bio-RD and PAOP in dechlorination of higher-chlorinated PCBs and of PAOP in degradation/mineralization of lower-chlorinated PCBs, respectively. For the PAOP, both experimental evidences and theoretical calculations suggested that degradation rate and efficiency decreased with the increased PCB chlorine numbers. Relative to the Bio-RD and PAOP, Bio-RD-PAOP had significantly higher PCB removal efficiencies, of which values were PCB congener-specific. For example, removal efficiency of Bio-RD-PAOP in removing PCB88 is 2.50 and 1.86 times of that of Bio-RD and PAOP, respectively. In contrast, the efficiency is 1.66 and 3.35 times of Bio-RD and PAOP, respectively, for PCB180 removal. The PAOP-derived oxidizing species (mainly sulfate free radical) significantly decreased microbial abundance, particularly of the organohalide-respiring Dehalococcoides. Notably, co-existence of other microorganisms alleviated the inhibitive effect of oxidizing species on the Dehalococcoides, possibly due to formation of microbial flocs or biofilm. This study provided a promising strategy for extensive remediation of organohalide-contaminated sites, as well as new insight into impact of PAOP-derived oxidizing species on the organohalide-respiring community.
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Affiliation(s)
- Rifeng Wu
- Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-Sen University, Guangzhou 510006, China
| | - Shangwei Zhang
- Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-Sen University, Guangzhou 510006, China
| | - Shanquan Wang
- Environmental Microbiomics Research Center, School of Environmental Science and Engineering, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-Sen University, Guangzhou 510006, China.
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Lotufo GR, Michalsen MM, Reible DD, Gschwend PM, Ghosh U, Kennedy AJ, Kerns KM, Rakowska MI, Odetayo A, MacFarlane JK, Yan S, Bokare M. Interlaboratory Study of Polyethylene and Polydimethylsiloxane Polymeric Samplers for Ex Situ Measurement of Freely Dissolved Hydrophobic Organic Compounds in Sediment Porewater. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2022; 41:1885-1902. [PMID: 35512673 PMCID: PMC9545451 DOI: 10.1002/etc.5356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 12/19/2021] [Accepted: 05/02/2022] [Indexed: 05/04/2023]
Abstract
We evaluated the precision and accuracy of multilaboratory measurements for determining freely dissolved concentrations (Cfree ) of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in sediment porewater using polydimethylsiloxane (PDMS) and low-density polyethylene (LDPE) polymeric samplers. Four laboratories exposed performance reference compound (PRC) preloaded polymers to actively mixed and static ex situ sediment for approximately 1 month; two laboratories had longer exposures (2 and 3 months). For Cfree results, intralaboratory precision was high for single compounds (coefficient of variation 50% or less), and for most PAHs and PCBs interlaboratory variability was low (magnitude of difference was a factor of 2 or less) across polymers and exposure methods. Variability was higher for the most hydrophobic PAHs and PCBs, which were present at low concentrations and required larger PRC-based corrections, and also for naphthalene, likely due to differential volatilization losses between laboratories. Overall, intra- and interlaboratory variability between methods (PDMS vs. LDPE, actively mixed vs. static exposures) was low. The results that showed Cfree polymer equilibrium was achieved in approximately 1 month during active exposures, suggesting that the use of PRCs may be avoided for ex situ analysis using comparable active exposure; however, such ex situ testing may not reflect field conditions. Polymer-derived Cfree concentrations for most PCBs and PAHs were on average within a factor of 2 compared with concentrations in isolated porewater, which were directly measured by one laboratory; difference factors of up to 6 were observed for naphthalene and the most hydrophobic PAHs and PCBs. The Cfree results were similar for academic and private sector laboratories. The accuracy and precision that we demonstrate for determination of Cfree using polymer sampling are anticipated to increase regulatory acceptance and confidence in use of the method. Environ Toxicol Chem 2022;41:1885-1902. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.
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Affiliation(s)
- Guilherme R. Lotufo
- Environmental Laboratory, US Army Engineer Research and Development CenterVicksburgMississippiUSA
| | - Mandy M. Michalsen
- Environmental Laboratory, US Army Engineer Research and Development CenterVicksburgMississippiUSA
| | - Danny D. Reible
- Department of Civil, Environmental, and Construction EngineeringTexas Tech UniversityLubbockTexasUSA
| | - Philip M. Gschwend
- Department of Civil and Environmental EngineeringMassachusetts Institute of TechnologyCambridgeMassachusettsUSA
| | - Upal Ghosh
- Department of Chemical, Biochemical, and Environmental EngineeringUniversity of Maryland Baltimore CountyBaltimoreMarylandUSA
| | - Alan J. Kennedy
- Environmental Laboratory, US Army Engineer Research and Development CenterVicksburgMississippiUSA
| | | | - Magdalena I. Rakowska
- Department of Civil, Environmental, and Construction EngineeringTexas Tech UniversityLubbockTexasUSA
| | - Adesewa Odetayo
- Department of Civil, Environmental, and Construction EngineeringTexas Tech UniversityLubbockTexasUSA
| | - John K. MacFarlane
- Department of Civil and Environmental EngineeringMassachusetts Institute of TechnologyCambridgeMassachusettsUSA
| | - Songjing Yan
- Department of Chemical, Biochemical, and Environmental EngineeringUniversity of Maryland Baltimore CountyBaltimoreMarylandUSA
| | - Mandar Bokare
- Department of Chemical, Biochemical, and Environmental EngineeringUniversity of Maryland Baltimore CountyBaltimoreMarylandUSA
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Yan S, Bokare M, Ghosh U. Equilibrium Porewater Measurement of PCBs and PAHs Using Direct Water Extraction and Comparison with Passive Sampling. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:10020-10029. [PMID: 35759616 PMCID: PMC9302434 DOI: 10.1021/acs.est.2c00312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The freely dissolved concentration of hydrophobic pollutants in sediment porewater (Cpw) is a critical driver for exposure to aquatic organisms, bioaccumulation, toxicity, and flux across interfaces. In this research, we compared direct porewater extraction and passive sampling for Cpw measurements of a range of PCBs and PAHs in field-collected sediments. The direct water extraction method provided accurate quantification of Cpw for low to moderately hydrophobic PCB and PAH compounds (log Kow < 6.5) that compared well with independent measurements performed using four passive sampling methods. Direct water extraction was adequate to assess narcosis toxicity of PAHs to benthic organisms that is driven by the concentrations of low to moderately hydrophobic PAHs (naphthalene to chrysene), even for a hypothetical sediment that had a tenth of the PAH concentrations of the study sediments and was assessed to be nontoxic. Prediction of PCB bioaccumulation in benthic organisms agreed within 50% for all measurement methods, but it was apparent that for less contaminated sediments, the direct water extraction method would likely have detection limit challenges, especially for the strongly hydrophobic PCBs. To address the uncertainty of the Cpw measurement of the strongly hydrophobic compounds and naphthalene, a new extrapolation approach is demonstrated that can be applicable for both direct water extraction and passive sampling methods.
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Šrédlová K, Cajthaml T. Recent advances in PCB removal from historically contaminated environmental matrices. CHEMOSPHERE 2022; 287:132096. [PMID: 34523439 DOI: 10.1016/j.chemosphere.2021.132096] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 08/26/2021] [Accepted: 08/28/2021] [Indexed: 06/13/2023]
Abstract
Despite being drastically restricted in the 1970s, polychlorinated biphenyls (PCBs) still belong among the most hazardous contaminants. The chemical stability and dielectric properties of PCBs made them suitable for a number of applications, which then lead to their ubiquitous presence in the environment. PCBs are highly bioaccumulative and persistent, and their teratogenic, carcinogenic, and endocrine-disrupting features have been widely reported in the literature. This review discusses recent advances in different techniques and approaches to remediate historically contaminated matrices, which are one of the most problematic in regard to decontamination feasibility and efficiency. The current knowledge published in the literature shows that PCBs are not sufficiently removed from the environment by natural processes, and thus, the suitability of some approaches (e.g., natural attenuation) is limited. Physicochemical processes are still the most effective; however, their extensive use is constrained by their high cost and often their destructiveness toward the matrices. Despite their limited reliability, biological methods and their application in combinations with other techniques could be promising. The literature reviewed in this paper documents that a combination of techniques differing in their principles should be a future research direction. Other aspects discussed in this work include the incompleteness of some studies. More attention should be given to the evaluation of toxicity during these processes, particularly in terms of monitoring different modes of toxic action. In addition, decomposition mechanisms and products need to be sufficiently clarified before combined, tailor-made approaches can be employed.
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Affiliation(s)
- Kamila Šrédlová
- Institute for Environmental Studies, Faculty of Science, Charles University, Benátská 2, 12801, Prague 2, Czech Republic; Institute of Microbiology of the Czech Academy of Sciences, Vídeňská 1083, 14220, Prague 4, Czech Republic
| | - Tomáš Cajthaml
- Institute for Environmental Studies, Faculty of Science, Charles University, Benátská 2, 12801, Prague 2, Czech Republic; Institute of Microbiology of the Czech Academy of Sciences, Vídeňská 1083, 14220, Prague 4, Czech Republic.
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