Enhanced Mobilization of Field Contaminated Soil-bound PAHs to the Aqueous Phase under Anaerobic Conditions

Kim, Han Soo; Lindsay, Katherine S.; Pfaender, Frederic K.

doi:10.1007/s11270-007-9562-2

Cited by 12 publications

(6 citation statements)

References 36 publications

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“…In contrast, it has been argued that long-term exposure to NER in soil may be harmful to receptors. For instance, enhanced PAH mobilisation has been speculated in long-term aged (50 years) soils from manufactured gas plant sites (MGP) under anoxic conditions and other changing environmental conditions such as temperature 55,59,60 . Some studies also reported that higher organisms may have the capacity to access HOC residues, which were hitherto classified as inaccessible by microbial processes; this is due to differences in uptake mechanisms and exposure conditions such as gut conditions of specific organisms, including humans 38,47,[61][62][63][64][65] .…”

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confidence: 99%

Residual hydrophobic organic contaminants in soil: Are they a barrier to risk-based approaches for managing contaminated land?

Umeh

Duan

Naidu

et al. 2017

Environment International

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Risk-based approaches to managing contaminated land, rather than approaches based on complete contaminant removal, have gained acceptance as they are likely to be more feasible and cost effective. Risk-based approaches aim to minimise risks of exposure of a specified contaminant to humans. However, adopting a risk-based approach over alternative overly-conservative approaches requires that associated uncertainties in decision making are understood and minimised. Irrespective of the nature of contaminants, a critical uncertainty is whether there are potential risks associated with exposure to the residual contaminant fractions in soil to humans and other ecological receptors, and how they should be considered in the risk assessment process. This review focusing on hydrophobic organic contaminants (HOCs), especially polycyclic aromatic hydrocarbons (PAHs), suggests that there is significant uncertainty on the residual fractions of contaminants from risk perspectives. This is because very few studies have focused on understanding the desorption behaviour of HOCs, with few or no studies considering the influence of exposure-specific factors. In particular, it is not clear whether the exposure of soil-associated HOCs to gastrointestinal fluids and enzyme processes release bound residues. Although, in vitro models have been used to predict PAH bioaccessibility, and chemical extractions have been used to determine residual fractions in various soils, there are still doubts about what is actually being measured. Therefore it is not certain which bioaccessibility method currently represents the best choice, or provides the best estimate, of in vivo PAH bioavailability. It is suggested that the fate and behaviour of HOCs in a wide range of soils, and that consider exposure-specific scenarios, be investigated. Exposure-specific scenarios are important for validation purposes, which may be useful for the development of standardised methods and procedures for HOC bioaccessibility determinations. Research is needed to propose the most appropriate testing methods and for assessing potential risks posed by residual fractions of HOCs. Such investigations may be useful for minimising uncertainties associated with a risk-based approach, so that consideration may then be given to its adoption on a global scale. This review critically appraises existing information on the bioavailability of HOC residues in soil to establish whether there may be risks from highly sequestered contaminant residues.

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confidence: 99%

Residual hydrophobic organic contaminants in soil: Are they a barrier to risk-based approaches for managing contaminated land?

Umeh

Duan

Naidu

et al. 2017

Environment International

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“…OM modulates the fate of pollutants in multiple ways, including their storage, mobility, persistence, toxicity and bioaccumulation (Chapman et al, 1998;Redman et al, 2002;Eggleton & Thomas, 2004), as well as by controlling the main biogeochemical routes through its effects on the riverine chemical environment, especially on the redox potential (Kim et al, 2008).…”

Section: Om As a Modulator Of The Fate Of Pollutantsmentioning

confidence: 99%

Altered organic matter dynamics in rivers and streams: ecological consequences and management implications

Elosegi¹,

Pozo²

2016

Limnetica

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Altered organic matter dynamics in rivers and streams: ecological consequences and management implicationsScientists have spent decades measuring inputs, storage and breakdown of organic matter in freshwaters and have documented the effects of soil uses, pollution, climate warming or flow regulation on these pivotal ecosystem functions. Large-scale collaborative experiments and meta-analyses have revealed some clear patterns as well as substantial variability in detritus dynamics, and a number of standardized methods have been designed for routine monitoring of organic matter inputs, retention and breakdown in different conditions. Despite the knowledge gathered, scientists have been relatively ineffective at convincing managers of the importance of organic matter dynamics in freshwaters. Here we review the existing information of the role of organic matter as a) an element structuring freshwater habitats, b) a source or sink of nutrients, c) a food resource for heterotrophs, d) a source of pollution, e) a modulator of the fate of pollutants, f) a source of greenhouse gases, g) a potential source of environmental problems, and h) a diagnostic tool for ecosystem functioning. Current knowledge in some of these points is enough to be transferred to management actions, although has seldom been so. Some other points, such as the interactions between organic matter and emerging pollutants, offer interesting research questions.

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“…The few studies that addressed possible effects of NOM reduction state on the sorption of organic pollutants have exclusively used apolar model compounds. The majority of these studies reported altered organic pollutant sorption upon changes in the redox states of contaminated soils and sediments (e.g., reaeration of reduced samples). − The complexity of the investigated systems, however, impaired assessing whether changes in NOM redox state contributed to altered sorption. Coates et al reported decreased naphthalene sorption to microbially reduced Aldrich HA as compared to the unreduced HA .…”

Section: Introductionmentioning

confidence: 99%

Assessing the Effect of Humic Acid Redox State on Organic Pollutant Sorption by Combined Electrochemical Reduction and Sorption Experiments

Aeschbacher

Brunner

Schwarzenbach

et al. 2012

Environ. Sci. Technol.

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Natural Organic Matter (NOM) is a major sorbent for organic pollutants in soils and sediments. While sorption under oxic conditions has been well investigated, possible changes in the sorption capacity of a given NOM induced by reduction have not yet been studied. Reduction of quinones to hydroquinones, the major redox active moieties in NOM, increases the number of H-donor moieties and thus may affect sorption. This work compares the sorption of four nonionic organic pollutants of different polarities (naphthalene, acetophenone, quinoline, and 2-naphthol), and of the organocation paraquat to unreduced and electrochemically reduced Leonardite Humic Acid (LHA). The redox states of reduced and unreduced LHA in all sorption experiments were stable, as demonstrated by a spectrophotometric 2,6-dichlorophenol indophenol reduction assay. The sorption isotherms of the nonionic pollutants were highly linear, while paraquat sorption was strongly concentration dependent. LHA reduction did not result in significant changes in the sorption of all tested compounds, not even of the cationic paraquat at pH 7, 9, and 11. This work provides the first evidence that changes in NOM redox state do not largely affect organic pollutant sorption, suggesting that current sorption models are applicable both to unreduced and to reduced soil and sediment NOM.

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Enhanced Mobilization of Field Contaminated Soil-bound PAHs to the Aqueous Phase under Anaerobic Conditions

Cited by 12 publications

References 36 publications

Residual hydrophobic organic contaminants in soil: Are they a barrier to risk-based approaches for managing contaminated land?

Residual hydrophobic organic contaminants in soil: Are they a barrier to risk-based approaches for managing contaminated land?

Altered organic matter dynamics in rivers and streams: ecological consequences and management implications

Assessing the Effect of Humic Acid Redox State on Organic Pollutant Sorption by Combined Electrochemical Reduction and Sorption Experiments

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