| 1. |
- Abel, Sebastian, et al.
(författare)
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Mixing and capping techniques for activated carbon based sediment remediation Efficiency and adverse effects for Lumbriculus variegatus
- 2017
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Ingår i: Water Research. - : Elsevier BV. - 0043-1354 .- 1879-2448. ; 114, s. 104-112
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Tidskriftsartikel (refereegranskat)abstract
- Activated carbon (AC) has been proven to be highly effective for the in-situ remediation of sediments contaminated with a wide range of hydrophobic organic contaminants (HOCs). However, adverse biological effects, especially to benthic organisms, can accompany this promising remediation potential. In this study, we compare both the remediation potential and the biological effects of several AC materials for two application methods: mixing with sediment (MIX) at doses of 0.1 and 1.0% based on sediment dw and thin layer capping (TLC) with 0.6 and 1.2 kg AC/m(2). Significant dose dependent reductions in PCB bioaccumulation in Lumbriculus variegatus of 35-93% in MIX treatments were observed. Contaminant uptake in TLC treatments was reduced by up to 78% and differences between the two applied doses were small. Correspondingly, significant adverse effects were observed for L. variegatus whenever AC was present in the sediment. The lowest application dose of 0.1% AC in the MIX system reduced L variegatus growth, and 1.0% AC led to a net loss of organism biomass. All TLC treatments let to a loss of biomass in the test organism. Furthermore, mortality was observed with 1.2 kg ACim(2) doses of pure AC for the TLC treatment. The addition of clay (Kaolinite) to the TLC treatments prevented mortality, but did not decrease the loss in biomass. While TLC treatments pose a less laborious alternative for AC amendments in the field, the results of this study show that it has lower remediation potential and could be more harmful to the benthic fauna.
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| 2. |
- Arp, Hans Peter H., et al.
(författare)
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Review of polyoxymethylene passive sampling methods for quantifying freely dissolved porewater concentrations of hydrophobic organic contaminants
- 2015
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Ingår i: Environmental Toxicology and Chemistry. - : Wiley. - 0730-7268 .- 1552-8618. ; 34:4, s. 710-720
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Forskningsöversikt (refereegranskat)abstract
- Methods involving polyoxymethylene (POM) as a passive sampler are increasing in popularity to assess contaminant freely dissolved porewater concentrations in soils and sediments. These methods require contaminant-specific POM-water partition coefficients, K-POM. Certain methods for determining K-POM perform reproducibly (within 0.2 log units). However, other methods can give highly varying K-POM values (up to 2 log units), especially for polycyclic aromatic hydrocarbons (PAHs). To account for this variation, the authors tested the influence of key methodological components in K-POM determinations, including POM thickness, extraction procedures, and environmental temperature and salinity, as well as uptake kinetics in mixed and static systems. All inconsistencies in the peer-reviewed literature can be accounted for by the likelihood that thick POM materials (500m or thicker) do not achieve equilibrium (causing negative biases up to 1 log unit), or that certain POM extraction procedures do not ensure quantitative extraction (causing negative biases up to 2 log units). Temperature can also influence K-POM, although all previous literature studies were carried out at room temperature. The present study found that K-POM values at room temperature are independent (within 0.2 log units) of POM manufacture method, of thickness between 17m and 80m, and of salinity between 0% and 10%. Regarding kinetics, monochloro- to hexachloro-polychlorinated biphenyls (PCBs) were within 0.2 log units of equilibrium after 28d in the mixed system, but only dichloro-PCBs achieved near equilibrium after 126d in the static system. Based on these insights, recommended methods and K-POM values to facilitate interlaboratory reproducibility are presented.
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| 3. |
- Hale, Sarah E., et al.
(författare)
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A synthesis of parameters related to the binding of neutral organic compounds to charcoal
- 2016
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Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 144, s. 65-74
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Forskningsöversikt (refereegranskat)abstract
- The sorption strength of neutral organic compounds to charcoal, also called biochar was reviewed and related to charcoal and compound properties. From 29 studies, 507 individual Freundlich sorption.coefficients were compiled that covered the sorption strength of 107 organic contaminants. These sorption coefficients were converted into charcoal-water distribution coefficients (K-D) at aqueous concentrations of 1 ng/L, 1 mu g/L and 1 mg/L. Reported log K-D values at 1 mu g/L varied from 0.38 to 8.25 across all data. Variation was also observed within the compound classes; pesticides, herbicides and insecticides, PAHs, phthalates, halogenated organics, small organics, alcohols and PCBs. Five commonly reported variables; charcoal production temperature T, surface area SA, H/C and 0/C ratios and organic compound octanolwater partitioning coefficient, were correlated with K-D values using single and multiple-parameter linear regressions. The sorption strength of organic compounds to charcoals increased with increasing charcoal production temperature T, charcoal SA and organic pollutant octanol-water partitioning coefficient and decreased with increasing charcoal O/C ratio and charcoal H/C ratio. T was found to be correlated with SA (r(2) = 0.66) and O/C (r(2) = 0.50), particularly for charcoals produced from wood feedstocks (r2 = 0.73 and 0.80, respectively). The resulting regression: log K-D = (0.18 +/- 0.06) log K-ow + (5.74 +/- 1.40) log T + (0.85 +/- 0.15) log SA + (1.60 +/- 0.29) log OC + (-0.89 +/- 0.20) log HC + (-13.20 +/- 3.69), r(2) = 0.60, root mean squared error = 0.95, n = 151 was obtained for all variables. This information can be used as an initial screening to identify charcoals for contaminated soil and sediment remediation.
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| 4. |
- Hale, Sarah E., et al.
(författare)
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Sorption of the monoterpenes alpha-pinene and limonene to carbonaceous geosorbents including biochar
- 2015
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Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 119, s. 881-888
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Tidskriftsartikel (refereegranskat)abstract
- The sorption of two monoterpenes, alpha pinene and limonene to the carbonaceous geosorbents graphite, bituminous coal, lignite coke, biochar and Pahokee peat was quantified. Polyethylene (PE) passive samplers were calibrated for the first time for these compounds by determining the PE-water partitioning coefficients and used as a tool to determine sorption to the carbonaceous geosorbents. Log KPE-water values were 3.49 +/- 0.58 for alpha pinene and 4.08 +/- 0.27 for limonene. The sorption of limonene to all materials was stronger than that for a pinene (differences of 0.2-13 log units between distribution coefficients for the monoterpenes). Placing K-d values in increasing order for a pinene gave biochar approximate to Pahokee peat approximate to bituminous coal approximate to lignite coke < graphite. For limonene the order was: Pahokee peat approximate to biochar approximate to bituminous coal < graphite approximate to lignite coke. Micropore (defined as pores <1.5 nm) and nanopore surface area (defined as pores 1.5 nm to 50 nm) normalised carbonaceous geosorbent-water distribution coefficients were also calculated. There was no clear correlation of these distribution coefficients with SA. Elemental composition was used to assess the degree of condensation (or alteration) of the carbonaceous geosorbents. The degree of carbonisation increased in the order; Pahokee peat < lignite coke < bituminous coal < biochar < graphite, however this was not correlated with an increase in the experimental distribution coefficients.
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| 5. |
- Hale, Sarah E., et al.
(författare)
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The role of passive sampling in monitoring the environmental impacts of produced water discharges from the Norwegian oil and gas industry
- 2016
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Ingår i: Marine Pollution Bulletin. - : Elsevier BV. - 0025-326X .- 1879-3363. ; 111:1-2, s. 33-40
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Tidskriftsartikel (refereegranskat)abstract
- Stringent and periodic iteration of regulations related to the monitoring of chemical releases from the offshore oil and gas industry requires the use of ever changing, rapidly developing and technologically advancing techniques. Passive samplers play an important role in water column monitoring of produced water (PW) discharge to sea-water under Norwegian regulation, where they are used to; i) measure aqueous concentrations of pollutants, ii) quantify the exposure of caged organisms and investigate PW dispersal, and iii) validate dispersal models. This article summarises current Norwegian water column monitoring practice and identifies research and methodological gaps for the use of passive samplers in monitoring. The main gaps are; i) the range of passive samplers used should be extended, ii) differences observed in absolute concentrations accumulated by passive samplers and organisms should be understood, and iii) the link between PW discharge concentrations and observed acute and sub-lethal ecotoxicological end points in organisms should be investigated.
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| 6. |
- Hilber, Isabel, et al.
(författare)
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Bioavailability and bioaccessibility of polycyclic aromatic hydrocarbons from (post-pyrolytically treated) biochars
- 2017
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Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 174, s. 700-707
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Tidskriftsartikel (refereegranskat)abstract
- Bioaccessibility data of PAHs from biochar produced under real world conditions is scarce and the influence of feedstock and various post-pyrolysis treatments common in agriculture, such as co composting or lacto-fermentation to produce silage fodder, on their bioavailability and bioaccessibility has hardly been studied. The total (C-total), and freely dissolved (i.e., bioavailable) concentrations (C-free) of the sum of 16 US EPA PAHs of 43 biochar samples produced and treated in such ways ranged from 0.4 to almost 2000 mg/kg, and from 12 to 81 ng/L, respectively, which resulted in very high biochar-water partition coefficients (4.2 < log K-D < 8.8 L/kg) for individual PAHs. Thirty three samples were incubated in contaminant traps that combined a diffusive carrier and a sorptive sink. Incubations yielded samples only containing desorption-resistant PAHs (C-res). The desorption resistant PAH fraction was dominant, since only eight out of 33 biochar samples showed statistically significant bioaccessible fractions (f(bioaccessible) = 1 - C-res/C-total). Bioavailability correlated positively with C-total/surface area. Other relationships of bioavailability and accessibility with the investigated post-pyrolysis processes or elemental composition could not be found. PAH exposure was very limited (low C-free, high C-res) for all samples with low to moderate C-total whereas higher exposure was determined in some biochars with C-total > 10 mg/kg.
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| 7. |
- Kupryianchyk, Darya, et al.
(författare)
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Positioning Activated Carbon Amendment Technologies in a Novel Framework for Sediment Management
- 2015
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Ingår i: Integrated Environmental Assessment and Management. - : Wiley. - 1551-3777 .- 1551-3793. ; 11:2, s. 221-234
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Forskningsöversikt (refereegranskat)abstract
- Contaminated sediments can pose serious threats to human health and the environment by acting as a source of toxic chemicals. The amendment of contaminated sediments with strong sorbents like activated C (AC) is a rapidly developing strategy to manage contaminated sediments. To date, a great deal of attention has been paid to the technical and ecological features and implications of sediment remediation with AC, although science in this field still is rapidly evolving. This article aims to provide an update on the recent literature on these features, and for the first time provides a comparison of sediment remediation with AC to other sediment management options, emphasizing their full-scale application. First, a qualitative overview of advantages and disadvantages of current alternatives to remediate contaminated sediments is presented. Subsequently, AC treatment technology is critically reviewed, including current understanding of the effectiveness and ecological safety for the use of AC in natural systems. Finally, this information is used to provide a novel framework for supporting decisions concerning sediment remediation and beneficial reuse.
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| 8. |
- Kupryianchyk, Darya, et al.
(författare)
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Treatment of sites contaminated with perfluorinated compounds using biochar amendment
- 2016
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Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 142, s. 35-40
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Per- and polyfluorinated compounds (PFCs) have been attracting increasing attention due to their considerable persistence, bioaccumulation, and toxicity. Here, we studied the sorption behavior of three PFCs, viz. perfluorooctanesulfonic acid (PFOS), perfluorooctanecarboxylic acid (PFOA), perfluorohexanesulfonic acid (PFHxS), on one activated carbon (AC) and two biochars from different feedstocks, viz. mixed wood (MW) and paper mill waste (PMW). In addition, we explored the potential of remediating three natively PFC contaminated soils by the addition of AC or biochar. The sorption coefficient i.e. Freundlich coefficients Log KF, (μg/kg)/(μg/L)n, for the two biochars were 4.61 ± 0.11 and 4.41 ± 0.05 for PFOS, 3.02 ± 0.04 and 3.01 ± 0.01 for PFOA, and 3.21 ± 0.07 and 3.18 ± 0.03 for PFHxS, respectively. The AC sorbed the PFCs so strongly that aqueous concentrations were reduced to below detection limits, implying that the Log KF values were above 5.60. Sorption capacities decreased in the order: AC > MW > PMW, which was consistent with the material’s surface area and pore size distribution. PFC sorption to MW biochar was near-linear (Freundlich exponent nF of 0.87–0.90), but non-linear for PMW biochar (0.64–0.73). Addition of the AC to contaminated soils resulted in almost complete removal of PFCs from the water phase and a significant (i.e. 1–3 Log unit) increase in soil–water distribution coefficient Log Kd. However, small to no reduction in pore water concentration, and no effect on Log Kd was found for the biochars. We conclude that amendment with AC but not biochar can be a useful method for in situ remediation of PFC-contaminated soils.
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| 9. |
- Manickam, Theeba, et al.
(författare)
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Biochar Application in Malaysian Sandy and Acid Sulfate Soils : Soil Amelioration Effects and Improved Crop Production over Two Cropping Seasons
- 2015
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Ingår i: Sustainability. - : MDPI AG. - 2071-1050. ; 7:12, s. 16756-16770
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Tidskriftsartikel (refereegranskat)abstract
- The use of biochar as an agricultural soil improvement was tested in acid sulfate and sandy soils from Malaysia, cropped with rice and corn. Malaysia has an abundance of waste rice husks that could be used to produce biochar. Rice husk biochar was produced in a gasifier at a local mill in Kelantan as well as in the laboratory using a controlled, specially designed, top lift up draft system (Belonio unit). Rice husk biochar was applied once to both soils at two doses (2% and 5%), in a pot set up that was carried out for two cropping seasons. Positive and significant crop yield effects were observed for both soils, biochars and crops. The yield effects varied with biochar type and dosage, with soil type and over the cropping seasons. The yield increases observed for the sandy soil were tentatively attributed to significant increases in plant-available water contents (from 4%-5% to 7%-8%). The yield effects in the acid sulfate soil were likely a consequence of a combination of (i) alleviation of plant root stress by aluminum (Ca/Al molar ratios significantly increased, from around 1 to 3-5) and (ii) increases in CEC. The agricultural benefits of rice husk biochar application to Malaysian soils holds promise for its future use.
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| 10. |
- Mayer, Philipp, et al.
(författare)
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How to Determine the Environmental Exposure of PAHs Originating from Biochar
- 2016
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 50:4, s. 1941-1948
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Tidskriftsartikel (refereegranskat)abstract
- Biochars are obtained by pyrolyzing biomass materials and are increasingly used within the agricultural sector. Owing to the production process, biochars can contain polycyclic aromatic hydrocarbons (PAHs) in the high mg/kg range, which makes the determination of the environmental exposure of PAHs originating from biochars relevant. However, PAH sorption to biochar is characterized by very high (10(4)-10(6) L/kg) or extreme distribution coefficients (K-D) (>10(6) L/kg), which makes the determination of exposure scientifically and technically challenging. Cyclodextrin extractions, sorptive bioaccessibility extractions, Tenax extractions, contaminant traps, and equilibrium sampling were assessed and selected methods used for the determination of bioavailability parameters for PAHs in two model biochars. Results showed that: (1) the K-D values of typically 10(6)-10(9) L/kg made the biochars often act as sinks, rather than sources, of PAHs. (2) Equilibrium sampling yielded freely dissolved concentrations (pg-ng/L range) that were below or near environmental background levels. (3) None of the methods were found to be suitable for the direct measurement of the readily desorbing fractions of PAHs (i.e., bioacessibility) in the two biochars. (4) The contaminant-trap method yielded desorption-resistant PAH fractions of typically 90-100%, implying bioaccessibility in the high mu g/kg to low mg/kg range.
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