| 1. |
- Selck, H., et al.
(författare)
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Assessing and managing multiple risks in a changing worldThe Roskilde recommendations
- 2017
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Ingår i: Environmental Toxicology and Chemistry. - Hoboken, NJ : Wiley. - 0730-7268 .- 1552-8618. ; 36:1, s. 7-16
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Tidskriftsartikel (refereegranskat)abstract
- Roskilde University (Denmark) hosted a November 2015 workshop, Environmental RiskAssessing and Managing Multiple Risks in a Changing World. This Focus article presents the consensus recommendations of 30 attendees from 9 countries regarding implementation of a common currency (ecosystem services) for holistic environmental risk assessment and management; improvements to risk assessment and management in a complex, human-modified, and changing world; appropriate development of protection goals in a 2-stage process; dealing with societal issues; risk-management information needs; conducting risk assessment of risk management; and development of adaptive and flexible regulatory systems. The authors encourage both cross-disciplinary and interdisciplinary approaches to address their 10 recommendations: 1) adopt ecosystem services as a common currency for risk assessment and management; 2) consider cumulative stressors (chemical and nonchemical) and determine which dominate to best manage and restore ecosystem services; 3) fully integrate risk managers and communities of interest into the risk-assessment process; 4) fully integrate risk assessors and communities of interest into the risk-management process; 5) consider socioeconomics and increased transparency in both risk assessment and risk management; 6) recognize the ethical rights of humans and ecosystems to an adequate level of protection; 7) determine relevant reference conditions and the proper ecological context for assessments in human-modified systems; 8) assess risks and benefits to humans and the ecosystem and consider unintended consequences of management actions; 9) avoid excessive conservatism or possible underprotection resulting from sole reliance on binary, numerical benchmarks; and 10) develop adaptive risk-management and regulatory goals based on ranges of uncertainty. Environ Toxicol Chem 2017;36:7-16. (c) 2016 SETAC
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| 2. |
- Rämö, Robert A., 1989-
(författare)
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Sediment remediation using activated carbon: amending knowledge gaps
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Many coastal sediments have accumulated large quantities of contaminants from past anthropogenic activities and now act as a secondary emission source of legacy pollutants to coastal ecosystems. New sediment remediation strategies are needed to address widespread sediment pollution. This thesis focuses on the harbour of Oskarshamn in the Baltic Sea, contaminated by PAHs, PCBs, TBTs, dioxins, and metals from past emissions, and aims to improve knowledge on in situ sediment remediation using activated carbon, a strong sorbent for hydrophobic organic contaminants. Thin-layer capping using activated carbon aims to sequester contaminants in sediment and reduce their bioavailability to aquatic organisms without having to remove or physically isolate the contaminated sediment from the aquatic environment.Questions remain on the efficacy and persistence of activated carbon thin-layer capping in turbulent waters, and on potential adverse effects of activated carbon on benthic communities. We studied the role of activated carbon particle size on contaminant sequestration, sorbent retention (Paper I), and adverse effects in benthic macroinvertebrates (Paper III). We also assessed effects of activated carbon amendment on nutrient cycling and meiofauna communities (Paper II), and whether granular activated carbon (GAC, >300 µm) reduces toxicity to the benthic sentinel amphipod Monoporeia affinis in Oskarshamn harbour (Paper IV).We found that powdered activated carbon (PAC, <300 µm) is much more effective in sequestering PAHs and PCBs than GAC in the short term (Paper I), but that PAC is readily resuspended in turbulent water, whereas GAC may remain on the sediment surface, leading to a higher persistence of GAC over time (Paper I). Thin-layer capping with PAC raised porewater pH and reduced meiofauna abundance, nitrate reduction, nitrate release fluxes, and phosphate release fluxes by at least 50 % (Paper II). This indicates that thin-layer capping with PAC affected both sediment microbial and meiofaunal communities, potentially through the increased pH and sequestration of dissolved organic matter onto activated carbon, rendering it less available to microbial organisms.We observed strong biological responses in macroinvertebrates, with reduced weight, carbon assimilation, and gut microvilli in the polychaete Marenzelleria spp. exposed to ingestible PAC, contrasted by increased weight and carbon assimilation in polychaetes exposed to noningestible GAC (Paper III). This indicates that amendment with PAC caused starvation, i.e., that the polychaete ceased ingesting sediment or that PAC reduced the bioaccessibility of food co-ingested with the sorbent. These effects were present but less pronounced in the clam Limecola balthica (Paper III), indicating that biological responses are species dependent. A toxicity bioassay (Paper IV) showed that sediment amendment using GAC effectively reduced mortality and reproduction impairments in the amphipod Monoporeia affinis.Overall, the thesis demonstrates that GAC may have positive effects on benthic macroinvertebrates, high persistence in turbulent water, and reduces toxicity of highly contaminated sediments. We show that PAC is a highly effective sorbent, but may cause strong adverse effects on benthic macroinvertebrates, meiofauna, and microbial nutrient cycling. Thus, non-ingestible granular activated carbon appears to be a better choice for remediation of contaminated coastal sediments.
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| 3. |
- Bonaglia, Stefano, et al.
(författare)
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Capping with activated carbon reduces nutrient fluxes, denitrification and meiofauna in contaminated sediments
- 2019
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Ingår i: Water Research. - : Elsevier BV. - 0043-1354 .- 1879-2448. ; 148, s. 515-525
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Tidskriftsartikel (refereegranskat)abstract
- Sediment capping with activated carbon (AC) is an effective technique used in remediation of contaminated sediments, but the ecological effects on benthic microbial activity and meiofauna communities have been largely neglected. This study presents results from a 4-week experiment investigating the influence of two powdered AC materials (bituminous coal-based and coconut shell-derived) and one control material (clay) on biogeochemical processes and meiofauna in contaminated sediments. Capping with AC induced a 62‒63% decrease in denitrification and a 66‒87 % decrease in dissimilatory nitrate reduction to ammonium (DNRA). Sediment porewater pH increased from 7.1 to 9.0 and 9.7 after addition of bituminous AC and biomass-derived AC, respectively. High pH (>8) persisted for at least two weeks in the bituminous AC and for at least 24 days in the coconut based AC, while capping with clay had no effect on pH. We observed a strong impact (nitrate fluxes being halved in presence of AC) on nitrification activity as nitrifiers are sensitive to high pH. This partly explains the significant decrease in nitrate reduction rates since denitrification was almost entirely coupled to nitrification. Total benthic metabolism estimated by sediment oxygen uptake was reduced by 30 and 43 % in presence of bituminous coal-based AC and coconut shell-derived AC, respectively. Meiofauna abundances decreased by 60‒62 % in the AC treatments. Taken together, these observations suggest that AC amendments deplete natural organic carbon, intended as food, to heterotrophic benthic communities. Phosphate efflux was 91 % lower in presence of bituminous AC compared to untreated sediment probably due to its content of aluminum (Al) oxides, which have high affinity for phosphate. This study demonstrates that capping with powdered AC produces significant effects on benthic biogeochemical fluxes, microbial processes and meiofauna abundances, which are likely due to an increase in porewater pH and to the sequestration of natural, sedimentary organic matter by AC particles.
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| 4. |
- Rämö, Robert A., et al.
(författare)
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Biological Effects of Activated Carbon on Benthic Macroinvertebrates are Determined by Particle Size and Ingestibility of Activated Carbon
- 2021
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Ingår i: Environmental Toxicology and Chemistry. - : Wiley. - 0730-7268 .- 1552-8618. ; 40:12, s. 3465-3477
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Tidskriftsartikel (refereegranskat)abstract
- The application of activated carbon (AC) to the surface of contaminated sediments is a promising technology for sediment remediation in situ. Amendment with AC has proved to be effective in reducing bioavailability and sediment-to-water release of hydrophobic organic contaminants. However, AC may cause positive or negative biological responses in benthic organisms. The causes of these effects, which include changes in growth, reproduction, and mortality, are unclear but are thought to be related to the size of AC particles. The present study investigated biological response to AC ranging from ingestible powdered AC to noningestible granular AC in two benthic deposit feeders: the polychaete Marenzelleria spp. and the clam Limecola balthica (syn. Macoma balthica). In the polychaete, exposure to powdered AC (ingestible) reduced both dry weight and carbon assimilation, whereas exposure to granular AC (noningestible) increased both dry weight and carbon assimilation. Responses in the clam were similar but less pronounced, indicating that response levels are species-specific and may vary within a benthic community. In addition, worms exposed to the finest ingestible AC particles had reduced gut microvilli length and reduced gut lumen, indicating starvation. These results strongly suggest that biological responses to AC depend on particle ingestibility, whereby exposure to ingestible particles may cause starvation through reduced bioavailability of food coingested with AC or due to rejection of AC-treated sediment as a food source.
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| 5. |
- Rämö, Robert A., et al.
(författare)
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Environmental risk assessment of pesticides in the River Madre de Dios, Costa Rica using PERPEST, SSD, and msPAF models
- 2018
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Ingår i: Environmental Science and Pollution Research. - : Springer Science and Business Media LLC. - 0944-1344 .- 1614-7499. ; 25:14, s. 13254-13269
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Tidskriftsartikel (refereegranskat)abstract
- This study assesses the ecological risks (ERA) of pesticides to aquatic organisms in the River Madre de Dios (RMD), which receives surface runoff water from banana, pineapple, and rice plantations on the Caribbean coast of Costa Rica. Water samples collected over 2 years at five sites in the RMD revealed a total of 26 pesticides. Their toxicity risk to aquatic organisms was assessed using three recent ERA models. (1) The PERPEST model showed a high probability (>50 %) of clear toxic effects of pesticide mixtures on algae, macrophytes, zooplankton, macroinvertebrates, and community metabolism and a low probability (<50 %) of clear effects on fish. (2) Species sensitivity distributions (SSD) showed a moderate to high risk of three herbicides: ametryn, bromacil, diuron and four insecticides: carbaryl, diazinon, ethoprophos, terbufos. (3) The multi-substance potentially affected fraction (msPAF) model showed results consistent with PERPEST: high risk to algae (maximum msPAF: 73 %), aquatic plants (61 %), and arthropods (25 %) and low risk to fish (0.2 %) from pesticide mixtures. The pesticides posing the highest risks according to msPAF and that should be substituted with less toxic substances were the herbicides ametryn, diuron, the insecticides carbaryl, chlorpyrifos, diazinon, ethoprophos, and the fungicide difenoconazole. Ecological risks were highest near the plantations and decreased progressively further downstream. The risk to fish was found to be relatively low in these models, but water samples were not collected during fish kill events and some highly toxic pesticides known to be used were not analyzed for in this study. Further sampling and analysis of water samples is needed to determine toxicity risks to fish during peaks of pesticide mixture concentrations. The msPAF model, which estimates the ecological risks of mixtures based on their toxic modes of action, was found to be the most suitable model to assess toxicity risks to aquatic organisms in the RMD. The PERPEST model was found to be a strong tool for screening risk assessments. The SSD approach is useful in deriving water quality criteria for specific pesticides. This study, through the application of three ERA models, clearly shows that pesticides used in plantations within the RMD watershed are expected to have severe adverse effects on most groups of aquatic organisms and that actions are urgently needed to reduce pesticide pollution in this high biodiversity ecosystem.
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