| 1. |
- Nybom, Inna, et al.
(author)
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Effects of Organic Carbon Origin on Hydrophobic Organic Contaminant Fate in the Baltic Sea
- 2021
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In: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 55:19, s. 13061-13071
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Journal article (peer-reviewed)abstract
- The transport and fate of hydrophobic organic contaminants (HOCs) in the marine environment are closely linked to organic carbon (OC) cycling processes. We investigated the influence of marine versus terrestrial OC origin on HOC fluxes at two Baltic Sea coastal sites with different relative contributions of terrestrial and marine OC. Stronger sorption of the more than four-ring polycyclic aromatic hydrocarbons and penta-heptachlorinated polychlorinated biphenyls (PCBs) was observed at the marine OC-dominated site. The site-specific partition coefficients between sediment OC and water were 0.2–1.0 log units higher at the marine OC site, with the freely dissolved concentrations in the sediment pore-water 2–10 times lower, when compared with the terrestrial OC site. The stronger sorption at the site characterized with marine OC was most evident for the most hydrophobic PCBs, leading to reduced fluxes of these compounds from sediment to water. According to these results, future changes in OC cycling because of climate change, leading to increased input of terrestrial OC to the marine system, can have consequences for the availability and mobility of HOCs in aquatic systems and thereby also for the capacity of sediments to store HOCs.
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| 2. |
- Rämö, Robert A., et al.
(author)
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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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In: Environmental Toxicology and Chemistry. - : Wiley. - 0730-7268 .- 1552-8618. ; 40:12, s. 3465-3477
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Journal article (peer-reviewed)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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