MEPS 449:27-39 (2012)  -  DOI: https://doi.org/10.3354/meps09546

ABSTRACT: Ecotoxicological effects of 2 carbonaceous and 7 mineral capping materials suggested for in situ remediation of contaminated sediments in the Grenland fjords, Norway, were investigated in a mesocosm experiment. The primary objective was to compare the various materials with regard to potentially harmful effects on the benthic ecosystem. The materials assessed were activated carbon, Kraft-lignin, sand and clay materials, and 3 industrial by-products. Using sediment box-core samples with intact benthic communities, effects on structural (bacterial, macro- and meiofauna diversity) and functional (sediment-to-water nutrient fluxes, oxygen fluxes and bacterial production) endpoints were assessed. Significant deviations from the control (no capping) were detected for all of the tested materials for at least one endpoint. Generally, materials similar to the indigenous sediment (clay, sand) had relatively low deviations from the control, whereas industrial products (plaster, 2 types of crushed marble) resulted in deviations for most endpoints and large reductions in community richness and abundance. For example, at the end of the experimental period, the number of macrofauna taxa was <10 in these treatments, compared to >27 in uncapped mesocosm and field control sediments. The results from the study show that reducing harmful ecosystem effects from thin-layer capping by selecting capping materials based on robust, multi-endpoint mesocosm bench-tests is both possible and recommendable. Potential ecosystem impacts are particularly important to consider when large areas and areas with adequate ecological status are considered for thin-layer capping.

KEY WORDS: Remediation in situ · Activated carbon · Clay · Structural and functional effects · Benthic organisms · Sediment · Mesocosm

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Cite this article as: Näslund J, Samuelsson GS, Gunnarsson JS, Nascimento FJA, Nilsson HC, Cornelissen G, Schaanning MT (2012) Ecosystem effects of materials proposed for thin‑layer capping of contaminated sediments. Mar Ecol Prog Ser 449:27-39. https://doi.org/10.3354/meps09546 Export citation Share:    Facebook - - linkedIn