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LABORATORY AND FIELD-BASED ASSESSMENT OF THE EFFECTS OF SEDIMENT CAPPING MATERIALS ON ZINC FLUX, BIOAVAILABILITY, AND TOXICITY
Cervi, E.C., K. Thiamkeelakul, M. Hudson, A. Rentschler, S. Nedrich, S.S. Brown, et al.
Environmental Toxicology and Chemistry 39(1)240-249(2020)
The efficacy of AquaBlok™ limestone, and limestone-bone char capping materials for decreasing Zn dissolution from sediments under natural and reasonable worst-case conditions (pH = 5.5) was evaluated. Field exposures were conducted in situ in limnocorrals and ex situ in core tube mesocosms. Simultaneous in situ and ex situ toxicity tests were conducted using Daphnia magna, Hyalella Azteca,, and Chironomus dilutes exposed to surficial sediments, caps, and hypolimnetic overlying waters for 4 d. No differences in responses between treatments involving sediment capping materials in both in situ and ex situ tests were observed, likely due to dissolved Zn in surface water being below the hardness-adjusted threshold effects levels (164 µg/L). Both studies provided site-specific data to select an effective remedy with reduced uncertainty compared to laboratory and chemistry-only approaches. https://setac.onlinelibrary.wiley.com/doi/pdf/10.1002/etc.4612
Environmental Toxicology and Chemistry 39(1)240-249(2020)
The efficacy of AquaBlok™ limestone, and limestone-bone char capping materials for decreasing Zn dissolution from sediments under natural and reasonable worst-case conditions (pH = 5.5) was evaluated. Field exposures were conducted in situ in limnocorrals and ex situ in core tube mesocosms. Simultaneous in situ and ex situ toxicity tests were conducted using Daphnia magna, Hyalella Azteca,, and Chironomus dilutes exposed to surficial sediments, caps, and hypolimnetic overlying waters for 4 d. No differences in responses between treatments involving sediment capping materials in both in situ and ex situ tests were observed, likely due to dissolved Zn in surface water being below the hardness-adjusted threshold effects levels (164 µg/L). Both studies provided site-specific data to select an effective remedy with reduced uncertainty compared to laboratory and chemistry-only approaches. https://setac.onlinelibrary.wiley.com/doi/pdf/10.1002/etc.4612
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