Bioavailability assessment in activated carbon treated coastal sediment with in situ and ex situ porewater measurements

WATER RESEARCH

卷:185

Article

Yan, Songjing¹  Rakowska, Magdalena²  Shen, Xiaolong²  Himmer, Theresa³  Irvine, Cameron⁴  Zajac-Fay, Rachel⁵  Eby, Jamie⁶  Janda, Danielle⁷  Ohannessian, Sharon⁸  Reible, Danny D.^1,2 

[1] Texas Tech Univ, Dept Chem Engn, Lubbock, TX 79409 USA

[2] Texas Tech Univ, Dept Civil Environm & Construct Engn, Lubbock, TX 79409 USA

[3] Jacobs Engn, Boston, MA 02116 USA

[4] Robertson Bryan, Elk Grove, CA 95624 USA

[5] Jacobs Engn, Tampa, FL 33609 USA

[6] Port Oakland, Oakland, CA 94607 USA

[7] Dept Navy DoN, Base Realignment & Closure Program Management Off, San Diego, CA 92014 USA

[8] Redhorse Corp, San Diego, CA 92101 USA

关键词: Composite activated carbon;    Passive samplers;    Bioaccumulation;    Sediment remediation;    PCBs;   

DOI  :  10.1016/j.watres.2020.116259

来源: Elsevier

【 摘 要 】

Passive sampling and bioaccumulation assessments were used to evaluate the performance of activated carbon (AC) remediation of polychlorinated biphenyl (PCB) contaminated sediment offshore in Parcel F of the former Hunters Point Naval Shipyard (HPNS) (San Francisco, California). Two different composite AC materials, AquaGate+ PAC (TM) (86 tons) and SediMite (TM) (24 tons) were placed on the sediment surface covering an area of 3200 m(2). PCB tissue concentrations in the clam Macoma nasuta were reduced 75 to 80% in pilot amendment areas after 8 months and 84-87% in non-lipid normalized tissues after 14 months during in situ monitoring, confirming the effectiveness of the AC at reducing bioavailability of the PCBs. Polydimethylsiloxane (PDMS) passive samplers were applied to evaluate and monitor freely dissolved concentrations (C-free) of PCBs in sediment porewater before AC placement (i.e., during baseline) and at 8 months, 14 months and 26 months following placement. Although AC composite materials were placed only at the surface, 80% reductions were observed to a depth of 16 cm after 8 months and up to 26 cm after 26 months in AquaGate+PAC treatment area. Total PCB porewater concentrations in surface sediments (1-6 cm) were reduced 89 and 91% in the AquaGate+ PAC and SediMite areas during final sampling. Ex situ passive sampling showed porewater concentrations 2-5 times larger than in situ measurements due to the absence of hyporheic exchange in laboratory measurements and near equilibration between sediment and porewater. Estimated post placement ex situ porewater concentrations were more consistent with a model of bioaccumulation using the octanol-water partition coefficient (K-OW) as a bioaccumulation factor leading to a hypothesis that the bioaccumulation factor in the deposit feeding clam is better estimated by equilibrium ex situ porewater measurements. (C) 2020 Elsevier Ltd. All rights reserved.

【 授权许可】

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