Bioturbation facilitates DDT sequestration by activated carbon against recontamination by sediment deposition

Abstract

We evaluated bioturbation as a facilitator for in situ treatment with a thin layer of activated carbon to treat dichlorodiphenyltrichloroethane (DDT)-contaminated sediment and contaminant influx by sediment deposition. Using the freshwater worm Lumbriculus variegatus as a bioturbator, microcosm time-series studies were conducted for 4 mo and monitored for DDT flux and porewater concentration profiles by polyethylene passive samplers. With bioturbators present, the thin-layer activated carbon amendment reduced DDT flux by >90% compared with the same simulated scenario without activated carbon amendment. In contrast, a clean sediment cap without activated carbon was ineffective in reducing flux when bioturbation was present. In simulated scenarios with contaminant influx through deposition of contaminated sediment, bioturbation facilitated in situ activated carbon treatment, reducing 4-mo DDT flux by 77% compared with the same scenario without bioturbation. Porewater concentration profiles and activated carbon dose profiles confirmed effective mixing of activated carbon particles down to 1-cm depth. A mass transfer model was developed to predict flux with consideration of bioturbation and sediment deposition processes. Predicted flux values were consistent with experimental results and confirm that bioturbation activity helps reduce DDT sediment-to-water fluxes in activated carbon-treated sediment with recontamination by contaminated sediment deposition. To our knowledge, this is the first study to combine experimental and modeling results showing how bioturbation enhances activated carbon amendment effectiveness against ongoing contaminant influx by sediment deposition. Environ Toxicol Chem 2018;37:2013-2021. © 2018 SETAC.

Passive Sampling-Based versus Conventional-Based Metrics for Evaluating Remediation Efficacy at Contaminated Sediment Sites: A Review

“…Without AC, bioturbation diluted any depositing sediment, causing no reduction in flux, bioaccumulation, or sediment LDPE uptake from controls. However, adding a thin layer of AC reduced sediment-to-water fluxes and sediment LDPE uptake, even with depositing contaminated sediment …”

Biological and physical drivers of bio-mediated sediment resuspension: A flume study on Cerastoderma edule

“…It happens at a local scale, but the effects may be important for broader landscape processes (Widdows & Brinsley, 2002;Bentley Sr, et al, 2014;Walles, et al, 2015). The bioturbators' ecosystem engineering [sensu (Jones, et al, 1994;Jones, et al, 1997)] of wet sediment dynamics impacts the short-and long-term development of coastal geomorphology (Winterwerp, et al, 2018;Gao, 2019), ecology (Zhu, et al, 2016;Lukwambe, et al, 2018;Mermillod-Blondin, et al, 2018;Savelli, et al, 2019) and services provided to the human society (Barbier, 2013;Bouma, et al, 2014;Lin, et al, 2018;Silva, et al, 2019). The role of bioturbation should hence be taken into account in order to implement Ecosystem-Based management of coastal areas (Braeckman, et al, 2014;Van der Biest, et al, 2020).…”

Model of Activated Carbon Dose and Sediment–Water Diffusion Fluxes of Hydrophobic Organic Chemicals: Implications for Sediment Remediation

“…18−20 Although overlying water is renewed fast, the concentrations of HOCs that organisms are exposed to near the sediment−water interface and in overlying water could be affected by the escaping fluxes of HOCs from the contaminated sediment. 21,22 Consequently, the change in the sediment−water diffusion flux of a target compound could be an alternative parameter for assessing the remediation efficiency.…”