Macrophyte Sorption and Bioconcentration of Elements in a Pilot Constructed Wetland for Flue Gas Desulfurization Wastewater Treatment

Abstract

The sorption and bioconcentration of Hg, Se, and As were measured in Schoenoplectus californicus and Typha angustifolia in a pilot constructed wetland receiving wastewater inflows containing these elements at potentially hazardous levels. Results indicated that these species bioconcentrated Hg, Se, and As at factors of up to 1,911, 10,981, and 4,927, respectively. Plant tissue concentrations decreased as Hg, Se, and As were translocated from the roots to the aerial portions of the plant. Greatest element concentrations in S. californicus were found in roots, indicating that an exclusion mechanism may be responsible for element tolerance by this plant species. Greater root:shoot transfer of Hg, Se, and As was observed with T. angustifolia than with S. californicus, suggesting that element tolerance was more likely due to an internal detoxification mechanism. To completely assess ecological risks associated with the use of constructed wetlands, contaminant bioavailability for plant uptake, translocation, and bioconcentration must be considered.

Transport and Transformation of Selenium and Other Constituents of Flue‐Gas Desulfurization Wastewater in Water‐Saturated Soil Materials

“…Furthermore, Se fractions representing <5% of the total are excluded from the results. Water‐soluble, exchangeable, and ligand‐exchangeable Se are relatively more mobile and bioavailable, whereas organically associated, elemental, recalcitrant organic, and residual Se are considered to be more stable Se forms (Kulp and Pratt, 2004; Oram et al, 2008; Sundberg‐Jones and Hassan, 2007; Wright et al, 2003). The findings of the SEP for both the TS and ES original materials are discussed in the supplemental material.…”

“…To our knowledge, the mechanism of FGD WW Se retention in soil has not been addressed in detail. Sequential extraction procedures (SEPs) have been used to indirectly assess the elemental speciation (e.g., Se, As, and Hg) of wetland sediments that were treated with FGD WW (Sundberg-Jones and Hassan, 2007), but information regarding the direct speciation of these constituents has not been reported. Because other constituents in FGD WW and its composition can significantly influence changes in the oxidation state of Se (Zhang et al, 2003), it is important to assess the retention mechanisms via direct chemical speciation.…”

Heavy metal removal in phytofiltration and phycoremediation: the need to differentiate between bioadsorption and bioaccumulation

“…Furthermore, the BCF has been proposed as one of the two arbitrary criteria for classifying aquatic New Biotechnology Volume 30, Number 1 November 2012 RESEARCH PAPER Hg, Se, As [27] www.elsevier.com/locate/nbt 5 plants as hyperaccumulators. Such criteria are: (a) its ability to take up more than 0.5% dry weight (dw) of a given element, and (b) its ability to bioconcentrate the element in their tissues, resulting in a bioconcentration factor (BCF) higher than 1000 [41].…”

“…It is worth noticing that BAF and IAF were much higher than those observed in batch systems reaching values as high as 65,623 AE 3300 for BAF (Table 3) (Olguín et al, unpublished results). In the case of emergent macrophytes, a plant surface bioconcentration factor (BCF) has been proposed to evaluate the metal adsorption [27]. In relation to photosynthetic microorganisms, Mehta and Gaur [19] have compiled a large number of reports related to microalgae and cyanobacteria metal uptake indicating a wide range (from 0.01 to 999.50 mg g À1 ) depending on the metal and microorganism.…”

Influences of Coal Ash Leachates and Emergent Macrophytes on Water Quality in Wetland Microcosms

“…Emergent macrophytes help facilitate this filtration by slowing the flow of water and wind, sequestering chemicals, releasing oxygen in the rhizosphere, and providing algal and microbial habitat (Vymazal 2013;Bhatia and Goyal 2014;Preussler et al 2015;Sundberg-Jones and Hassan 2007). Constructed wetland treatment systems (CWTS) containing emergent macrophytes can potentially be effective for treating CCR wastewater, though the literature on this topic is limited (Ye et al 2001a, b;Dorman et al 2009).…”