Influences of Coal Ash Leachates and Emergent Macrophytes on Water Quality in Wetland Microcosms
- First Online:
- 49 Downloads
The storage of coal combustion residue (CCR) in surface water impoundments may have an impact on nearby water quality and aquatic ecosystems. CCR contains leachable trace elements that can enter nearby waters through spills and monitored discharge. It is important, therefore, to understand their environmental fate in affected systems. This experiment examined trace element leachability into freshwater from fly ash (FA), the most common form of CCR. The effects on water quality of FA derived from both high and low sulfur coal sources as well as the influences of two different emergent macrophytes, Juncus effusus and Eleocharis quadrangulata, were evaluated in wetland microcosms. FA leachate dosings increased water electric conductivity (EC), altered pH, and, most notably, elevated the concentrations of boron (B), molybdenum (Mo), and manganese (Mn). The presence of either macrophyte species helped reduce elevated EC, and B, Mo, and Mn concentrations over time, relative to microcosms containing no plants. B and Mo appeared to bioaccumulate in the plant tissue from the water when elevated by FA dosing, while Mn was not higher in plants dosed with FA leachates. The results of this study indicate that emergent macrophytes could help ameliorate downstream water contamination from CCR storage facilities and could potentially be utilized in wetland filtration systems to treat CCR wastewater before discharge. Additionally, measuring elevated B and Mo in aquatic plants may have potential as a monitoring tool for downstream CCR contamination.
KeywordsCoal combustion residues Fly ash Phytoremediation Juncus effusus Eleocharis quadrangulata Wetland Boron Manganese Molybdenum
- Brodie, G. A. Constructed wetlands for treating acid drainage at Tennessee Valley Authority coal facilities. Proceeding of the International Conference on the Use of Constructed Wetlands in Water Pollution Control, 461–470 (1990).Google Scholar
- Michaud, S. C., & Richardson, C. J. (1989). Relative radial oxygen loss in five wetland plants. In D. A. Hammer (Ed.), Constructed wetlands for wastewater treatment: municipal, industrial and agricultural (pp. 501–507). Chelsea: Lewis Publishers.Google Scholar
- Mitsch, W. J., & Gosselink, J. G. (2015). Wetlands (5th ed.pp. 647–648). Hoboken: Wiley.Google Scholar
- Pohlert, T. The pairwise multiple comparison of mean ranks package (PMCMR). R package, http://CRAN.R-project.org/package=PMCMR (2014).
- Richardson, C. J. (1989). Freshwater wetlands: transformers, filters or sinks? In R. R. Sharitz & J. W. Gibbons (Eds.), Freshwater wetlands and wildlife. Conf-8603101. DOE Symposium Series NO. 61 (pp. 25–46). Oak Ridge: U.S. DOE.Google Scholar
- Wickham. (2001). The split-apply-combine strategy for data analysis. Journal of Statistical Software, 40, 1–29.Google Scholar
- WCA (2014). “Coal Statistics” World Coal Association. www.worldcoal.org/resources/coal-statistics. Accessed 21 Apr 2015.
- Ye, Z. H., Whiting, S. N., Lin, Z. Q., Lytle, C. M., Qian, J. H., & Terry, N. (2001a). Removal and distribution of iron, manganese, cobalt and nickel within a Pennsylvania constructed wetland treating coal combustion by-product leachate. Journal of Environmental Quality, 30, 1464–1473.CrossRefGoogle Scholar