Influence of heavy metals in root chemistry of Cyperus vaginatus R.Br: A study through optical spectroscopy Rupak Aryal a, * , Ramkrishna Nirola b , Simon Beecham c , Binoy Sarkar b a Centre for Water Management and Reuse, School of Natural and Built Environments, University of South Australia, Mawson Lakes, SA 5095, Australia b Future Industries Institute, University of South Australia, Mawson Lakes, SA 5095, Australia c Division of Information Technology, Engineering and the Environment, University of South Australia, Mawson Lakes, SA 5095, Australia article info Article history: Received 7 January 2016 Received in revised form 4 April 2016 Accepted 4 April 2016 Available online xxx Keywords: Metal pollution Urban runoff Wetland abstract Phyto-sequestration of heavy metals originating from urban runoff entering into wetland systems is one of the ways to mitigate the pollution. Due to the chemical environment of runoff wetlands, the plants and especially their roots are often stressed. While growing on contaminated environment, wetland plants undergo a number of physio-chemical changes in their roots, stems and leaves in the form of ecological adaptations. In this study, the three category samples of the macrophyte Cyperus vaginatus R.Br. growing in a wetland, near to the wetland (<20 m) and far from the wetland (>100 m) were collected to determine heavy metals and organic matter status in roots. This study revealed hyperaccumulation of metals in plants growing in the wetland compared to nearby and far from the wetland. Statistical analysis showed metals accumulating pattern to be distinct for each sampling category based on location. The UV spectra of C. vaginatus root produced a distinct shoulder peak at 324 nm whereas the plants growing far from the wetland showed a spectroscopic shoulder at 267 nm. The plant root growing near to wetland showed both shoulders at 324 nm and 267 nm but with reduced peak height. Statistical analysis of UV spectra also followed location specificity pattern. UV spectral result was further validated by FTIR analysis where plants growing in wetland and near to wetland possessed spectra similar to UV spectral results. This observation leads us to conclude that C. vaginatus R.Br. exhibited changes in root chemical composition to tolerate metal toxicity and perform phytoaccumulation. © 2016 Elsevier Ltd. All rights reserved. 1. Introduction Urban runoff is an important source of both inorganic and organic pollutants (Chong et al., 2011; Sidhu et al., 2013). Among these runoff pollutants, metals are considered to be potentially hazardous to plants and animals especially in urban wetlands (Obarska-Pempkowiak and Klimkowska, 1999; Otte, 2001; Cheng et al., 2002). Due to their persistency, metals often accumulate in runoff-receiving water bodies such as wetland well beyond the safety level (Nzengy'A and Wishitemi, 2000). However, metals such as copper (Cu), iron (Fe), manganese (Mn), nickel (Ni) and zinc (Zn)) are essential for specific metabolic responses in plant cells, where the elevated concentration of metals in soils and sediments cause hyperaccumulation in plants and sequestration of heavy metals into their biomass (Otte, 2001; Sabale et al., 2012). Remediation of heavy metals using macrophytes in engineered wetlands has been proven to be an effective tool for reducing a range of pollutants that are often found in urban runoff (Obarska- Pempkowiak and Klimkowska, 1999; Karpiscak et al., 2001; Cheng et al., 2002; Vymazal and Brezinova, 2015). Moreover, in terms of treating water quality, vegetated systems over wetlands are preferred over complex engineering solutions (Michailides et al., 2013; Sultana et al., 2015; Zhao et al., 2016). Selection of plant species for engineered wetland comprises the basis of healthy and meaningful wetland ecosystems (Davis and Froend, 1999). Several studies in metal polluted areas have demonstrated that vegetated wetlands can be successful in removing metals (Salt et al., 1995; Khan et al., 2009). As such studies indicate that metal uptake by plants usually decreases in the order roots > stems > leaves (Nirola et al., 2016) to lead us to investigate the root chemistry. Uptake of metals by plants faster than they are metabolised or * Corresponding author. E-mail addresses: rupak.aryal@unisa.edu.au (R. Aryal), ramkrishna.nirola@ mymail.unisa.edu.au (R. Nirola), simon.beecham@unisa.edu.au (S. Beecham), Binoy.Sarkar@unisa.edu.au (B. Sarkar). Contents lists available at ScienceDirect International Biodeterioration & Biodegradation journal homepage: www.elsevier.com/locate/ibiod http://dx.doi.org/10.1016/j.ibiod.2016.04.008 0964-8305/© 2016 Elsevier Ltd. All rights reserved. International Biodeterioration & Biodegradation xxx (2016) 1e7 Please cite this article in press as: Aryal, R., et al., Influence of heavy metals in root chemistry of Cyperus vaginatus R.Br: A study through optical spectroscopy, International Biodeterioration & Biodegradation (2016), http://dx.doi.org/10.1016/j.ibiod.2016.04.008