Evaluation of Biomonitoring Approach to Study Lake Contamination by Accumulation of Trace Elements in Selected Aquatic Macrophytes: A Case Study of Kanewal Community Reserve, Gujarat, India

Abstract

Abstract. A biomonitoring study was carried out at Kanewal reservoir, an internationally important wetland listed in Asian Directory of Wetlands, designated as a "Wetland of National Importance" and a proposed community reserve of Gujarat State, India, to ascertain the degree of trace element contamination. The study focused on assessment of trace element contamination in certain aquatic macrophytes to be used as biomonitors, in comparison with water and sediments (abiotic monitor) for heavy metal pollution. Good information was provided by analyzing the roots, stems and leaves of native aquatic plants (biomonitors) represented by seven species: Eichhornia crassipes, Echinochloa colonum, Hydrilla verticillata, Ipomoea aquatica, Nelumbo nucifera, Typha angustata and Vallisneria spiralis, along with surface sediments and water, were analyzed for Cd, Co, Cu, Ni, Pb and Zn contamination. The highest concentrations of the trace elements were measured in Eichhornia crassipes and the lowest in Nelumbo nucifera. Based on the concentration and toxicity status observed in the lake's vegetation, the six metals are arranged in the following decreasing order: Zn > Cu > Ni > Cd > Co > Pb. Compared with the standard, normal and critical toxicity range in plants, the detected value of Pb falls within normal range, while that of other elements were within the critical range. However, Zn and Cu showed the highest concentration and alarming toxicity levels, which are considered as one of the most hazardous pollutants in Kanewal reservoir. Certain species of aquatic macrophytes are also proposed as biomonitors (and/or biofilters) such as Eichhornia crassipes and Typha angustata, which are the two most useful species in biomonitoring studies due to their ability to accumulate elements in high concentration in the roots and its availability throughout the year. The results showed the significant difference in accumulation of metals like Zn, Cu and Ni in different plant organs, which showed more accumulation in roots than that of stems and leaves. High positive correlation between combinations of different metal pairs in plant's root, stem or leaf system was established.

Concentration of Some Heavy Metals in Aquatic Macrophytes in Reservoir Near City Kragujevac (Serbia)

“…Results of numerous studies show a tendency to increase of the concentration of metals in sediment compared with water (6,10,24,34). Results of our research show increased concentrations of Fe in the water, and Mn in sediment.…”

Evaluation of uptake rate of heavy metals by Eichhornia crassipes and Hydrilla verticillata

“…E. crassipes has more tolerance towards toxicity as compare to H. verticillata, as H. verticillata died earlier than E. crassipes, whereas E. crassipes survives for longer time even in higher concentrations of toxic metals. Such aquatic macrophytes can be termed as active biomonitors (Nirmal kumar et al 2006).…”

Macrophytes as passive bioindicators of trace element pollution in the aquatic environment

“…Consequently, the uptake efficiency and concentrations of essential metals (e.g., Fe, Mn, Cu, Zn) in plant tissues are usually higher than the concentrations of nonessential metals (e.g., Cd, Cr, Co, Pb, Ni; Kurilenko & Osmolovskaya, 2007; Li et al, 2015). Furthermore, macrophytes show various abilities to accumulate elements in roots, shoots, and/or leaves (Fritioff & Greger, 2006; Krems et al, 2013; Kumar et al, 2007); organs with higher physiological activity (leaves and roots) are expected to have greater metal concentrations than those with low activity (e.g., stems, flowers; Sawidis et al, 1995; Vardanyan & Ingole, 2006). It seems that essential metals are readily transported from belowground to aboveground tissues for metabolic use, but there are no specific transport pathways for nonessential elements (Cardwell et al, 2002).…”

“…Considering this, the selection of species for accumulation bioindication should be based on the knowledge of local conditions and composition of plant communities, species ecology, habitat and range, effect of pollutants on plant uptake as well as physiology, species‐pollutant kinetics, interactions between pollutants, and other elements, variation within and between populations (Beeby, 2001; Bonanno & Lo Giudice, 2010; Klink et al, 2016; Zaghloul et al, 2020). However, irrespective of these criteria, the most common and widespread species (Greger & Kautsky, 1993; Kumar et al, 2007) and the ones that are available throughout the year (Kumar et al, 2006) are usually considered in the first place when selecting macrophytes.…”

“…Furthermore, macrophytes show various Note: Letters correspond to the symbols in Figure 2. References: Cardwell et al, 2002;Dhir et al, 2009;Jackson, 1998;Krems et al, 2013;Pokorny & Kvet, 2003;Ravera et al, 2003;Schuyler, 1984;Wetzel, 2011 abilities to accumulate elements in roots, shoots, and/or leaves (Fritioff & Greger, 2006;Krems et al, 2013;Kumar et al, 2007); organs with higher physiological activity (leaves and roots) are expected to have greater metal concentrations than those with low activity (e.g., stems, flowers; Sawidis et al, 1995;Vardanyan & Ingole, 2006). It seems that essential metals are readily transported from belowground to aboveground tissues for metabolic use, but there are no specific transport pathways for nonessential elements (Cardwell et al, 2002).…”