Pollution indicandum and marble waste polluted ecosystem; role of selected indicator plants in phytoremediation and determination of pollution zones

The absence or presence of particular plant species indicates specific level of pollution. It was hypothesized that the marble waste polluted ecosystem also host specific plant indicators that can grow, survive and tolerate more successfully than others and can be utilized in better managements of such systems. The current research work was therefore, conducted to determine the indicators of marble polluted region of Buner, Pakistan. Ecological techniques using varying sized quadrats i.e., 1 x 1 m(2), 5 x 2 m(2) and 10 x 2 m(2) for herbs, shrubs and tree species were used respectively. Standard protocols were used to prepare soil samples and plant parts (root, leaf and shoot) for Atomic Absorption Spectrophotometry. Indicator i.e., Populus alba L., Arundo donax L., Erigeron canadensis L and Morus alba L. were identified via Indicator Species Analyses (ISA) in various polluted zones. All the collected data were put in MS Excel for analyses in PCORD through Cluster Analysis (CA), Two Way Cluster Analysis (TWCA) and ISA. CANOCO software was used to examine the impact of miscellaneous environmental variables in zonation via both direct and indirect gradient techniques i.e., Detrended Correspondence Analysis (DCA) and Canonical Correspondence Analysis (CCA). A total of 102 plant species belonging to 95 genera and 48 families were recorded in the marble waste polluted ecosystem. CA and TWCA through Jaccard Distance measurements and Wards Linkage methods gave rise to 3 major polluted zones. These zones were i) Heavily Polluted Zone (HPZ), ii) Moderate Polluted Zone (MPZ) and iii) Less Polluted Zone (LPZ). The recorded values of Biological Concentration Factor (BCF), Translocation Factor (TF) and Bioaccumulation Coefficient (BAC) for analyzed heavy metals i.e. Fe, Mg, Ca, Na and Cu in root and shoot of P. alba L., A. donax L., and M. alba L. showed that these species were significant phytostabilizers and E. canadensis L. was phytoextracters and hence best indicandum of marble waste polluted ecosystems. It was concluded that among all the measured environmental variables, higher phosphorus level, higher pH, moderate potassium and lower electrical conductivity (EC) had significant effects (p <0.05) on the functions of these indicators as phytoremediaters. It is recommended to develop green belts of these indicators around the marble industrial areas for the better management and hazardous free environment. (C) 2019 Elsevier Ltd. All rights reserved.