A holistic approach to bring sustainability and resilience via Plant and Microbe populations in the Marble Waste Polluted Ecosystem of Khyber Pakhtunkhwa, Pakistan

Abstract

Marble industry is one of the major waste generating industries. Marble mining and processing result in environmental deterioration in the form of water, soil and air pollution. This dissertation aims to find out the physio-chemical properties of sampled vegetation and soil of the marble waste polluted ecosystems with emphasis on the role of specific indicators (plants and Fungi) in remediation of potential toxic elements (heavy metals) and NDVI changes in the marble polluted region of the Khyber Pakhtunkhwa province, Pakistan. Quadrat quantitative ecological techniques were adapted for sampling of vegetation. All the collected data of plant species and environmental variables were analyzed using different statistical techniques including Two-way Cluster Analysis, Indicator Species Analysis, Ordinary Least Square, Logistic and Probabilistic Models, Species Area Curves, Bivariate Analysis, Detrended Correspondence Analysis, Canonical Correspondence Analysis and Structural Equation Modeling. Indicator species were determined using Indicator Species Analysis that exhibit more fortitude and contest against marble waste polluted ecosystem for each polluted zone. The identified plant indicators, its prestigious dignity concerning various environmental variables was then examined through direct gradient analysis i.e., Canonical Correspondence Analysis (CCA) and Structural Equation Modelling (SEM) for most suitable indicator species. Some of the selected indicators were further assessed for their phytoremediation ability and physiological response (i.e., proline osmolytes, chlorophyll-a, chlorophyll-b & total carotenoid contents) growing naturally in the subtropical Marble Waste Polluted Ecosystem (MWPE). Micro fungi were isolated, characterized and identified from the MWPE. Malt extract agar media was used for fungus growth and isolation of pure colonies. All the fungal isolates were characterized via Lacto-phenol cotton blue stain for their anatomical examination. The hyphae length and width of fungi were measured in micrometer (µm) using Piximeter software. Nuclear ribosomal Internal Transcribed Spacer (ITS) was amplified using ITS1-F and ITS4-R universal primers. ITS sequences were compared via BLAST network service of National Center for Biotechnology Information (NCBI) to affirm identification of micro fungus species. While, the spatial distribution of heavy metals (Potential toxic elements) was constructed using ArcGIS 10.8. Google Earth Engine (GEE) was used for the calculation/ extraction of NDVI from 1986 to 2021. A total of 220 plant species belong to 164 genera and 65 different plant families were recorded from Subtropical vegetation zones of Khyber Pakhtunkhwa, Pakistan. TWCA classified all the stations and plants into three primary vegetation zones i.e., Humid, Semi-humid and Dry subtropical, based on Sorenson distance and Ward‘s linkage methods. The topmost indicators recorded for these vegetation zones were Ficus carica, Catharanthus roseus and Erigeron canadensis (Humid), Morus nigra, Datura innoxia and Persicaria glabra (Semi humid), Dalbergia sissoo, DRSML QAU 2 Withania somnifera and Saccharum bengalense (Dry subtropical indicators) based on Indicator Values in the region. Out of 220 plant species, 19 indicator plants, i.e., Adiantum capillus-veneris, Ailanthus altissima, Albizia lebbeck, Calotropis procera, Cynodon dactylon, Datura innoxia, Debregeasia salicifolia, Desmostachya bipinnata, Dodonaea viscosa, Erigeron bonariensis, Ficus carica, Morus alba, Morus nigra, Parthenium hysterophorus, Persicaria glabra, Ricinus communis, Setaria viridis, Tamarix aphylla and Withania somnifera were the significant phytoextractor and phyto-stabilizer of potential toxic elements (Cr, Ni, Cu, Mn, Zn, Fe, Co, Cd, Ca and Mg) based on bioaccumulation coefficient, translocation and biological concentration factors. These indicators increase the accumulation of proline osmolyte and decrease chlorophyll-a, chlorophyll-b and total carotenoids as a defense or survival mechanism against marble waste polluted ecosystems. These results were reconfirmed through mixed effect modeling and bivariate regression. Preliminary results identified a total of six pure micro fungal isolates. Their molecular identification and phylogeny resulted Aspergillus brasilensi, Aspergillus sydowii, Aureobasidium leucosper, Fusarium petroliphilum, Curvularia aeria and alternaria alternata fungal species from marble wastewater polluted ecosystem. Morphologically most of these strains comprehended aseptate hyphae and black, brown, green, white to dark green colors. Whereas, anatomically these strains range from cylindrical to round, hyaline in lacto phenol blue, thick to thin walled, smooth to ornamented surface with sharp scale and fusoid to ellipsoid in shape. Among the identified micro fungi Aspergillus sydowii, Aspergillus brasilensi, Curvularia aeria and Alternaria alternata showed a significant mycoremediation ability against marble pollution. Furthermore, a significant NDVI difference was found in the marble polluted and non-polluted regions. The non polluted areas have higher NDVI than the marble polluted regions. The overall average NDVI in the marble polluted and non-polluted regions were 0.263 and 0.382, respectively. It is concluded that the studied plant indicators and micro fungi of marble waste have a significant role in the remediation of Marble Waste Polluted Systems (MWPS). Increasing proline accumulation and decreasing chlorophyll contents with an increase in pollution in the studied plant show resistance of the biome/biosphere in response to the external abiotic Lithospheric toxicities. It is recommended that these plant species could be grown to remediate the Marble Waste Polluted Systems (MWPS) in the marble processing industries and its catchments.