IMPACT OF GADOON AMAZAI INDUSTRIAL ESTATE ON GROUNDWATER AND ENVIRONMENT: AN INTEGRATED APPROACH

Abstract

The Peshawar Basin, Khyber Pakhtunkhwa (KPK) is experiencing increase in industrial development, agricultural activities, and rapid urbanization, all of which demand a rising supply of quality water. The Peshawar Basin is sanctified with abundant water supply, stored in the Quaternary deposits. In the Quaternary, siliciclastic supply is found in the sedimentary archives of the Peshawar Basin. The basin is filled with fluvial-floodplain clays, which are covered by thick lacustrine-glaciofluvial rhythmites. Alluvial fans are found in the south of the basin with loess deposits being stratified on top of the alluvial fans. The shallowest strata is composed mainly of fluvial sediments recently deposited by the Kabul River. The shallowest gravels and boulders mark the upper bound of aquifers, and is hence susceptible to percolation of contaminated surface water into aquifers due to the high permeability. The research is to integrate non-invasive geoelectrical technologies, hydro-geochemical and geospatial analysis to monitor the quality of surface water and groundwater resources. This study evaluates impacts of Gadoon Amazai Industrial Estate (GAIE) on water resources in the Swabi district. These methods were successfully used in investigating Quaternary alluvial plain of the Swabi District, due to their economic nature, fast processing steps of these methods and compatibility. The 2D electrical resistivity tomography (ERT) survey comprised 28 profiles. The survey was planned along streams which are carrying wastewater from the Gadoon Amazai Industrial Estate (GAIE) and nearby agricultural land. A multichannel electrode system WDJD-4 was used. The ERT data was acquired in form of grids using the Wenner electrode configuration. The 05 Grids were near streams carrying effluents and the 01 Grid is used for reference values. ERT resistivity data was processed for inversion using the RES2D software, and the obtained true resistivity section was interpreted. ERT identified the contaminated sandy clays (resistivity ≤10 ohm-m). Contaminated aquifer (resistivity 10-60 ohm-m) and the fresh water aquifer zone (resistivity 60-100ohm-m). The high resistivity zone (≥ 300 ohm-m) is marked as bed of dry gravels and boulders. A series of 1D Vertical electrical soundings (VES) were acquired for 40 locations using a DDC-8 resistivity meter. The VES data is processed stepwisely by curve matching and inversion has been done using IPI2WIN. The lithologs and their correlation generated the geoelectrical cross-sections VES described four geoelectrical layers (clay with gravels, saturated gravels and boulders, dry gravel and boulders, and bed rock). In addition to delineating various types of aquifer, VES also depicted that the beds of coarser sediments are thickening towards the southwest of the explored area (Maini, Sogandy and Topi). The aquifers identified were unconfined owing to the presence of shallowest unconsolidated gravels and boulders. Hydro-geochemical techniques quantify the contamination of water resources as well as soil of the Gadoon Plain. The statistical analysis and spatio-temporal interpolation of pre monsoon and post-monsoon time period showed the fluxes of hydrological cycles. Total 110 samples of water from the dry season and wet season and 30 soil samples from irrigation lands were used to collect the hydro-geochemical data. Both samples were tested for heavy metals (HMs) such as sodium (Na), potassium (K), calcium (Ca), Magnesium (Mg), Iron (Fe), arsenic (As), Zinc (Zn), lead (Pb), mercury (Hg), and cadmium (Cd) using an Atomic Absorption spectrophotometer. Heavy Metals concentrations were found to be greater than permissible bounds, especially during dry seasons (WHO 2017). Furthermore, it was shown that surface water of streams carrying waste from industry, had a higher pollution concentration than groundwater from water runoff. All water samples have been analyzed for pH, electrical conductivity (EC), turbidity, and total dissolved solids (TDS) using physicochemical methods. Samples of subsurface water (SSW) had their microbial concentrations were estimated. In addition, precipitation and infiltration dilute heavy metal concentrations in post-monsoon, resulting in lower levels than before the monsoon. Atomic Absorption spectrometry is used to measure the concentration of major elements and heavy metals (HM’s). Agricultural area irrigated with industrial effluent proved to show anomaly in heavy metals concentrations. The Inverse distance weightage tool is used for spatial distribution of heavy metal concentrations in water samples as well as in soil samples. In Gandaf, geogenic sources seem to be the source of increased amount of Hg and Pb. The quantities of all other trace elements are rising near GAIE, indicating that industrial effluents are degrading water and soil quality by introducing potentially harmful constituents. In addition to damaging crops, toxic materials become part of the food chain. In order to protect the country's non-renewable water resources, this comprehensive research recommends that the effects of all industrial zones be monitored. Local governments, public health agencies, policymakers, and specialists in water resources would all benefit from the results of this research as well.