Estimation of Heavy Metals Enrichment and Geo-Accumulation Associated with Habitat Quality from Selected Wildlife Parks

Abstract

ABSTRACT Perpetually intensifying soil contamination is an anthropogenic phenomena, which is a global environmental concern. An important tool for the evaluation of contamination levels and ecosystem health is the assessment of soil quality, which can be used to evaluate prospective ecological threats to both organisms and the environment. The aim of this study was to quantify the soil heavy metal pollution levels to assess the site quality of three wildlife parks in different climatic zones of Punjab, Pakistan, where several wild animals were housed for the purpose of conservation. A robust method for calculation, absolute deviation from median (median ± (2 × MAD)), was used to compute geochemical background value of each heavy metal. Single (geoaccumulation index – Igeo and enrichment factor – EF) and complex (pollution load index (PLI)) indices were used to recognize whether the detected heavy metals Pb, Cr, Zn, Cd, Co, Mn and Ni levels in the soil are consequences of anthropogenic or natural sources. In comparison between sites, the heavy metal enrichment for Pb, Cr, Cd and Zn was recorded high at Jallo Forest and Wildlife Park succeeded by Murree Wildlife Park and Bahawalnagar Wildlife Park. Pb, Zn, Cd and Cr showed high EF values at Jallo Forest and Wildlife Park while Igeo values of Pb, Cr, Cd, Mn and Zn were greater at Murree Wildlife Park indicating high heavy metal geoaccumulation. The highest heavy metal contamination site with reference to soil quality was Murree Wildlife Park (PLI = 1.12), which was followed by Jallo Forest and Wildlife Park and Bahawalnagar Wildlife Park with PLI values 1.05 and 0.80, respectively. Analysis by hierarchical clustering (HCA) showed high degree of variation between heavy metal concentrations at all sites with the exception of Pb and Zn. As documented from the present study, significant levels of enrichment and contamination with heavy metals were recorded for soils of selected sites. Further assessment is mandatory because the chosen study sites were situated in climatically diverse areas with reference to environmental factors, topography, climatic condition and their impact on the accumulation patterns in soil as well as in animals.