Metal contamination of surface soils of industrial city Sialkot, Pakistan: a multivariate and GIS approach

Abstract

In this study concentrations of selected metals viz., Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Na, Ni, Pb and Zn in surface soils of Sialkot city known worldwide for tanneries and pharmaceutical industries were measured to assess the status of urban soil pollution and to identify sources of contamination. Hierarchical cluster analysis (HACA) indicated concentrations of Mg and Ca related to parent rock material, Cd, Co, and Pb with traffic related activities, Cr, Cu, Ni and Zn either associated with automobiles activities or industrial pollution and Fe, K and Na related with anthropogenic activities or lithogenous materials. Correlation analyses and principal component analysis based on factor analysis confirmed the results of HACA. Spatial distribution maps exhibited relatively higher concentrations of Cd, Co, Cu, Ni, Pb, Cr and Zn along traffic routes in the city and streams. The results highlighted concentration of Cd, Ni, Cr, Zn, and Pb measured in urban soil exceeded the permissible limit of surface soils and advocated an imperative need for detailed baseline investigations of spatial distribution of heavy metals and other contaminants for the formulation of geochemical database that should be made available to stakeholder involved in monitoring, assessment and conservation of soil contamination for future planning and management of the Sialkot city.

Enrichment, risk assessment, and statistical apportionment of heavy metals in tannery-affected areas

“…Elevated Na concentration can damage soil structure in certain soil types by limiting water movement and replacing Ca/Mg ions affecting plant growth. Na levels (1,782 mg/kg) in our earlier study on urban soils of Sialkot were quite lower than present study due to substantial tanneries input (Malik et al 2010). Mg becomes available to plants at higher pH.…”

“…Chromium showed stronger affinities with OM with higher level of enrichment and accumulation and is highly toxic to biological organisms (Kabata-Pendias 2004). Relation of Na and Ca with OM % was also described by Malik et al (2010) in urban soils of Sialkot district with low OM contents which ranged from 0.04-0.7 %. Linear regression analysis revealed that soil properties viz.…”

“…Over the last decades, soil contamination problems related to discharge of untreated industrial/urban effluents and wastes, indiscriminate use of chemical fertilizers/pesticides in surface soils and sewage irrigation have emerged as major environmental problems. There are serious concerns about the quality of surface soils in urban and peri-urban areas, considering the potential negative environmental influences from the tanning industry (Malik et al 2010). …”

“…In Pakistan, few studies have been conducted so far to determine the level of heavy metals in the soils around the cities (Tariq et al 2006;Malik et al 2010). Different pollution indices that may help in quantification, monitoring studies, and regional management plans are also less often applied.…”

Evaluation of heavy metal and total petroleum hydrocarbon contamination of roadside surface soil

“…Pb released from emissions gets translocated from the roots to the shoot and leaves in plants (Christiana and Samuel 2013). Urban soils are marked with elevated levels of heavy metals due to extensive anthropogenic activities related to vehicular emissions and traffic, industrial and urban waste, mining, smelting and manufacturing by metal industries, wear and tear of tires, building materials and road activities, fertilizers and agricultural run-off (Lu et al 2010;Mahanta and Bhattacharyya 2011;Malik et al 2010;Montoneri et al 2014). Heavy metal accumulation in soil, their origin and interactions with soil properties act as bioindicators in many environmental-monitoring studies (Qishlaqi and Moore 2007).…”