title: Characterization of tannery effluent wastewater by proton-induced X-ray emission (PIXE) analysis to investigate their role in water pollution.
abstract: BACKGROUND
  Over the last few decades, the chromium-based tanning industry has shown rapid growth in Pakistan. However, the rules and regulations promulgated by the government are not strictly followed for processing the effluent discharge from the tanneries. Consequently, tannery effluents have become a great source of water pollution in surrounding areas.
  
  
  METHODS
  In this case study, characterization of tannery effluent wastewater (TW), shallow groundwater (SW), and deep groundwater (DW) samples was carried out to determine the source of water pollution in the district of Kasur, Pakistan.
  
  
  RESULTS
  The concentrations of calcium (Ca), chlorine (Cl), chromium (Cr), iron (Fe), potassium (K), Mg, sulfur (S), silicon (Si), and Sr in TW were significantly higher than SW and DW, which also exceeded the international limits. In addition, increased concentrations of major toxic elements (Cl, Cr, Fe, K, Ni, and Si) were also observed in SW, which were higher in comparison to DW. Strikingly, the concentrations of Cr and Si in various DW samples were also beyond World Health Organization (WHO) safe limit, which reinforced the trend that water pollution in the area is directly linked to the distance from the source (TW). The particle-induced X-ray emission (PIXE) indices also suggested that TW is a main contributory source of water-based pollution in the area, which is imposing great threat to local inhabitants due to known hazardous and carcinogenic potential of these elements.
  
  
  CONCLUSIONS
  Protecting the water resources will be a formidable challenge in the study area, which requires modernization of tannery industry, thereby improving the recovery and recycling of TW. Moreover, PIXE analysis presented here as a successful tool, could serve as landmark for the contemporary research in environmental toxicology.
authors.affiliation: Angiogenesis and Toxicology Research Laboratory, Department of Pharmacology & Toxicology, University of Veterinary and Animal Sciences, Abdul Qadir Jilani Road, Lahore, 54600, Pakistan.
authors.forename: Lubna
authors.initials: L
authors.lastname: Shakir
authors.forename: Sohail
authors.initials: S
authors.lastname: Ejaz
authors.forename: Muhammad
authors.initials: M
authors.lastname: Ashraf
authors.forename: Nisar
authors.initials: N
authors.lastname: Ahmad
authors.forename: Aqeel
authors.initials: A
authors.lastname: Javeed
mesh_terms: D060766:Drinking Water / Q000737:chemistry; D004784:Environmental Monitoring / Q000379:methods*; D060587:Groundwater; D007220:Industrial Waste / Q000032:analysis*; D010154:Pakistan; D013052:Spectrometry, X-Ray Emission / Q000379:methods*; D013633:Tanning; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D060766:Drinking Water; D007220:Industrial Waste; D014874:Water Pollutants, Chemical