Enrichment and geo-accumulation of heavy metals and risk assessment of sediments of the Kurang Nallah--feeding tributary of the Rawal Lake Reservoir, Pakistan.
Heavy metal concentrations in sediments of the Kurang stream: a principal feeding tributary of the Rawal Lake Reservoir were investigated using enrichment factor (EF), geoaccumulation index (Igeo) and metal pollution index (MPI) to determine metal accumulation, distribution and its pollution status. Sediment samples were collected from twenty one sites during two year monitoring in pre- and post-monsoon seasons (2007-2008). Heavy metal toxicity risk was assessed using Sediment Quality Guidelines (SQGs), effect range low/effect range median values (ERL/ERM), and threshold effect level/probable effect level (TEL/PEL). Greater mean concentrations of Ni, Mn and Pb were recorded in post-monsoon season whereas metal accumulation pattern in pre-monsoon season followed the order: Zn>Mn>Ni>Cr>Co>Cd>Pb>Cu>Li. Enrichment factor (EF) and geoaccumulation (Igeo) values showed that sediments were loaded with Cd, Zn, Ni and Mn. Comparison with uncontaminated background values showed higher concentrations of Cd, Zn and Ni than respective average shale values. Concentrations of Ni and Zn were above ERL values; however, Ni concentration exceeded the ERM values. Sediment contamination was attributed to anthropogenic and natural processes. The results can be used for effective management of fresh water hilly streams of Pakistan.
Environmental Biology and Ecotoxicology Laboratory, Department of Environmental Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, PO 45320, Pakistan.
Azmat
A
Zahra
Department of Environmental Engineering, College of Environmental & Resource Sciences, Zhejiang University, Hangzhou 310058, People's Republic of China.
Muhammad Zaffar
MZ
Hashmi
Environmental Biology and Ecotoxicology Laboratory, Department of Environmental Sciences, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, PO 45320, Pakistan. Electronic address: r_n_malik2000@yahoo.co.uk.
Riffat Naseem
RN
Malik
Department of Building and Architecture Engineering, Bahauddin Zakariya University, Multan, Pakistan.
Zulkifl
Z
Ahmed
D004784:Environmental Monitoring; D019216:Metals, Heavy / Q000032:analysis*; D010154:Pakistan; D018570:Risk Assessment; D045483:Rivers / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis*
D019216:Metals, Heavy; D014874:Water Pollutants, Chemical
Enrichment factor; Geo-accumulation index; Heavy metals; Multivariate analysis; Sediments