Heavy metals in three commercially valuable cyprinids in the river Panjkora, district Lower Dir, Khyber Pakhtunkhwa, Pakistan

Abstract

This study was conducted in river Panjkora (Khall, upstream; Timergara, downstream) and its tributary (Konhaye stream, reference site) at district Lower Dir. The study was aimed to assess heavy metal load in gills, liver, kidneys, and muscles of three fish species, namely Schizothorax esocinus, Racoma labiata, and Crossocheilus diplocheilus. The heavy metals, including nickel, cadmium, lead, copper, zinc, chromium, iron, and manganese were determined using an atomic absorption spect-rophotometer. Nickel and cadmium were not detected in any of the collected specimens at all sampling sites. Concentration of the detected metals varied significantly depending upon fish species and tissue type. Crossocheilus diplocheilus showed higher accumulated concentration of heavy metals while R. labiata contained the least. Schizothorax esocinus and R. labiata displayed significant differences in their concentrations of metals. The order of accumulation of heavy metals in different tissues was liver>kidneys>muscles>gills. Data demonstrated that heavy metal levels in the studied species were within permissible limits and thus, apparently suitable for human consumption. Currently, the river contains a sewage burden, and continued heavy pollution may ultimately lead to serious problems in the future.

Keywords:

• river Panjkora
• Konhaye
• Lower Dir
• heavy metals
• pollution

Acknowledgments

The authors would like to thank Mr Ikram Ullah, Mr Atta Ullah, and Mr Zia Ullah for their help in collecting fish specimens. We also thank Mr Said Hasan (PhD scholar, Centre of Biotechnology and Microbiology, University of Peshawar) and Dr Javid Ali (scientific officer, PCSIR Laboratories Complex, Peshawar) for their help in heavy metals analysis.

Disclosure statement

No potential conflict of interest was reported by the authors.