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Metal uptake and histological changes in gills and liver of Oreochromis mossambicus inhabiting Indus River.

2013; University of Punjab (new Campus); Volume: 45; Issue: 1 Linguagem: Inglês

0030-9923

Farhat Jabeen, Abdul Shakoor Chaudhry,

Heavy metals in environment

This study monitored the accumulation of selected metals (Mn, Pb, Cu, Zn, Hg and Cr) in river water and in muscles, gills and livers and their effect on the histology of gills and liver of Oreochromis mossambicus from a low (reference), medium (CH) and high (SK) polluted sites of the Indus River in Mianwali district of Pakistan. Mn, Cu, Zn and Cr levels in the water of three selected sites were within the safe limits of international water quality but the concentrations of Pb and Hg were above the international standards. Mn, Cu, Zn and Cr in fish tissues showed significant differences between sites (P < 0.01). These metals showed tissue specific differences (P < 0.001). While the Mn, Hg and Cr levels were higher in muscles, gills and liver of fish than the WHO standards, the Pb and Cu levels were within the permissible limits for fish as a food for human consumption. More metal concentration was observed in livers than the gills and muscles. Most common gill abnormalities observed in Oreochromis mossambicus inhabited in the polluted area were desquamation of lamellar epithelium, hypertrophy of epithelial cells, lifting up of lamellar epithelium, intraepithelial oedema, aneurysm, hyperplasia, and haemorrhage in the gill filament. Histology of liver revealed the presence of heterogeneous parenchyma characterized by vacuolization, foci of necrosis, hypertrophy of nuclei and degenerated hepatocytes. In conclusion the evidence of pathological alterations in gills and livers of Oreochromis mossambicus appeared to be a useful bio-marker to assess the impact of metal pollution in water on the health of fish and higher levels of Cr, Mn and Hg in edible part of fish are worrying as it may cause health related problems in the consumers of the study area. The study was carried out in Mianwali District of Pakistan, which is located along the bank of the Indus River and is rich in natural minerals and rocks being excavated in commercial quantities as previously reported by Jabeen and Chaudhry (2010a, b). The inland fisheries in Pakistan are heavily dependent upon the Indus River and this river is among the top 10 World's Rivers which are at risk (Wong et al., 2007) The Indus River is at risk due to climate change, water extraction, agricultural pollution and water infrastructure. The Indus River is critical for Pakistan's 160 million people, and irrigates 80% of its 21.5 million hectares of agricultural land (Rizvi, 2001). Heavy metals from both natural and anthropogenic sources are continually released into aquatic ecosystems, which could be a serious threat