Seasonal determination of heavy metals in muscle, gill and liver tissues of Nile tilapia,Oreochromis niloticus(Linnaeus, 1758) from the tributary of the Ganga River, India

Aquatic biota is contaminated with heavy metals as a result of anthropogenic activities and industrialization. Heavy metals, that is copper (Cu), chromium (Cr), lead (Pb) and zinc (Zn), were analysed in Oreochromis niloticus collected from the Gomti River at Lucknow and Jaunpur sites, India, from 2011 to 2012. Accumulation of heavy metals was estimated in different tissues of tilapia. At both study sites (Lucknow and Jaunpur), metal accumulation in different tissues of this fish was found to be in the following order: Zn > Pb > Cr > Cu in muscles, Zn > Pb > Cr > Cu in gills and Pb > Cr > Cu > Zn in liver. However, it was established that the level of heavy metals in all fish organs at the Lucknow site (except Pb and Zn in gills) was higher. The determined bioconcentration factor of heavy metals in different fish organs at the Lucknow site was as follows: Cu (26.5), Cr (38.33), Pb (52.33), Zn (23.41) in muscles, Cu (36.5), Cr (56.33), Pb (95.66) and Zn (31.66) in gills and Cu (381.50), Cr (367.33), Pb (410.33), Zn (23.16) in liver. Meanwhile, at the Jaunpur site, the bioconcentration factor was found to be slightly lower: Cu (17.5), Cr (22.66), Pb (35.50), Zn (16.63) in muscles, Cu (25), Cr (30), Pb (146.5), Zn (37.81) in gills and Cu (215), Cr (266.33), Pb (438), Zn (24.63) in liver. The bioaccumulation level and bioconcentration factor indicated that fish at the Lucknow site slightly suffered from heavy metal pollution.Dėl pramonės vystymosi ir kitokios žmogaus veiklos vandens flora ir fauna užteršiama sunkiaisiais metalais. Buvo tiriamas vario (Cu), chromo (Cr), švino (Pb) ir cinko (Zn) kaupimasis įvairiuose Nilo tilapijos (Oreochromis niloticus), pagautos 2011–2012 m. Indijoje, Gomti upėje ties Lucknow ir Jaunpur, audiniuose. Abiejose tyrimo vietose sunkieji metalai įvairiuose audiniuose kaupėsi taip: raumenyse Zn > Pb > Cr > Cu, žiaunose Zn > Pb > Cr > Cu, kepenyse Pb > Cr > Cu > Zn. Tačiau ties Lucknow visuose tilapijos organuose sunkiųjų metalų kiekiai (išskyrus Pb ir Zn žiaunose) buvo didesni. Šioje tyrimo vietoje sunkiųjų metalų biokoncentracijos įvairiuose žuvies organuose faktorius buvo: Cu (26,5), Cr (38,33), Pb (52,33), Zn (23,41) raumenyse, Cu (36,5), Cr (56,33), Pb (95,66) ir Zn (31,66) žiaunose, Cu (381,50), Cr (367,33), Pb (410,33), Zn (23,16) kepenyse. Jaunpur tyrimo vietoje biokoncentracijos faktorius buvo mažesnis: Cu (17,5), Cr (22,66), Pb (35,50), Zn (16,63) raumenyse, Cu (25), Cr (30), Pb (146,5), Zn (37,81) žiaunose ir Cu (215), Cr (266,33), Pb (438), Zn (24,63) kepenyse. Sunkiųjų metalų bioakumuliacijos lygis ir biokoncentracijos faktorius rodo, kad Lucknow tyrimo vietoje žuvys yra paveiktos sunkiųjų metalų taršos.