Distribution and bioaccumulation of heavy metal in water, sediment and fish tissue from the River Mahananda in Seemanchal zone, North Bihar, India

In the present study, distribution, and bioaccumulation of Cu, Zn, Cd, and Pb were analysed in water, sediment and freshwater fish tissues of Catla catla and Mystus seenghala which were seasonally collected from River Mahananda in Seemanchal zone. The results showed that except Pb, level of Cu, Zn and Cd in water were below than allowance limit of WHO (2008), while level of Cu, Zn and Cd in sediment was higher than a toxicity reference value (TRV) recommended by USEPA (1999), except Pb. Heavy metal concentration in water and sediment were recorded in the order: Cu>Pb>Zn>Cd and Zn>Cu>Pb>Cd, respectively. The seasonal variation of this metal in water was in the sequence: rainy>winter>summer, and in sediment summer>winter>rainy. Bioaccumulation of studied metal by different tissues of M. seenghala was maximum than C. catla , and found that following order of magnitude: liver>gill>muscle. The order of studied metal concentration in liver Zn>Pb>Cu>Cd, in Gills Zn>Pb>Cu>Cd, in muscle Zn>Pb>Cu. Pb was only metal whose concentration was higher than FAO, FAO/WHO and WHO standards in all examined tissues of both species . Bioaccumulation of Pb in different tissues of both fishes was observed maximum in summer followed by winter and rainy (monsoon) seasons. Bioaccumulation factor (BAF) of all four metals in organs of M. seenghala was higher than C. Catla. Metal index value (MI) > 1 for Cd and Pb in water suggests that worse quality of water. The levels of heavy metals accumulated in two fishes might be due to the increase in agricultural influx water, domestic wastes, poultry farm, municipal and some other anthropogenic activities. This study shows that River water in the studied zone is a serious concern of human health and selected fishes do not feed directly without proper treatment of the riverine ecosystem, and potential danger may occur in the future.