Chemical Profile and Heavy Metal Concentration in Water and Freshwater Species of Rupsha River, Bangladesh

Abstract

The present study was undertaken to evaluate the chemical profile of the water and to determine heavy metal concentrations in water and muscles of certain freshwater fish and crayfish species of Rupsha River, Bangladesh. The concentrations of heavy metals were determined in six fish and crayfish species: Peneaus monodon, Macrognathus aculeatus, Gudusia chapra, Channa punctatus, Glossogobius giuris and Barilius bola. Fish and crayfish samples as well as chemical parameters of water were measured in three different sampling stations for six months during the year of 2010. Three sampling stations in the Rupsha River were - main industrial discharge site (S1), river site close to effluents from fish processing plants, brick yards and agricultural runoff (S2), and apparently low industrial waste discharge point but rich in sewage and municipal wastes admixing with Fe compounds from Ship breaking yard (S3). The heavy metals concentrations were determined by Atomic Absorption Spectrophotometer. Among the water quality parameters, the values of Dissolved oxygen (DO), Nitrate-Nitrogen (NO3-N) and Ammonia Nitrogen (NH3-N) were detected beyond the acceptable limit whereas pH and alkalinity were within the permissible limits, respectively. DO levels below and NO3-N levels beyond suitable limits indicated a low water quality of Rupsha River and therefore, a habitat unfavorable for fish and other aquatic animals. Heavy metals measured from the river water were Pb, Zn, Fe and Mn, and those from fish and crayfish muscles were Fe, Cu, Zn, Pb, Cr, Mn and Ni. The heavy metal concentrations in Rupsha River water were found within the permissible limits except for Fe. The mean Fe concentrations were recorded to be 0.68±0.48, 0.77±0.38 and 0.67±0.35 mgL-1 at sampling points S1, S2 and S3, respectively. The accumulations of heavy metals in fish and crayfish muscles were found within the permissible limits. However, bioaccumulation factor (BAF) for metals in fish and crayfish muscles showed unacceptable concentrations for Zn, Pb and Mn. BAF results indicate that consumption of fish and crayfish species from Rupsha River is likely to exert health hazards for human being.