Materials and Methods
Water samples and Sediment samples were collected in
June 2008 from various stations ( region of
maximum/minimumwater flow, inlet and outlet
areas).Sediments were collected via a polyethylene corer,
preserved according to standard methods. Samples were
digested in acid-cleaned Teflon microwave vessels with
5ml of ultrapure nitric acid and 2ml ultrapure
hydrofluoric acid. and were digested for 30min at 200°C.
After allowing at least 2h for cooling, the vessels were
opened and 0.8g boric acid was added to dissolve the
fluoride precipitates and were detected by Atomic
Absorption Spectrometer. pH and salinity were measured
with a YSI 33 model portable conductivity meter.
Fish samples[Catla,Silver carp , Common carp,
Tilapia(Oreochromis niloticus), Mrigal Etroplus
suratensis, Murrels (Channa marulius), Nandus nandus
Amblypharyngodon mola Catfishes (Heteropneustes
fossilis) ]were purchased from the lakes. The size of the
fish collected varied, depending on the species, between
12 cm and 54 cm, and their age was from 6 months to 1
years.Fish from each variety dissected to separate organs
(flesh, gills, liver and kidney) according to FAO method.
The separated organs were put in petridishes to dry at 120
oC until reaching a constant weight. The separated
organs were placed into digestion flasks and ultrapure
Conc. HNO3 and H2O2 (1:1 v/v) was added . The
digestion flasks were heated to 130 oC until dissolution ,
diluted with water and analysed for heavy metal
concentration using atomic absorption Spectrometer