EFFECTS OF WATER HARDNESS ON THE TOXICITY OF ZINC TO SAROTHERODON MOSSAMBICUS (PETERS)
D. MONI *
DEPARTMENT OF ZOOLOGY, BHARATHIAR UNIVERSITY, COIMBATORE-641046, INDIA.
S. SAM MANOHAR DHAS *
DEPARTMENT OF ZOOLOGY, SCOTT CHRISTIAN COLLEGE, NAGERCOIL-629002, INDIA
*Author to whom correspondence should be addressed.
Abstract
The toxicity of metals and inorganics to different fish species in the aquatic medium depend much on water quality. Static bioassy tests were conducted using con mercial grade zinc sulphate (ZnSO, 7 HO) to study the toxic effects on hard waters. The sublethal concentrations of zinc on the common fresh water food fish S. mossambicus in three water samples of varying hardness were calculated. The sublethal concentration was 2.5 mg/Zn/l; 5.5 mg/Zn/l and 17 mg Zn/l with various samples having hardness of 32 mg/l; 192 in gll and 320 mg/l as CaCO.