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Effect of calcium and magnesium hardness on acute copper toxicity to Indian major carp, Labeo rohita (Hamilton) and catfish, Channa punctatus (Bloch)
Author(s) -
Adhikari S
Publication year - 2003
Publication title -
aquaculture research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.646
H-Index - 89
eISSN - 1365-2109
pISSN - 1355-557X
DOI - 10.1046/j.1365-2109.2003.00895.x
Subject(s) - alkalinity , catfish , magnesium , calcium , carp , biology , copper , labeo , zoology , veterinary medicine , metallurgy , fishery , chemistry , materials science , fish <actinopterygii> , medicine , organic chemistry
Four experiments were conducted to evaluate the effects of calcium and magnesium hardness on the acute toxicity of copper sulphate to Indian major carp, rohu ( Labeo rohita , Hamilton) fingerlings and juvenile catfish ( Channa punctatus , Bloch) in medium alkalinity experiments. A preliminary bioassay determined the 96 h LC 50 of copper sulphate to be 0.56 mg L −1 for L. rohita fingerlings and 11.78 mg L −1 for juvenile C. punctatus placed in water with calcium hardness and total alkalinity set at 100 mg L −1 CaCO 3 . In the first experiment, rohu were exposed to 0.56 mg L −1 copper sulphate in environments where calcium hardness was varied from 50 to 350 mg L −1 CaCO 3 and total alkalinity was 100 mg L −1 CaCO 3 . As calcium hardness increased, copper‐induced rohu mortalities decreased significantly from 90% at 50 mg L −1 CaCO 3 to 7% at 350 mg L −1 CaCO 3 . In the second experiment, rohu were exposed to 0.56 mg L −1 copper sulphate in environments where magnesium hardness was varied from 50 to 350 mg L −1 CaCO 3 with total alkalinity set at 100 mg L −1 CaCO 3 . Hundred percent mortality was observed in magnesium‐based hardness treatments. In the third experiment, catfish were exposed to 11.78 mg L −1 copper sulphate in environments where calcium hardness was varied from 50 to 400 mg L −1 and total alkalinity was 100 mg L −1 CaCO 3 . As calcium hardness increased, copper‐induced catfish mortalities decreased significantly from 90% at 50 mg L −1 CaCO 3 to 4% at 400 mg L −1 CaCO 3 . In the fourth experiment, catfish were exposed to 11.78 mg L −1 copper sulphate in environments where magnesium hardness was varied from 50 to 400 mg L −1 CaCO 3 , with total alkalinity set at 100 mg L −1 CaCO 3 . In this case, 100% mortality was also observed in magnesium‐based treatments. Mortality rates in magnesium hardness treatments were consistent with those in the second experiment. These data suggest a calcium‐specific mechanism with respect to acute copper toxicity both in rohu and catfish.