ScienceAsia 27 (2001) : 157-164 |doi: 10.2306/scienceasia1513-1874.2001.27.157
Effects of Humic Acid and Water Hardness on Acute Toxicity and Accumulation of Cadmium in the Freshwater Fish ( Puntius gonionotus Bleeker )
R Mungkunga, ES Upathamb, P Pokethitiyookc *, M Kruatrachuec and C Panichajakula
ABSTRACT: The effects of humic acid and water hardness on acute cadmium toxicity and accumulation were determined, using Puntius gonionotus Bleeker. The toxicities were expressed as the median lethal concentration (LC50) and the 96-h LC50 value of cadmium was 2.30 mg/L. Three different types of water hardness were used: soft, moderately-hard and hard, with total hardness concentrations of 55, 113, and 225 mg/L CaCO3, respectively. The acute cadmium toxicity and accumulation significantly decreased by increasing water hardness concentration. An increase in humic acid concentrations (0.5, 5.0, and 50 mg/L) also decreased cadmium toxicity and accumulation. Moreover, simultaneous increases in humic acid and water hardness concentrations also resulted in a decrease in cadmium toxicity. However, they were less effective in decreasing cadmium accumulation than the effect of water hardness or humic acid alone.
a Department of Environmental Science, Faculty of Science, Kasetsart University, Bangkok 10220, Thailand.
b Department of Biology, Faculty of Science, Mahidol University, Bangkok 10400, and Faculty of Science, Burapha University, Chonburi 20131, Thailand.
c Department of Biology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand.
* Corresponding author, E-mail: email@example.com
Received 22 Jan 2001, Accepted 3 May 2001