Short-term chronic effects of cadmium and zinc of survival, growth and hispathology of postlarval penaeus monodon (fabrius) /
by Judith R. Silapan.
- Diliman, Quezon City : University of the Philippines Diliman, 1999.
- ix, 57 pages : illustrations ; 28 cm.
Thesis (Master of Science in Marine Science) University of the Philippines
Includes bibliographical references.
For comparative purposes, the toxicity of cadmium and zinc to postlarval Penaeus monodon (Fabricius) was evaluated using short-term chronic tests. Toxicity to the postlarvae was measured in terms of survival, growth and histopathology over 8 and 15 days. The 96-hr LCso (lethal concentration) values were 1.83 mg Cd"/L and 3.16 mg Zn*/L. The IC3s (inhibition concentration) values were 0.08 to 0.63 mg Cd”“/L and 0.42 to 0.76 mg Zn”*/L. For survival, the SCv (short-term chronic value) 0.6 mg Cd?*/L was slightly but consistently lower than the 1.8 mg Zn’*/L. For growth, the sensitivity of the postlarvae to the two contaminants overlapped in some cases (0.21 to 0.6 mg Cd?*/L and 0.21 to 1.32 mg Zn°*/L) with Cd values generally lower than Zn by one to within an order of magnitude. Histopathological responses were observed in the hepatopancreas of the postlarvae. Animals from the control and lower concentrations of Zn (0.001, 0.01 and 0.1 mg/L) showed normal histology. At concentration of Zn that affected growth (1.0 mg/L), the most prominent structural change was the presence of a lot of large secretory cells compared to very few smaller, absorptive or storage cells. The latter were in many cases, devoid of vacuoles. On the other hand, animals exposed to Cd had no defined cell- type abnormalities even at concentration which affected growth (0.1 mg/L) The apparent reduction in size of the various cells found in the hepatopancreas and the general looseness in the organ’s appearance did not correlate with increasing Cd concentration.
Penaeus monodon--Effects metals on Cadmium--Toxicity testing Zinc--Toxicity testing