| Abstrakt: |
A laboratory study was conducted to determine copper toxicity to theendoparasitic trematode Posthodiplostomum minimum (MacCallum) relative to snail first intermediate hosts and bluegills (Lepomis macrochirus Rafinesque) as second intermediate hosts. To determine copper effects on cercariae, the life-cycle stages of P. minimum were established in the laboratory. A 96-h median lethal concentration (LC50) test for bluegills was performed, and the calculated value of 0.892 mg/L total Cu was considered in selection of copper concentrations for all other experiments. Snail hosts (Physella gyrina (Say)) exposed to copper concentrations equal to 0, 8.9, 22.3, 44.6, and 89.2 mu g/L Cu, exhibited a significant toxic response with -64% and -87% mortality occurring in the 44.6 and 89.2 mu g/L concentrations, respectively. The 7-d LC50 for snails was 38.0 mu g/L Cu. Free-swimming cercariae exposed to the same copper concentrations exhibited a similar toxic response with a 9-h LC50 of 32.0 mu g/L Cu and a 12-h LC50 of 26.0 mu g /L Cu. [ABSTRACT FROM AUTHOR] |
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