الفهرس | Only 14 pages are availabe for public view |
Abstract The present work was conducted to study the effect of X-ray on the biotic potential, and cercaria! production of laboratory and field fresh water snails, B.alexandrina and B.truncatus. The effect of different sublethal concentrations of cobalt (Co++) and chrome (Cr+++) on the survival rate, the egg production and the growth rate of both laboratory and field snails was also considered. Also the accmnulation of cobalt and chrome in the shells and soft parts of snails was studied. Considering the effectiveness of X-ray on the survival rate, the higher the dose of X-ray, the higher was the rate of mortality and vice versa. As a general trend B.alexandrina proved to be more tolerant to X-ray when compared with B.truncatus. The low doses of X-ray 0.2, 3 and 5 rad had no effect on the egg laying capacity of the field strain of Biompholaria and Bulinus, while the dose of 20 rad decreased the egg production. The hatchability percentage of B.alexandrina and B.truncatus in early stages of development was higher when exposed to 0.2 rad |