The Effects of Landfill Leachate on the Behavior, Feeding Rate, and Growth Rate of the Freshwater Prosobranch Snail Elimia Potosiensis
The current study examined the effects of landfill leachate on the behavior, feeding rate, and growth rate of the prosobranch snail Elimia potosiensis by comparing two sites, one non-contaminated (Site NC) and one contaminated (Site C). The copper concentration resulting in a decreased feeding rate was also established. An in-situ enclosure experiment at Site NC indicated that snails acclimated within one week and reached a net movement of 60 cm in an upstream direction. Comparison of Site NC and C indicated landfill leachate did not adversely affect snail movement after an initial acclimation period. After two weeks 73% of the snails at Site C moved upstream a distance > 79 cm and at Site NC 51% moved upstream a distance > 79 cm. Measurements for a 12-d static feeding rate study indicated no consistent reduction in feeding rates when snails were exposed to water alage from Site C. However, growth rates over the 12-d showed a 30% less weight gain in snails exposed to Site C water and algae than that from Site NC. A laboratory study exposing snails to different concentrations of copper revealed that concentrations as low as 0.01 ppm resulted in death or severe stress with two days, and 0.001 ppm resulted in a reduction in feeding rates. The current study suggests that landfill leachate has little effect on snail movements or feeding, but results in a substantial reduction in growth rate. The hig sensitivity of snails to copper suggests that some of the response of linfill leachate could be due to heavy metals.
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