Bisphenol A (BPA) is a chemical compound commonly found in many plastics and epoxy resins. Plastic water bottles exposed to high temperature, such as being left in a hot car, will elute from the resin in the plastic and into the water. BPA eluted into water supplies has been shown to cause effects in estrogen pathway. We used the Ramshorn snail as the model organism because this species reproduces rapidly and cleans organic debris in the tank. This made the snails an excellent indicator of the harshness of the tank water. The acute and chronic ecotoxicological effects of BPA have been shown to cause differences in fecundity, mortality, and hormonal regulation in various organisms. We examined the effects of seven concentrations of BPA ranging from 0 to 50 milligrams per liter on Ramshorn snails. We predicted to find that increased concentrations of BPA would result in higher rates of mortality and lower rates of fecundity. For mortality we determined the lethal concentration (LC50) at which 50% of the populations died. To examine fecundity we examined not only the numbers of egg clutches laid by survivors, but the numbers of eggs per clutch.
Results/Conclusions
All snails above 5 mg/l died before 12 hours, with a 100% survival rate of the remaining concentrations. For 0.05 mg/l, 0.25 mg/l, and 1.0 mg/l there were 6, 4, and 5 clutches laid respectively. The total average number of eggs per clutch was 5.3, 6.5, and 9.4. These were not statistically significantly different from our control total number of clutches (3) and average number of eggs per clutch (8). In previous studies Marisa cornuarietis were exposed to lower than environmentally relevant concentrations of BPA to examine mortality and fecundity. As the concentration of BPA increased the mortality rates increased as well as the rate of reproduction. We believed this may be a mechanism to produce numerous offspring to increase survival in the harsh water condition. Our results and the results of previous studies show that Ramshorn snails are affected by BPA at lower concentrations than those tested on other wildlife groups. In the future, the LC50 needs to be studied between 3 to 5mg/L since the LC50 was not determined during the original experiment. Another aspect that can be further observed during the next study is: why the number of clutches and eggs increased with higher concentration of BPA?