Pharmaceutical waste present in freshwater ecosystems adversely affect resident microorganisms, and indirectly other species, according to UW-Madison zoologist Colleen Flaherty.
Flaherty studied how the presence of commonly prescribed drugs, such as antidepressants, antibiotics and cholesterol-lowering drugs, affect Daphnia, a type of zooplankton, when the drugs are present both individually and in combination.
\Damphnia play a key ecological role in freshwater sources. They are an intermediate organism in these ecosystems'they eat the algae and are eaten by the fish,"" Flaherty said. ""If something happens to Daphnia, it could affect both the algae and the fish populations.""
The results of her short-and long-term studies relating to Daphnia's exposure to a variety of drugs vary.
In the short-term studies, zooplankton growth was stunted and more male offspring were present during exposure to antibiotics and cholesterol-lowering drugs. However, in the longer-term studies, offspring exposed to antibiotics had longer life spans, cholesterol-lowering drugs no side effects and an antidepressant a greater number of offspring.
When exposed to two drugs simultaneously, a cholesterol-lowering drug and antidepressant, Daphnia offspring had a 90 percent mortality rate, as well as more physiological deformities affecting motility.
