Nearly 30-90% of the pharmaceuticals we digest are excreted in its active form. These active pharmaceuticals collect sewage systems and eventually make their way to streams, rivers, lakes, and oceans. What are the effects of these pharmaceuticals on aquatic and marine organisms?
In a recent study, scientists exposed crustaceans, the amphipod Echinogammarus marinus, common in the freshwaters of Portugal to multiple drugs. Amphipods demonstrated increased response to light (phototaxis) and gravity (geotaxis) when exposed to serotonin.
As background, serotonin is the neurotransomiter that produces that happy feeling and serves to regulate our moods by aiding with sleep and reducing anxiety and depression. Interestingly, certain parasites are known to increasing swimming behavior in amphipods through increasing serotonin levels. Amphipods with parasite loads also exhibited increased photo- and geotaxis. All this “extra” swimming makes the amphipods stand out to predators, allowing the parasite to complete the next host phase, i.e. the predator, in its lifecycle.
The effects of Fluoxetine (Prozac, Sarafem) were also tested on amphipods. Fluoxetine works by increasing the amount of serotonin in the system. As expected, Flouxetine significantly altered phototaxis and geotaxis activity with the greatest change occuring at concentrations of 100 nanograms per liter.
Take home message: Our use of antidepressants kill off that little crustaceans and generally alter the ecological interactions of organisms in the water.
Guler, Y., & Ford, A. (2010). Anti-depressants make amphipods see the light Aquatic Toxicology DOI: 10.1016/j.aquatox.2010.05.019