From the FEB/MAR issue of Seed:
Credit: Jimmy Turrell
Though surveys have detected over 80 pharmacological compounds in US waterways--including painkillers, blood-pressure and heart medications, birth control pills, anti-fungal agents, Prozac, Viagra, anti-seizure medications, steroids, nicotine byproducts and antibiotics—whether this actually means anything is a mystery. "Little is definitively known," says the EPA, "regarding any real hazard posed by trace concentrations."
That's partially a function of testing equipment; it wasn't until the late 1990s that technology became readily available to detect drugs at subtherapeutic levels. "It still takes specialized equipment," said Dana Kolpin, a US Geological Survey expert on emerging contaminants. "But in reality [these compounds] have probably been out there as long as we've been using pharmaceuticals."
The FDA ascertains effects of therapeutic doses in people over a brief window, not what tiny quantities do over a lifetime. And some drugs may become more concentrated moving up the food chain. Even if no particular drug is present in a high enough concentration to have adverse effects by itself, the interaction between several could add up to affect species in unforeseen ways.
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What is known is that drugs are affecting ecosystems where they're introduced: Hormones in the water skew the sex ratios of fish and amphibians. Other pharmaceuticals can affect the physiology of plants and animals, and antibiotics alter the natural balances of microbial flora and fauna in various ecosystems. Perhaps of greatest concern, notes Kolpin, is that low levels of antibiotics in the environment may contribute to increasing antibiotic resistance among bacteria. Longitudinal data has yet to trickle in, so the jury is still out on whether the trace amounts present are enough to have deleterious effects.
Gradually, scientists hope to learn more about how drugs move through the environment and what their effects are. Because, as the old saying goes, what you don't know could make you sterile. Or something like that.