How Anxious Humans are Making Fish Fearless

Studies are showing that low levels of antianxiety medication, such as Xanax or Valium, are entering our water systems after leaving the human body and causing behavioral changes in fish populations. A recent study, exposing European perch to low levels of oxazepam—an antianxiety compound the human body excretes while on antianxiety medication—highlights the disquieting effect that human drugs can have on the natural hardwire settings of other life forms.

The fish exposed in this study exhibited higher levels of aggression and consumed prey at faster rates. They were also more likely to venture into dangerous situations and risk predator confrontations. These behavioral changes suggest broader implications for the natural processes supporting aquatic life. Greater predation, for example, could lead to fluctuations in predator-prey ratios and population size.  The unintended consequences of low-level drug exposure on aquatic systems and other exposed life forms remains uncertain, but the study calls attention to the disruptive capability that prescription drugs can have on the balance and stability of environmental life systems and cycles.

Photo credit:  Luc Viatour
Photo credit: Luc Viatour

Anti-anxiety meds are not the only prescription drugs entering water systems. A 2002 U.S. Geological Survey sampling of 139 U.S. streams in 30 states found 80 percent contained prescription and non-prescription drugs, steroids, and reproductive hormones. Perhaps of greatest concern are drugs administered during chemotherapy, as these substances can be highly toxic. Chemotherapeutic drugs are known to be genotoxic—which means that they are targeted to attack DNA—and many are also cytotoxic, making them highly lethal to living cells. According to a report by the Occupational Safety and Health Administration, “[s]ome of these [chemotherapy] drugs have been known to cause cancer, reproductive and developmental problems, allergic reactions and other adverse effects that can be irreversible even after low-level exposure.” Many of these drugs continue to remain active after they pass through the human body, which is why regulation of this waste is critical.

At present, regulation is lacking. The EPA and FDA remain at odds on how to keep pharmaceutical drugs, particularly chemo drugs, from contaminating the environment. The EPA suggests that the FDA should issue standards and guidelines for handling the waste because these chemicals are regulated as drugs. The FDA counters that the EPA is in fact responsible because the chemicals enter the natural environment as waste.

Pharmaceutical contamination in public water supplies is a source of increasing concern and public health study. Individuals taking prescription medications are flushing compounds into the environment that are often laced with behavior-altering compounds that can have a noticeable impact on smaller and more susceptible life forms. The dearth of information surrounding the cumulative, synergistic, and latent effects of low-dose exposure on living organisms suggests that these contaminants should be  regulated and monitored. Until more information about the effects of exposure is available, the government and pharmaceutical industry would be wise to exercise greater deference to the precautionary principle. This might include  measures to ensure public water supplies are properly treated to remove pharmaceutical compounds and more sophisticated disposal methods for human waste from patients undergoing chemotherapy.

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