Minnesota—a relatively unpolluted state if you don’t count the iron mine tailings and farm run-off—today released Pharmaceutical and Endocrine Active Chemicals in Minnesota Lakes. This study of 50 lakes looked at the presence of 125 chemicals, including DEET (found in 76 percent of the lakes, making it the most frequently discovered chemical), bisphenol A (second most frequent, in more than 40 percent), and cocaine (third, in roughly a third of the lakes studied). Also, less frequently, the steroid androstenedione (which can occur naturally), the antidepressant amitriptyline, and carbadox (a veterinary antibiotic).
The first image that comes to mind is jacked-up fishermen, swathed in DEET, popping antidepressants and relieving themselves over the gunnels. This may not be accurate, but the study’s authors admit they have no good explanation for how these substances are getting into the water.
Consider carbadox. In the U.S., it’s approved only for use in swine because it’s classified as a genotoxic carcinogen; Canada and the EU have banned it altogether. And yet it appeared in 28 percent of the lakes studied. “The detection of this antibiotic in lakes that are not associated with areas of swine or any livestock production is perplexing. Whether this indicates that carbadox is being used for off-label purposes or if it is transported to lakes through unknown mechanisms is not clear.”
The cocaine is equal puzzling. Previous studies have found the drug with some frequency in lakes and rivers tainted by waste water treatment plants. “However,” the authors note, “no other studies to our knowledge have demonstrated that cocaine is present in ambient lake water not associated with a WWTP effluent source. The detection of cocaine in surface water is also consistent with the reported volume of cocaine that is currently used in the U.S., estimated at 157 tons per annum (UN drug report, 2011) – an amount that is comparable to the annual production of many commonly prescribed pharmaceutical compounds.”
The amounts of each chemical are measured in nanograms per liter (ng/L), or parts per trillion (ppt). This is so minute, it barely qualifies as a trace. One PPT is comparable to a single drop in a swimming pool that is 43 feet deep and as long and wide as a football field. The maximum DEET concentration was 125 ppt; the maximum carbadox concentration was 121 ppt. Max cocaine concentration was 5.3.
The presence and frequency of the chemicals is intriguing, particularly given that several of the lakes were located in the (we have assumed) pristine Boundary Waters Canoe Area Wilderness.
If you don’t know what to make of this, you are not alone. Thanks to the emergence of amazingly precise analytical tools, we can know that we and our children are exposed to infinitesimal amounts of chemicals, the health and safety impacts of which are unknown and likely to stay that way. As many as 80,000 chemicals are in use “but only 91 are regulated by the Federal Clean Water Act.” There are indications, though, that even at these low levels chemicals are affecting fish, mice and other species.
The FDA is moving on some of the tens of thousands of unregulated chemicals. The agency is slated to begin a review of triclosan, the germ-killing ingredient found in an estimated 75 percent of antibacterial liquid soaps and body washes,” which is suspected of altering thyroid hormones and reproductive hormones.
Meanwhile, triclosan contamination is moving quickly through the environment. The Minnesota study found it in 14 percent of the lakes, with a maximum concentration of 11.8 ppt. This is somewhat surprising, since the chemical “was not detected in an earlier investigation of Minnesota lakes.”
