Health and weight effects of medicine metabolites in water?
May 18, 2013 12:12 PM   Subscribe

I'm aware that there are metabolites of the many various medicines that people take in the water supply in many US cities and towns. What are the health effects of this (known or theoretical)? Has drug residue/metabolites ever been linked to weight gain in humans? How can it be removed from the water (is reverse osmosis the only way)?
posted by mintchip to Health & Fitness (5 answers total) 2 users marked this as a favorite
Yes, some type of reverse osmosis is the only way I've seen/heard of that really works 100% for sure. I'd imagine some big multi-stage commercial filtration systems would take a decent swing at removing it too, but I haven't seen anything directly relating to this that affirmatively said that.

I will note that there's a LOT of woo stuff out there about water filtration. I actually groaned when I saw the question because of how much crap you'll have to sift through, and how much of it ties in to weird woo about medication in the water supply, the evils of flouride, and various other stuff. A lot of the people with descent testing info seem to be affiliated with or just believing in some camp of woo like that.
posted by emptythought at 12:23 PM on May 18, 2013 [2 favorites]

The number of molecules of medication X that is in the water that comes out of your tap is going to be extraordinarily low. For it to cause any symptoms in a human drinking it from tap water, it would have to be an extraordinarily potent medication, so much so that the people taking it would probably die instantly.
posted by gjc at 12:38 PM on May 18, 2013 [2 favorites]

One of the main health effects I have noticed regarding this issue is that worrying about it causes people very great stress. Whether or not it's a valid concern becomes secondary to the efforts expended to avoid all potential waterborne contaminants. I'm not trying to minimize your concerns or handwave them away, this is just something I've observed firsthand with two people in my life who became somewhat obsessed with the matter.
posted by elizardbits at 12:54 PM on May 18, 2013 [2 favorites]

Although this paper is from 2009, it will give you a pretty good understanding of what's in the water, how much is there, how much gets removed via traditional methods, and a few new ways to treat the water going forward: Fate and removal of pharmaceuticals and illicit drugs in conventional and membrane bioreactor wastewater treatment plants and by riverbank filtration, by Petrovic & al.

Your questions about health effects are a little bit tougher to answer. None of the contaminants listed in the paper come within three or even four orders of magnitude of their minimum effective doses. Later, I'll talk about whether or not this is a perfect measure, but for now let's just assume it is and try to work through an example.

For instance, atenolol is a ß-blocker that may cause weight gain and is listed in the Petrovic paper as being measured at concentrations between 0.0004 and 0.001 milligrams per liter. The NOAEL (no observed adverse effect level) of atenolol is 0.8mg/kg/day, or 64mg for an 80kg human, and the usual prescribed dose is between 50 and 100mg per day.

Assuming you drink 3L of water every day and we use the highest reported concentration of 0.001mg/L, in one year you would ingest about 1.095mg, about 80% of the single instance ED50 for our theoretical 80kg human-sized dog, or about 2% of the commonly-prescribed daily human dosage. Keep in mind, this would be your intake over one year, and doesn't even begin to account for the fact that your body clears 95% of however much atenolol you ingest within 24 hours (using atenolol's 6-7 hour half-life as a benchmark). For comparison, a person taking 50mg of atenolol every day for a year would ingest sixteen thousand times more atenolol than you would by drinking from the tap.

And that's important, in 2011, Bull & al. wrote a paper on how to best assess health hazards from drugs in drinking water. Appropriately, it's titled "Therapeutic dose as the point of departure in assessing potential health hazards from drugs in drinking water and recycled municipal wastewater." The paper is fascinating and approaches the same problem by working with Margins of Exposure and Uncertainty Factors. The paper concludes that a factor of 1000 is probably an adequate safety margin for most drugs (but that for carcinogens it may be important to increase that by another couple orders of magnitude).

I encourage you to run similar calculations for other drugs that might concern you. Chock full as we are with Shakespeare's atoms, it is sometimes more valuable to think not about whether we've been exposed to a given substance, but rather how much we've been exposed to. New research seems to be focusing on the combined exposure of all drugs within a class (all ß-blockers, for instance), and it may be that someday there will be convincing evidence of measurable health effects on a population level. That evidence does not exist today, and I doubt that the effects will be clinically-relevant on the individual level., but what do I know IANAD IMO BBQ ROFL ALL MODELS 18 OR OVER.
posted by The White Hat at 4:12 PM on May 18, 2013 [10 favorites]

The White Hat covered it pretty well: the effects of these low concentration compounds in drinking water is probably only significant in long-term population-level studies. It is unlikely that all of the effects that these contaminants can be realistically be discovered. Reverse osmosis is probably the only reliable way to remove them but on a slight tangent there are foods you can eat in order to increase physiological detoxification processes which may attenuate the the effects of any ingested drugs such as broccoli.
posted by brocklee at 12:10 AM on May 21, 2013

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