One of the triumphs of 19th and 20th century public health was the provision of piped water into cities and towns. With the use of modern methods of disinfection (primarily chlorination) water as a source of mass distributed poisons rapidly receded, and with it the preponderance of infectious diseases that were the scourge of urban life. Urban water supplied were an efficient means to provide a healthy required substance, water, to the whole population and once. But of course it is also an efficient means to distribute unhealthy stuff -- not just microbes but chemicals. I've worked on the health of effects of chemicals in drinking water for many years and I wish I could say that the chemicals that occupied much of my professional attention -- solvents, organic contaminants, by-products of the disinfection process -- were off the radar screen. They aren't. They are still around and causing trouble. But now the radar screen has gotten more crowded, with blips representing chemicals that mimic hormones and more and more often, pharmaceuticals. A paper just published in the journal Environmental Science & Techonology (ES&T) is quite surprising. Surveying 29 water supplies serving more than 28 million people, the most frequently found chemicals were unregulated organics, all pharmaeuticals except for one regulated pesticide.
Here's the top 11 (via New Scientist):
- Atenolol, a beta-blocker used to treat cardiovascular disease
- Atrazine, an organic herbicide banned in the European Union, but still used in the US, which has been implicated in the decline of fish stocks and in changes in animal behaviour
- Carbamazepine, a mood-stabilising drug used to treat bipolar disorder, amongst other things
- Estrone, an oestrogen hormone secreted by the ovaries and blamed for causing gender-bending changes in fish
- Gemfibrozil, an anti-cholesterol drug
- Meprobamate, a tranquiliser widely used in psychiatric treatment
- Naproxen, a painkiller and anti-inflammatory linked to increases in asthma incidence
- Phenytoin, an anticonvulsant that has been used to treat epilepsy
- Sulfamethoxazole, an antibiotic used against the Streptococcus bacteria, which is responsible for tonsillitis and other diseases
- TCEP, a reducing agent used in molecular biology
- Trimethoprim, another antibiotic
These 11 were found in over half the source waters (at the intake to the treatment plant) but only three of them (atrazine, meprobamate, and phenytoin) made it through treatment plants into the water that comes out of our faucets. Moreover they were found in fairly small quantities (nanograms/l, i.e., parts per billion). Whether these levels are of public health concern as drinking water contaminants is a matter of debate, but they are plausibly of environmental concern. They got there by first passing through wastewater treatment plants into the environment and then into a water source and our drinking water. Thus they exposed many other organisms upstream of our kitchens and bathrooms and at much higher levels.
An interesting (and surprising) finding is that the 3 treatment plants using reservoirs with no input from wastewater and no recreational use (swimming and boating on the reservoir or lake) had the lowest number of the 51 assayed chemicals in their source waters. Four reservoirs had no direct input of wastewater but allowed recreational water use. In these source waters the number of individual chemicals was similar to treatment plants that drew water from source waters with direct input from wastewater sources.
Another surprise. Prescription information is a poor guide:
The most prescribed pharmaceutical in 2006 and 2007 in the U.S. (27), atorvastatin [Lipitor], was detected in only three source waters and was not detected in any finished or distribution waters. Conversely, the most frequently detected prescription pharmaceuticals (carbamazepine, gemfibrozil, meprobamate, sulfamethoxazole, and trimethoprim) were not included in the top 200 prescribed pharmaceuticals for 2006 or 2007. Only atenolol (ranked no. 99 in 2007) and phenytoin (ranked no. 128 in 2006 and no. 151 in 2007) were frequently detected in source water. Thus, prescription information alone is a poor proxy for source water occurrence because it does not take into account the dosage, pharmacokinetics, removal during wastewater treatment, or environmental fate. (Bennotti et al., ES&T)
It turns out that some chemicals are much more affected by oxidation by disinfectants like ozone or chlorine (less so by chloramines). Ozone was, overall, the best oxidant of pharmaceuticals.
The good news is that this may cut out one step in taking your pills with a glass of water. You may just need the glass of water.
I agree that it's pretty early on to tell if these levels of pharmaceuticals are contributing to negative health outcomes in humans. It's definitely something to keep in mind though.
The proper disposal of drugs involves crushing up pills in a plastic bag, mixing the powder with some material that addicts won't touch (used coffee grounds), and throwing them away. I believe its roughly the same for liquid medications, the idea is to mix them with something near inedible and then throw them in the garbage.
Perhaps to save the environment, you could throw away your drugs in that old jar of peanut butter you won't eat, because ziploc bags require petroleum to manufacture, and to buy them just for the purpose of disposing of drugs is arguably a waste of resources. Recycle, reduce, reuse.
Evan -- I could be mistaken, but the last time a study like this came out, I got the impression it wasn't so much the drugs people flushed whole, as the drugs they excreted. After all, lots of drugs aren't fully metabolized by the body.
In a related matter, it's probably a bad idea to flush cat poop; toxoplasmosis kills sea otters.
This is actually reassuring to me that my tap water is pretty safe to drink. I think that the bigger issue is environmental damage before the water is treated.
Caia: Yes, the main cause of the problem could very well be from excreted drugs. I think flushing unused or expired drugs can also be a large contributor.
I'm aware that there is probably a larger amount of unmetabolized drugs excreted by all drug users in the US than there is flushed directly, since most people on the mentioned medications don't just throw away entire bottles, they seem to be fairly important medications and they're probably sticking to them.
My concern is, out of all the people in the US that have excess or unwanted prescription drugs, what percentage of them do we think are aware of the proper way to dispose of them? I'd imagine the toilet is the method of disposal in, oh, say 90% of those homes (though I have no evidence to support that). It's just not something people hear about in their everyday lives or Google. Not to mention if you're "independent" enough to punt on your physician's prescription, you probably aren't the sort to search out how to best get rid of the drugs in an environmental context.
Maybe the inserts with their microscopic type should include information on the proper disposal method of the drug. I actually read those things, so maybe other folks do as well.
When my father died a few years back, I was left with hundreds of prescription drug bottles filled with lots of very powerful painkillers and heart drugs. I called several pharmacies and hospitals in the Palm Springs, CA area and NONE of them could tell me what to do with them.
Nearly all of them said to flush the medication down the toilet! I didn't do that since his residence was on a septic system and the drugs would have permeated into the water system used by his mobile home park.
That park is home to hundreds of seniors, many who take the same drugs as my dad did and who are going to die. Their heirs will call around and get the same answers I did, flush the stuff. Most of them will. If the places that sell and distribute these drugs don't know what to do with them when they are no longer needed, how can the average person?
I finally found a pharmacy in my own state (Indiana) who took them and had them destroyed.
When my father passed away, we also had a number of bottles of leftover pharmaceuticals. My pharmacist recommended that we dissolve them in a quart of hot water and then pour the water into a pan of kitty litter, which we then put out with the garbage. It ended up in the landfill, just as it would have if we had thrown the pills in the trash, so except for making it difficult for someone going through the trash to grab on to some pills, I'm not sure of the point. The drugs that were left from his end-of-life stay at the nursing home were individually packed in blister packs, and were able to be diverted for use by other patients.
MoM: I think the main points with that method are to keep the drugs out of the hands of people desperate enough to go through the garbage to find pills, and to keep them from being directly injected into our water supply.
If the drugs wind up in a landfill, that's a pretty safe distance from any water source, at least in most places in the US(!). Also, most(!) landfills are sealed underground with plastic tarp and concrete to prevent seepage and the probability that drugs in a landfill will seep into sources of drinking water is reduced. While it's possible that animals who have made a habitat out of landfills could consume the drugs, it's fairly unlikely given all the more appealing food stuffs present in a landfill, especially given the drugs are dissolved in kitty litter, which can easily be displaced across the landfill.
This isn't to say that it's entirely impossible for the drugs to reach drinking water from a landfill, but the harmful effects to the environment and our water quality are almost certainly reduced.
Evan: I agree, except with the part about the plastic liner. Too many places still rely on a layer of native clay. But you're correct, absorbing the dissolved drugs into what is basically dried clay would certainly help tie it up and would definitely render it unconsumable.