Saturday, July 18, 2009

More biological experiments

Oonae and others at Hopeless but Not Serious have been discussing drinking water from garden hoses vs. straight out of a tap. The discussion about the chemicals that can leach out of PVC garden hoses reminded me of a story about drugs in the water supply.

From the Journal of Environmental Health, Cocaine in surface waters: a new evidence-based tool to monitor community drug abuse:
Cocaine and its main urinary metabolite (benzoylecgonine, BE) were measured by mass spectrometry in water samples collected from the River Po and urban waste water treatment plants of medium-size Italian cities. Drug concentration, water flow rate, and population at each site were used to estimate local cocaine consumption.

We showed that cocaine and BE are present, and measurable, in surface waters of populated areas. The largest Italian river, the Po, with a five-million people catchment basin, steadily carried the equivalent of about 4 kg cocaine per day. This would imply an average daily use of at least 27 ± 5 doses (100 mg each) for every 1000 young adults, an estimate that greatly exceeds official national figures. Data from waste water treatment plants serving medium-size Italian cities were consistent with this figure.
Remember Walking My Watershed in which I learned that I am drinking treated waste water from the Hyperion Sewage Treatment Plant that serves greater LA?

Cocaine and its metabolites are not the only chemicals found in water. Drugs in the water by Peter Montague, written in 1998 explains the issue (and editorializes):
A new class of water pollutants has been discovered during the past six years.[1] Pharmaceutical drugs given to people and to domestic animals including antibiotics, hormones, strong pain killers, tranquilizers, and chemotherapy chemicals given to cancer patients are being measured in surface water, in groundwater and in drinking water at the tap. Large quantities of drugs are excreted by humans and domestic animals, and are distributed into the environment by flushing toilets and by spreading manure and sewage sludge onto and into soil.

German scientists report that anywhere from 30 to 60 drugs can be measured in a typical water sample, if anyone takes the time to do the proper analyses.[2] The concentrations of some drugs in water are comparable to the low parts-per-billion (ppb) levels at which pesticides are typically found.[1] To some people this is reassuring, but others are asking, "What is the long-term effect of drinking, day after day, a dilute cocktail of pesticides, antibiotics, pain killers, tranquilizers and chemotherapy agents?"

The first study that detected drugs in sewage took place at the Big Blue River sewage treatment plant in Kansas City in 1976. The problem was duly recorded in scientific literature and then ignored for 15 years.[3] In 1992, researchers in Germany were looking for herbicides in water when they kept noticing a chemical they couldn't identify.[4] It turned out to be clofibric acid (CA), a drug used by many people in large quantities (1 to 2 grams per day) to reduce cholesterol levels in the blood.[1] Clofibric acid is 2-(4)-chlorophenoxy-2-methyl propionic acid, a close chemical cousin of the popular weed killer 2,4-D.1 Based on that early discovery, the search for clofibric acid (CA) in the environment was stepped up.
We must limit our technological interventions into nature long before we have definitive scientific proof of harm. This is the principle of precautionary action, and if we don't adopt it, nature will get along just fine without us.

1. Hans-Rudolf Buser and Markus D. Muller, "Occurrence of the Pharmaceutical Drug Clofibric Acid and the Herbicide Mecoprop in Various Swiss Lakes and in the North Sea," Environmental Science And Technology Vol. 32, No. 1 (1998), pgs. 188-192.

2. Janet Raloff, "Drugged Waters," Science News Vol. 153, No. 12 (March 21, 1998), pgs. 187-189.

3. C. Hignite and D.L. Azarnoff, "Drugs and drug metabolites as environmental contaminants: chlorophenoxyisobutyrate and salicyclic acid in sewage water effluent," Life Sciences Vol. 20, No. 2 (January 15, 1977), pgs. 337-341.
Do read the whole thing. Any biochemists want to weigh in on this topic?

And read Free-range kid?
I don’t understand why some people complain about the bad language the kids pick up in the car. There is nothing more likely to give me a spurt of joy than hearing Eila holler out from the backseat, MOVE ALONG YOU BASTARDS, THE LIGHT IS GREEN! It’s so frolicsome. I get a kick out of just knowing how much she’s enjoying herself.

1 comment:

  1. Well, since you asked...

    I remember when the cocaine study came out. As you say, it is an interesting example of using unusual techniques to try to get a good estimate of drug use in a community. I wouldn't worry about the amount of cocaine the average person drinking that water ingests, though- it is way below active amounts.

    I also remember when some of the research about pharmaceuticals in our water came out. They make their way into our water supply not just because they are excreted, but also because for years people were told to flush unused pills down the toilet. Now we're supposed to "foul" the unused pills with dirt, ashes, or salt, seal the container, put it in two plastic bags, and then throw it away. I doubt most people go to the trouble, particularly since I had to search pretty hard to find those instructions earlier this year, when I decided that it was time to clean out my medicine cabinet.

    Another source of chemicals in our water supply is the shampoos, body washes, etc that we all use.

    I'm not sure which source would worry me most- there are probably higher levels of the chemicals from shampoos, but the drugs are designed to be bioactive at relatively low concentrations. I don't actually worry much about either, because the amounts found are generally pretty low- below the level of activity.

    If I were feeding a baby formula, though, I'd probably use filtered water. The dose of a chemical required for activity is highly dependent on body weight, and babies go through a lot of formula.

    We routinely drink filtered water anyway, because I don't like the taste of my city water when it is unfiltered. A cheap carbon filter (like the kind you put in one of those "water purification" pitchers you can buy) should trap a lot of these things- they are all organic chemicals (in that they are all carbon-based), so should adsorb pretty well on the filters.

    I had to laugh about the cussing in the car bit. I have been trying not to swear when driving, but I do still occasionally complain about the behavior of another driver. When I do, I now hear a worried little voice from the back seat: "what happen to you, Mommy?" That is Pumpkin's universal question if she senses anyone is upset or hurt. Or if you fall asleep while telling her a story at bedtime.


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