- Duckling in what we hope is drug-free water
Due to the high level of public interest in our previous post on drugs in drinking water, Jackie has prepared an excellent update, including resources on the environmental impacts of many common drugs….
Cheers! It’s time to regulate the drugs in that glass (or bottle) of water.
This spring, Associated Press reported that trace amounts of drugs had been found in drinking water in American cities. We also told you about an equivalent Canadian study. The resulting public concern set off a flurry of water testing.
However, no one knows what to do with the resulting data. We do not have either the science or the baseline data to detect and set maximum acceptable levels of pharmaceuticals (i.e., active ingredients and excipients) in drinking water, whether bottled or from the tap.
Are tiny levels of drugs in bottled or tap water a health risk? We just don’t know. Drug concentrations in drinking water are low – one expert says that a person would need to drink a million glasses of water to ingest the amount of ibuprofen in a single tablet. Drugs may be a much more serious environmental problem than they are a health problem: fish reproduction seems to be profoundly affected by low levels of estrogens in rivers and lakes, and veterinary diclofenac is wiping out India’s vultures.
The human toxicology of active ingredients in pharmaceuticals is relatively well established. However, that of the so-called “inactive” ingredients in medications, called excipients, is much less clear. These substances include fillers, diluents, wetting agents, solvents, emulsifiers, coatings, dyes, sweeteners, flavours, inks, preservatives and sustained-release matrices. The US Food & Drug Administration’s 2003 Guidance for Industry: Nonclinical Studies for Development of Pharmaceutical Excipients recognizes the need to develop a database that includes safety profiles for new excipients, and to establish permissible and safe limits for each under various clinical use scenarios (e.g., duration of use, route of administration).
Another area where we have limited toxicity information is nanotechnology. Nanoparticles are extremely small (a human hair is around 100,000 nanometres in diameter) and as they readily penetrate cells, targetted drug delivery – i.e., to the site of action – will be possible. We know that nanoparticles may differ significantly from their macroscale counterparts, but we don’t yet regulate their specific qualities.
Even once we understand the safety of all individual active ingredients and excipients, it will be far from obvious what environmental and human health threat they may pose when mixed together at tiny levels and consumed by people of all ages who may be taking other drugs. This is a fearsomely complex question. It will be particularly hard to answer since the soupy mixture of drugs that ends up in water varies from time to time and from place to place. It depends on many factors, including the ability of water treatment plants to remove drugs, local hydrogeology, and medication-consuming and disposing habits of citizens. And the data keeps changing, as new drugs are introduced and as we improve technologies to detect contaminants and to treat water.
The most important thing that everyone can do about this problem is to properly dispose of surplus or stale dated pharmaceuticals, including used patches – return them to your pharmacist, don’t flush them down the drain!
A second option is to buy “greener” drugs. Sweden is the first country to evaluate the environmental impact of drugs, and is developing a list of “environmentally classified medications”. This permits consumers and health professionals to take environmental harm into account when selecting medications. Many common medications are already listed and all medications marketed in Sweden are expected to be classified by 2010. Try at http://www.janusinfo.se/imcms/GetDoc?meta_id=7236 — click links on right – go in and see how your medication is classified!! and http://www.sll.se/upload/Miljö/A4.1.klassific.pdf. Please note that drugs are listed by their chemical name, not by their brand name – to look up chemical names, click here.
Dianne Saxe and Jackie Campbell