Today’s entry is about the water itself, or rather, what’s in the water. Though we in the developed world can rest assured that we can drink from the tap without much risk of waterborne infection, we encounter a different sort of baddies in our water, namely toxic chemicals. Most of us have gotten used to using Britas or other water filters to filter our drinking water, but it may be a good idea to start filtering your shower water too. Let’s start with a quick round-up of what may appear in the water.
1. Biological contaminants – This category includes bacteria, viruses, fungi, etc. Fortunately, as I said, here in the developed world we don’t generally have to worry about these guys, but there are a few really stubborn critters that can slip through the defenses, albeit in very small amounts.
2. Metals – This category primarily includes lead, though there a few others in the list as well, including arsenic and chromium. Lead is a well-known concern in older homes because of the use of lead piping prior to 1986. However, even newer homes may have some amount of lead in the water – the government allows a lead content of up to 8% in new piping. This is important to be aware of, because the lead enters the water once the water enters the house – after it’s been filtered by the public works. Thus a second filtering is necessary.
3. Volatile Organic Compounds (VOCs) – VOCs make up a large and diverse group, but most VOCs are byproducts of manufacturing or industrial farming. Examples of well-known VOCs include MBTE and formaldehye. Their effects are similarly broad, but they can impair liver function, kidney function, the nervous system, the immune system, and some have carcinogenic effects. These are filtered by the public works, and the EPA has set acceptable levels for their presence in drinking water. At acceptable levels, the compounds have been judged not to cause disease, so that’s good, but I haven’t seen studies on the effect of encountering multiple VOCs simultaneously.
4. Trihalomethanes (THMs) – THMs can enter the drinking water through a number of routes, but one of the primary ones in the US is via water purification. In many states, chlorine is used as part of water purification processes, lending the water a slightly taste, and forming THMs. One of the best known, most common of these compounds is chloroform. Many THMs are considered carcinogenic. These also have approved acceptable levels, at which point they are believed not to contribute to disease, but again, multi-exposure is poorly studied.
(For more info about your tap water, go visit the EPA’s Ground and Drinking Water Homepage.)
Long story short, there are some nasty chemicals in the water you drink and shower with. The question, however, is whether or not they actually enter your body. These compounds differ markedly in their chemical activity, so some can be absorbed through the skin, whereas others cannot – inorganic lead (the type found in lead piping), for example, is essentially inabsorbable through the skin, whereas VOCs can be absorbed transdermally, albeit at a slow rate. However, one of the major issues in showering is that these chemicals become aerosolized, which then leads to them being inhaled. Inhalation is a rapid route of absorption for many compounds, for the same anatomy that makes the lungs especially good at taking in oxygen makes them similarly effective at taking in airborne chemicals. This is especially an issue for THMs, and chloroform has been the subject of much study.
Chloroform is a proven animal carcinogen and a suspected human carcinogen, which primarily targets the kidneys and liver. As I stated previously, showering is a major contributor to chloroform concentrations of indoor air, which has been attributed to lack of ventilation when showering, as well as the heat of the water. Hot water in particular seems to not only encourage formation of THMs in chlorinated water, but it also encourages aerosolization of those compounds. Regarding the real-life health effects of chloroform resulting from showering, the jury is still out, for Canadian studies showed that the risk of cancer due to chloroform in tap water is quite low, a Spanish study showed that chloroform levels comparable to what we encounter regularly are enough to cause bladder cancer.
As stated previously, each of these compounds is at an acceptable level in the water, but the sum total of encountering multiple pollutants has not to my knowledge been assessed. Sure, the levels of chloroform in the water may be sufficiently low enough that chloroform alone won’t cause you much damage, but consider the other THMs that may be in your water. Then add the VOCs, a massive category, some compounds of which may not yet be described. Then add the air pollution you encounter on a daily basis, which if you’re an American is pretty high. Add these all together and you’ve got a pretty heavy daily load. Take my advice – cut down at least part of that load. A good shower filter (an activated carbon filter) can reduce your exposure to water-borne toxic chemicals.
That’s all for now. Tune in next week when we talk about basic hydrotherapy for improved energy, better mood and increased sense of well-being.