Pollution In Public Water Sources
Pollution In Public Water Sources
Gary Ginsberg (Toxicologist) gives expert video advice on: What are sources of water contamination in private wells?; Is it safer to drink water from a private well or a public source?; What contamination might affect my drinking water from public sources? and more...
What are sources of water contamination in private wells?
If you are living within a quarter mile of a gas station, of a dry cleaner, of a landfill, of some old industry, or some waste site, the contamination from those sites can last years and they can leach through soil in rain water, get down to the water table, and flow toward your home, and affect the quality of your drinking water.
Is it safer to drink water from a private well or a public source?
People on a private well may think that they've got it great, because they don't have to pay some big water company to get their water. They have their own personal supply of drinking water. The problem with that is that no-one is testing the water to see how pure or not pure it is. There can be a lot of local sources of contamination that flow underground, and your plumbing can intercept those plumes of contamination and then bring that right up into your drinking water and into your shower, in your bathroom. The fact that it is not tested can lead you down the path of months to years, because these things don't always have a taste effect on the water, they may not smell, but you can end up with years' worth of contamination without even knowing about it. The classic story is, you get people calling the health department saying, my 3 dogs all died of the same kind of cancer, other people on the street are having problems. We just tested our water and it's got high levels of benzene or it's got high levels of perchloroethylene in it. How long has this been going on? Well, if they had tested their water years before, they could have avoided that kind of exposure, and maybe some of the health risks that were occurring. Testing of your own private water supply is something the value of is much underappreciated by most people
Why is chlorine in my water supply?
To basically disinfect the water. To kill bacteria. In the bad old days of drinking water, people would get typhoid and dysentery from contaminated water supplies. We've largely eradicated those problems through the use of disinfectants that are chlorine based. That's a great public health success story. The problem is that chlorine is very reactive and it doesn't just stay as chlorine. By the way, chlorine will give the water sort of that swimming pool kind of taste or odor to it and it may also dry the skin and dry your hair when you're taking a shower, so chlorine by itself does have some properties of concern, but the biggest concern with chlorine in today's drinking water from urban supplies is that it is reactive and it breaks down into what are called trihalomethanes. Chloroform is sort of the poster-child or the prototypical chemical in that regard, and that class of compounds are known as weak carcinogens, and also, they have some reproductive health risks, so there have been some epidemiology studies linking people who drink city water to having a greater rate of miscarriage, or to having slightly elevated rates of certain cancers (bladder cancer being one in particular), and the odds ratios, or the risk levels, aren't real high, but nevertheless, epidemiology is a fairly blunt science, and just seeing any signal at all raises some concern. So, the point with city tap water and these chlorine compounds is to try to be exposed less, especially for pregnant women and young children, and you could accomplish that very simply through water filters, because these compounds are absorbed out on activated carbon, and if you put a water filter in between your tap and your drinking water glass, you could remove 98 to 99% of the chlorine and the chlorine by-products and thereby safeguard your children and yourself.
Should I be worried about water contamination from landfills and waste sites?
Those concerns are mostly for private wells because those are local sources of contamination that in a large reservoir setting, they would be so diluted out that it really wouldn't lead to much contamination; however if you are on a small public supply, that may be bringing water to your house from ground water sources, from wells, these sources can contaminate those wells; however, those public water supplies do need to test, whereas you're very vulnerable in your own personal well because nobody is doing that testing if you're not doing it; most people don't test their water supplies at all or not often enough to know; so again if you are within a quarter of a mile of these sources, you should probably be testing the drinking water when you first move into the house, and then maybe once every five years.
How do private wells and public supplies differ in contaminants?
Potential sources of contamination for private wells are if you are within a quarter mile of gas stations, dry cleaners, old factories they can be abandoned for 20 years but the contamination can live underground a long time, waste sites, landfills, and all farms and garden shops, nurseries from the pesticides. These types of contaminants can percolate through layers of soil in rain water hit the ground water and they can move down gradient towards your water supply and contaminate your local supply and if you are not testing, the public water supplies are testing. But if you are not testing at least every 5 years, then you are not finding out about those sources of contamination that could be moving towards your house. And again that's most important if you are living within a quarter mile of these kinds of contamination sources.
When should I test my drinking water if I have a private well?
If you have a private well, you should have your water tested when you move into the house. You can actually make fixing the water a condition of your purchase of their property. If you didn't think about tha and you are now living in the house, you should test your drinking water from your private well right away. That test will be good for at least a couple of years. If you are living within a quarter mile of the kinds of sources we have already talked about, then you should probably retest your water every 5 years for the suite of things like pesticides, volatile chemicals that could come from gas stations, industrial chemicals like perchloroethylene that could come from dry cleaners, and trichoethylene that could come from metalworking shops.