Anyone have some thoughts, opinions, or some well researched information about the risks of toxic chemicals in natural water sources?
Water filters for backpacking don't remove chemical toxins, only the larger sized threats like bacteria and cysts. Having a water filter doesn't mean it's perfectly safe to use. Up till now, for some reason, I figured that if I had a water filter that removed bacteria I could use it to drink whenever I needed to get more water. BPL philosophy gets you thinking about avoiding the weight of carrying clean drinking water. But recently I've started asking all kinds of questions:
Should I only drink the water I carry from tested municipal sources?
How high are the risks of drinking water that is 'unsafe'?
What 'best' practices should backpackers follow to prevent drinking from chemically polluted water sources?
How remote from civilization should a water source be for it to be considered 'safe' from being contaminated by toxic chemicals?
I don't often see discussion on backpacking forums about the risks of toxic chemicals in water sources, let alone the FAQ guide. For the most part, it seems that most backpackers only appear concerned with eliminating the risks from bacteria and cysts (and sometime about BPA in bottles). Often people support claims with questionable proof, claiming "I've not gotten sick yet".
I was curious about the possibility that carcinogenic chemicals might be in the water sources where I was planning to backpack long distance. So I started looking into it more and educate myself. Locally there are trails that run several 100 miles along rivers, as well as near to urban environments. At first I had thought I might be able to use my 0.2 micron filter system so that I didn't have to carry the heavy weight of too much water on me. I've seen videos and read about hikers who only carry a liter or two, planning to filter more water at the next source. I figured that this is what I should do as well. I've also read about AT through hikers who are drinking from water sources only an hour from cities like D.C.
I contacted local and regional government environmental agencies to inquire about this. I wanted to have a better idea just how polluted the local river water is. They only said there is "a level of unknown risk", and they advise to only drink from treated and tested municipal water sources. As far as they know, the rivers and lakes along the trails were not regularly tested for any specific industrial chemicals. They said they just don't have enough manpower and funding. They said that water sources are 'recovering' from over a hundred years of heavy industrial abuse. Even if they are tested a few times a year, it's possible that by the time I'm out there filtering drinking water from the river someone can have dumped illegal waste into the water.
There are articles in the news often about pollution. Pipelines are suddenly discovered to be leaking thousands of barrels of carcinogenic gas and oil into the groundwater. It recently happened in a local provincial park, and the pipeline company estimates that 90,000 liters of gasoline leaked into the soil. The area is surrounded by farmland as well. Much of agriculture uses pesticides and fertilizers and these toxins run off and concentrate into the streams.
Then what if I carry enough water with me while I'm near cities? How remote from the city is considered 'safe' to filter water from a stream? Over a hundred miles north of the Minnesota border in the Ontario wilderness there was mercury poisoning of inhabitants and contamination of river water because of the paper and pulp industry back in the '70s. And apparently mercury doesn't just break down and disappear. Mercury concentrations in 1975 ranged as high as 5.98 parts per million. Guidelines for the safe consumption of fish is 0.2 ppm. A 1999 report from the government of Canada revealed 17,671 indigenous people had blood-mercury levels ranging from 20-699 ppb (parts per billion).
In other remote locations the mining operations pollute large amounts of fresh water producing an effluent of acids, sulphides, toxic heavy metals and more. According to the EPA the Appalachian valley waterways are affected by pollution from mining. And what about fracking? (If it sounds obscene, that's because it is.) Across the continent, oil and gas wells have been injecting chemicals into the ground and contaminating ground water. The industry claims it doesn't pollute, and the EPA studies have found benzene in ground water, which is known to cause cancer and other health problems. (An interesting article: http://www.npr.org/2011/12/08/143386908/epa-connects-fracking-with-water-contamination)
Here's an interesting list by the EPA of Drinking Water Contaminants ( http://water.epa.gov/drink/contaminants/index.cfm). For many it shows a goal level of zero parts per million for guidelines of what is considered 'safe'.
So aside from educating yourself, and only drinking from municipal water sources what should you do?
After hours of 'looking into it', I'm still facing a level of unknown risk if I drinking filtered water from a river when backpacking light. Just how high is that risk? Who knows? Anyone?
Your thoughts, comments, and questions on this topic are always appreciated.