UKC

I bought one of these water filters recently, with the aim of using it to top-up on longer rides in the UK http://bit.ly/1KaHwlg My hesitancy though, is figuring out how remote a water source is needed to be relatively safe from pesticides and other man-made chemicals. Anyone else use one? I ride in the Midlands (Leicestershire, Derbyshire, Lincolnshire, Northamptonshire, etc), and often come across small streams and my concern is whether the levels of agricultural chemicals is too much of a risk?

In reply to FrankBooth:

No helpful answer but very interested as well. Currently reviewing a filter and wondered exactly the same.

In reply to TobyA:
The TravelTap from http://www.drinksafe-systems.co.uk/products.php claims to filter out all nasty chemicals.

In reply to FrankBooth:

Try it. If you wake up the next day 6 ft 8 you know it had something in it!

I'd also be interested in an answer.

In reply to FrankBooth:

UKC Dan just checked for me with the UK distributors of the MSR filter I'm trying. It's a pretty top level (expensive!) filter designed for the US military and very impressive in many ways BUT it won't remove chemicals such as fertilizers and the like. I wonder if any chemists here can explain why, but I suspect that it might be that those sort of chemicals once in solution are smaller than the viruses, bacteria etc that filters do get? My GCSE chemistry and biology doesn't help much here I'm afraid

In reply to TobyA:


The chemicals in fertilisers are orders of magnitude smaller than viruses - think of it this way viruses (much smaller than bacteria on the whole) are made out of thousands of large carbon chains each with hundreds of carbon atoms in them, whereas most bog standard water soluble chemicals would be in the order of 10s or maybe 100 carbon atoms. So a filter is not going to physically remove chemicals by sieving the water (essentially what most filters do).
What will remove some chemicals is sticking them to a filter, so-called 'activated carbon' can do that to some extent, which is why it is found in many filters but it won't be able to form bonds with all chemicals you might encounter in polluted lowland water supplies, and I imagine it would get saturated before too long. Thus why MSR can't guarantee nor even recommend their filters for that purpose.

In reply to munro90:

Thanks munro90 - I figured it had to be along those line but getting an idea of order of magnitude of size between a virus and chemical held in solution in water is really helpful. Thanks.

In reply to FrankBooth:

Generally I would think if it's farm land or there is farm land (crops) upstream then it may well have fertilizers/pesticides in it. I would think anywhere with grazing land hills etc with sheep etc roaming free would be fertilizer/pesticde free. Seasonality will add a lot of variation too depending on how often crops and land are treated.

In reply to balmybaldwin:

that's a good point - an obvious indicator when you think about it!

I assume that most farmland will release contaminants to some degree, so part of my curiosity is around how big or small (or fast or slow running) a stream needs to be to consider a safe source?

In reply to FrankBooth:

I live in Lincolnshire and i'm not sure i would be happy taking water from any of the streams around here due to the agriculture.
As a cyclist also, and having done lots of miles one trick you can use is to visit the numerous churchyards and graveyards on your travels. These very often have a tap for people to use whilst tending graves or gardening. Many times i've filled up my bottles from these sources.

In reply to LG-Mark:

good point, likewise there are many long established paths that have similar facilities - they just sometimes take a bit of looking for e.g. the south downs way has a water tap every 5-10 miles or so.

Another place to look especially on farmland is water troughs for animals - farmers tend not to poison their livestock - obviously be careful and polite if challenged but I remember the days when it was normal to knock on the door of a house and ask for a top up of water bottles