Water Filters

[bagpuss]

Moderator comment: Post about Water Filters moved here to new post from "Descent 310" post in Descent section: https://ukcaving.com/board/index.php?threads/descent-310.34524/

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Front cover: Mike Wise on the Second Pitch in Longwood Valley Sink, Mendip. Photo: Mark Burkey
Back cover: Tim Allen, Nick Bairstow and Dave Gledhill in the Echo Chamber, Gavel Pot. Photo: Bartek Biela

Descent Subscription – Descent Magazine

www.descentmagazine.co.uk

Descent 310 is published this week, so prepare to see some of the best writing and photography from the caving world.

In local news, we have major finds to report from the Peak District, South Wales, the North York Moors, the North Pennines, the Forest of Dean and the Yorkshire Dales.

Features:

Surprise Holiday Cave
Marcus Greatwood describes a moment of serendipity while holidaying in Spain.

Terranauts and Deep Time
Polly Judd talks to director Robert Petit about his film Underland.

Into the Echo Chamber
Tim Allen reports on another magnificent Yorkshire Dales find by the Space Miners.

The Great Geoff Yeadon
Geoff Yeadon was undoubtedly one of the greats of the caving world. Following his death at the age of 75, Geoff Crossley, Martin Grass and Mick Nunwick pay tribute to him.

Discovering Giants in Longwood Valley Sink
In this second instalment of her two-part article, Alison Moody concludes the tale of the outstanding discoveries that have recently been made in Longwood Valley Sink, on Mendip.

Decarbonising Expeditions
As part of our series of articles on sustainable caving, Becka Lawson – with a little help from Julian Todd – offers some words of wisdom on how we can cut our carbon emissions without sacrificing our time spent exploring caves.

A Motorcycle Diary
Peter Ryder recalls a cave-themed road trip through the Pyrenees.

Families, Ducks and Frogs
Jen Sloan reports on a caving trip for six young families to the Yorkshire Dales.

LifeStraw Peak Series Collapsible Squeeze Bottle
Chris Scaife and Carolina Smith review a bottle with its own built-in filtration system.

Curious about Life Straw, if it's being used in caves, but doesn't filter out metals, isn't there a risk? I know there's also been stories in the media of people getting sick when using these type of products, I used a filter bottle last year on Dartmoor where the water was fairly low and prob not the best and became ill, can't be sure if it was down to the water though.

Walkers sick after drinking river water on the West Highland Way

Two walkers on the long distance route fell severely ill after drinking from a burn despite using filters.

www.bbc.co.uk

 

[Cantclimbtom]

Curious about Life Straw, if it's being used in caves, but doesn't filter out metals, isn't there a risk? I know there's also been stories in the media of people getting sick when using these type of products, I used a filter bottle last year on Dartmoor where the water was fairly low and prob not the best and became ill, can't be sure if it was down to the water though.

Walkers sick after drinking river water on the West Highland Way

Two walkers on the long distance route fell severely ill after drinking from a burn despite using filters.

www.bbc.co.uk

As far as I know they don't remove viruses (https://eu.lifestraw.com/pages/our-technology) , so if you're drinking water where sheep or other livestock live, then a straw might not be safe. Life Straw recommended for back country USA (away from livestock) but not sure if advisable for somewhere like Wales, Scotland, Yorkshire, etc where sheep will live. Compare to correct use of "purification" tablets.

Will have to read Descent when it arrives and see if they have warnings/caveats about any limitations

 

[Cantclimbtom]

The Science Behind LifeStraw Filtration

A 0.2-micron pore is 350 times smaller than a human hair and small enough to block bacteria, parasites, and microplastics. Learn how LifeStraw's hollow fiber membrane technology works, what it removes, and when you need a 0.02-micron purifier instead.

lifestraw.com

"...Viruses are smaller than bacteria and parasites, often measuring between 0.02 and 0.3 microns. Because of their size, additional purification methods may be recommended in areas where viral contamination is a concern..."

So IMHO... in areas with sheep, cattle or human waste you should treat with purification tablet or boiling instead or as well as Life Straw

 

[Carolina Smith]

The Science Behind LifeStraw Filtration

A 0.2-micron pore is 350 times smaller than a human hair and small enough to block bacteria, parasites, and microplastics. Learn how LifeStraw's hollow fiber membrane technology works, what it removes, and when you need a 0.02-micron purifier instead.

lifestraw.com

"...Viruses are smaller than bacteria and parasites, often measuring between 0.02 and 0.3 microns. Because of their size, additional purification methods may be recommended in areas where viral contamination is a concern..."

So IMHO... in areas with sheep, cattle or human waste you should treat with purification tablet or boiling instead or as well as Life Straw

From what we read when preparing for the review, LifeStraw does remove heavy metals, lead included: https://help.lifestraw.com/en-US/articles/what-lifestraw-removes-393249
I don't think there are any water filters that remove viruses, so in areas were the water could be contaminated, as you say, the filter can be used in combination with purification tablets.

 

[bagpuss]

From what we read when preparing for the review, LifeStraw does remove heavy metals, lead included: https://help.lifestraw.com/en-US/articles/what-lifestraw-removes-393249
I don't think there are any water filters that remove viruses, so in areas were the water could be contaminated, as you say, the filter can be used in combination with purification tablets.

Depends on the specific filter according to the link shared, so could end up with one that doesn't filter metals..

'The Original LifeStraw (Personal Water Filter Straw): This classic hiking tool uses a hollow fiber membrane designed only to remove bacteria, parasites, and microplastics. It does not filter heavy metals like lead. '

 

[tim.rose2]

I've been using a Water to Go filter bottle when out walking for several years now. Never been ill, but I do only use it with water that looks drinkable in the first place. That said, there's plenty of sheep piss in the 'clean looking' streams that run off most UK hills. I've also used it kayaking in freshwater lakes / lochs in the UK, simply drinking the pond water when I got thirsty. Their filters do claim to remove viruses / heavy metals etc. Never used it underground - I've always taken a bottle of water / done without / drank from underground sources which others seemed to have previously with out getting the shits.

 

[andrewmcleod]

Combining a filter and a UV sterilizer should work very well - the filter gets the 'big' stuff and the UV gets the 'small' stuff (do the filtering first).
Boiling and chemical treatment are probably still reliable.
Neither of the above (nor any other practical portable treatment) will deal with non-biological issues such as heavy metal contamination.

 

[nearlywhite]

Combining a filter and a UV sterilizer should work very well - the filter gets the 'big' stuff and the UV gets the 'small' stuff (do the filtering first).
Boiling and chemical treatment are probably still reliable.
Neither of the above (nor any other practical portable treatment) will deal with non-biological issues such as heavy metal contamination.

You'd be doing well for heavy metal contamination to cause significant health issues from occasional drinking of wild streams - pre-existing health issues/heavy metal loading from routine usage i.e. dodgy pipes at home.

I think not drinking water from lead mines is probably a good idea.

The bigger risk generally is viruses and parasites.

As with all risk, you can't eliminate it. If you reduce particulate matter you will reduce your load and exposure to most hazards in drinking water and you might find that risk reduction to be more than adequate. You might find if you are more vulnerable that sterilising alongside is a very good idea.

I've used their products in the past and they've been fine. I've also drunk a lot of unfiltered water in the 'wilderness' and have largely been fine too - but I can see situations where I'd use a filter.

Not drinking stagnant water, checking streams for biological debris and 'small and often' can do a lot of work, and a filter can add to that.

 

[spelfish]

It's worth taking extra precautions if you're taking omeprazole or other proton pump inhibitors as you'll be more vulnerable to water-borne infections. Boiling or chlorination will both work but they're both time-consuming. In all cases, the water should be clear - if it's not, let it settle or filter through a cloth to get rid of the worst lumps.

Boiling. The WHO recommends bringing water to a rolling boil for one minute at sea level, then allowing it to cool. This should kill almost all viruses, bacteria and parasites. At higher altitudes where water boils at a lower temperature, you'll need to boil for longer - 3 minutes at 1000 metres, for example. At alpine caving altitudes, it should be longer still.
You'll be left with rather flat-tasting water when it cools, but if you shake it up a lot, the taste will improve. Or you can add a pinch of salt.

Chlorination. This is also effective and should also be performed on clear water. However, it takes quite a long time to work - hepatitis A virus will survive for 15-30 minutes, bacteria may survive longer and some parasites (eg cryptosporidium) can survive for days (which is one reason it's such a pernicious organism when it gets into the public water supply). The best strategy is probably to wait for 30-60 minutes after chlorination, then drink through a filter straw in case there are surviving bacteria or parasites. If the straw contains activated charcoal, it will reduce the swimming pool taste (but check it's also capable of filtering out bacteria).

 

[alanw]

Up at Gaping Gill, for personal consumption, after filtering, I use Oasis Water Purification Tablets, containing Sodium dichloroisocyanurate (troclosenum natricum or NaDCC) at the WHO recommended concentration. I use beck water when it's clear, and otherwise try to catch rainwater.

It seems NaDCC is effective against viruses, bacteria and some parasites, but not against oocysts (Toxoplasma and cryptosporidium).

A few links:

Disinfection efficacy of sodium dichloroisocyanurate (NADCC) against common food-borne intestinal protozoa - PubMed

The present study was conducted to investigate the efficacy of sodium dichloroisocyanurate (NaDCC) on the infective stages of common food-borne intestinal protozoa; Entamoeba histolytica (E. histolytica), Giardia lamblia (G. lamblia), Cryptosporidium, Cyclospora and Microsporidia; beside its...

pubmed.ncbi.nlm.nih.gov

https://www.akvopedia.org/wiki/Chlorine_(NaDCC)

https://www.who.int/docs/default-source/wash-documents/wash-chemicals/sodium-dichloroisocyanurate-chemical-fact-sheet.pdf?sfvrsn=9933313f_4

Sodium dichloroisocyanurate

www.who.int

 

[Lankyman]

Is iodine still used? About 30 years ago we took little bottles with us on a year-long trip abroad and used them to treat dodgy water (5 drops to a litre IIRC). Apart from constipation in Bombay and spewing my guts up (dodgy rice in Nepal) we seemed to emerge unscathed.

 

[mikem]

Various older BEC members - "I've been drinking water from st Cuthbert's for years and it's had no effect"

Having said that, environmental health tried to stop shipham residents from eating vegetables they'd grown due to the levels of cadmium, until they pointed out that they had a higher life expectancy than the national average...

 

[Max bowen]

I've been using a Water to Go filter bottle when out walking for several years now. Never been ill, but I do only use it with water that looks drinkable in the first place. That said, there's plenty of sheep piss in the 'clean looking' streams that run off most UK hills. I've also used it kayaking in freshwater lakes / lochs in the UK, simply drinking the pond water when I got thirsty. Their filters do claim to remove viruses / heavy metals etc. Never used it underground - I've always taken a bottle of water / done without / drank from underground sources which others seemed to have previously with out getting the shits.

I’ve used a water 2 go bottle for a while now and purposefully drank absolutely disgusting water when I got it to try it out and I’ve been fine haha

 

[paul]

An interesting and informative YouTube video by Stephen J Reid about water filters and viruses: