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arsenic and other pollutants in Lermer-Chapala aquifer

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According to an article in today's Mexico News Daily (mexiconewsdaily.com), in 2001 arsenic and fluoride in the Lermer-Chapala aquifer were in "concentrations 10 times greater than what are deemed tolerable limits for human consumption," and now "concentrations [of pollutants] have doubled in some places, and arsenic--a carcinogen--has been recorded at 20 and up to 30 times over its acceptable levels." Does anyone have information about the levels of arsenic and other pollutants in tap water at Lakeside?

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I don't believe that tap water in Lakeside comes from the lake at all but from wells. I've heard that there is arsenic in the water in Chapala but not further west. Guadalajara draws some of it's water from the lake.

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Yes water comes from wells lakeside. I had my Upper Ajijic water tested and it was very hard but safe. Depending on where you are your results may vary. My well is well above the lake and fed from the mountains. Do some reading about this if concerned and do a test. You may want to switch to reverse osmosis or other methods. These are not simple things to remove. Our normal filter systems here will not remove arsenic/fluoride from water. This being the particle filter feeding into a charcoal filter going to UV light. FYI most jug water here is reverse osmosis so you folks who buy good water are safe. Note I said good jug water!! Not a good place to save money unless you have your own water tester meter which many folks do have to check out bottled water. Note Calcium and Sodium show up on results for meter so you could have a sky high reading that is harmless from city water. Results from Bottled water should be close to zero as possible.

Go read about this on the internet. Google " Can I remove arsenic/flouride from my drinking water".

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Yes water comes from wells lakeside. I had my Upper Ajijic water tested and it was very hard but safe. Depending on where you are your results may vary. My well is well above the lake and fed from the mountains. Do some reading about this if concerned and do a test. You may want to switch to reverse osmosis or other methods. These are not simple things to remove. Our normal filter systems here will not remove arsenic/fluoride from water. This being the particle filter feeding into a charcoal filter going to UV light. FYI most jug water here is reverse osmosis so you folks who buy good water are safe. Note I said good jug water!! Not a good place to save money unless you have your own water tester meter which many folks do have to check out bottled water. Note Calcium and Sodium show up on results for meter so you could have a sky high reading that is harmless from city water. Results from Bottled water should be close to zero as possible.

Go read about this on the internet. Google " Can I remove arsenic/flouride from my drinking water".

.

"You may want to switch to reverse osmosis or other methods. These are not simple things to remove. Our normal filter systems here will not remove arsenic/fluoride from water. "

Note that arsenic is very easy to remove from drinking water using the common method of using activated carbon. Only the simplest wound-string sediment-filter-only systems cannot remove arsenic. Pretty much all other drinking water treatment systems include either activated carbon or RO that easily remove ALL arsenic.

e.g. The simplest Brita pitchers and Brita faucet filters remove arsenic with activated carbon, Pur's little faucet filters on your kitchen sink tap remove all arsenic using activated carbon, etc.

Fluoride removal is more difficult, as activated carbon is not sufficient. It takes RO to remove fluoride.

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Guadalajara draws some of it's water from the lake.

Nobody in Guadalajara drinks unfiltered tap water,not even poor people,they buy garrafones,unless they want "tripas torcidas".

.Fluoride removal is more difficult, as activated carbon is not sufficient. It takes RO to remove fluoride.

"Do you realize that flouridation is the most monstrously concieved and dangerous communist plot we have ever had to face?"

General Jack D Ripper.

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Snowyco I found some disagreement about whether our normal charcoal filters will do the job. Many sites suggest RO. Thus what I posted. Found enough negative references to make me question whether it is sufficient or not. One site said R.O. or Distillation only. Not saying I know just what I found. On the official Oregon health department site it does not even mention filters as a treatment for arsenic in drinking water. Guess I am confused now. Also some sites suggest special arsenic filters before normal filters.

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Filtration does not remove chemicals in solution; only particles.

Wells penetrate aquifers; so if the arsenic is in the aquifer, it is also in well water.

There seem to be some misunderstandings.

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When I had the city water tested it was considered safe. Wonder if different wells get water out of different locations underground. When I use a TDS meter I see 650ppm before home water treatment in upper Ajijic. I measured 350ppm in La Floresta so the water must vary from well to well right??

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When I had the city water tested it was considered safe. Wonder if different wells get water out of different locations underground. When I use a TDS meter I see 650ppm before home water treatment in upper Ajijic. I measured 350ppm in La Floresta so the water must vary from well to well right??

Conceivably, every well could have different water.

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We need to look at water delivery service, suggestions please on where to order "good water".

We have been using Kayta water, locally owned, for many years. So do many local restaurants.

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Filtration does not remove chemicals in solution; only particles.

Wells penetrate aquifers; so if the arsenic is in the aquifer, it is also in well water.

There seem to be some misunderstandings.

.

" Filtration does not remove chemicals in solution; only particles. "

This claim is absolutely incorrect and false.

Reverse osmosis, ion exchange, adsorption (activated carbon), and adsorbents do well at removing arsenic from drinking water.

When properly maintained: These kinds of filtration methods can remove almost ALL "chemicals in solution", reliably producing good clean safe drinking water.

Common filtration using activated carbon works well at removing most common contaminants, as long as the filter is not overloaded with too many contaminants. Activated carbon filters have a HUGE but finite number of active adsorbant sites, which means the activated carbon filters are excellent at removing large organic molecules (like dissolved pesticides, herbicides, dyes, and industrial solvents).

This same property means: Activated carbon filters are modestly efficient at removing heavy metals (like Ni, Cd. Cr, As, & Pb), but are very poor at absorbing small metal ions in water (like Na, Ca, Mg, etc).

Back to Arsenic contamination in drinking water:

Arsenic in drinking water typically comes from iron-bearing rocks, mine tailings, or from agricultural run-off pollution.** The chemical form of arsenic present in the water is critical in knowing if activated carbon will remove all of our arsenic in water contamination.* Arsenic exists in primarily two oxidation states (two common species) in natural water samples: arsenic+3 => As(III) ~ and arsenic +5 => As(V).

As (III) is roughly 10X more toxic to animal and plants than As(V). ... Activated carbon removes As(V) more efficiently than As(III).

But: When Iron +3 => Fe(III) is present in drinking water, it oxidizes/converts the As(III) to As(V) - making the Arsenic easily adsorbed by activated carbon.

This means that some internet "studies" mistakenly add As*(III) to the water for their activated carbon testing - and they mistakenly report that activated carbon did not work well. => The species/form of arsenic is critical to knowing if activated carbon will work.

This means that when our water has iron (from iron pyrite mineral rocks or arsenopyrites), our water contains the form of Arsenic that is well-adsorbed by activated carbon .

https://books.google.com.mx/books?id=hMA70VU36qUC&pg=PA104&lpg=PA104dq=is+arsenopyrite+As%28III%29+or+As%28V%29&source=bl&ots=AN5jnkqbZY&sig=9ObrKs01Ns3VNmvCKge7PNO-Ggw&hl=en&sa=X&ved=0ahUKEwjXsIO38b_JAhUJOCYKHYMEAN0Q6AEIOjAG#v=onepage&q=is%20arsenopyrite%20As%28III%29%20or%20As%28V%29&f=false

"Application of Activated Carbon for Removal of Arsenic Ions from Aqueous Solutions, RANSARI* and M SADEGH, Chemistry Department, Guilan University, Rasht, Iran POB 41335-1914, E mail: ransari@guilan.ac.ir, Received 26 August 2006; Accepted 3 October 2006"

================================

Human-caused arsenic pollution can almost always be traced to mining or mining-related activities or agricultural run-off (from fertilizers, herbicides, fungicides & pesticides).

*http://www.ncbi.nlm.nih.gov/pubmed/18982996

**http://water.usgs.gov/nawqa/trace/pubs/gw_v38n4/

==========================

Finally, to answer LCScats concerns:

Small kitchen-sink faucet filters may have limited capacity to absorb arsenic, especially high concentrations of As(III).

(but NOTE that our waters likely have enough Iron(III) to convert the As(III) over to As(V) that IS adsorbed by activated carbon)

In any case, the little kitchen-sink faucet-filters have such small amounts of activated carbon, that they must be changed FAR more frequently than the big cartridge activated carbon filters, because the kitchen-filters adsorbent sites get "filled" by contaminated water. ... If you have fairly clean (not-heavily contaminated) drinking water, the kitchen filter lasts much longer than when it has to filter modestly-contaminated water - but typical home water-filtration system activated carbon cartridges work for a long time.

http://pubs.acs.org/doi/abs/10.1021/bk-2005-0915.ch020

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Snowy:

Filtration Definition: Filtration is a mechanical or physical process to separate solid particulates from fluids.

Adsorption or reverse osmosis processes are not technically filtration.

Activated carbon can both filter and adsorb. Reverse osmosis is a membrane separation process that blocks the transport of dissolved salts across the membrane leaving potable water. We don't use RO "filters" for removing solid particulates as they become fouled quickly.

This is why full water treatment starts with the separation of solid particulates and then progresses to the removal by adsorption or RO of dissolved pollutants.

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Thank you. That is exactly the situation, and you explained it well.

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Kayta, Santorini, and Ciel bottled water tested fine with my TDS meter when I bought bottled water. Never tested others brands.

Which elements/compounds/pathogens does a TDS meter test for? Can specific elements/compounds/pathogens be isolated and quantified, i.e. how many of what?

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Which elements/compounds/pathogens does a TDS meter test for? Can specific elements/compounds/pathogens be isolated and quantified, i.e. how many of what?

Total dissolved solids-nothing more.
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Thanks for taking the time Snowco to explain what I saw and it makes perfect sense now. Also thanks to the person who wrote Dr. Strong.

So is anyone going to test our city water in Ajijic??

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Most people won't want to go to the expense of testing Ajijic's water. It is mainly used for bathing, clothes washing and lawns. The water in the decrepit lines is not the same quality as the water in the wells.

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Yo1, you said "I don't believe that tap water in Lakeside comes from the lake at all but from wells." That is the aquifer that the report was speaking of, arsenic is absorbed through the skin while showering.

 

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I drank tap water in Chapala, simply filtered and sometimes treated with UV, but often not, from age 65 to 78  and still do not glow in the dark, or exhibit other symptoms. Now, at 81, I suspect that something may eventually kill me, but I am too busy to worry about it.

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