Does filtered water have less estrogenic activity?
July 23, 2011 11:05 PM   Subscribe

Does a water filter filter plastics like BPA? Is there a way to test my tap water for them? Are there water filters that do not contain plastic? Does Aquafina or any other filter plastics?

I read that other estrogenic compounds besides BPA are leeched by plastic water bottles. I'm wondering if filtered water has less of them.
posted by vash to Health & Fitness (10 answers total) 3 users marked this as a favorite
A water filter cannot filter BPA. BPA is a chemical used in plastic manufacturing. It can't be filtered out.
posted by sanka at 11:18 PM on July 23, 2011

Anything can be filtered out of water one way or another. If you're unduly freaked out about BPA, get a BPA-free container and fill it with stuff filtered by reverse osmosis/carbon. If you're truly OCD, drink distilled.

Bottled water manufacturers these days mostly just filter tap water. No guarantees on what's in it.
posted by t_dubs at 11:26 PM on July 23, 2011 [1 favorite]

BPA isn't a plastic per se, but a chemical used to make plastic. As it is, the solubility of BPA is 120-300ppm at room temperature which isn't a high solubility but is somewhat soluble (I'm not saying anything about the safety of that much BPA, just the amount that could be in water). It would be like trying to filter salt out of water and frankly impossible.
posted by Mister Fabulous at 2:16 AM on July 24, 2011

You absolutely can remove BPA with an activated charcoal filter (abstract doesn't say how well it works, though), which many commercial filters use. Charcoal filters don't work by literally filtering particulates. Instead, they have a intermolecular binding affinity for a number of contaminants that may very well be dissolved; they tend to work reasonably well for organic compounds, of which BPA is one.

Mister Fabulous: you absolutely can filter salt out of water. It's called reverse osmosis, and it's done all over the world every day on scales ranging from home use to mega-industrial.
posted by Dr.Enormous at 3:19 AM on July 24, 2011 [1 favorite]

It's my understanding that you have to worry about BPA leeching into your water when it sits for a long time in plastic containers. So if you have a classic Brita filter, where water runs through a filter and then sits in a plastic pitcher, you could pour the water out once it's been filtered, into a glass jar.

We have a Culligan faucet filter ( that the water runs through from the faucet. If I want a pitcher of cold water, I use the faucet that's mounted to & fill up a non-plastic pitcher. Otherwise we just fill up glasses one-off as needed.

We've decided this is a fairly decent way to avoid too much BPA at home, since the water passes right through the filter & really doesn't sit in contact with anything.
posted by lyra4 at 3:56 AM on July 24, 2011 [1 favorite]

posted by fiercecupcake at 11:23 AM on July 24, 2011

Whether through inadvertence or as a teaser I couldn't say, but the abstract in Dr.Enormous' link leaves a very nice little nugget outside the paywall:

The presence of electrolytes in the solution favor the adsorption process because of the screening effect produced between the positively charged carbon surface and the bisphenol A molecules, with a resulting increase in adsorbent−adsorbate interactions.

In other words, you should soften your water after you run it through the activated carbon because the presence of dissolved minerals will help the carbon pull things like BPA out of the water.

Also, reverse osmosis at home is extremely wasteful, producing up to 19 gallons of waste water for every gallon of output.
posted by jamjam at 12:05 PM on July 24, 2011

I'm not in an area where water is scarce.
posted by vash at 1:41 PM on July 24, 2011

In the US, your water company will be able to give you information on the quality of the water. I live in Southern Maine, and my water comes from Sebago Lake. It is clean and delicious, and people here who drink bottled water are nuts. The water company sends an annual report of their extensive testing, and the info is also on the web. I find it hard to believe that water shipped and stored in plastic is better, for most areas of the US.
posted by theora55 at 4:28 PM on July 24, 2011

A water filter cannot filter BPA. BPA is a chemical used in plastic manufacturing. It can't be filtered out.

sanka, your comment makes no sense. Of course chemicals can be filtered out; that is the whole point of filters. And you're wrong, anyway, about BPA.
posted by IAmBroom at 9:57 AM on July 25, 2011

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