BPA warnings

**tschafha** · 09-16-2008, 11:02 AM

Anybody have patients ask about the potential dangers of BPA and polycarbonate lenses?

**Chris Ryser** · 09-16-2008, 11:23 AM

Originally Posted by tschafha

Anybody have patients ask about the potential dangers of BPA and polycarbonate lenses?

Optical Poly lenses are hard coated (sealed) and can not leach any BPA into food or drink.

BPA problems can or could only arise from Poycarbonate bottles, so there should be no problem with lenses.

The problem lies in BPA’s activity as an endocrine disruptor. This substance mimics natural estrogens found in the body, thereby changing the normal function of the endocrine system. The results can include lowered sperm count in men and other male animals and is implicated in both testicular and breast cancers.

**Jacqui** · 09-16-2008, 11:51 AM

I still think it can be released, in potentially harmful quantities, when generating and edgeing. This is why I refuse to use any polycrap.

**Jacqui** · 09-16-2008, 12:32 PM

I seen this on MSN Canada

http://news.sympatico.msn.ctv.ca/abc...a_study_080916

Also this on Yahoo

http://news.yahoo.com/s/ap/20080916/...sphenol_safety

**maggiferous** · 09-16-2008, 04:09 PM

I wonder if that extends to containers as well...at our local Wegmans (grocery store chain) this summer, they were advertising polycarbonate, no-shatter cups and plates for picnics, in various colors. Said "polycarbonate" right on the stickers too. I chuckled to myself and wandered off in search of caffeine, but this makes me wonder.

**FullCircle** · 09-17-2008, 06:33 AM

Originally Posted by maggiferous

I wonder if that extends to containers as well...at our local Wegmans (grocery store chain) this summer, they were advertising polycarbonate, no-shatter cups and plates for picnics, in various colors. Said "polycarbonate" right on the stickers too. I chuckled to myself and wandered off in search of caffeine, but this makes me wonder.

Yeah, I wonder abou that too. At the risk of sounding like Chip, glass is where it's at in terms of drinking vessels. I never heard of any leaching issues with glass (except from my husband if someone uses a pilsner glass for milk.) and the only other issue I've ever heard was Vaseline glass. And whats wrong with a little pinging from your geiger counter? :hammer:

**chip anderson** · 09-17-2008, 07:00 AM

Can anyone explain why many plastics are appearently nearly 100% safe when intact as say a lens, or a cup or whatever. However when ground down with a grinder and mixed with water it somehow becomes lethal and must be handled in a specified EPA manner?

Chip

**Chris Ryser** · 09-17-2008, 08:19 AM

Originally Posted by chip anderson

Can anyone explain why many plastics are appearently nearly 100% safe when intact as say a lens, or a cup or whatever. However when ground down with a grinder and mixed with water it somehow becomes lethal and must be handled in a specified EPA manner?
Chip

Congratulations Chip.........this was your post number 9000

Polycarbonat is the cheapest plastic material available on the world market. It comes in pellets is molten down and then shot into the mold by injection. Usually there are racks of up to 6 parts on one rack. The mold is cooled off and opened and the part broken off from one to the other.

Other plastics as CR39 are made from a monomer that is cured for many hours until it has become finished. This material will never leach any chemicals once it is in its final stage.

When designing plastic for use withing the human body the FDA requires full testing for leaching which is a lengthy and expensive operation.

See about the properties of polycarbonate:

http://optochemicals.com/polycarbonate_properties.htm

RT · 09-17-2008, 08:47 AM

However when ground down with a grinder and mixed with water it somehow becomes lethal and must be handled in a specified EPA manner?

It doesn't require any special handling. The ONLY route that anyone connected with science has suggested for BPA leaching is via drink containers that are heated. Any speculation that grinding the lenses creates a similar route is just that...pure speculation. Or more appropriately...Cyberchrondria.

And of course, we need to get our government agencies right. There are NO specific polycarbonate guidelines from EPA (which is concerned about the environment). You may be thinking about OSHA (who is concerned with safety in the workplace), but they just consider grinding polycarbonate as a producer of nuisance dust that just requires ventilation.

Grind away!

**chip anderson** · 09-17-2008, 09:05 AM

I should have added this to the question:
Why should waste from our grinding and surfacing tools require specialized disposal? If it isn't toxic what's the problem with it going down the drain (as most of it does anyway) or being poured out into the sewer or whatever?

Chip

RT · 09-17-2008, 11:08 AM

Depends upon your sewer district. The one in my area doesn't want particulate matter going into the sewer simply because it clogs things up. Poly swarf would almost surely clog things up. There are plenty of things that aren't toxic but are still inappropriate to flush down the toilet.

Also, if you're using oil-based coolants (like if you're grinding glass) they might have a problem with that. And they might not like big vats of tint going into the sewer also. It probably varies from one sewer district to another, and also may depend upon volume.

**For-Life** · 09-17-2008, 11:34 AM

Originally Posted by chip anderson

I should have added this to the question:
Why should waste from our grinding and surfacing tools require specialized disposal? If it isn't toxic what's the problem with it going down the drain (as most of it does anyway) or being poured out into the sewer or whatever?

Chip

clogs up the sewer systems and pipelines. That means municipalities will have to spend millions of your tax dollars to dig up roads to replace piping and fix problems in water filtration zones.

Plus, the sludge from sewage is biodegradable, so they want to separate as much of the bad stuff from it as possible, to help keep our ground water clean.

**Chris Ryser** · 09-17-2008, 11:59 AM

Dumping lens grinding waste into the sewers...........................

Having toxic fumes in the back lab.......................

not venting them outside..............and if it is not possilbe use non toxic products that are available

Stop worrying about BPA on lenses, but start worrying about the fumes in your back lab, hot neutralizer fumes attack your liver - kidneys and not least but last ...........your brain functions.

Having good ventilation is of essence to get rid of toxic fumes and also ugly smells from lens grinding and that affects your immediate health.

**Leighlee** · 09-17-2008, 01:06 PM

Originally Posted by RT

Depends upon your sewer district. The one in my area doesn't want particulate matter going into the sewer simply because it clogs things up. Poly swarf would almost surely clog things up. There are plenty of things that aren't toxic but are still inappropriate to flush down the toilet.

Also, if you're using oil-based coolants (like if you're grinding glass) they might have a problem with that. And they might not like big vats of tint going into the sewer also. It probably varies from one sewer district to another, and also may depend upon volume.

It also depends on your water system...such as where your water comes from. In Key West, FL your water comes recycled toilet water. EWWWWWWWWW!