Are plastics still made with PCB's?
Here is the link:
http://health.yahoo.com/experts/drmao/20...
I had it in my head that PCB's are banned chemicals. Is this warning for real, or am I misunderstanding something?
Answer:
PCB's (PolyChlorinatedBiphenyl's) are a group of oily liquids used chiefly as transformer oil and sometimes found in the ballasts of old fluorescent lights. Some old paints and inks also contained PCB's. Like many other chlorinated aromatic compounds (like DDT), PCB's are very resistant to weathering and are heat resistant. They can be metabolized in living organisms however, and can be quite toxic. Like DDT, PCB's accumulate in body fat. Released into the environment, they pass up the food chain and become very concentrated at the top. Beluga whales in the St. Lawerence seaway are heavily polluted, as are "killer" whales off the Pacific coast.
PCB's are now banned and are not, nor ever were used in any plastics I am aware of. Perhaps the author of the article confused these compounds with another group of chemicals known as phthalates. These are added to plastics to make them rubbery and flexible. They are oily liquids like PCB's but not acutely toxic. However, di-octyl phthalate can mimic the female hormone estrogen and might be linked to the prevalance of breast cancer in developed countries. Phthalates are being gradually replaced by other compounds which are (supposedly) non-toxic. PBB's are PolyBrominated Biphenyls and were once used as fire retardants. Mixed with plastic, the concept was that they were sealed inside the product, but like phthalates, they will eventually leach out of plastics.
PCB's were once used as a sealant for the insides of silos. The concrete walls decomposed because of the acidic reaction of silage and needed a waterproof coat. Unfortunately, PCB's leached out of the coating and contaminated the milk supply. Most states required contaminated silos destroyed, but Indiana only required the sealant be painted over. This solved the problem temporarily, but the contamination re-appeared as the paint flaked off.
it's for real, but not all plastics contain PCBs.
Polychlorinated biphenyls are use in :
plasticisers in paints and cements
casting agents
fire retardant fabric treatments
adhesives
paints and water-proofing
railway sleepers.
Now a days PET bottles / Translucent Polycarbonate Water Bottle are made.
Polyethylene terephthalate (aka PET, PETE or the obsolete PETP or PET-P) is a thermoplastic polymer resin of the polyester family and is used in synthetic fibers; beverage, food and other liquid containers; thermoforming applications; and engineering resins often in combination with glass fiber. It is one of the most important raw materials used in man-made fibers.
Polycarbonates are a particular group of thermoplastic polymers. They are easily worked, molded, and thermoformed; as such, these plastics are very widely used in the modern chemical industry. Their interesting features (temperature resistance, impact resistance and optical properties) position them between commodity plastics and engineering plastics.
Dave, PCBs have not, to my knowledge, ever been used in plastics approved for food storage. You may be thinking of phthalates or bis-phenol A. Those are related compounds but only in a very general sense that they are based on aromatics.
This is a bad editing job by Yahoo or the author. He may mean a bunch of things, but not PCBs. It could be PVCs, BPAs, etc.
The answers post by the user, for information only, FunQA.com does not guarantee the right.
More Questions and Answers: