I've been thinking a lot about plastics recently.
It started when I read that the ubiquitous Nalgene bottles - which everyone in my office building seems to have one or more of (and I'm drinking from right now...) - are suspected of leaching bisphenol A (BPA), a suspected hormone disruptor, into the water that we then drink.

"Levels of 0.1 to 10 ppb of BPA, which are orders of magnitude above what can affect humans, are currently found in U.S. bodies,"
- Frederick vom Saal, Ph.D., a developmental biologist at the University of Missouri and lead author of one of the studies on BPA's effects.

BPA can leak from the linings of cans (nearly all can liners - even those for organic food - contain BPA). Plastic water bottles, baby bottles and dental sealants can all leach BPA. Wine is made in vats that have a resin lining that contains BPA.

It's still controversial to label BPA as a health risk, but some scientists have performed animal studies that have shown that exposure to BPA in the womb raises the risk of some cancers, lowers the resultant child's fertility and could contribute to behavioral problems such as hyperactivity.

Ninety-five percent of Americans were found to have the chemical in their urine in a 2004 monitoring study by the CDC.

BPA seems to mimic naturally occurring estrogen, which controls the development of the brain, the reproductive system and many other systems in the developing fetus.

The plastics industry denies that BPA is harmful in the doses that are present in humans, which are much lower than the amount set by the EPA in the 1980s. The threshold was set using high dose toxicity studies in rats that didn't look at hormone disruption in the rats or their offspring.

"That's why early toxicity studies found that the high doses were safe. The studies didn't look at the low doses that are now proving to cause a myriad of harmful effects in animals, including chromosomal damage in female egg cells and an increase in embryonic death in mice. A follow-up to this is a study indicating a relationship of BPA blood levels to miscarriages in Japanese women,"
- Frederick vom Saal, Ph.D

In 1998, geneticist Patricia Hunt noticed that the mice cells she was using had increased chromosomal damage - it shot up from 1 or 2% to 40%. She traced the damage to polycarbonate water bottles and cages that had been washed in a harsh detergent. Once the effected items were replaced with non-polycarbonate plastic, the error rates resumed their lower rate.

A January 2006 study indicates that BPA may enhance the risk of developing Type II diabetes. Angel Nadal, Ph.D., and his team at the University of Miguel Hernández de Elche in Alicante, Spain, found that BPA altered the function of the insulin producing cells in the pancreas of the mice.
Another study on mice, done by Ana Soto, M.D., a professor and researcher at Tufts University School of Medicine in Boston, found that BPA exposure while in the womb altered  mamary gland development at puberty.
Another study showed that if a mouse was exposed to BPA at levels that are around the range of common human exposure, the exposure resulted in chromosomally abnormal grandchildren with no further exposure.

Human studies on BPA have been too limited to reveal much, most having too small a sample to be counted as significant.
One of the small-sample studies found that blood levels ob BPA were three times higher in women who had suffered recurrent miscarriages. Another linked BPA to fibroids, adenomysois and cystic ovaries.

This isn't even the scariest thing about plastics. The scariest thing is how long they've been around. Basically, plastics have only been around since after World War II in any significant way. A little over 60 years. And we have no idea what they are doing to us.

Every day, we live in an ongoing experiment of environmental pollutants where we are the subjects.

BPA in our water bottles. PCBs and lead in the soil. Our cooking pans have PFOA. Diacetyl in our microwave popcorn. Declining testosterone levels in our men. Adult-onset asthma. Phthalates regularly used in neonatal intensive care units and adult sex aids.

It is sobering and terrifying - and COMPLETELY unavoidable.
For more information on plastics in our environment, please read the online excerpt from Alan Weisman's book "The World Without Us."

by Sand on 02/15/2008 12:26:12 PM EST

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