Plastic is everywhere: water bottles, dental sealant, the odd floating trash island. Over the years, researchers have raised the alarm about how chemicals from plastics might affect human health, often focusing on one chemical in particular: bisphenol A (BPA).
BPA is used to make a hard, clear type of plastic called polycarbonate. It's so ubiquitous that a 2009 study conducted by the Centers for Disease Control found that of the 2,517 people they tested, nearly all of them had detectable levels of BPA in their urine. New research hints that BPA-free plastic alternatives may not actually be any safer.
It all started 20 years ago, when researchers in the lab of geneticist Patricia Hunt realized that something was very wrong with their mice.
The process of making a healthy egg cell involves a series of cell divisions, during which chromosomes (the long strands of DNA that make up an organism's genome) are divided up into the newly-formed cells. If something goes wrong and the cells end up with an abnormal number of chromosomes, that's usually a very serious problem.
The researchers in Hunt's lab were studying this process when suddenly the egg cells of their mice--including the ones that were supposed to be normal--started showing major genetic abnormalities. Something in the environment of these mice was causing their egg cells to have problems dividing. It turned out that the problem was the plastic cages.
The mice were living in cages made of polycarbonate. A worker had accidentally used a harsh detergent to clean them, which caused them to release BPA. When the researchers replaced the cages, the egg cells went back to normal, and when they tried giving the mice BPA on purpose, the egg cells had the same problems as before. The researchers concluded that BPA is capable of causing genetic abnormalities in mice.
So, does this mean we should all go home and throw out all our plasticware? Maybe, maybe not. Humans have different metabolisms than mice, so it's completely possible that consuming the same substance could have a different impact on us, or have no impact at all.