Plastic poses another potential problem
Two more chemicals exuded from plastics now appear to pose potential problems.
Two substances leaching from polypropylene -- quaternary ammonium biocides and oleamide -- have been flagged by medical researchers at the University of Alberta as biologically active enough to distort laboratory drug experiments. Polypropylene is one of the most commonly used plastics worldwide, including ordinary laboratory instruments and containers.
The same sort of effects on experiments by bisphenol A (BPA) leaking from polycarbonate plastics trigged a chain of investigation that has lead to prohibitions of BPA in Canada in certain consumer products, and its designation a toxic substance .
Not enough is known about the two substances leaking from the plastic - quaternary ammonium biocides and oleamide - to know what hazard, if any, they might pose through exposure to consumer products made from polypropylene.
"It's very difficult to say whether we should be worried from a health point of view about this," said Andrew Holt, the paper's lead researcher and an assistant professor of pharmacology.
But Dr. Holt said that virtually all medical laboratories in the world routinely use materials, such as bottles and tubing, made from the polypropylene, putting their results at risk. "Scientists need to be aware of this," Dr. Holt said.
Other experts, though, said they were worried that plastics might be leading to human exposures, with unknown effects.
"We simply don't want these chemicals getting into our bodies," said Rebecca Sutton, senior scientist with Environmental Working Group, a U.S.-based advocacy organization.
The group wrote to the U.S. Environmental Protection Agency last month, objecting to an effort to loosen exposure standards for quaternary ammonium compounds.