Bisphenol A – New to the CDC List

Skalsky & Associates has expertise in plastics (both construction and food contact materials) and can assist you in evaluating exposures to Bisphenol A (BPA).  BPA is used in the production of polycarbonates, epoxy resins, phenolic resins, and diacrylates.  Polycarbonates, one of the most widely used plastics, accounts for 60% of the total production of BPA. Epoxy-based resins are used in a variety of consumer products that include decorative floor manufacture, lacquer coatings in cans, dental composites and sealants, and as additives in the production of vinyl and acrylic resins. Trace amounts of BPA monomer have been reported to leach out of polycarbonate and epoxy resins.

BPA has long been described as a weak estrogen.  Whether BPA can cause human health effects in adults is a matter of some debate.  However, the potential for harm to infants and the fetus is currently considered more probable than harm to adults.  BPA is believed to be metabolized and cleared quickly from the blood and excreted almost completely in 24 hours.  However, BPA has also been detected in adipose tissue at levels 8 to 10 times higher than in the blood.  The rate of clearance from adipose tissue is unknown.  The NHANES results indicate that BPA was detected in 92.6 % of the people tested. 

The levels of BPA in urine are:

• 6-11 years of age  GM => 4.32 µg BPA/g creatinine.   95th %  => 15.7 µg BPA/g creatinine
• 12-19 years of age  GM => 2.80 µg BPA/g creatinine.   95th %  => 11.8 µg BPA/g creatinine
• 20- + years of age  GM => 2.39 µg BPA/g creatinine.   95th %  => 10.0 µg BPA/g creatinine

 

According to the NHANES data, children 6 to 11 years old excrete higher levels of BPA than adults.  This increased level of excretion indicates that the body burden of BPA in children is considerably higher than in adults.

Over the past few years there has been an increase in the epidemiological evidence linking BPA to obesity, diabetes, and cardiovascular disease.  BPA is stored in fat and suppresses adiponectin release.  Adiponectin is an adipocyte-specific hormone that increases insulin sensitivity and reduces tissue inflammation. Thus, any factor that suppresses adiponectin release could lead to insulin resistance and increased susceptibility to obesity-associated diseases.

BPA can be detected in almost all human tissues and is most concentrated in the fat, the liver, and the brain.  The majority of our exposures to BPA occur through ingestion of foods in contact with Bisphenol A containing packaging.  However, there is a small component of exposure from indoor air and potentially from drinking water.  It is this indoor air and drinking water component that would be of potential concern for the construction industry.  Because of the increased intake of BPA by toddlers, household dust is often sampled.  BPA is found in 95% of the household dust samples analyzed.

Polycarbonate plastics are often used in construction and are present in many households.  Ongoing litigation of alleged health impact to infants using BPA containing baby bottles and sippy cups, may “spill over” into the construction industry.  Skalsky & Associates can assist you in evaluating exposures to BPA.