Information on Phthalates…Hunter Worsfold
Newly published research shows a significant increase in
preterm birth rates in women exposed to phthalates, a
commonly used group of chemicals sometimes found in
drinking water. How phthalates contribute to preterm birth is
currently unknown. Also unknown are the most relevant sources
of exposure. Water is one possible route but additional sources
may surprise you.
What are phthalates?
Also known as plasticizers, the primary use of phthalates
is to make plastics more pliable. They are found in hundreds
of products, including PVC pipes, medical tubing, flooring,
adhesives, detergents, clothing, food containers, plastic wraps
and personal care products (such as soaps, shampoos, hair
sprays and nail polishes). There are at least 13 metabolites of
phthalates excreted in urine, suggesting exposure in the general
US population is widespread. The most commonly used phthalate
is di-2-ethylhexyl phthalate, or DEHP. Adult women have
higher levels than men, presumably due
to increased use of cosmetics, body washes
and other personal care products. Their use
in plastic wraps and food storage containers
provides a source for leaching into food
(particularly during reheating) where the
product breaks down more rapidly.
Children are prone to increased
phthalate levels in their urine, likely due
to increased hand-to-mouth contacts with
contaminated dust or plastic products. One
study found increased exposure risks in
infants due to dermal adsorption following frequent use of infant
lotion, powder and shampoo. The Food and Drug Administration
(FDA) requires declaration of ingredients in cosmetics and thus,
consumers can determine if phthalates are in their retail products
by reading the label (the FDA has posted the results of a 2010
survey of cosmetics for phthalate content on their website, www.
labeling requirement does not extend to individual fragrance
ingredients or products used by professionals (i.e., in salons).
A call for phthalate reductions in children’s teethers, rattles
and pacifiers was issued in 1999 by the US Consumer Product
Safety Commission. Levels were legally restricted in children’s
toys in 2009 following the signing of the Consumer Product Safety
Improvement Act. Determining phthalate content in plastics is less
obvious; however, plastics with the recyclable label containing
the number three within the triangle are typically PVC and more
likely to contain the contaminant.
What are the health risks?
Despite medical advances, preterm birth rates have been
increasing over the last two decades. The cause of this increase is
not known; however, environmental factors are a plausible cause.
In a recent study, 482 pregnant women over a three-year time
frame were evaluated for nine types of phthalate metabolites in
their urine up to three times over the course of their pregnancy. Of
the 482 test subjects, 130 (27 percent) delivered prior to complete
gestation (defined as prior to 37 weeks). Those delivering preterm
were found to have been exposed to higher levels of at least four
types of phthalates: di-2-ethylhexyl phthalate (DEHP), mono-(2-
ethyl)-hexyl phthalate (MEHP), mono-(2-ethyl-5-carboxypentyl)
phthalate (MECPP) and mono-n-butyl phthalate (MBP). In fact,
those exposed to the highest levels were up to five times more
likely to experience a preterm birth.
Researchers are careful to warn that their study does not
prove phthalate exposures cause premature birth, but there does
appear to be an association, which means there is an indication that
phthalate exposures somehow contribute to
the adverse health outcome. For example,
coffee drinkers tend to have higher rates of
lung cancer. Coffee does not cause the lung
cancer. Rather, the fact that many partake
in smoking while having coffee leads to the
adverse effect. In this example, smoking is
causal, while coffee is associated with lung
cancer. An understanding of the pathway
of phthalates in the body and related side
effects that might lead to preterm birth is
critical to developing effective interventions.
Not enough is known about phthalates and their role in preterm
birth to justify any changes in prenatal care routines.
In addition to suspected pregnancy effects, exposure to
phthalates may cause mild stomach ailments, nausea and vertigo
in healthy populations. They are suspected endocrine-disrupting
compounds and repeated exposure over time may lead to damage
to the liver and testes, reproductive effects and cancer. Those
at highest risk appear to be dialysis patients or hemophiliacs,
where continued use of hospital tubing (the phthalate content
is among the highest of any other type of plastics) leads to
increased exposures. Scientists are uncertain about the health
effects of phthalates at current environmental exposure levels.
While the National Institute of Environmental Health Sciences
(NIEHS) states that the majority of phthalate compounds pose
minimal concern, the National Toxicology Program concluded
that high levels of certain types may affect human reproduction
Treating water to remove phthalates to acceptable levels at the tap is easily accomplished. POU treatment using granular activated carbon has been shown to be effective for reduction of phthalates in drinking water.
courtesy: Water Conditioning & Purification
A. Reynolds, MSPH, PhD