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Shea,
KM and the Committee on the Environment. 2003. Pediatric exposure
and potential toxicity of phthalate plasticizers. Pediatrics
111:1467-1474.
Background
on phthalates
Recent scientific
findings on phthalates and sperm
In
a review of the possible health risks created by exposure in the womb
and during early childhood, the American Academy of Pediatrics' Committee
on the Environment finds that there are too few human studies
to conclude phthalates are safe. None have examined risks to
fetuses in the womb or during early childhood. Yet animal studies clearly
establish that these life stages are the most sensitive to phthalate exposures.
The pediatricians write that "Phthalates are animal carcinogens and
can cause fetal death, malformations,and reproductive toxicity in laboratory
animals." And they call for research on the effects of phthalates
on vulnerable times of life, particularly in the womb and during early
childhood.
In
the meantime, a series of studies inarguably establish widespread human
exposures. And as the Academy report notes, replacements for phthalate
uses could be designed. Indeed, in two common uses of phthalates creating
exposures today--for cosmetics and certain types of medical equipment--replacements
are already available.
Their
review concludes with a series of cautiously worded findings, summarized
below:
- Phthalates
are of concern because of known toxicities established through animal
experiments.
- Human
exposure to phthalates is universal. Food is considered to be the major
source of exposure to DEHP and DINP; medical exposures are also important
for DEHP.
- While
data indicate that DEHP and DINP are animal carcinogens, the mechanisms
involved may not be relevant to carcinogenesis in people. Both, however,
are developmental toxicants, with the developing male reproductive system
the most sensitive system identified to date. These mechanisms are different
from those involved in carcinogenesis.
- "No
studies have been performed to evaluate human toxicity from exposure
to these compounds." [ed. note: actually in Winter 2002/Spring
2003, three
studies were published suggesting adverse effects in adult men's
sperm quality.]
- Children
may be at higher risk of adverse effects of phthalates, "because
of anticipated higher exposures during a time of developmental and physiologic
immaturity."
- Exposures
to DEHP resulting from the use of DEHP-containing PVC-made medical equipment
"are of concern." Doses within the range of those caused by
intensive medical treatment are known to cause damage to the immature
male reproductive tract in animals. "No studies evaluate the effect
of medical exposures to DEHP and [its metabolite] MEHP on testicular
function in humans."
- Medical
institutions may find it necessary to reassess uses of phthalate-containing
medical equipment, including in neonatal and pediatric intensive care
units. While phthalate-containing PVCs offer some advantages, "interventions
designed to minimize DEHP exposure in the medical setting could be designed.
- Better
data on phthalate exposures in the womb and in childhood, and about
phthalate toxicology in general, would help guide decisions about risks
and replacements. This should include research into phthalates effects
on non-human primates as well as studies of sensitive human populations,
such as pregnant and lactating women, premature infants, full-term infants,
and children.
While
this
assessment falls far short of resolving the very public controversy over
health risks of phthalate exposure, it does serve to disprove unequivocally
the frequent assertion by industry that decades of experience and exposure
to phthalates establishes their safety: Absence of proof of harm
of phthalates can only be taken to be proof of ignorance, not a demonstration
of safety.
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