Several new studies indicate that common industrial chemicals
called phthalates (pronounced tha-lates) in food and water may be
interfering with development of the reproductive system in both
boys and girls.
** For 20 years, large numbers of baby girls in Puerto Rico
between the ages of six months and 2 years have been experiencing
premature breast development, a condition called precocious
thelarche (pronounced thee-larky). Since 1970, there have been
4674 cases of precocious thelarche recorded in Puerto Rico, where
the condition is now occurring in 8 out of every 1000 baby girls,
or just under 1%. Compared to a group of baby girls studied in
Minnesota, precocious thelarche in Puerto Rico is 18 times as
For 20 years, scientists have tried to link the alarming epidemic
in Puerto Rico to artificial hormones in meat, pharmaceutical
manufacturing wastes, and infant formula containing high levels
of phytoestrogens (plants that contain natural estrogen-like
chemicals), but no satisfactory explanation has emerged. Now
researchers have found evidence linking precocious thelarche to
Blood samples from two groups of girls in Puerto Rico -- 41 baby
girls with precocious thelarche and 35 with normal development --were
examined for pesticides and phthalates. Pesticides were not
found in either group. Phthalates were present in the blood of
68% of the precocious thelarche group and 14% of the control
group. Phthalates tend not to bioaccumulate, so phthalates
measured in blood are likely to reflect current exposures, not
Phthalates are common industrial chemicals used in building
materials, food packaging and food wrap, toys and other
children's products, medical devices, garden hose, shoes, shoe
soles, automobile undercoating, wires and cables, carpet backing,
carpet tile, vinyl tile, pool liners, artificial leather, canvas
tarps, notebook covers, tool handles, dishwasher baskets, flea
collars, insect repellents, skin emollients, hair sprays, nail
polish, and perfumes.
(The Environmental Health Network in California has petitioned
the U.S. Food and Drug Administration to require labeling of
perfumes that contain toxic phthalates, such as Calvin Klein's
One particular phthalate -- di-(2-ethylhexyl) phthalate, or DEHP
-- accounted for 88% of the total phthalates measured in the
precocious thelarche group and 80% of the total phthalates in the
control group. The average levels of DEHP in the control group
were 70 ppb and in the precious thelarche group 450 ppb -- more
than six times as great.
Some phthalates mimic estrogen (female sex hormone) and others
interfere with androgen (male sex hormone).[3,4,5] In laboratory
animals, some phthalates can cause birth defects and can disrupt
hormones, leading to altered sexual development. Regarding
reproductive and developmental effects in laboratory animals,
phthalates vary in potency, with DEHP being about 10 times as
potent as the other phthalates.
The average daily consumption of DEHP by children in the U.S. is
estimated to be 5.8 milligrams per day. The most important
source of DEHP exposure is contaminated baby formula, food and
water contaminated by contact with plastic containers and food
wrap, and plastic toys and pacifiers made soft by the addition of
DEHP. Because Puerto Rico is an island, above-average quantities
of prepared foods are shipped there packaged in
This small study does not prove that phthalates are causing
premature sexual development among baby girls in Puerto Rico,
but, combined with what is known about phthalates from laboratory
animal studies, it provides a strong suggestion that phthalates
may be contributing to the epidemic.
** A very recent study reveals that phthalates are present in the
blood of adult Americans "at levels we are concerned about,"
according to John Brock, a chemist with the federal Centers for
Disease Control (CDC) in Atlanta. Brock and his colleagues
studied phthalates in the blood of 289 adults and found levels
"higher than we anticipated."[6,7]
Many laboratory products (such as plastic tubing) contain
phthalates. As a consequence, phthalates are often found in
samples analyzed in laboratories because lab equipment
contaminates the samples. For the past decade, scientists have
been finding phthalates in human tissue samples, but they have
assumed they were measuring lab contamination. Consequently, no
one has raised an alarm about phthalates in adult humans, until
To measure phthalates in human urine, Brock and his colleagues
developed specialized techniques for identifying metabolic
byproducts of phthalates; in other words, they learned how to
measure the chemicals that are produced when phthalates are
processed by a human liver and kidney. By this means, Brock could
be sure his team was measuring human exposures to phthalates and
not merely contamination introduced into samples from laboratory
Brock tested for and found seven phthalate metabolites in human
urine. The four phthalate metabolites found at the highest levels
came from DEHP, DEP (diethyl phthalate), BzBP (butyl benzyl
phthalate) and DBP (di-N-butyl phthalate). "From a public health
perspective, these data provide evidence that phthalate exposure
is higher and more common than previously suspected," Brock and
his colleagues concluded. They offered additional reasons for
** The highest phthalate levels were measured among women of
child-bearing age (20 to 40) -- about 50% higher than among
groups of different age and gender.
** DEHP, DBP and BzBP are known to cause birth defects in
laboratory animals. (Note that BzBP is sometimes known as butyl
benzyl phthalate, or BBP.)
** DBP is toxic to the testicles.
** The metabolites of BzBP and DEHP that Brock measured are toxic
to sertoli cells (the cells that produce sperm). Next month a new
study will conclude once again that for three decades there has
been a steady (1.5% per year) decline in the quantity of sperm
produced by men living in industrialized countries. No one
knows if exposure to phthalates is involved in the decline.
** Administration of DBP and DEHP to pregnant rats interferes
with the fetal development of male rats. DBP is widely used in
perfumes, nail polishes, and hair sprays, allowing for efficient
absorption through the lungs.
Phthalates were recently measured in baby food and infant
The National Research Council (NRC) (of the National Academy of
Sciences) discussed two phthalates in its July, 1999, study of
endocrine-disrupting chemicals (see REHW #665 ). The NRC noted
that female rats exposed to BzBP in water prior to mating
produced male offspring with significantaly smaller-than-average
testicles, and reduced sperm counts.[10,pg.21] A subsequent
attempt to reproduce this experiment failed to achieve the same
results, for reasons that remain unknown.
The NRC also noted that DBP has been shown in several animal
studies to cause atrophy of the testicles, and destruction of
sertoli cells (the cells that produce sperm). A multigenerational
study concluded that "DBP is a reproductive and developmental
toxicant to both adult and developing rats and that DBP had
greater effects on the second generation than [on] the first
generation."[10,pg.122] A different study showed that pregnant
rats dosed with DBP at a particular time during pregnancy
produced offspring with significant incidence of undescended
testicles.[10,pg.123] In humans in industrialized countries, the
occurrence of undescended testicles (a condition called
cryptorchidism) has been increasing in recent decades.
Dr. Louis Guillette, a University of Florida zoology professor
and a member of the NRC committee that studied hormone-disrupting
chemicals, says that Brock's study of phthalates in adults "is
going to rewrite how we look at phthalates.... Phthalates have
been something of concern up to this point. Basically they're
going to leap upward in terms of concern."
In the U.S., the National Institutes of Health (NIH) has created
a new Center for the Evaluation of Risks to Human Reproduction
(CERHR). In June of this year, a CERHR panel of experts concluded
its evaluation of seven phthalates. Although the CERHR study has
not yet been published, CERHR issued a press release July 14 in
which they acknowledged that the panel of experts had expressed
"concern" that exposure of pregnant women to DEHP might adversely
affect the development of their offspring. DEHP is the
chemical measured in baby girls with precocious breast
development in Puerto Rico.
As scientific and medical evidence accumulates, linking
phthalates to reproductive disorders in humans, the chemical
industry is digging in its heels for a 50-year fight. The
industry produces a billion pounds of phthalates every year and
has no intention of acknowledging that its products may cause
birth defects, infertility or hormone disruption.
Because the chemical industry is so wealthy and donates huge
quantities of cash to election campaigns (a perfectly legal form
of bribery), in the U.S. there is almost no way to get rid of
chemicals that have frightening characteristics, like phthalates.
They are here to stay. "I can tell you that we're going to be
working on phthalates for a long time here at CDC," says John
Brock. On the other hand, a citizen revolt could change the
election financing system almost overnight and immediately reduce
the political power of the chemical industry. Change is possible,
but only if people get angry and get involved. (See
--Peter Montague (National Writers Union, UAW Local 1981/AFL-CIO)
 Ivelisse Colon and others, "Identification of Phthalate
Esters in the Serum of Young Puerto Rican Girls with Premature
Breast Development," ENVIRONMENTAL HEALTH PERSPECTIVES Vol. 108,
No. 9 (September 2000), pgs. 895-900. Available at http://-
 Janet Raloff, "Girls may face risks from phthalates," SCIENCE
NEWS Vol. 158 (September 9, 2000), pg. 165.
 Catherine A. Harris and others, "The Estrogenic Activity of
Phthalate Esters In Vitro," ENVIRONMENTAL HEALTH PERSPECTIVES
Vol. 105, No. 8 (August 1997), pgs. 802-811. Available at:
 Susan Jobling and others, "A Variety of Environmentally
Persistent Chemicals, Including Some Phthalate Plasticizers, Are
Weakly Estrogenic," ENVIRONMENTAL HEALTH PERSPECTIVES Vol. 103,
No. 6 (June 1995), pgs. 582-587. Available at: http://-
 Janet Raloff, "New Concerns About Phthalates; Ingredients of
common plastics, may harm boys as they develop," SCIENCE NEWS
Vol. 158 (September 2, 2000), pgs. 152-154.
 Benjamin C. Blount and others, "Levels of Seven Urinary
Phthalate Metabolites in a Human Reference Population,"
ENVIRONMENTAL HEALTH PERSPECTIVES Vol. 108, No. 10 (October
2000), pgs. 972-982. Available at: http://ehpnet1.niehs.nih.gov/-
 Daniel P. Jones, "Troubling chemicals detected in people,"
HARTFORD [Connecticut] COURANT August 26, 2000, pg. unknown.
Available at http://archives.seattletimes.nwsource.com/cgi-bin/-
 Shanna H. Swan and others, "The Question of Declining Sperm
Density Revisited: An Analysis of 101 Studies Published
1934-1996," ENVIRONMENTAL HEALTH PERSPECTIVES Vol. 108, No. 10
(October 2000), pgs. 961-966.
 Jens H. Petersen and T. Breindahl, "Plasticizers in total
diet samples, baby food and infant formulae," FOOD ADDITIVES AND
CONTAMINANTS Vol. 17, No. 2 (February 2000), pgs. 133-141.
 Committee on Hormonally Active Agents in the Environment,
HORMONALLY ACTIVE AGENTS IN THE ENVIRONMENT (Washington, D.C.:
National Academy Press, 1999).
 National Toxicology Program, Center for the Evaluation of
Risks to Human Reproduction, Expert Panel Review of Phthalates,
press release dated July 14, 2000, available at http://-ntp-
or by phoning Bill Grigg at (301) 402-3378 or Sandra Lange at