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Executive Summary
Californians face increasing
obstacles to healthy development, from the moment of conception until they themselves
attempt to conceive. Problems like premature birth; male genital defects; learning,
attention, and emotional disturbances; early puberty; obesity; and low sperm
quality have been increasing in California and the nation as a whole over the
past several decades, impacting every stage of growth from conception to adulthood.
While a range of factors,
from lifestyle to heredity, may contribute to any one of these trends, a growing
body of research suggests that toxic chemicals play a significant role. Studies
are revealing chemical contamination in human bodies, finding associations between
chemical exposure and human disabilities and disease, and demonstrating toxic
effects at increasingly lower levels of exposure.
The findings of this report
are by no means comprehensive. While well-known toxicants like mercury, lead,
dioxin, and PCBs have been clearly linked to human health damage, thousands
of other chemicals that people are exposed to in the home have never been studied
for health effects. Here we focus on the most recent science surrounding several
emerging chemical hazards—a growing body of evidence showing that chemicals
found in the home and in common consumer products may hinder normal development.
Chemical exposure is
widespread.
Human bodies are the repository for countless chemicals encountered in everyday
experiences and found in common consumer products. Exposure to these substances
during fetal development is unavoidable.
• Phthalates, used to “plasticize”
some food containers, plastic wrap, toys, shampoos, perfumes, and beauty products,
are among the most frequently found contaminants in human bodies.
• Flame retardants, added
to foams, plastics, and electronics, have been found at exponentially increasing
levels in women in California; levels in U.S. women have reached up to 75 times
the levels found in Europe and Japan.
• Bisphenol-A, the main
ingredient in hard polycarbonate plastics for baby bottles, drinking water bottles,
and food containers, has been detected in pregnant women in Germany and Japan.
It is one of the top 50 production-volume chemicals in the U.S., and exposure
likely is widespread.
• Pesticides and their breakdown
products are commonly found in people. In a recent study, the U.S. Center for
Disease Control and Prevention found 13 different pesticides in the average
American, out of 23 pesticides under consideration.
At each stage of life,
toxic chemicals may hinder normal development.
Even before their first
breath, insurmountable challenges, from premature birth to birth defects, await
an increasing number of children.
Premature birth, which
raises the risk for reduced intelligence and learning and attention problems
throughout life, is 23 percent more frequent now than in the 1980s in the United
States. One potential factor may be phthalates:
• Babies exposed to a common
phthalate in utero are born a week earlier on average than babies without
exposure.
Birth defects are the leading
cause of infant death in the U.S. While the specific causes of most birth defects
are unknown, they could be linked to a variety of chemical exposures, including:
• Phthalates. In male lab
rats, phthalate exposure in utero leads to undescended testicles and
malformed urinary tracts. The frequency of these conditions in baby boys doubled
from 1970 to 1993 in the United States.
• Bisphenol-A. In experiments
with mice, bisphenol-A can induce the genetic defect that causes Down’s syndrome,
at levels comparable to those found in women tested to date.
• Pesticides. One study
found an association between miscarriages caused by birth defects and commercial
pesticide applications within a nine square mile area around the home. Another
study found that boys conceived during the period of most intense application
of the herbicide 2,4-D were five times more likely to have a birth defect than
boys with no unusual exposure.
Infancy and early childhood
is a time marked by rapid growth and learning. However, a growing number of
California children are suffering from developmental disorders that impair their
ability to learn normally.
Neurodevelopmental and
mental health disabilities are rapidly rising in California. Autism cases in
California have more than tripled since 1994, and the number of students in
public schools with learning disabilities increased 65% from 1985 to 1999. No
one cause has been implicated, but scientific evidence raises questions regarding
numerous potential factors, including exposure to toxic flame retardants, bisphenol-A,
perchlorate, pesticides, and the well-established culprits of lead, mercury,
dioxin, and PCBs. Consider:
• Flame-retardant chemicals
given to newborn mice in small doses permanently impair their learning and behavior,
and small doses of bisphenol-A produce hyperactivity.
• The rocket fuel component
perchlorate, found in the drinking water sources of 16 million Californians,
affects the thyroid hormone system at very low levels of exposure. Children
born to mothers with thyroid problems have higher rates of learning disabilities.
• Children exposed to agricultural
pesticides show deficiencies in intellectual development, stamina, balance,
hand-eye coordination, and short-term memory.
As children develop into
young adults, they struggle with the rapid changes in their bodies that lead
to sexual maturity. However, several unexplained trends suggest that children
face additional health challenges at this stage of life, including early puberty
and obesity.
In the last four decades,
the number of obese adolescents in the U.S. has quadrupled, and girls in the
U.S. appear to be reaching puberty six months to one year earlier than in the
past, with a small number of girls developing breast tissue when they are as
young as three years of age. Both trends could be tied to endocrine-disrupting
chemical exposures in utero.
• Rodents exposed to bisphenol-A
give birth to female offspring that grow faster, weigh more, and enter puberty
earlier. If applicable to humans, these effects could predispose exposed children
toward obesity and early puberty.
Finally, upon reaching
adulthood, many people choose to have children of their own. However, chemical
exposures may be contributing to infertility and other reproductive difficulties.
Sperm density has declined
40% in the U.S. since World War II. Exposure to phthalates, pesticides, and
flame retardants may be contributing to this trend.
• Men with high levels of
phthalates or pesticides in their urine (including diazinon, heavily used in
California agriculture) tend to have low levels of sperm production.
• Male rats exposed to even
a single low dose of PBDE flame retardants while in the womb have significantly
decreased sperm counts.
Reducing exposure can
prevent harm.
Several instances where regulatory agencies took action demonstrate the value
of reducing exposure for human health:
• The EPA banned household
uses of the pesticides chlorpyrifos and diazinon in 2001. It appears that this
health-protective
action had a nearly immediate effect. After 2001, mothers in New York City had
lower levels of these compounds in their bodies and, remarkably, gave birth
to heavier and longer babies than those born before the pesticide ban.
• The phasing out of leaded
gasoline and other efforts to reduce lead exposure have reduced the number of
children with toxic levels of lead by half over the last decade.
Policy Reforms
The newly discovered connections
between chemicals and disease outlined here just begin to scratch the surface
of the potential impact of chemicals on public health. Tens of thousands of
industrial chemicals on the market have not been tested for developmental health
effects at low doses. No public health information exists for close to half
of the high production-volume chemicals. Moreover, where significant evidence
of harm to public health already exists, inadequate resources and legal authority
often prevent regulatory agencies from taking protective action.
In order to protect children
from toxic exposures, we must take firm steps to remedy the ignorance about
health effects of widely-used chemicals and empower regulatory agencies to ensure
that consumer products do not contain dangerous chemicals. These steps include:
1) Phasing out chemicals
that persist in the environment, accumulate in organisms, or for which evidence
of potential harm to human health exists from exposure.
2) Requiring chemical manufacturers
to develop analytical techniques to detect the chemicals they produce, and relevant
breakdown products, in environmental media and organisms, and to submit these
techniques to the state. Currently, taxpayers pay for scientists to guess at
what emerging chemical threats may be present in our environment and bodies
and then develop the testing methods to detect them. This causes significant
delay in determining which chemicals pose the greatest threat to public health.
3) Requiring chemical manufacturers
to supply the state and federal government with toxicity data for their products,
including low-dose effects on development and reproduction. The European Union
recently developed a model policy, known as Registration, Evaluation and Authorization
of Chemicals (REACH), that would vastly increase the amount of information available
to determine the safety of chemical products.
4) Encouraging the federal
government to stop lobbying heavily against the new European Union chemicals
policy on behalf of U.S. industry, and to take a stronger stand for public health.
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