Autism
in Children Linked to Environmental Factors
BRICK FAMILIES STILL SEEK ANSWERS ON AUTISM
By KIRK MOORE STAFF WRITER
When parents William
and Bobbie Gallagher pressed government officials to investigate why their
children and so many others here are autistic, they suggested it might be worth
checking into pollution and environmental factors. A 2001 federal report discounted possible connections between
autism and pollution. But the stories coming out of Brick got the attention of
other scientists, who have published new findings showing how some of the
chemicals detected here more than a decade ago ‹ when tested in combination and
at higher concentrations ‹ have the potential to affect nervous system
development in shellfish embryos.
"That's exactly what we were trying to say. What no one ever looks
at is the cumulative effect of these chemicals," said Bobbie Gallagher, a
mother of two autistic children. "That's one of the scariest things about
when they do these (environmental) studies. They only look at each compound
individually."
The contaminants
bromoform, chloroform and tetrachloroethylene triggered increases in a
component of an enzyme thought to influence neural development ‹ perhaps
offering a clue about how exposure to pollution mixes might affect human neural
development and enigmatic conditions, including childhood autism that was
reported at a higher than expected rate in Brick, said lead researcher Carol L.
Reinisch of the Marine Biological Laboratory at Woods Hole, Mass. "The issue really came down to looking
at the chemicals singly and in combination," said Reinisch, 59, a
scientist known for her work on polychlorinated biphenyls (PCBs) contamination
in lobsters and other marine animals. "What this study showed is it's the
mixture of these chemicals that cause the uptick in an enzyme that's very
important to neural development." Reinisch said the study was inspired in
part by news stories about a 2000-01 survey by the federal Agency for Toxic
Studies and Disease Registry (ATSDR) that looked at rates of autism among
Brick's school-age children population.
ATSDR experts then said they could not connect autism cases and local
pollution, and found no clear or convincing evidence of environmental pathways
that would have consistently exposed pregnant women to contaminants in
water.
ATSDR officials
wouldn't comment on the new toxicological study, because the scientists used
upper test levels that exposed clam embryos to 100 and 1,000 times the
concentrations observed here. " We have seen the study, but the mixtures
in that study are at different concentrations" than reported in 2001, said
Rachel Powell, a media officer with the agency. Even with that caution, several Brick parents, who worked to
focus official attention on the township's autistic population, said the latest
findings may lend credibility to the idea that local environmental conditions
can play a role in autism. "Do I
think it's environmental? I'm leaning that way," said Diana Gerlach,
president of a newly formed parents-teachers association for Brick's
special-needs students.
The study itself is a
significant milestone in environmental toxicology, according to Reinisch and
her colleagues, Jill A. Kreiling and Raymond E. Stephens. "This is one of the first reports demonstrating
that a mixture of environmental pollutants can act synergestically to alter a
critically important biochemical pathway in the developing embryo," they
wrote. Autism is a neurological disorder that leaves children with limited
ability to communicate or interact socially, a condition usually diagnosed by
age 3. Experts have been worried by an apparent rise nationally in autism
rates; scientists are trying to determine how much of that reflects more
accurate diagnoses, or an actual increase in autism frequency.
Studies by the federal
Centers for Disease Control and the ATSDR estimated that one in 150 children in
Brick was autistic, or three times the average national frequency. Since then, a study of autism frequency in Staffordshire,
England, has suggested such higher rates may actually be the norm. Some
research suggests genetics, rather than environment, may be key to causing the
condition. In the ATSDR effort,
researchers reviewed medical literature and compiled a list of contaminants
suspected of contributing to autism or similar conditions, such as pervasive
developmental disorder and Asperger's disorder.
Out of a list of about
60 contaminants, three substances ‹ trichloroethylene (TCE),
tetrachloroethylene (PCE), and a family of compounds, including bromoform and
chloroform, known as trihalomethanes (THMs) ‹ were found to have been in some
of the wells supplying Brick's municipal water at various times from 1987 to
1995 in very low levels of a few parts per billion, well below public health
guidance for drinking water. TCE and
PCE were present in several small wells that supplied a small percentage of
drinking water, but in levels too low to cause harm, according to the ATSDR.
Levels of trihalomethanes were elevated during certain periods and places, but
no clear pattern was found between those elevated levels and the pregnancy
period for children in the CDC's prevalence study.
Ground water under the
long-closed French's Landfill, a Superfund toxic waste site on Sally Ike Road,
is contaminated with hazardous chemicals, but the study concluded that
residents would not have been exposed to that water. ATSDR scientists looked,
too, at potential upstream pollution sources in the Metedeconk River, but
concluded the river could not have been contaminated at levels capable of
harming people.
In the toxicological
study, Reinisch and her fellow scientists treated developing surf clam embryos
with different combinations of PCE, bromoform and chloroform and observed the
effects. At the upper levels, they
tested the embryos with combinations that were 100 and 1,000 times higher than
the traces reported in Brick ‹ multiplying by factors of 10, in what scientists
refer to as orders of magnitude.
Chloroform was used at a maximum concentration of 240 parts per million,
above its maximum reported incidence in Brick at 240 parts per billion.
Bromoform and tetrachloroethylene were tested at 5 ppm and 6 ppm, above their
Brick occurrences at 5 ppb and 6 ppb respectively.
Clam neurons are a
useful model for studying cell development, said Reinisch, who helped develop
the method for use in polychlorinated biphenyls research, along with her
student, Cynthia Smith, while they were at the Tufts University veterinary
school. Treating the embryos with a
"cocktail" of all three compounds boosted production of a subunit of
protein kinase A or PKA, an enzyme that is believed to play a key role in
neural development, according to the team's report. Fluctuations in PKA help
activate or inactivate other important proteins, thus influencing nerve growth
and how neural networks are constructed during early life stages, they
wrote. Earlier research on
polychlorinated biphenyls showed they inhibit enzyme production, while
"the Brick chemicals do not, they bump it up," Reinisch said.
Funded with a grant from the
U.S. Environmental Protection Agency, the peer-reviewed study was published in
this month's issue of Environmental Toxicology and Pharmacology, a scientific
journal. The question of why some chemicals have such enhanced effects only in
combination is a leading edge in toxicological studies, and more are on the
way, Reinisch said. "Most
chemicals in the environment do not exist in isolation, they exist in
mixtures," said Chris Saint, a scientist with the EPA's National Center
for Environmental Research, which funded the experiments. "Our particular
interest is in developing new methodologies." Since the mid-1980s, such risk assessment was "traditionally
done on a chemical-by-chemical basis," Saint said. More recently, newer laws on food quality
and safe drinking water have empowered the agency to look for "cumulative
estimates of risk" that encompass chemical and environmental factors,
genetics, nutrition and other combined stresses on human health, he said. "The Canadians are really looking into
this," Reinisch said. "This is going to be a big push in the Great
Lakes region." As for the Brick chemicals study, the Environmental
Protection Agency is funding a second phase for the Marine Biological
Laboratory to test the contaminants on zebrafish, Reinisch said.
Parents feel
vindicated. The 2001 ATSDR report fell short of what parents were expecting,
when the paper was presented at a public meeting without explanation or
additional information from federal workers, Bobbie Gallagher recalled. Now,
she says, she's happy that other scientists picked up on those findings to
explore the potential of chemical synergy effects. "We feel a little vindicated, because ATSDR kind of hung us
out to dry with that study. The town was going crazy," said William
Gallagher, Bobbie's husband, who had pressed local officials and members of
Congress to get the investigation started. "We didn't deserve that. Now,
we feel a little vindicated."
For further information about chemical factors in autism
& other conditions, as well as healthy alternatives
to toxic products, Liberty Goodwin, Director, Toxics
Information Project (TIP) at 401-351-9193 or liberty@toxicsinfo.org Website:
www.toxicsinfo.org