June 22, 2004: Milk from cows raised in some
parts of California may expose infants and children
to more of a toxic rocket fuel chemical than is considered
safe by the U.S. Environmental Protection Agency (EPA)
and the State of Massachusetts, according to unreleased
tests by state agriculture officials and independent
laboratory tests commissioned by Environmental Working
In the first study to look for perchlorate in California
supermarket milk, EWG found the rocket fuel chemical
in almost every sample tested - 31 out of 32 samples
purchased from grocery stores in Los Angeles and Orange
counties. The average level of perchlorate in the samples
was 1.3 parts per billion (ppb) — just above the
EPA's currently recommended safe dose of 1 ppb.
Through a state Public Records Act request, EWG also
obtained results of tests for perchlorate in milk by
the California Department of Food and Agriculture (CDFA),
which the agency has not made public or provided to
state health officials. CDFA's tests found perchlorate
in all 34 samples of milk collected from unspecified
sources in Alameda, Sacramento, and San Joaquin counties.
The average level of perchlorate in the samples was
5.8 ppb, or just below the state's recently set Public
Health Goal of 6 ppb.
A computer-assisted analysis of federal dietary data
shows that by drinking milk contaminated with the levels
of perchlorate found in the two studies, half of all
children 1 to 5 would exceed EPA's provisional daily
safe dose just by drinking milk, and more than a third
would get twice that dose. One-third of children 6 to
11 would get a larger dose than EPA says is safe, with
one-fifth consuming twice as much.
Perchlorate, the explosive component of solid rocket
fuel, can affect the thyroid gland's ability to make
essential hormones. For fetuses, infants and children,
disruptions in thyroid hormone levels can cause lowered
IQ, mental retardation, loss of hearing and speech,
and motor skill deficits.
Currently there are no enforceable perchlorate safety
standards at the state or federal level. The state's
Public Health Goal of 6 ppb will be used to set a final
drinking water standard, expected early next year.
"Our findings are not a call for California mothers
to stop drinking milk or stop giving it to their children,"
said Bill Walker, EWG Vice President/West Coast. "They
do show that the state must set a drinking water standard
that fully protects public health. Mothers should not
be forced to wonder if milk is affecting their child's
growth and development."
Perchlorate contaminates more than 350 drinking water
sources in California alone. Nationally, perchlorate
contamination of drinking water has been confirmed by
testing in 22 states. Among contaminated sources is
the Colorado River, which not only provides drinking
water for Los Angeles, Phoenix, Las Vegas and other
cities, but also irrigates 1.4 million acres of farmland
in California and Arizona. Many crop and feed plants,
including lettuce, cucumbers, tomatoes and alfalfa,
concentrate perchlorate in their tissues when grown
with contaminated water. The perchlorate ingested by
cows in their water and feed is passed along in milk.