Organic Consumers Association

Pesticides & Methyl Bromide Use
in California Still a Major Hazard

Pesticides in Water Threaten Aquatic Life
October 7, 2003

A recent U.S. Geological Survey (USGS) study of water samples collected in
California's San Joaquin Valley reveals pesticide concentrations more than
10 times higher than proposed limits. USGS researchers gathered samples of
rainfall, storm-water runoff, and river water during the winter of 2000
through 2001 to determine concentrations and water travel patterns for two
common organophosphate pesticides, diazinon and chlorpyrifos. They found
concentrations of these pesticides at levels that are dangerous to aquatic
life and clearly demonstrate the ability of pesticides to move far beyond
the scope of their initial application.

These same pesticides are prone to airborne pesticide drift and have been
found in unhealthy concentrations in air samples collected up to 72 feet
from the application site (see the PANNA report, "Secondhand Pesticides:
Airborne Pesticide Drift in California," ). Pesticide
drift also contributes to high concentrations of pesticides in rainfall as
pesticides volatize into the lower atmosphere, are washed back to earth with
rain, and run-off into rivers. USGS scientists attributed 68 percent of
diazinon concentrations found in river water samples to rainfall.

The two pesticides monitored in the study, chlorpyrifos and diazinon, are
insecticides most commonly used during the dormant winter season and are
applied via crop dusting planes or tractors equipped with spray mechanisms.
These pesticides were once popular for home use, but the U.S. Environmental
Protection Agency (U.S. EPA) recently initiated phaseouts because studies
showed that existing exposures levels were a high risk to children's health.
Both chemicals are neurotoxins, inhibiting proper transmission of nerve
impulses. Both are highly toxic to aquatic life.

Chlorpyrifos and diazinon are frequently found in toxic levels in streams,
in part because their application period coincides with the rainy season.
Surveys from previous years found similarly toxic levels of chlorpyrifos and
diazinon in streams and groundwater throughout the nation, and especially in
California's waters. A 1992-95 survey of ground and surface waters of the
San Joaquin-Tulare Basins revealed concentrations of diazinon and
chlorpyrifos at levels doubling those considered safe for aquatic life and,
in the case of diazinon, also exceeding safe drinking-water levels.

Unfortunately there is no single, regulatory organization determining health
and safety limits on the concentrations of these pesticides in water, making
monitoring and restrictions difficult to implement. The California
Department of Fish and Game has set concentration baselines necessary to
maintain a healthy aquatic environment. Of the water samples collected, a
total of 78 contained concentrations exceeding these limits, 60 samples for
diazinon and 18 for chlorpyrifos. In all, researchers collected 220 samples.

The California Department of Pesticide Regulations (CA DPR) has initiated
their own concentration limits through the proposed Dormant Spray Water
Quality Initiative. When the USGS study results are compared to these
proposed guidelines, pesticide concentrations in water samples exceeded
limits by up to a factor of 10 for diazinon and 7.4 for chlorpyrifos.
Although the CA DPR states that these levels are of no consequence to human
health, they do pose grave threats to aquatic life. In addition to
establishing concentration limits, the CA DPR initiative would require
mandatory controls to limit drift and water run-off of these pesticides and
provide ongoing monitoring of concentration levels.

The USGS report is part of an ongoing effort to monitor pesticide levels in
water. Initiated in 1991, the National Water-Quality Assessment (NAWQA)
program conducts surveys of various water quality indicators, including
pesticide levels. A recent NAWQA study found 90 percent of water and fish
samples collected contained at least one pesticide, some of which have not
been used in decades, testimony to the persistence of these chemicals in the
Sources: Diazinon and Chlorpyrifos Loads in Precipitation and Urban and
Agricultural Storm Runoff during January and February 2001 in the San
Joaquin River Basin, California, Celia Zamora, Charles R. Kratzer, Michael
S. Majewski, and Donna L. Knifong, USGS, 2003, ; The Quality of Our Nation's
Waters: Nutrients and Pesticides, USGS NAWQA, 1999, ; Secondhand Pesticides: Airborne
Pesticide Drift in California, Susan Kegley, Anne Katten, & Marion Moses,
Californians for Pesticide Reform, 2003, ;
Water Quality in the San Joaquin-Tulare Basins, California, 1992-95, Neil M.
Dubrovsky, Charles R. Kratzer, Larry R. Brown, Jo Ann M. Gronberg, Karen R.
Burow, USGS, 1998,


Respirators required in fields; New regulations on the use of
methyl bromide are changing the way farming is done in Monterey
County and across the state
Quinn Eastman
Monterey Herald (CA)
Monday, September 29, 2003

Trying to balance health concerns and the needs of agriculture,
state regulators this week announced changes in rules governing
the use of a chemical that many Monterey County growers rely on.

The new regulations require respirators for agricultural workers
applying methyl bromide and cap the amount of the fumigant that
can be applied in defined geographic areas.

The question of where to set safety thresholds for methyl bromide
previously has prompted lawsuits in Monterey and Ventura
counties and disputes among state officials and health experts.

The federal government agreed to an international treaty phasing
out the fumigant by 2005 because of its destructive effect on
atmospheric ozone, but federal officials have applied for
exemptions based on agriculture's argument that there is no
feasible alternative.

Fruit and vegetable growers say methyl bromide is the most
effective way to rid the soil of pests before planting. The
strawberry industry depends more on methyl bromide than other
fruit growers do because of the need to replant every year.

Restrictions on methyl bromide, along with the rising price, are
putting economic pressure on growers.

New components of the state regulations for growers add respirator
requirements to monthly limits on working hours. Also new is an
annual cap of 270,000 pounds for each area of 36 square miles, a
level not yet reached in California.

Bob Roach, assistant agricultural commissioner for Monterey
County, says the new regulations actually will allow growers and
applicators more flexibility because of the approval of a more
portable respirator cartridge.

While refining the regulations on methyl bromide use, the state
Department of Pesticide Regulation backed off an earlier plan to
keep a temporary safety threshold for methyl bromide in the air at
one part per billion for children. The new reference levels for
seasonal exposure are raised to nine parts per billion for children,
and 16 parts per billion for adults.

"We have serious problems with the newer (standards)," said Mike
Meuter, a lawyer for California Rural Legal Assistance.

His group helped sue the Department of Pesticide Regulation and
the Monterey County Agricultural Commissioner in 2001,
claiming that the levels of methyl bromide in the air near several
Monterey and Santa Cruz county schools were high enough to
endanger students' health.

Last year, the state agency settled the lawsuit, agreeing to
incorporate the latest safety studies into its rules dealing with
seasonal exposure. Monitoring near schools such as Pajaro Middle
School in Watsonville and La Joya Elementary in Salinas detected
levels between one and eight parts per billion.

"It's moving the goalposts. We think it's inappropriate," said

Regulators figure out the acceptable exposure levels by starting
with toxicity studies performed on animals, then dividing by an
uncertainty factor, usually one hundred, that takes into account the
differences between animals and humans and within populations.

"Dogs respond differently to toxins, and they can't tell us that they
have headaches or feel tired," explained George Alexeev, a
pesticide specialist at the office of Environmental Health Hazard
Assessment. His agency disagreed with the Department of
Pesticide Regulation's decision on where to set the reference
exposure level for methyl bromide, noting problems interpreting
the results of recent toxicity studies. He also cited the opinion of an
earlier National Academy of Sciences panel that had recommended
keeping the one part per billion standard.

Susan Kegley, a toxicologist working for the Pesticide Action
Network, said extra caution needs to be taken because children are
more sensitive to toxins. She wants more studies to determine
whether methyl bromide could interfere with their developing
nervous systems.

"We think the state isn't putting enough margin for error in its
safety standard," she said.
At Pajaro Middle School, site of previous monitoring for methyl
bromide residues, teacher Sherry Alderman said, "I just worry
whether I or one of my students will get cancer in 10 years."

Glenn Brank, communications director for the state pesticide
agency, said California's regulations on methyl bromide are stricter
than any other state's. He suggested that health advocates push for
a national regulatory standard, noting that Florida last year used
more methyl bromide than California.

Neil Nagata, a strawberry grower who works on regulatory issues
with the California Strawberry Commission, says methyl bromide
as used in the field has an immediate effect similar to tear gas:
"You notice it right away."

Methyl bromide is a heavy, odorless gas and is usually mixed with
chloropicrin, another fumigant, which produces the tear gas effect.
Applicators then inject it into the ground while the fields are
covered by tarps. Nagata said the tightening of state regulations has
made it more difficult to fumigate, so what once took five days
now takes a month. He wondered if the consequent spreading out
of methyl bromide use might be counter-productive for health

Since the price of application has increased by more than 50
percent -- to more than $1,500 per acre -- the cost eats into profits,
hitting small farms harder than larger farms.

Some fruit growers are experimenting with alternatives such as
other fumigants like Telone and methyl iodide, but none have been
approved by state regulators. Roberto Rodriguez, who sells
strawberries at the open-air market on Alvarado Street in
Monterey, said the farm where he worked switched to Telone a few
years ago because the price of Telone per acre was half of methyl
bromide's. He says he has worked on growing strawberries near
Route 129 for twenty years using methyl bromide, but when he

sets up his own farm soon, he's switching to an organic approach,
without soil fumigation, because "it's safer."

As part of a comment period prior to formal implementation of the
new rules, the Department of Pesticide Regulation is holding
hearings in Sacramento, Ventura and Salinas. The Salinas hearing
is scheduled for 6 p.m. Nov. 17 at the Salinas Community Center,
950 N. Main St.

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