Kathy Brunetti, Agriculture Program Supervisor
California Department of Pesticide Regulation
1020 N Street Room 161, Sacramento, California, USA 95814-5624
voice (916) 324-4100, FAX (916) 324-4088, email@example.com
Our Web site: http://www.cdpr.ca.gov
DPR TO BEGIN NEW PHASE OF METHYL BROMIDE MONITORING PROGRAM
SACRAMENTO -- The next phase of Cal/EPA's Department of Pesticide
Regulation's continuous evaluation of methyl bromide use will commence this
month when DPR begins a six-month program of monitoring methyl bromide
fumigations throughout the state.
DPR scientists plan to monitor a minimum of two fumigations a
month, beginning in late July and continuing through February 1998. DPR
will also conduct a study comparing air sampling methods.
"Beginning in January 1993, DPR and the county agricultural
commissioners imposed a series of restrictions on methyl bromide use in
field fumigations to provide better protection for workers and others who
may be near fumigation sites," said DPR Director James W. Wells. "No other
state has adopted these safety measures, and they far exceed national
DPR based these safety measures on more than 1,000 field-measured
air samples from 11 fumigations. In all 11 cases, the calculated buffer
zones provided at least a 100-fold margin of safety. Because these
fumigations were done during summer weather, additional monitoring was done
last winter to evaluate methyl bromide air concentrations in cold, stable
"We periodically check to make sure things are working as they
should and the public is protected," said Wells. "We plan to continue
methyl bromide monitoring through the rest of the year."
DPR scientists will start monitoring this month, beginning in
Ventura County. DPR plans to monitor about two fumigations monthly through
February 1998. Sixteen air sampling devices will be used to collect data
at varying distances from each treated field. Among sites to be monitored
will be applications to fields that are near homes. Meteorological data
will also be collected to measure wind speed, wind direction, ambient
temperature, and relative humidity.
DPR also has scheduled a laboratory project in cooperation with the
State Department of Health Services to compare different kinds of equipment
used to collect air samples around fumigation sites. DPR expects to begin
this study this summer.
"We expect the results of these studies to round out our already
large data base on methyl bromide and help us fine-tune the restrictions,
if needed," said Wells.
"Monitoring done last winter has already paid benefits," said
Wells. "The initial 11 studies we used to develop the use restrictions
were done in summer. We wanted to do winter monitoring to find out if we
should modify the use practices to take into account the more stable
atmospheric conditions you typically get in winter."
In December 1996, and January and February 1997, DPR scientists
took air samples around six methyl bromide field fumigations. "These were
real-world fumigations, not done for benefit of the study," Wells said.
"Three used a relatively new technique, in which hot methyl bromide gas is
pumped into a drip irrigation system. We found that the standard buffer
zones we require around fumigations are not large enough when the hot gas
method is used. We immediately established a minimum buffer zone of
one-half to one mile around the fumigations."
A buffer zone is the area between the edge of a treated field and
nearby occupied buildings or land areas (for example, parks) where people
may gather. The zone extends in all directions around a treated area.
The other three studies done last winter produced ambiguous
results, Wells reported. "Three studies are not really enough from which
to draw firm, scientifically based conclusions. But to be on the safe
side, we will be enlarging the buffer zones for winter conditions before
those fumigations happen at the end of the year. We may fine-tune them
further based on additional monitoring next winter."
Methyl bromide is a gaseous fumigant that kills insects, mites,
rodents, nematodes, termites, weeds, and organisms that cause plant
diseases. Farmers use methyl bromide to treat soil before planting many
vegetable, fruit and nut crops, and forest nurseries. After harvest, methyl
bromide protects crops from pest damage during storage and transportation.
It is also used for termite control in homes and other structures, and to
control insects in mills, ships, railroad cars and other transportation