Allergy sufferers don't cotton to defoliants, but link is unclear

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Allergy sufferers don't cotton to defoliants, but link is unclear

By Barbara

The Fresno Bee

(Published October 2, 2000)

The low hum of crop-dusting planes, dropping out of the sky like steel

dragonflies over cotton fields in the San Joaquin Valley, signals the

beginning of cool nights, foggy mornings -- and sneezing and wheezing.

Each fall, doctors have waiting rooms filled with red-eyed, stuffy-nosed

patients whose symptoms seem to ebb and flow in rhythm with the beginning

and end of cotton defoliant season.

Complaints about the chemicals -- sprayed on cotton to strip the plants of

their leaves -- are about as old as the practice of mechanical harvesting,

but cotton farmers say they are being accused, tried and convicted on

circumstantial evidence that hasn't been tested by scientific research.

" I sure don't want to pooh-pooh people's symptoms, " said Betancourt, a

westside cotton farmer. " But if it's just anecdotal -- accusations by

circumstantial evidence -- maybe we need to do an objective study and nail

this thing down. "

Doctors are the first to admit they don't have proof that defoliants are the

cause of their patients' respiratory distress. They can only go by what they

see in their offices during the months of September and October, when cotton

is defoliated.

" Almost all of my asthma patients and patients with sinus problems, they

really get worse this time of year, " said Dr. Malik Baz, an allergy

specialist at the Allergy Center in Fresno.

But Baz admits his patients' misery could have as much to do with nature as

man's manipulation of his environment. Weed pollen counts go up in the fall,

as does the number of mold spores. Defoliants, he said, are just another

substance to factor into the mix of respiratory irritants in the air.

Without health studies, it's hard to know whether blaming defoliants for

respiratory problems is justified, he said. Most studies of cotton

defoliants look at occupational exposures for workers in the fields and not

at the potential health risks of exposure to chemicals floating in the air

or attached to dust particles.

Pesticide watchdogs say information is lacking on the effects of breathing

airborne defoliants, but they argue the sheer number of chemicals being

sprayed on cotton fields in the Valley makes it probable that people are

being exposed.

Neurotoxin worries some

Cotton farmers depend on chemicals to strip leaves that would clog

mechanical harvesters and stain cotton green. The Pesticide Use Report,

issued by the California Department of Pesticide Regulation, shows that

835,449 pounds of four of the most widely used chemicals were sprayed to

defoliate Fresno County's 145,000 acres of harvested cotton in 1999.

The top four defoliants: Sodium chlorate, 569,807 pounds; S,S, S-tributyl

phosphorotrithioate (DEF), 156,754 pounds; Paraquat dichloride, 98,834

pounds; and Thidiazuron (Ginstar EC), 10,054 pounds.

Of particular concern to environmentalists is the use of the organophosphate

known as DEF. Organophosphates are neurotoxins that disrupt the transmission

of nerve signals.

DEF is " a nasty one. It's not one you want to be next to, " said

Kegley, a staff scientist at Pesticide Action Network, an environmental

activist group working to reduce the use of pesticides.

Little research has been done on the effects of breathing organophosphates,

but a 1999 study of DEF by the state Department of Pesticide Regulation

found little risk from breathing the chemical in ambient air around cotton

farms.

The study showed " in terms of short-term exposure, the levels of exposure to

DEF were very low, " said Jay Schreider, DPR primary state toxicologist.

However, the foul odor associated with DEF could be smelled at very low

concentrations. DEF is readily degraded to n-butyl mercaptan, a substance

that gives off the smell of rotten eggs that is similar to the odor added to

natural gas.

The DPR report said offensive odors can trigger symptoms in people, such as

headaches and nausea.

The study said reports of eye and lung irritation by people in communities

near cotton fields may be due to n-butyl mercaptan, but " no reliable air

monitoring data for n-butyl mercaptan was available. "

Cheryl Gorman can't ignore the smell of rotten eggs on her way to and from

work as an elementary teacher in Kerman. She has a stuffed nose and sinus

headache during most of the fall, while cotton fields around the school are

being defoliated.

" I just know, during this time of the year, I'll be taking my allergy

medicine and treating my allergy symptoms, " Gorman said.

In the past few years, organophosphates have caused fewer complaints because

manufacturers changed formulas to eliminate the tell-tale rotten egg or

sulfuric odor. The pesticide, one of the most regulated, cannot be applied

within a half-mile of residential areas and when winds are higher than 10

mph.

But the defoliants remain an environmental concern, Kegley said. " Only pure,

clean air belongs in our lungs. "

Newer materials, which are less volatile, are gaining favor with farmers,

said Ron Vargas, county director and farm adviser in the Madera County

Office of the University of California ative Extension.

" What I see is five years down the road, we're going to have materials that

have been developed that are going to seriously mitigate this problem, " he

said of people complaining about defoliants causing headaches and

respiratory problems.

Betancourt is using the defoliant Ginstar on his Pima cotton. " We use a lot

less of the phosphate -- which is the one that smells the worse -- than we

ever have before because there are alternatives that weren't there before, "

he said.

He questions widespread claims that pesticides cause congestion and sinus

headaches. A year ago, he said, he had people complaining about headaches a

week before any cotton fields in the area were defoliated.

How could someone, he said, living 60 miles away in Clovis, be affected by

the crop dusting he does on his cotton fields in Cantua Creek and

Tranquillity?

If test results showed the chemical in measurable quantities in the air in

Clovis, " I'd say you've got the smoking gun, " he said. " Otherwise, I would

look at other stuff. "

The Central Valley has an air-quality problem, especially during stagnant,

hot fall days, Betancourt said. " I would suspect there are worse things in

the air than the defoliant spray. "

But allergists say it may not take a high concentration of chemicals to

trigger allergic responses in patients who are extremely sensitive to

irritating substances, such as dust, pollen, mold spores, perfumes -- and

chemicals.

In the patient who is not sensitive, the body may not recognize the

defoliant as a big enough threat to launch an all-out assault by secreting

more mucus to trap the offending particles and coughing to push them out.

But for the patient who is hypersensitive to irritants, it could cause

coughing and the bronchial tubes to spasm, said Dr. A.M. Aminian with the

Allergy Institute of Fresno.

" The best thing for everyone to do is to avoid the irritants to the

bronchial tubes, " Aminian said. " And that includes any irritant chemicals or

fumes. "

Defoliants' role is unclear

If fewer pollen particles and mold spores were in the air, it's possible

breathing tiny amounts of defoliants wouldn't bother his patients, Baz said.

But, with high pollen and mold counts, they're primed and ready to react to

any irritant.

Without more studies on the effects of defoliants, it's hard to know whether

the chemicals are to blame for the wheezing and sneezing, he said. " There

are just no good studies. "