Description

Guthion is the common name of an organophosphorus insecticide. It is a formulation that includes the active ingredient of azinphos-methyl.

Guthion does not occur naturally in the environment.

Pure guthion is a colorless to white odorless crystalline solid. Technical-grade guthion is a cream to yellow-brown granular solid.

Uses

• Pesticide uses

Guthion is used to control pest insects on many crops, especially apples, pears, cherries, peaches, almonds, and pistachios.

Many uses of guthion have been cancelled by the EPA and its few remaining uses are being phased out.

Sources

Guthion is primarily released to air from its use as an insecticide. Guthion is sprayed on crops primarily using ground-based spray equipment, although it can also be sprayed on crops from light-weight planes and helicopters.

Although a large part of the spray lands directly on the crop, some of the smaller droplets that make up the spray can be carried away from the crop by the wind to nearby water bodies and soils.

Guthion residues may also reach nearby rivers, streams, lakes, or ponds by water runoff and erosion that occurs during rainfall.

Manufacturing facilities that produce guthion can also release it to the environment during the production process.

How guthion breaks down

Guthion is not very persistent in the environment.

Guthion is degraded to many other compounds by microorganisms found in soil and water. It is also degraded by sunlight and by reacting with water.

Guthion does not evaporate very quickly from soil and water. It attaches strongly to soil surfaces and does not easily move into groundwater below the soil surface.

Food—primary source of exposure

You are primarily exposed to guthion by ingesting foods treated with this pesticide. Apples, pears, peaches, and cherries are crops most likely to contain guthion residues, but fewer residues are being found as guthion use in agriculture has been diminishing.

Air

You may be exposed to guthion in air in areas close to fruit orchards or other crops where guthion is used.

Workplace

People who work in agricultural jobs such as pesticide applicators, fruit pickers, and other farm workers can be exposed to higher levels of guthion than the average individual, probably by skin contact with the insecticide and by inhalation.

Families of workers can also be exposed because residues on workers’ hands, clothes, vehicles, or other personal items can be brought into the home.

Children

Children playing on or near areas that have been treated with guthion may be exposed to guthion in soil by skin contact, when they accidentally or intentionally put soil into their mouths, and through hand-to-mouth activity.

Children can also be exposed through food and drink. Since children have more fruit in their diets, their exposure to guthion may be higher than for adults on a body weight basis.

Enter your body

• Inhalation

If you breathe air containing guthion, you may absorb it into your body through the lungs.

• Ingestion

Most guthion in food or water can be absorbed from the digestive tract.

• Dermal Contact

Guthion may enter your body across the skin.

Leave your body

Once in the body, guthion is rapidly broken down and eliminated from the body mainly in the exhaled air, urine, and feces.

Human exposure

Guthion affects the normal function of the nervous system by interfering with an important enzyme called acetylcholinesterase. Exposure to guthion can result in signs or symptoms of nervous system damage shortly after exposure.

If you experience these symptoms, you should seek medical attention immediately. Emergency rooms have drugs that stop the harmful effects of guthion.

Laboratory animals

Symptoms observed in animals exposed to high levels of guthion include excess saliva, watery eyes, and muscle twitching.

It is likely that humans exposed to high levels of guthion will have similar effects.

Cancer

Guthion has not been shown to cause cancer in people or animals.

The Department of Health and Human Services (DHHS), the EPA, and the International Agency for Research on Cancer (IARC) have not classified the carcinogenic potential of guthion in humans.

Effects in children

We do not know whether children are more sensitive than adults to the health effects of guthion. The main target for guthion in adults is the nervous system, in particular acetylcholinesterase. It is expected that this will also be the main target in children.

Birth defects

We do not know if guthion can cause birth defects or other damage to developing children.

Studies in animals have found decreases in fetal growth, nervous system damage, and reduced survival, but only at doses that also caused harmful health effects in the mothers.

Wash fruits and vegetables

To reduce the risk of exposure to guthion residue on fresh fruits or vegetables, wash the foods prior to eating them.

If you go to an orchard and pick your own fruit, make sure you wash your hands when you are finished since guthion residues can be absorbed through the skin.

Those who live in agricultural areas

If you live near a farm where frequent ground or aerial spraying takes place, you may want to remain indoors with your children and pets while the crops are being sprayed to lessen your exposure.

You should discourage your children from entering areas treated with guthion. Discourage your children from eating dirt and putting their hands in their mouth. Make certain your children wash their hands frequently, especially before eating.

If children play in grass fields or orchards, any pesticides used in these areas could collect on clothing. Regular laundering of clothing can reduce the potential for this exposure.

Measuring effects

Guthion, like other organophosphorus pesticides, interferes in the human body with an enzyme called acetylcholinesterase. Most of the signs and symptoms resulting from guthion poisoning are due to this interference with acetylcholinesterase.

A blood test that measures acetylcholinesterase in the red blood cells or a similar enzyme in plasma may be useful for detecting exposures to potentially harmful levels of guthion.

Detecting exposure

Because guthion changes to other compounds in the body quickly, it is difficult to directly analyze the amount of guthion in a person’s body. Three chemicals formed when guthion breaks down can be measured in the urine. However, these three compounds are not specific to guthion only, but may also indicate exposure to other organophosphorus pesticides.

Food

The EPA has set tolerances for residues of guthion in various raw food products of 0.2–5 parts of guthion per million parts of food (ppm).

Workplace air

OSHA set a legal limit of 0.2 milligrams per cubic meter (mg/m³) guthion in air averaged over an 8-hour work day.

NIOSH designated a limit of 10 mg/m³ as a concentration that is immediately dangerous to life and health.