Agricultural chemicals include thousands of formulations such as petroleum products, pesticides, growth regulators, buffers, nutrients and fertilizers, and veterinary medications. These chemicals may be used in solid, granular, powder, pellet, or block form; liquids in mists and sprays; or in gaseous form as fumigants or fuels. Application of chemicals to crops may be by aircraft, vehicles or stationary sources; injection of gas, liquid or solids into water soil, animals, or feed; or gaseous exposure in fumigation cells. Animals may be dipped in pools of dilute insecticides to remove surface insects. To save on manpower and fuel, it is common to apply five or more chemicals at once to a crop, making it difficult to determine which are the relevant agents (Lessenger, 2006).
Depending on the operation, a farmworker may:
- apply the chemicals to soil, crops or animals;
- assist with the mixing, application or storage,
- simply work in the vicinity of the chemicals.
Exposures occur in three ways:
- transdermal (varies with chemical solubility, hygiene and protective equipment)
- inhalation (varies with aerosol characteristics, ambient ventilation and respiratory protection)
- ingestion (varies with hygiene and protective equipment)
Use of personal protection (goggles, gloves, respirators, suits, boots) is of considerable importance, but less important than selection of the least toxic agents, use of formulations that decrease risk of exposure and careful consideration of environmental conditions associated with chemical application.
The table below is a compilation of chemicals recommended by integrated pest management researchers in New York, New Jersey, Pennsylvania and New England for apple growers (largest apple producing states). These are gathered from state tree fruit guidelines. Information on toxicology and treatment was gathered from: material safety data sheets and the EPA publication “Recognition and Management of Pesticide Poisonings.” (For a free copy call 703-305-7666.)
Chemicals used on northeastern orchards, toxicology and treatment
|Toxicology||Chemical Family||Common Name||Product Name||Treatment|
|Carbamates affect the CNS and symptoms include fatigue, weakness, dizziness, sweating, headache, nausea, cramps, diarrhea, muscle twitching and slurred speech. Seizures, coma and cardiorespiratory depression can occur with higher doses.||Carbamates||Carbaryl||Sevin 4F, 50 WP, 80 WS, Sevin XLR Plus 4EC||Clear patient’s airways, give oxygen if necessary. Administer atropine sulfate. Decontaminate skin by removing clothing and washing skin and hair thoroughly with soap and water. Flush eyes with clean water 10-15 minutes. Avoid adrenergic amines unless absolutely necessary.|
|Manzate||Dithane / Manzate / Penncozeb, Manex 4F|
|Metiram||Polyram 80 DF|
|None||Topsin-M 70WP, Ziram 76DF, 76 WDG|
|Organophosphate exposure affects nerve- endings and symptoms include headache, nausea, dizziness, sweating, salivation, muscle twitching, weakness, tremors, cramps, confusion, blurred vision or tightness in the chest (trouble breathing).||Organo-Phosphates (Exposure can be determined by a cholinesterase test)||Azinphosmethyl||Azinphos-M 50WS, Azinphosmethyl 50WP, Guthion 50WS||Clear patient’s airways, administer oxygen if necessary. Administer atropine sulfate. Glycopyrolate can be effective with continuous infusion. Pralidoxime can be administered if organophosphate exposure is known and patient is experiencing a severe poisoning. Decontaminate skin by removing clothing and washing skin, hair thoroughly with soap and water. Flush eyes with clean water 10-15 minutes.|
|Chlorpyrifos||Lorsban 4EC, 50WS|
|Dermal absorption varies and most of the dose is stored in fat tissue. These substances mainly affect the nervous system. Exposure symptoms include headache, dizziness, tremor, confusion, hyperesthesia and paraesthesia and convulsions.||Organochlorines||Diazinon||Diazinon 50 WP||Convulsions should be treated with anticonvulsants and patient should be taken to a trauma center if there is no reduction in seizures. Benzodiazepines therapy is recommended. Administer oxygen, decontaminate skin by removing clothing and washing skin, hair thoroughly with soap and water. Flush eyes with clean water 10-15 minutes. Do not give patients any drugs, which would increase myocardial irritability.|
|BTs are a natural chemical agent; human infections are rare. Only one human ingestion is known to have caused fever and GI symptoms. Skin irritation or sensitization have not been reported by mixers or applicators||Bacillus Thuringiensis||BT||Aza-Direct 1.2L, Biobit XL 2.1 FC, HP 6.4WP, Bt endotoxin formulation, Dipel 10.3 DF||Dermal exposures-Use soap and water to remove BT from skin. Use clean water or a saline solution to flush eyes. For ingestion watch patient for signs of bacterial gastroenteritis. Treat symptomatically and give fluid support.|
|Risk of systemic toxicity is low, however, central nervous system toxicity while uncommon, is more dangerous and can result in seizures or disturbed consciousness.||Synthetic Pyrethroid||Asana XL 0.66EC||Dermal exposures-Use soap and water to remove from skin, keep vapors from eyes and face. Use Vitamin E to avoid parasthetic reaction. Eye exposures can be dangerous, use clean water or a saline solution to flush eyes. For recent ingestions of large quantities GI decontamination is a good option. For small amounts or treatment delayed oral treatment with activated charcoal is recommended.|
|Other||Streptomy-cin||Agrimycin 17WP||If a large, recent ingestion has occurred, the physician should consider inducing vomiting.|
For further assistance: NPTN-National Pesticide Telecommunication Network – Offers assistance for diagnosis, treatment, and investigation of chemicals 1-800-858-7378 9:30-7:30 EST
Acute chemical poisoning Two extensive guides on agricultural chemical guides and one 60-minute webinar are presented here.
- Physician’s guide to pesticide poisoning by DE Stevenson, Texas Agricultural Extension Service, Texas A & M University, College Station, Texas.
- Recognition and Management of Pesticide Poisonings, R Reigart and J Roberts. US EPA. Spanish version: Reconocimiento y Manejo de los Envenenamientos por Pesticidas
- Webinar: Identification and Management of Pesticide Poisoning. 06/10/2008. 60 minute webinar by Mike Rowland, MD, of the Migrant Clinician’s Network [PDF of slides].
- National Pesticide Information Center
- Environmental Protection Agency Pesticides
- Chemical Action Network (PAN) Databases:
Long-term exposure The most recent data on associations between agricultural chemicals and long-term health effects indicate a range of cancer and non-cancer effects. For more details see the following reviews:
- Cancer health effects of pesticides: Systematic review, by K.L. Bassi
- Non-cancer health effects of pesticides: Systematic review and implications for family doctors, by M. Sanborn
Talking to patients about pesticides When patients have concerns about pesticide exposure, some of the following materials may be useful to assisting in discussing exposure and prevention.
These sections are excerpted from A LITTLE BIT OF POISON…WILL IT KILL YOU? Pesticide Education Manual for Community Health Workers and Promotores de Salud [English]; POCO VENENO..¿NO MATA? Manual del promotor para la educación comunitaria sobre plaguicidas [Spanish], by A. Liebman, Migrant Clinician’s Network.
- What are pesticides? [p 12]
- How are people exposed [p 17]
- How much can pesticides hurt us [p 24]
- Pesticides in the home [p 27]
- How do we protect ourselves and our families? [p 37]
- What is the Worker Protection Standard or WPS for farmworkers? [p 39]