Carbaryl

Carbaryl is the common name for a chemical known as 1-naphthyl methylcarbamate. Its chemical formula is C12H11NO2, and molecular weight is 201.2 g/mol. Carbaryl is a white crystalline solid that is slightly soluble in water. It is essentially odourless and its odour threshold has not been established. Carbaryl was first registered in the United States in 1959. Currently, over 300 products containing carbaryl are actively registered with the United States Environmental Protection Agency. Carbaryl belongs to a family of chemicals that kill or control insects known as carbamates. [fusion_builder_container hundred_percent=”yes” overflow=”visible”][fusion_builder_row][fusion_builder_column type=”1_1″ background_position=”left top” background_color=”” border_size=”” border_color=”” border_style=”solid” spacing=”yes” background_image=”” background_repeat=”no-repeat” padding=”” margin_top=”0px” margin_bottom=”0px” class=”” id=”” animation_type=”” animation_speed=”0.3″ animation_direction=”left” hide_on_mobile=”no” center_content=”no” min_height=”none”][1,2]

Uses [3]

Carbaryl is commonly sold under the trade name Sevin, and goes by trade names such as Adios, Carbamec, Denapon, Hexavin, and Panam. Its primary use is as an insecticide on various commercial crops, including but not limited to corn, soybean, cotton, citruses, pears, and nuts. In addition to also being effective as a molluscicide and acaricide, carbaryl can also be used to treat pest infestations, such as that due to species of lice, on livestock, poultry, pets, and in the case of head lice, on people.

In the Environment [1]

  • Soil: Depending upon conditions, carbaryl has a half-life ranging from 4 to 72 days in soil. Carbaryl breaks down faster in sandy, flooded, or well-aerated soils.
  • Plants: Carbaryl has an average half-life of 3.2 days on plant leaves.
  • Water: Carbaryl does not dissolve well in water and sticks to soil. However, carbaryl is widely used and can last a long time under the right conditions. Carbaryl is commonly found in groundwater.
  • Air: Carbaryl has low potential to evaporate from water, soil, and other treated surfaces.
  • Carbaryl is practically non-toxic to birds such as ducks, quail, geese, and pheasants.
  • It ranges from slightly to highly toxic to several species of fish.
  • Carbaryl ranges from moderately to very highly toxic to marine invertebrates, such as shrimp and oysters.
  • Carbaryl is very highly toxic to aquatic invertebrates such as shrimp and stoneflies. It can also damage frog tadpoles during their development.
  • Carbaryl is very high in toxicity to honey bees and can harm beneficial insects.

Sources & Routes of Exposure

Sources of Exposure [2]

  • Individuals are most likely to be exposed to carbaryl dermally or by inhalation during the manufacture, formulation, and application of this pesticide.
  • The general public may be exposed to carbaryl from spray drift in regions surrounding agricultural areas.
  • Carbaryl has been detected at low levels in surface water and in food.

Routes of Exposure [4]

The main exposure routes for carbaryl are:

  • Inhalation;
  • Skin absorption;
  • Ingestion;
  • Skin and/or eye contact

Health Effects [2]

Acute Effects

  • Acute occupational exposure of humans to carbaryl has been observed to cause cholinesterase inhibition (which impairs central nervous system (CNS) function), resulting in nausea, vomiting, bronchoconstriction, blurred vision, convulsions, coma, and respiratory failure.
  • Acute carbaryl exposure in humans may also cause eye and skin irritation.
  • Tests involving acute exposure of rats, mice, rabbits, and guinea pigs have demonstrated carbaryl to have moderate to high acute toxicity from ingestion and moderate acute toxicity from dermal exposure.

Chronic Effects

  • Chronic exposure to carbaryl results in cholinesterase inhibition, which is reversible upon discontinuation of exposure. Headaches, memory loss, muscle weakness and cramps, and anorexia are caused by prolonged low-level exposure of humans to carbaryl resulting from cholinesterase inhibition.
  • Kidney and liver effects have been observed in rats chronically exposed to carbaryl by ingestion.
  • EPA has not established a Reference Concentration (RfC) for carbaryl.
  • The Reference Dose (RfD) for carbaryl is 0.1 milligrams per kilogram body weight per day (mg/kg/d) based on kidney and liver toxicity in rats.

Reproductive/Developmental Effects

  • No information is available on the reproductive or developmental effects of carbaryl in humans.
  • Two studies produced teratogenic effects in dogs fed carbaryl, but dogs were judged inappropriate for human health risk assessment because of differences in metabolism. Other studies demonstrating teratogenic effects also caused maternal toxicity.
  • Reduced fertility and litter size and increased mortality in offspring have been observed in rats exposed to carbaryl in their diet over three generations.

Cancer Risk

  • No information is available on the carcinogenic effects of carbaryl in humans.
  • No significant increase in tumour incidence was found among exposed animals in several studies.
  • EPA has not classified carbaryl for carcinogenicity.

Safety [5]

First Aid Measures

  • Swallowed: If poisoning occurs, contact a doctor or Poisons Information Centre (ph: 13 11 26).
  • Eye: Immediately irrigate with copious quantities of water for at least 15 minutes. Seek medical assistance.
  • Skin: If material is splashed onto the skin, remove any contaminated clothing and wash skin thoroughly with water and soap if available and give one atropine tablet every 5 minutes until dryness of the mouth occurs. Urgently transport to hospital or doctor.
  • Inhaled: Remove victim to fresh air. Apply resuscitation if victim is not breathing – DO NOT use direct mouth-to-mouth method if victim ingested or inhaled substance; use alternative respiratory method or proper respiratory device – Administer oxygen if breathing is difficult.
  • Give on atropine tablet every 5 minutes until dryness of the mouth occurs. Seek immediate medical assistance.

First Aid Facilities:

  • Eye wash fountain;
  • Safety shower and normal wash room facilities.

Exposure Controls & Personal Protection

Engineering Controls

  • Carbaryl is a toxic material and a single significant exposure may cause death.
  • Maintain adequate ventilation at all times.
  • Prevent accumulation of gas(es) in hollows or sumps.
  • Eliminate any sources of ignition.
  • DO NOT enter room unless monitored by another person (ie buddy-buddy system).
  • Sampling of the atmosphere if possible should be conducted automatically instead of human operator and any leaks discovered should then be directed digitally to a command centre where the event can be acted upon, with all appropriate procedures being implemented and including any protective equipment as outlined in this MSDS.

Personal Protective Equipment

The following personal protective equipment is recommended when handling carbaryl:

  • CLOTHING: PVC, Nitrile, Neoprene, Natural rubber or any other type of apron or splash suit as recommended by the manufacturer.
  • GLOVES: PVC, Nitrile, Neoprene, Natural rubber or any other type of glove as recommended by the manufacturer.
  • EYES: Chemical goggles or face shield to protect eyes.
  • RESPIRATORY PROTECTION: Avoid breathing of gases. Select and use respirators in accordance with AS/NZS 1715/1716. When gases exceed the exposure standards then the use of an atmosphere-supplied, positive pressure demand self-contained or airline breathing apparatus supplied air respirator complying with the requirements of AS/NZS 1715 is recommended. Filter capacity and respirator type depends on exposure levels.
  • If entering spaces where the airborne concentration of a contaminant is unknown then the use of a self-contained breathing apparatus (SCBA) with positive pressure air supply complying with AS/NZS 1715 / 1716, or any other acceptable International Standard is recommended.

Regulation

United States [4,6]

NIOSH: The National Institute of Occupational Safety & Health has set a Relative Exposure Limit (REL) for carbaryl of TWA 5 mg/m3.

OSHA: The Occupational Safety & Health Administration has set a Permissible Exposure Limit (PEL) for carbaryl of TWA 5 mg/m3.

ACGIH: The American Conference of Governmental Industrial Hygienists has set a Threshold Limit Value (TLV) for carbaryl of TWA 5 mg/m3.

Australia [7]

Safe Work Australia: Safe Work Australia has set a Time Weighted Average (TWA) concentration for an 8-hour workday of 5 mg/m3 for carbaryl.

References

http://npic.orst.edu/factsheets/carbgen.pdf

http://www.epa.gov/ttn/atw/hlthef/carbaryl.html

http://www.toxipedia.org/display/toxipedia/Carbaryl

http://www.cdc.gov/niosh/npg/npgd0100.html

http://www.kendon.com.au/Catalogue/MSDS/horticultural/CarbarylLiquidInsecticide.htm

http://www.cdc.gov/niosh/idlh/63252.HTML

http://www.safeworkaustralia.gov.au/sites/SWA/about/Publications/Documents/772/Workplace-exposure-standards-airborne-contaminants.pdf

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