Monday, March 14, 2005


Laboratory tests showed that 27 Philippine school children who died after eating cassava root treats last week were poisoned with a carbamate pesticide, according to Philippine Health Secretary Manuel Dayrit. He told a news conference that the food was probably prepared in an environment that was highly toxic and contaminated with chemical poisons and bacteria. The vendors who sold sweetened cassava roots as recess snacks to the children--7 to 13 years--denied that they improperly prepared the food.

Cabamate pesticides are commonly used in farms and households not only in the Philippines but here and in many other countries.

Carbaryl (1-napthyl N-methylcarbamate) or ( 4F carbaryl ) trade name Sevin®, for example, is widely used in garden and lawn insect sprays and dusts; wasp and hornet sprays; snail and slug granules, pellets, and baits; flea and tick shampoos, powders, and sprays for dogs and cats. It is also used as a pesticide on apples, beans, grapes, oranges, pears, peas, tomatoes and corn and grains. The long term effects on humans and animals are not known. Carbaryl is extremely toxic to aquatic invertebrates and certain estuarine organisms. It is extremely toxic to honeybees. It is moderately toxic to both warm water and coldwater fishes and has only low toxicity to birds. The US Environmental Protection Agency (EPA) says carbaryl has a moderate to low toxicity in mammals. Based on established tolerances, the theoretical maximum residue contribution for carbaryl residues in the human diet is calculated to be 5.48 mg/day. The acceptable daily intake (ADI) of carbaryl is 0.1 mg/kg/day. The maximum permissible intake (MPI) is 6 mg/day, according to the US government. A one year dog feeding study is being requested in order to determine the effects of carbaryl on kidney dysfunction. The results of these data may require that the ADI for carbaryl be recalculated, according to the EPA.

Among other carbomate pesticides are aldicarb; 4-benzothienyl-N-methyl carbamate; bufencarb (BUX); carbaryl; carbofuran; isolan; 2-isopropyl phenyl-N-methyl carbamate; 3-isopropyl phenylmethyl carbamate; maneb; propoxur; thiram; Zectran; zineb, and ziram. Carbamic acid from which the pesticides are derived, is colorless and odorless, causes depression of bone marrow and degeneration of the brain, nausea, vomiting. Unlike the event in the Philippines, we have not had a mass disaster involving children ingesting an acute, fatal dose of a carbamate but what are the long term effects of carbamate residues any of us eat on our produce, inhale or get it on our skins?

Another common carbamate we may ingest is ethyl carbamate---better known as Urethane®. It is used as an intermediate in the synthesis of a number of chemicals. It is also a chemical substance that forms naturally during the fermentation process and thus has been a potential problem in wine making and distilled spirits, according to the FDA. The agency provides advice for preventing its formation in wine making. Acute (short-term) exposure of humans to high levels of ethyl carbamate may result in injury to the kidneys and liver and induce vomiting, coma, or hemorrhages. No information is available on the chronic (long-term), reproductive, or developmental effects of ethyl carbamate in humans.An increased incidence of lung tumors has been observed in rodents exposed to ethyl carbamate by oral or inhalation exposure. The International Agency for Research on Cancer (IARC) has classified ethyl carbamate as a Group 2B, possibly carcinogenic to humans.

You may not be able to do anything about residues on what you buy in the supermarket unless you have certified organic produce, which is usually more expensive. If you can't afford it, you can certainly thoroughly wash your fruits and vegetables in running water in an effort---perhaps futile--to reduce the amount of carbamates you take in. You can, however, make an effort to avoid the use of carbamate-containing pesticides around your home and garden. If there are no alternative methods available to you, read the labels carefully and precisely follow the directions.

Better choices for house, garden and pets, in many cases, are the natural insecticides obtained by extraction of the chrysanthemum flowers, the pyrethrins. They usually have "safe for humans and animals" somewhere on the label. They may, however, cause allergic reactions in the sensitive.

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