Antigua
Following is the second of the two-part piece on the subject by Peter Roderick, writing in the Antigua Sun.
If you omitted to read the first part of the article and clicked straight to this one, you may be interested in backtracking to Part 1 after which you can come right back here to complete your read.
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Malathion fogging has been causing controversy…for years. I did some research…and discovered that there are two very different points of view on the matter. Through it all, I came to certain conclusions which appear not to be in dispute.
Malathion is classified as an organophosphate insecticide. It is the most widely used organophosphate insecticide in the United States.
The people who manufacture malathion normally sell their product in a very pure state when it leaves the factory. It should contain less than five per cent of impurities. Pure malathion is said to have a relatively low toxicity to humans. We have the manufacturers’ solemn promise that their product will not harm us when used according to their instructions. What instructions? Here’s a sample -
Precautions: Keep out of reach of children. Hazardous if swallowed, inhaled, or absorbed through the skin. Avoid breathing spray mist or dust. Avoid contact with skin, eyes or clothing. Wash exposed skin areas thoroughly with soap and water after working with malathion. Clean contaminated clothing before reuse. Do not contaminate feed or foodstuffs. Do not treat dairy barns. Do not apply to pastures while occupied by dairy animals. Do not treat any plants while in bloom. Avoid contaminating any body of water. Wash treated food before eating. Do not apply to eyes or ears (except in ointment form) or nose of any animal. Do not store product near food, feed, fertilisers, seed, and like commodities. Highly toxic to fish and bees. Emulsifiable concentrate formulations may cause injury to young cucurbits and ornamentals (crassula; holly; African violet; petunia; sabina and canaerti junipers; Boston, maidenhair and pteris ferns).
Malathion is approved by the Environmental Protection Agency (EPA) of the USA.
The EPA doesn’t actually test malathion. It approves the product based on information supplied by the manufacturer.
Diluting malathion with diesel can result in a product which weakens mosquitoes but does not kill them. This can give rise to mosquitoes which become resistant to malathion.
While malathion itself is not considered toxic, it can and sometimes does contain impurities which are in fact highly toxic.
Malathion is highly toxic to bees.
Malathion is toxic to fish, aquatic invertebrates, and aquatic life stages of amphibians (I think this means tadpoles. If you notice that there are less tree frogs around (Antigua); this might be the reason).
Some female rats which were fed high doses of malathion for two years developed higher incidences of liver tumours, i.e. cancer. The males were apparently not affected.
Malathion should not be used on fruits or vegetables immediately before consumption.
Malathion should not be inhaled.
If malathion is absorbed into the body it is quickly metabolised into toxic chemicals.
Malathion should not be stored at temperatures exceeding 25 degrees Celsius or 77 degrees Fahrenheit. Above this temperature it will progressively break down into highly toxic by-products.
People who work with malathion for long periods should have frequent blood tests to check the level of cholinesterase in their blood.
Malathion fogging should only be carried out by individuals who are properly trained and are fully conversant with the manufacturers instructions for use of the product. Use of the product by untrained individuals may constitute a public health hazard. It can also ruin the paint on your car.
Here’s an excerpt from the Fyfanon directions for use –
Droplet size
1. The Mass Median Diameter (MMD) of the droplets should not exceed 17 microns. The MMD is the drop diametre which divides the spray volume into two equal parts; i.e., 50 per cent of the volume are drop sizes below the MMD and 50 per cent are above the MMD.
2. Spray droplets should not exceed 32 microns in size. Three per cent of the spray droplets (six droplets out of 200) can exceed 32 microns providing the MMD does not exceed 17 microns and no droplets exceed a maximum of 48 microns. Larger droplets, when transported by natural air currents, impinge more readily on objects in their pathway and will permanently damage automobile-type paints.
3. More than one-half of the total spray mass must consist of droplets in the 6 to 18 micron range to achieve adequate dispersal of insecticide over a 300-foot swath.
4. A minimum of two-thirds, preferably four-fifths of the total spray must consist of droplets not exceeding 24 microns in range.
Fyfanon was sprayed widely in New York City and on Long Island in September 1999 to kill adult mosquitoes and combat a newly emerging public health threat, the West Nile virus.
Fyfanon’s active ingredient, malathion, is highly toxic to lobsters and after heavy rains washed the insecticide out to sea the lobster population was virtually wiped out. The local lobstermen sued and reached a tentative settlement in a class-action suit against Cheminova, the maker of the Fyfanon. The company agreed to pay $12.5 million.
An article on the BBC news Web site dated 28 March 2008 cites a new study which found a strong link between long term exposure to pesticides and the development of Parkinson’s disease. Parkinson’s is a progressive, degenerative, neurological condition which causes uncontrollable trembling of the arms and legs. There is currently no cure.
In summary, the benefits of widespread malathion fogging to prevent the outbreak of dengue should be carefully weighed against the possible risks to the general population and to the environment.
There is much that can be done by ensuring that all roadside drains are regularly cleared of debris to eliminate stagnant waters where mosquitoes abound. Perhaps we should focus more on cleanliness than on another quick fix from the chemistry laboratories.
Submitted by Peter Roderick
Source:Antigua Sun
