WITH TOURISM ON THE INCREASE, MARGARET REICHLIN MAKES A PLEA FOR MORE RESEARCH INTO THE EFFECTS OF HOLIDAY CHEMICALS.
'WHERE ARE YOU going on holiday this year?... Oh, how gorgeous. All that lovely sun... Got your flight booked? Had all your jabs?... And got your bug stuff? Remember the sunscreen... Have a wonderful time.'
And off we go, with innoculations, sun screens, insect repellent, insecticides, both spray and slow-release, and new mosquito nets. What could possibly go wrong?
To be honest, we don't know the full extent of the dangers, but there are alarming indications that illness and even death may be the result of the combinations of chemicals absorbed through the skin by holiday-makers today. And one researcher has suggested that illness akin to Gulf War Syndrome may even be possible. The problem lies in the 'cocktail' of chemicals that we absorb through the course of a holiday.
A traveller starts at the airport and boards the plane, with its full complement of fire retardants, stain resistants, and the other protective chemicals. At some airports, the cabin is sprayed with insecticides, the chemicals used probably being pyrethroids. D-Phenothrin is approved by the World Health Organisation (WHO) for this purpose. Permethrin is now ubiquitous, and travellers may be enjoying the benefits of these while still dealing with innoculations. 
Upon arrival at the destination, it's on with the insect protection, often DEET (Diethyltoluamide). This may come with a range of other ingredients and propellants, such as Isobutane, N-Butane, Alcohol de nat, Propane, caprylic/capic or triglycerides.  A range of chemist recommended insecticides may include Prallethrin, Bio-allethrin, Tetramethrin, DAllethrin, all pyrethroids, or even Dichlorvos, which is currently under review.  In addition the hotel may already be using its own insecticides.
Then there is sunscreen, which will usually contain at least 20 ingredients, most of which will be absorbed by skin quickly. Going out at night? Then it's on with deodorant, perfumes...
So where does the Gulf War come into all this? Professor Mohamed Abou-Donia is a leader in the field of research into the 'cocktail effect' of chemicals. His work, first with chickens, then with rats, involved the three main chemicals used in the Gulf War. Each was regarded as fairly harmless on its own, but they were used collectively to protect troops. These chemicals were DEET, Permethrin and Pyridostigmine Bromide. 
Professor Abou-Donia's work showed that combinations of chemicals are not a matter of addition of effect, but of multiplication. When toxic chemicals enter the body they should be detoxified by enzymes and proteins, but if these are occupied by dealing with the first chemical, then new chemicals might be able to advance, combining toxicities as they go.
Each of the chemicals in Abou-Donia's work can be tolerated up to a point that varies in each human body. His experiments with chickens showed that exposed to any combination of two chemicals the birds experienced weight loss, diarrhoea, shortness of breath, leg weakness, or tremors. The combination of three produced paralysis or even death. 
Now chickens, of course, are not humans, and the final blame for Gulf War Syndrome is still being heavily disputed. In short, the full effect of chemical cocktails on humans is still to be measured. Yet people are still travelling, supported by products backed by governmental health departments, and coming home complaining of anything from respiratory problems to apparent viruses.
Some don't come home at all. What if the traveller, as so sadly happened to two young, healthy girls in 1999, dies suddenly abroad for no apparent reason? Does anyone ask about chemical usage, even when one of them was known to have used DEET on the night she died? Do not the verdicts themselves prompt questions? 'Sudden Adult Death Syndrome'? 'Exertion in a strange environment'? 
The potential effects of these chemicals, when taken alone, is not well-known to the general public. Pyrethrum was a relatively safe insecticide (though nothing that is designed to kill living organisms is ever really safe) but its effects were limited, so when the public began to be aware of the dangers of man-made pesticides such as DDT and Lindane, and turned to 'natural' ones, 'Pyrethrum' was often listed large on the nice green label, and only in the very small print did one find Piperonyl Butoxide, used as an enhancer. Here we are in the world of synergies, well understood when in the interests of manufacturers. Piperonyl Butoxide works by decreasing the body's ability to toxify other chemicals. It can cause kidney, liver and adrenal damage. If the synergistic effects are so clearly recognised when in the interests of industry, why are they ignored in the area of the public's safety?
The effects of organophosphates are now fairly well-known, and anyone who wishes to know more can obtain a copy of MS 17, Medical Aspets of Work Related Exposure to Organo-phosphates from HSE Books, PO Box 1999, Sudbury, Suffolk. And anyone thinking of buying a Dichiorvos insecticide for their summer holiday should be aware that it is currently under review by the Pesticide Safety Directorate.
It is one of the problems of the growing chemical load in our lives that no one records the total load in any home or workplace. No wonder most people have a desire to head to that faraway place where the air is warm and clean and the sun always shines. But what is the reality? You are leaving behind a chemical soup. What are you heading towards? What chemical cocktail are you concocting for yourself? It is time we found out.
Margaret Reichlin is a pesticide victim. Further information on chemical cocktails can be found in Vyvyan Howard's Synergistic effects of chemical mixtures from The Ecologist Vol 27 No 5.
(1.) pesticides News, Pesticides Trust, March 1999; British Airways News, 17 December 1999; Action against Allergy, Summer 1999; Pilots Challenge Pesticide Cover-up, Sunday Telegraph, 17 January 1999.
(2.) Daily Telegraph, 29 October 1999.
(3.) Boots Healthcare Information. Malaria. January 2000.
(4.) Chemical Injury Information Network, Our Toxic Times, September 1996; Pesticides Trust, Pesticides News, March 2000; Counting the Cost, Radio 4, 25 May 2000.
(6.) Daily Mail, 29 October and 9 December 1999.
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