Is an Englishman's home his chemical dump?
Our homes are the target of hundreds of products containing toxic chemicals, many of which have had little research. Other chemicals come to us as 'unprescribed environmental drugs', mainly in our food. The construction materials in houses and the repairs they are subject to introduce other toxic chemicals.
Toxic household wastes can include: household cleaners, automotive products, home maintenance and improvement products, lawn and garden products and batteries.
Household cleaners can have the following toxic ingredients: caustic soda, petroleum distillates, petroleum naptha, turpentine, isopropanol, oxalic acid, hydrogen chloride and sulphuric acid.
Products for the car may contain: xylene, toluene, acetone, freon 12, dichlorodifluoromethane, cresol and methyl chloride, some of which can also be found in home improvements products.
Pesticides used in the garden can include: 2,4,-D, Silvex, 2,4,5-T, acrolein, aldicarb, aldrin, arsenic acid, aziridine, carbamates, chlordane, creosote, DDE, DDT, dieldrin, dimethoate, dinoseb, disulphoton, endosulphan, endrin, heptachlor, lindane, methoxychlor, methyl parathion, parathion, pentachlorophenol, phorate, toxaphene, trichlorophenol and warfarin.
Other common household objects may be made from more heavy metals and chemicals than we realise. Batteries contain sulphuric acid, mercury, mercuric oxide, silver oxide, lead, lead peroxide, lead sulphate, and cadmium. Photo processing chemicals to which we may be exposed indirectly include silver, selenium, sulphuric acid and heptane. Electronic items may have lead or silver solder, or may emit mercury vapour. Fire retardants contain brominated compounds such as polybrominated diphenyl ethers (PBDEs).
Household exposures to harmful chemicals may not have been anticipated by regulators. A study by S Gurunathan et al, reported in Environmental Health Perspectives [available from PEX], found the accumulation of chlorpyrifos, an OP insecticide, on residential surfaces and toys accessible to children. The study established for the first time that a semi-volatile pesticide will accumulate on and in toys and other sorbant surfaces in a home via a two-phase physical process that continues for at least two weeks post-application. The estimated acute dose that a small child of 3 to 6 years old could receive as a result could be as high as 356 micrograms per kilo per day.
Children are particularly vulnerable to pesticide exposure: their body size is smaller than adults', and their immune systems less developed. Studies have found that exposure of children via food can exceed the Acute Reference Dose by up to five times, via insecticidal shampoos by up to five times, and their exposure to vapourisers and sprays in the home can be high.
PBDEs are persistent chemicals which bioaccumulate, and have dioxin-like properties. The average concentration of PBDE congeners has risen from 72 to 4010 pg/g of lipid during the last 25 years. One congener, 2,2',4,4'-getraBDE (BDE47) was predominant in all pooled samples, and constituted 60 to 70 per cent of the total amount of PBDEs. The concentration of PBDEs was observed to have doubled in 5 years.
Chloracne, which binds to the human thyroid receptor protein, is semi-volatile and has been found from off-gassing.
We are all now exposed to a mixture of chemicals in the environment. There are between 300 and 500 chemical residues in everybody in the population. These are mostly man-made chemicals, released into the environment in only the last fifty years. We have no way of measuring the toxicity of such complex mixtures, and there are no unexposed populations to use as controls. Precaution is the only option.
An article by Dr Vyvyan Howard and Gesa Staats de Yanes criticising current methods of risk assessment and proposing methods based on robust hazard assessment data was included in Newsletter 3, available from PAN UK.
[As published in PEX Newsletter No.4, September 1999]