Carpets – toxic accumulation

Carpets have frequently been treated with pesticides to prevent insect and microbial damage. Householders may also apply pesticides to fitted carpets. This report explains the effects on the environment and human health.

Chemical treatments 
Products applied externally or by impregnation as part of the manufacturing process are not covered by the Control of Pesticide Regulations 1986 or the Chemicals (Hazard Information and Packaging for Supply) Regulations 1994. The Institute for Environment and Health (IEH) recommend that products treated with pesticides should be clearly labelled and cite pre-treated carpets as secondary sources of exposure in relation to indoor air quality(1). The US Environmental Protection Agency (EPA) further recommends that new carpets are aired outdoors before installation, and indoor areas should be well ventilated for 48-72 hours after carpet fitting(2).
    Carpets are frequently sold with ‘pest proof’ guarantees, which can be as long as ten years. Therefore the pesticides applied at the manufacturing stage remain active for long periods of time. Two products applied to carpets during the manufacturing process are Dynomite®(3,4) and Actigard®(5,6). Actigard® contains isothiazolinone-compounds and permethrin derivative(7).
    Carpets, particularly those made of wool, are often treated against damage from moths. Traditional moth repellents are designed to repel adults and often contain naphthalene, which is cumulatively toxic(8) and emits vapour that can produce toxic reactions in sensitive individuals(9). Pyrethroids are often applied to wool in dye-baths. Although the practice of using organochlorines has ceased, treated carpets may still exist in some households(10).
    The London Hazards Centre has received reports of pesticide exposure implicating malathion and dichlorvos and bendiocarb residues have reportedly been found clinging to carpet fibres(11).

Environmental and health effects
In 1997 the Environment Agency reported a high number of incidences where Environmental Quality Standards (EQS) of water were exceeded, mostly in the North East and Midlands regions. The incidences relate to moth-proofing agents used in the manufacturing of textiles specifically; 81 involving permethrin, 53 involving cyfluthrin and 15 involving PCSD/eulan(12).
    Carpets absorb outdoor pesticides, which may be brought inside on footwear and clothing or drift in through open windows or doors. Evidence suggests that the amount of pesticide residues found inside homes is greater than would be expected from actual indoor applications(13). Studies of indoor air quality in American homes found five to ten times higher concentrations of pesticides than was found in outdoor air. Pesticides that would normally be degraded in a matter of days by the action of sunlight and bacteria may persist for years in carpets(14). For example, despite the banning of DDT in the US in 1972 residues were found in 90 out of 362 Midwestern homes during 1992 to 1993(15).    
    The US EPA state that 80% of most people’s exposure to pesticides occurs indoors(16). House dust found in carpets readily attracts and holds indoor chemical pollutants. As permethrin adsorbs to dust and surfaces(17), ingestion of permethrin, rather than inhalation, may be an important exposure route(18).
    Children and infants are infinitely more susceptible to chemical exposure(19) than adults as their rapidly developing organs are more prone to damage and their smaller body weight ratio. It is estimated that children may ingest 100 milligrams of house dust a day, five times more than adults, as they play or crawl on carpets(20). The inhalation of vapour emissions, dermal absorption of residues on surfaces and the ingestion of residues adsorbed to house dust greatly increase the likelihood of exposure to a cocktail of pesticides. The IEH highlight the clear potential of pesticides to cause immediate toxic effects but state that the effects on health of low-level, long-term exposure to background residues are unclear(21).

Limiting exposure
Regular vacuum cleaning, particularly beneath furniture and along skirting boards should prevent clothes moth and carpet beetle infestations. Cleaning carpets with a water vacuum cleaner or by steam cleaning is recommended to control pests. Vacuuming will also prevent the build up of potential food sources such as organic debris. Pesticide treatments should be used as a last resort and applied locally to affected areas.

Conclusion
Allergy sufferers may welcome a house dust mite free carpet but consideration of possible sensitivity to pesticides must also be taken into account. Children and infants are clearly more susceptible to pesticide exposure than adults and their everyday activities lead to increased exposure levels. Pesticides applied within the household adsorbed by house dust clinging to carpet fibres in addition to those applied during the manufacturing process will undoubtedly add to the cocktail of pesticide residues in the home. (AW) 

Useful contact: Healthy Flooring Network, Women’s Environmental Network, PO Box 30626, London E1 1TZ, Email.

References
1. Institute for Environment and Health, Indoor Air Quality: Pesticides in the Home, IEH report for the DETR, uk, October 1999.
2. US EPA, The Inside Story, A Guide to Indoor Air Quality, http://www.epa.gov.iaq/pubs/insidest.html.
3. The Carpet Information Centre, www.carpetinfo.co.uk, (Kingsmead Carpets).
4. Richards plc, via the Women’s Environmental Network, personal communication, November 2000.
5. Ibid.
6. Clariant UK Ltd, via the Women’s Environmental Network, personal communication, November, 2000.
7. Ibid.
8. A-Z of Chemicals in the Home (3rd Ed),Total Environment Centre and Australian Consumers’ Association, Sydney, 1996, pp93-94.
9. Common-Sense Pest Control, W Olkowski, S Daar and H Olkowski, Taunton Press, 1991, pp203-208.
10. Op. cit. 8.
11. London Hazards Centre, personal communication, November 2000.
12. Pesticides in the Aquatic Environment 1997, Pesticides Section, The Environment Agency, National Centre for Ecotoxicology & Hazardous Substances, Wallingford, Oxon, 1999, p24.
13. Op. cit. 2.
14. Everyday Exposure to Toxic Pollutants, WR Ott and JW Roberts, Scientific American http://www.sciam.com/1998/0298issue/0298ott.html
15. Ibid.
16. Op. cit. 2.
17. Op. cit. 1.
18. Op. cit. 1.
19. Indoor Exposure to Pesticides and the Association with Childhood Cancer, Imperial College, C Grey, September 1999, pp94.
20. Op. cit. 14.
21. Op. cit. 1.

[This article first appeared in Pesticides News No.50, December 2000, p20]