Surveys show that most of us maintain a home arsenal against a variety of house and garden pests, and use an average of three to four pesticide products a year (J Expo Anal Environ Epidemiol, 2000; 10: 159-67; Sci Total Environ, 2006; 368: 465-70). Yet, household pesti-cide use is increasingly being linked to serious adverse health effects.
French researchers reported that the use of pesticides, especially insecticides, by either parent during pregnancy was significantly associa-ted with childhood acute leukaemia and non-Hodgkin's lymphoma (NHL). Although this isn't proof of a causal relationship, it does suggest that domestic pesticides may play a role in these childhood blood cancers, especially if children are exposed in the womb (Environ Health Pespect, 2007; 115: 1787-93). Even more worrying is that this was, in fact, old news.
A study of 162 leukaemia patients found a link between household pesticides and a higher risk of child-hood leukaemia. Also, early expos-ures were more significant than later ones, with the greatest risk during pregnancy. Women exposed at this critical time were more than twice as likely to have a child with leukaemia compared with unexposed women (Environ Health Pespect, 2002; 110: 955-60).
Other studies have also found links between early-life pesticide exposure and blood-cancer risk (Environ Health Pespect, 2007; 115: 1787- 93). In fact, the risk of childhood leukaemia increased nearly four times when pesticides were used in the home at least once a week, and more than six times when garden pesticides were used at least once a month (J Natl Cancer Inst, 1987; 79: 39-46). Children whose mothers used pesti-cides in the home once or twice a week were more than two times as likely to develop NHL. Those whose mothers used pesticides most days were seven times more likely to have the disease (Cancer, 2000; 89: 2315-21).
Other childhood cancers are linked to household pesticides. There is, for example, a slightly higher risk of Wilms' tumour (of the kidney) among children whose mothers used insecticides in the home (Environ Health Perspect, 2007; 115: 134-7).
Childhood brain cancers and tumours of the connective tissue are also linked to home pesticides (Envir-on Health Perspect, 1997; 105: 1214-20; Arch Environ Contam Toxicol, 1993; 24: 87-92; AmJ Public Health, 1995; 85: 249-52). Some of the worst offenders are weed-killers, flea and tick products, and bug bombs.
Children are probably more vul-nerable to pesticides because they spend more time with pets, on the floor and in the garden-all places where pesticides are used. This, together with their lower body weights, still-developing organs and higher metabolic rates, puts them at an increased risk for adverse toxic effects (Krieger R, ed. Handbook of Pesticide Toxicology, 2nd edn. Academic Press, 2001: 887-904).
Exposure to pesticides can also take place in the womb and through breastfeeding. Also, as children's de-toxification pathways are incomplete, they have fewer defences against toxic assaults. In addition to cancer, pesticide exposure can lead to reproductive, neurological, neuro-behavioural and endocrine effects (Aust Fam Physician, 2007; 36: 1002-4).
But it's not just children who are at risk. There's growing evidence of serious health effects in adults, too.
A French study of nearly 700 adults found that those who said they used pesticides on their house plants were more than twice as likely to have brain cancer as those who never used such chemicals (Occup Environ Med, 2007; 64: 509-14).
Pesticide exposure can lead to neurological disorders that are now considered common in old age-which is hardly surprising as pesti-cides are neurotoxic to people as well as to insects (Front Biosci, 2008; 13: 1240-9). People who used pesticides at home or at work had a 60-per-cent greater risk of developing Parkinson's, a disease of the central nervous system. The strongest links were found with herbicides, and insecticides such as organochlorides and organophosphates (BMC Neurology, 2008; 8: 6; doi:10.1186/1471-2377-8-6).
A US study of household pesticides also suggested that their use may increase the risk of Parkinson's disease (Lancet, 2000; 355: 1701).
Pesticide overexposure is not just an occupational hazard of agricultural and factory workers; scientists now believe that our homes, gardens and schools may be a more important source of exposure, especially among children (Pediatr Clin North Am, 2001; 48: 1185-98; Environ Health Pespect, 1995; 103: 550-4).
This makes sense, considering how pervasive household pesticides are. In 2000, UK householders doused their homes with 4306 tonnes of the stuff, worth around lb35 million (Thomas P. Living Dangerously. Dublin, Eire: New Leaf, 2003). In the US, 34.5 million kg (76 million lb) of it were used in American homes and gardens, according to a 2001 survey (Pediatr Clin North Am, 2001; 48: 1185-98).
Do we really need pesticides? Some experts suspect that people may be using pesticides more out of annoyance and fear rather than actual need. And even with a major insect problem, it is still possible to avoid the use of poisonous products (see box above). The most effective means of pest control is prevention: remove the pests' sources of food, water and entry into your home, and they won't be able to survive.
Prevention: a green option
- Seal cracks around windows and doors with caulk or weather-stripping
- Inspect groceries and used furniture for insects before bringing them home
- Trim plants and shrubs to keep them at least one foot away from your house
- Remove piles of scrap wood, mulch or leaves from around the outside of the house
- Clean up all spills and messes immediately
- Keep rubbish tightly sealed, and empty rubbish and recycling containers often
- Don't leave out dirty dishes
- Store all food (including petfood) in pest-proof containers with tight-fitting lids
- Clean out grease and crumbs from your kitchen regularly
- Repair leaky pipes and plumbing
- Get rid of old piles of paper and cardboard.
From the Agricultural Resources Center &
Pesticide Education Project factsheet, NC, USA