Lawns - the risk of pesticide use 

The UK non-agricultural sector used 5,400 tonnes of pesticide active ingredients during 2000(1). Over 175 pesticide products, containing over 13 active ingredients are specifically produced to control lawn problems in the UK(2). Our apparent obsession with creating an unnatural green carpet not only reduces biodiversity but also increases the risk of exposure to pesticides. 

Some extremely hazardous products are used by amateurs to manage lawns, and while products are used in a diluted form, the exposure rates can be considerable. Professional use in parks and playing fields can add to exposure levels.

Health and environmental risks
A total of 64 of the 175 products looked at contain 2,4-D, a herbicide, which is toxic orally, particularly in its undiluted form. It can be absorbed through the skin and by inhalation. Occupational exposure to 2,4-D has produced serious eye and skin irritation(3). As a phenoxy herbicide, there is evidence that 2,4-D is possibly carcinogenic to humans, according to the International Agency for Research on Cancer (IARC)(4).
    Chlorpyrifos, an organophosphate insecticide found in three of the products, can be absorbed through the skin and is a skin and eye irritant. It is one of the leading causes of acute insecticide poisoning in the US(5). Used by British troops in the Gulf War it is under scrutiny because of alleged birth defects and Multiple Chemical Sensitivity. Chlorpyrifos has been the subject of intense regulatory scrutiny in the US and as a result its use was severely restricted in 2000(6).
    The herbicide MCPA is a constituent of 53 of the products and can cause an allergic reaction resulting in pains, nausea, vomiting, itching and burning of the skin(7). It is a possible human carcinogen, according to IARC(8). 
    Mecoprop-p, a herbicide found in 42 of the products, is an IARC possible carcinogen(9). It is harmful if swallowed, irritating to skin and presents a risk of serious damage to the eyes(10). 
    Many people who are vulnerable to pesticide exposure, including children, the elderly, the sick and pregnant women, use public open spaces. Children are particularly susceptible to exposure as they absorb greater concentrations of pesticides per pound of body weight through inhalation, ingestion and contact with the skin. A child's immune system is less developed than that of an adult and may be less protected. Developing cells are more easily damaged than cells that have completed development. Cells divide very quickly during the rapid growth of childhood, making it more likely that a cellular mutation will be reproduced thus initiating cancer. 
    Children are more likely to be exposed to pesticides applied to lawns and turfed areas as they have more contact with the ground whilst playing and a higher rate of hand to mouth contact than adults(11). Pesticide residues from outdoor applications can be tracked into buildings on the soles of shoes adding to the chemical load of indoor air which poses a further risk of exposure(12).
    Pesticides not only present a risk to human health but also affect the environment. Some active ingredients pose a threat to beneficial insects, such as bees, which are essential pollinators, and others that are predators of insect pests. There is also a risk of water contamination from many active ingredients, including chlorpyrifos, which are subject to Local Environmental Risk Assessments for Pesticides (LERAP) Category A restrictions(13). 

Pesticide reduction
The Henry Doubleday Research Association estimates that lawns cover 90,000 hectares in the UK(14). Combined with municipal parks, sports pitches and other green spaces the coverage is much greater. There is a huge potential for householders and amenity managers to apply pesticide products to treat pest problems that can be treated using non-chemical methods. The development of grass genetically altered to be resistant to toxic herbicides will further encourage the use of such products(15).
    Practical measures to reduce pesticide use include developing a healthy soil, selecting a grass type that thrives in local conditions, mowing regularly leaving a high sward and allowing the clippings to be recycled into the soil, watering deeply but not too often, correcting thatch build-up and setting realistic goals(16).
    Many parks managers, grounds maintenance managers and green keepers are adopting an integrated approach to pest management to minimise the risks posed by pesticide use. Last year 55 Green Flag Park Awards were presented across the UK to those parks that are managed to a high standard of sustainable criteria, including the elimination or significant reduction of pesticide use(17). Parks, including Fryent Country Park in the London Borough of Brent, have further reduced their pesticide use by installing recycled plastic furniture replacing wooden structures containing toxic timber treatments(18). The grounds of Exeter University have been managed without pesticides for the last 10 years. Lawns and cricket pitches are seeded and maintained successfully and the healthy ecology of the grounds prevents pests and diseases taking a hold(19). Hockley Bowling Club in Essex has been managed organically for six years and is considered to be one of the best greens in the area. Worm casts are not a problem because the healthy management of the soil increases aeration and encourages worms to stay lower in the soil(20).

Conclusion
Pesticides used in the management of lawns can pose serious threats to public health and the environment and can be avoided. The management examples cited above have been adapted and perfected over many years and yield many benefits including increased public safety and increased wildlife value. The Pesticide Action Network UK's Local Action on Pesticide project is able to offer information, advice and training to amenity managers. (AW)

1. Crop Protection Handbook 2001, Crop Protection Association, Peterborough, UK.
2. Pesticides 2001, Pesticides Safety Directorate, The Stationery Office, London, 2001.
3. 2,4-D, Extoxnet data sheet, Pesticide Management Programme, Conrnell University, US, 1994.
4. IARC website, http:193.51.164.
5. Review of Chlorpyrifos, Memorandum from the US Environmental Protection Agency, undated.
6. Chlorpyrifos summary, Office of Pesticide Programs, US EPA, September 2000. www.epa.gov/oppsrrd1/op/chlorpyrifos/summary
7. R Whitehead, The UK Pesticide Guide 2001, CABI Publishing, Guildford 2001.
8. Op. cit. 4.
9. Op. cit. 4.
10. Op. cit. 7.
11. C Lazaroff, Pesticide Exposure Threatens Children at School, Environment News Service, http:/ens-news.com, January 2000.
12. The Inside Story, A Guide to Indoor Air Quality, US EPA, http://www.epa.gov.iaq/pubs/insidest.html
13. Op. cit 7.
14. J Norris, Lawns Are Not Astroturf, The Organic Way, Issue 160, HDRA, Summer 2000.
15. D Barboza, Suburban Genetics: Scientists Searching for a Perfect Lawn, New York Times, Sunday, July 8, 2000.
16. Healthy Lawn Healthy Environment, Prevention, Pesticides and Toxic Substances, US EPA, June 1992, www.epa.gov/oppfead1/Publications/lawncare.pdf
17. The Green Flag Park Awards 2000-2001 Raising Your Standard, The Civic Trust, Liverpool, 2001.
18. Alternatives to Pesticides workshop, London Borough of Brent and PAN UK, October 2000.
19. University success with pesticide reduction, Pesticides News 52, June 2001, p19.
20. J Steele, Bowling Green Goes Green, The Organic Way, HDRA.
21. CDS Tomlin, The Pesticide Manual 12 edition, British Crop Protection Council, Surrey, 2000.
22. Op cit 7.

[This article first appeared in Pesticides News No. 53, September 2001, pages 18-19]