Health Canada’s Pest Management Regulatory Agency (PMRA) is proposing continued registration of the herbicide ingredient 2,4-D for lawn and turf use after determining that the pesticide can be used safely on lawns and turf when label directions are followed. Because of public concerns over domestic uses of pesticides, the PMRA is asking that all registered pesticides undergo a thorough science-based risk assessment and that they must meet strict health and environmental standards before being approved for use in Canada.
A fully updated version of the PMRA news release and other 2,4-D information compiled and researched by the organization can be accessed by clicking here. Readers are encouraged to visit the site directly for the most updated information.
"The PMRA understands that the public may have concerns over domestic uses of pesticides and would like to convey that all registered pesticides undergo a thorough science-based risk assessment," the organization said in a statement. The news service Reuters reports that the PMRA will take a final decision on whether to ban the pesticide later this year after the public has been given a chance to make comments. "We have determined that 2,4-D can continue to be used safely by homeowners who choose to use it on their lawns provided that label instructions are followed," PMRA spokesperson Connie Moase told a news conference.
The proposed decision on 2,4-D is consistent with those of other countries, according to the PMRA. The U.S. Environmental Protection Agency’s re-evaluation, released in January 2005, is the most recent reassessment of 2,4-D. It also found 2,4-D to be acceptable for use on lawn and turf.
| ENVIRONMENTAL ACTIVISTS OPPOSE 2,4-D RE-EVALUATION |
In response to news that Health Canada’s Pest Management Regulatory Agency (PMRA) is reconsidering a proposed ban on the popular herbicide 2,4-D, Reuters news service reports that environmental activists are attacking the decision. "We're quite disgusted with it ... I don't think it's protecting the health of Canadians at all. There are certainly lots of ways you can maintain beautiful lawns and gardens without using 2,4-D," said Meg Sears of the Canadian Coalition for Health and Environment, in a report by Reuters writer David Ljunggren. 2,4-D, an active ingredient in a number of broadleaf weed control products is manufactuered by several major chemical companies, including Syngenta Crop Protection, Dow AgroSciences Canada, Bayer, Monsanto, DuPont Professional Products and BASF. PMRA’s Connie Moase said tests on animals had found no evidence that exposure to highly elevated levels of 2,4-D caused cancer. "The overall analysis shows no clear association between exposure to 2,4-D and human cancers," she told Reuters. However, the agency did say that "to promote risk reduction" users should use the pesticide at its lowest effective rate and added it would limit the number of times per year that an entire lawn could be sprayed. (See the “Proposed Changes” section in the main article at left for more information.) The PMRA also said it planned to start re-evaluating the use of 2,4-D on farms and would require users to set up buffer zones if they planned to use tractor-pulled containers to spray golf courses or sod farms. Sears said her group would make public submissions stressing its opposition to 2,4-D. "I can't say I'm very hopeful because the worldwide chemical industry is very powerful and has a lot more money than our volunteer organization," she said. |
The PMRA reviewed 2,4-D as part of the re-evaluation program currently underway in Canada. The purpose of this re-evaluation is to determine if the pesticides currently on the market that were registered before Jan. 1, 1995 meet modern health and environmental standards.
Before finalizing its decision, the PMRA is inviting stakeholders, including the scientific community and all other interested parties, to provide any additional information that may be relevant to this re-evaluation. The Proposed Acceptability for Continuing Registration (PACR2005-01), Re-evaluation of Lawn and Turf Uses of (2,4 Dichlorophenoxy) acetic Acid 2,4-D, and supporting background material can be found on the PMRA’s Web site at www.pmra-arla.gc.ca. The PMRA will consider all additional information prior to finalizing the decision. The comment period ends on April 22.
ABOUT THE 2,4-D RE-EVALUATION. The PMRA reviewed the extensive body of information available for 2,4-D, which included the following:
- An extensive proprietary database. Manufacturers of the 2,4-D ingredient provided the PMRA with a database comprised of over 100 toxicity tests in animals. In addition to mammalian toxicity studies, numerous other studies on chemistry, exposure, environmental fate, environmental toxicity and on efficacy also were provided.
- Published scientific information. These include reports, epidemiological studies and all other relevant scientific information published in scientific journals and other publicly available documentation.
- Foreign reviews. The PMRA reviewed the scientific assessments of 2,4-D from the United States, the European Union, New Zealand and the World Health Organization.
- Use pattern information collected by the PMRA. The PMRA collected and examined all available information from a variety of sources in order to properly characterize the use pattern of 2,4-D in Canada.
The re-evaluation included a science-based risk assessment to determine if the product can be used safely. This assessment consisted of:
- A health assessment that looked at the potential for 2,4-D to cause adverse health effects such as cancer, birth defects and endocrine disruption
- An assessment of all sources and routes (oral, dermal, inhalation) of potential exposure to 2,4-D, including exposure from the diet, drinking water and from contact with treated areas like lawns and gardens
- Homeowner as well as occupational exposure assessments (exposure encountered by the user/applicator of the product), both during and after application of 2,4-D
- A human health risk assessment that determined the toxicity in relation to the amount of exposure in all potentially exposed populations, including children
- An environmental risk assessment that considered risks to plants, birds, mammals and aquatic organisms, as well as fate in the environment
- An assessment of value as it relates to the efficacy of the product
Part of the human health assessment is to ensure that, when 2,4-D is used according to label directions, there is a large enough margin of safety between the level of exposure humans could be exposed to and any identified toxic effect during animal testing.
The PMRA’s assessment included the addition of extra safety factors to ensure that the most sensitive subpopulations, such as children and pregnant women, also were protected. The PMRA also took into consideration the unique physiology, behaviors and play habits of children, such as their lower body weights and hand-to-mouth contact while playing on treated grass.
In addition to the 2,4-D-specific animal toxicity data, the PMRA also considered the large body of epidemiological studies and reviews pertaining to 2,4-D and human health. The extensive body of scientific information examined by the PMRA included relevant data used by non-regulatory groups, such as the Ontario College of Family Physicians in their April 2004 Report. While that report focused on a subset of epidemiology studies from the public literature, the PMRA reviewed the extensive body of information available for 2,4-D to conduct a full human health risk assessment.
The examination of animal toxicity data from internationally accepted guideline studies using doses well above those to which humans are typically exposed, combined with exposure data obtained from well designed studies, is currently the best methodology available for assessing risks to human health. Based on the evaluation of the available information, as listed earlier, the PMRA determined that 2,4-D can be used safely when label directions are followed.
PROPOSED CHANGES. The PMRA is requiring some changes to the use of 2,4-D on lawn and turf to increase the protection of human health and the environment. The changes include:
- All application rates must be set to the lowest effective rate, consistent with the PMRA approach for all pesticides, to further minimize exposure to the products.
- Requiring buffer zones for liquid commercial-class products that are applied by tractor-pulled field sprayers used on golf courses or sod farms, in order to protect adjacent non-target vegetation.
- Directions for use such as limiting the amount of broadcast applications (i.e., treating the entire lawn) to two per season to further reduce exposure to humans and the environment.
Lawn & Landscape Associate Editor Jonathan Katz contributed to this report.