“I wouldn’t hesitate to let my children and dogs play on a lawn where lawn care products have been used,” stated Katherine von Stackelberg, Sc.D, “as long as the products were applied according to their respective labels.” As part of a series of studies commissioned by the Environmental Health Research Foundation, von Stackelberg selected four of the most commonly used lawn care products and reviewed them to evaluate the strength of the association between exposure and potential health effects. She reviewed the toxicological, epidemiological, and exposure data for bifenthrin, azoxystrobin, 2, 4-D and MCPA (a member of the same chemical family as 2,4-D).
Katherine von Stackelberg is principal of E Risk Sciences and a research manager at the Harvard Center for Risk Analysis. E Risk Sciences specializes in developing risk-based modeling tools to support environmental decision making. Much of her work has focused on incorporating quantitative uncertainty analysis (e.g., analytical, probabilistic and fuzzy methods) into the risk assessment process and she has been at the forefront of the effort to promote uncertainty analysis and methods for communicating uncertainty to support environmental decision-making.
The first study focused on bifenthrin, a synthetic pyrethroid and a known neurotoxicant to insects. It has biochemical origins in the natural insecticide pyrethrum, an extract of Chrysanthemums and is a commonly used insecticide on turf, in homes, and for agricultural applications. In this study, von Stackelberg reviewed the health effects and exposure data for bifenthrin and found no evidence for adverse health effects when used as directed. Similarly, the U.S. EPA released a cumulative risk assessment in 2011 for synthetic pyrethroids as a class and found that typical uses were not associated with potential risks. Given the clear benefits of bifenthrin use (a highly effective termiticide), a qualitative benefit-risk assessment suggests that benefits of the product when used as directed lead to significant benefits. Given the obvious benefits, it is likely that directed uses of bifenthrin have greater benefit than risk.
In von Stackelberg’s second study, she provided a review of azoxystrobin, which is one of a new class of fungicidal compounds derived from naturally-occurring strobilurins used in agriculture and lawn care. Azoxystrobin is a broad-spectrum, systemic fungicide that acts by inhibiting electron transport. It has the ability to provide protection against fungal diseases within a variety of crops. In the study, von Stackelberg found “that the evidence indicates that the potential for adverse health effects in humans resulting from exposure to azoxystrobin is low to non-existent.” The research also looked at the effect of azoxystrobin on dogs and found no adverse health effects.
A third study was recently completed by von Stackelberg reviewing the potential health effects of MCPA and 2,4-D, which are pesticides/herbicides used to control and eliminate broad leaf weeds. In presentations last fall at two scientific conferences, von Stackelberg indicated that these products are also ones which do not raise undue levels of concern. The full results of this study have been submitted for publication to a peer reviewed scientific publication and EHRF will release the full study when it has been accepted for publication.
“Significant research has been done on these products,” von Stackelberg explained, “and the weight of evidence indicates very little potential for adverse health effects associated with environmental exposures.” The U.S. Environmental Protection Agency carefully monitors and approves lawn care products for use. Over the years, it has eliminated questionable products from use on lawns. As part of the pesticide registration process, U.S. EPA evaluates and in some cases conducts independent research to evaluate potential risks and define acceptable uses. They have determined there is little or no health risk associated with exposure to bifenthrin, azoxystrobin, and MCPA—when the products are used as directed.
“Green space, particularly in urban areas, offers significant health benefits, which are described in the Environmental Health Research’s review of the literature. Maximizing these benefits may require the use of products to ensure a healthy, thriving green space, and the goal is to use products with the greatest efficacy and the least potential for risk,” stated von Stackelberg.
The Environmental Health Foundation has a report available online which reviews all of the literature on the benefits of green space. With this report, EHRF produced a comprehensive bibliography of current university and governmental research which outlines the importance of healthy lawns. From erosion control to water and air purification to carbon sequestration to increasing home values the research shows that healthy lawns provide important environmental benefits as well as help create the kind of ideal play surfaces that can help stem the problems associated with the growing epidemic of childhood obesity.
To see the full reports on bifenthrin and azoxystrobin, go to www.ehrf.info