SportsTurf

www.stma.org August 2016 | SportsTurf 23 A thletic fields make up a significant sector of managed turfgrass, and are common throughout society with more than 700,000 fields in the US. Athletic fields must be managed properly to ensure a uniform playing surface and minimize potential athlete injuries. Much research has documented the detrimental effects of weed populations on the integrity of the playing surface; hence, it's imperative to effectively control weeds and preserve the playing surface. SYNTHETIC PESTICIDES Synthetic pesticides are commonly used to control weeds and other pests in many facets of agriculture including specialty crops and noncropland areas such as athletic fields. Unlike many agricultural commodities that possess re-entry interval restrictions after pesticide applications, it's common and lawful to enter athletic fields and other turfgrass sites recently treated with pesticides in many US states. In such cases, it is permissible to re-enter a treated area after the application has dried. Currently, there is growing concern amid synthetic pesticide use and potential adverse effects on human and environmental health, which has caused some municipalities and local governments to ban pesticides on public properties including athletic fields. Some of the bans were adopted to reduce human pesticide exposure, while some were unfounded cases based solely on personal opinions. Specifically related to human health, routes of human pesticide exposure from treated athletic fields include dermal contact, nondietary ingestion, and inhalation. Dermal exposure accounts for most exposure on treated athletic fields and may be the result of direct contact with the playing surface (sliding, for example) or indirectly onto an object (balls, shoes, equipment, clothes, etc.) then transferred to humans. Pesticides vary in the amount that is absorbed via dermal exposure and the amount absorbed varies for different parts of the body. Previous research indicates ~5-15% of a pesticide may be absorbed through the skin on hands and forearms, while up to 100% may be absorbed on genitals. Oral exposure may be the result of carelessness or accident and a common route includes eating, hand-mouth contact, smoking or other tobacco use, without washing hands after being in contact with a pesticide-treated area. Inhalation exposure is a result of breathing pesticide vapors, dust or spray particles and is more problematic for pesticide applicators than athletes. DISLODGEABLE PESTICIDE RESIDUES Because of the growing concern amid synthetic pesticide use and associated potential health effects, recent research efforts have focused on quantifying dislodgeable pesticide residues from athletic fields and to elucidate influential factors with an overarching goal of devising best management practices to minimize dislodgeable foliar residues. The amount of pesticide that may be dislodged or transferred to athletes depends on pesticide properties including water solubility, persistence, vapor pressure, and sorption coefficients, among others, with pesticides ranging widely in these properties. For example, 2,4-dimethylamine salt (2,4-D; many trade names) is a commonly used postemergent herbicide and has a very high aqueous solubility (796,000 mg/L) while oxadiazon (trade name Ronstar), a commonly used preemergent herbicide, has a very low aqueous solubility (0.7 mg/L). This, among other factors, inherently affects the fate of pesticides and specifically affects the amount that is potentially dislodged or transferred to athletes. ARE DISLODGEABLE PESTICIDE RESIDUES A CONCERN ON ATHLETIC FIELDS? BY TRAVIS W. GANNON, PHD AND MATTHEW D. JEFFRIES FIELD SCIENCE

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