Golfer Exposure to Chlorpyrifos and Carbaryl Following Application to Turfgrass

Abstract

Exposure of golfers to pesticides following their application to turfgrass is of concern to regulators, turfgrass professionals, and consumers. Multipathway exposures were evaluated for golfers on turfgrass treated with chlorpyrifos and carbaryl. Air concentrations and transferable foliar residues (TFRs) were measured to assess potential respiratory and dermal exposures, respectively. At the same time, exposure to individuals simulating the play of golf was determined by dosimetry and urinary biomonitoring. Individual golfer exposure was determined in 76 rounds of golf following eight applications of chlorpyrifos and two applications of carbaryl. Estimated exposures to golfers following full course and full rate applications of chlorpyrifos and carbaryl were 19-68 times below current U.S. EPA acute reference dose (Rfd) values, indicating safe exposures under U.S. EPA hazard quotient criteria. Dermal exposure was determined to be the dominant exposure pathway to golfers, accounting for approximately 60% of the chlorpyrifos absorbed dose and 100% of the carbaryl absorbed dose. This study also provides a set of transfer factors (TFs) that may be used to determine dermal exposure of golfers to pesticides using transferable residue data.

Biomonitoring of Pesticides: Pharmacokinetics of Organophosphorus and Carbamate Insecticides

“…The calculation of absorbed dose was based on the amount of trichlorpyridinol collected in the urine over a 27-hour collection period, which was then adjusted to account for the amount of trichlorpyridinol excreted in the urine ( 71%) based on the previous pharmacokinetic analysis in humans (Nolan et al, 1984). The results of this study indicate that the estimated exposure to golfers was 19 to 68 times below the U.S. Environmental Protection Agency (EPA) reference dose (RfD) values, and dermal exposure was determined to be the predominant exposure pathway (Putnam et al, 2008).…”

“…The pharmacokinetics of organophosphorus and carbamate insecticides has been studied in a range of species, including humans (e.g., see Moody and Franklin, 1987;Nolan et al, 1984;Nong et al, 2008;Poet et al, 2004;Timchalk and Poet, 2008;Timchalk et al, 2002Timchalk et al, , 2006Timchalk et al, , 2007aTimchalk et al, , 2007bTomokuni et al, 1985;Tos-Luty et al, 2001;Wu et al, 1996). These insecticides are readily absorbed into the body and, based on the detection of metabolites in human urine, there is good evidence for widespread although low-level exposures (Aprea et al, 1999;Brouwer et al, 1993;Hill et al, 1995;Putnam et al, 2008;Shealy et al, 1997). These exposures can come from numerous sources, including ingestion of pesticide residues on foods or accidental as well as intentional ingestion of insecticides (Drevenkar et al, 1993).…”

“…In agricultural settings worker exposure studies have incorporated personal external monitoring to estimate the amount of chemical available from inhalation (i.e., breathing zone sampling pumps) and dermal absorption (i.e., patch method and hand washes). Where feasible, these studies have also incorporated biomonitoring to quantify the amount of absorbed dose (Chester, 1993;Franklin et al, 1981Franklin et al, , 1986Garabrant et al, 2008;Heudorf and Angerer, 2001;Putnam et al, 2008).…”

“…By converting the amount of trichlorpyridinol quantified in the urine based on the known pharmacokinetics of chlorpyrifos and trichlorpyridinol, it was possible to calculate both the pre-and post-exposure chlorpyrifos doses. A similar biomonitoring strategy was utilized to evaluate chlorpyrifos exposure in golfers following turf grass application (Putnam et al, 2008). This exposure assessment design involved collection of a pre-and post-exposure urine sample (27 hours).…”

“…These findings provide some confidence in the ability of biomonitoring results to reflect actual exposures resulting from both occupational and nonoccupational exposure to carbaryl. Putnam et al (2008) recently conducted an exposure study to evaluate golfers' exposure to chlorpyrifos and carbaryl following turf grass application. In this study the total carbaryl dose was determined by urinary biomonitoring of 1-naphthol.…”