Dislodgeable turf residues

Washing, wiping and vacuum techniques have also been employed to estimate foliar residue dislodgeability from turf grass (Popendorf et al 1975 Goh et al, 1986 Sears et al., 1987 Cowell et al., 1993 Black and Fenske, 1996). In one of these techniques, boots wrapped with cotton cheesecloth are used to determine the transfer of turf residues to the shoe soles (Sears et al., 1987). Another was somewhat similar to the PUF roller, employing the use of a PUF-covered paint roller (Cowell et al., 1993). 

Somewhat water-soluble pesticides such as acid herbicides will be washed from foliar surfaces and into subsurface soils by rainfall. For example, dislodge-able turf residues of 2,4-D after a 2.54-cm rainfall have been reported to be only 1-5% of those found at 4-8 h after application (Nishioka et al., 1996 USEPA, 1997c). However, dew or rain on aged turf residues may increase their dislodgeability (Nishioka et al, 1996). OP insecticides are semivolatile and will vaporize from surfaces after applications. Chlorpyrifos vaporizes rapidly from lawns if applied in aqueous formulations. Diazinon, which is used on lawns as well as indoors, dissipates even more rapidly. However, the persistence of OP... 

Goh, K.S., S. Edmiston, K.T. Maddy, D.D. Meinders and S. Margetich (1986). Dissipation of dislodgeable foliar residue of chlorpyrifos and dichlorvos on turf. Bull. Environ. Contam. Toxicol, 37, 27-32. 

Nishioka, N.G., H.M. Burkholder, M.C. Brinkman, S.M. Gordon and R.G. Lewis (1996). Measuring transport of lawn-applied herbicide acids from turf to home Correlation of dislodgeable 2,4-D turf residues with carpet dust and carpet surface residues. Environ. Sci. Technol, 30, 3313-3320. 

Pesticides may be tracked into the indoor environment after a certain outdoor apphcation [18, 19] or through transport from the workplace to the home (para-occupational or take-home exposure). Collection of floor dust both prior to and after lawn-apphed 2,4-dichlorophenoxyacetic acid (2,4-D), indicated that turf residues are transported indoors [20]. Carpet dust levels of 2,4-D and dicamba and carpet surface dislodgeable residue levels were highly correlated with turf dislodgeable residue levels [21]. 

Table 2 Liquid Turf Study Adult Dermal Dose of Chlorpyrifos Based on Dislodgeable Residue Data...

Each of these dislodging techniques tries to mimic ways that a person of a certain size or weight could contact the residues applied to turf. This is important because, should one of the techniques provide a more consistent means of dislodging than the others, it would allow risk assessments to be done that would give a good indication of the potential exposure and thus risk to an individual who comes in contact with the treated turf. It would also allow for better estimates to be made as to when the treated turf could be used by a typical homeowner. 

Curalan DF is a fungicide produced by BASF Corp. for the purpose of treating such diseases as brown patch and fusarium patch on turf. Curalan DF was applied to turf in California, Florida, and Pennsylvania at a rate of 5.6 lb of active ingredient in 80 gallons of finished spray solution per acre using a tractor-mounted boom sprayer. Four applications were made 14 days apart. These conditions were selected to reflect the maximum level of dislodgeable residue when the product is typically used in agricultural practice. 

When the residues are dislodged from turf, the Cenvir term can be determined, as the amount of residue per unit area that was sampled can be determined therefore, the units of the Cenvir term are typically pg/cm2. To calculate a transfer coefficient, however, additional work must be done to determine the amount of residue recovered on someone who performs a certain task on turf. This could be exercising, playing ball, running, rolling, etc. 

Because the transfer coefficient is calculated based on residues detected from the performance of a task, the final number is task dependent. The transfer coefficient is also dependent on the way the residues are dislodged from the turf, with different transfer coefficients being the result. Some of... 

Black, K.G. and R.A. Fenske (1996). Dislodgeability of chlorpyrifos and fluorescent tracer residues on turf Comparison of wipe and foliar wash sampling techniques. Arch. Environ. Contam. Toxicol, 31, 563-570. 

Cowell, J.E., S.A. Adams, J.L. Kunstman and M.G. Mueth (1993). Comparison of foliar and turf dislodgeable residue sampling techniques, in Pesticides in Urban Environments, K.D. Racke and A.R. Leslie (Eds), ACS Symposium Series 522, American Chemical Society, Washington, DC, USA, pp. 100-112. 

Sears, M.K., C. Bowhey, H. Braun, G.R. Stephenson (1987). Dislodgeable residues and persistence of diazinon, chlorpyrifos and isofenphos following their application to turf-grass, Pesticide Sci, 20, 223-231. 

USEPA (1997b). Evaluation of Dislodgeable Residue Collection Methods for Pesticide Applications on Turf, Report No. 600/R-97/107, National Exposure Research Laboratory, Research Triangle Park, NC, USA. 

Thompson D.G., G.R. Stephenson and M.K. Sears (1984). Persistence, distribution and dislodgeable residues of 2,4-D following its application to turf grass. Pesticide Sci., 15, 353-360. 

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