California roller

A short-handled modification of the CDFA (or California) roller was passed over an all-cotton dosimeter (1711 cm2) (Ross et al., 1991) to collect transferable chlorpyrifos at the University Club. All results were expressed as pg chlorpyrifos per cm2 of the collection surface. 

The California roller technique, which also was used to generate some of the data in this study, consists of placing a defined-size piece of cloth material onto the treated turf, covering the cloth with a plastic sheet, and then rolling over the plastic and cloth sheets with a roller that contains 25 lb of lead shot. Typically, the roller is pushed back and forth over the sheets 10 times. The cloth is then extracted and analyzed for residues. 

In the present study, the results from the turf-clipping technique and the California roller technique will be contrasted and discussed. It is hoped that this will give the reader a better understanding of some of the difficulties encountered in determining the risk associated with exposure of chemical residues on turf by humans. 

The two techniques used for determining the amount of residue available for human exposure were the turf-clipping technique and the California roller technique. The residues from the turf clippings were obtained from a... 

The cloth dosimeter from the California roller technique consisted of placing a 15.2-cm x 61.0-cm piece of cotton cloth on treated turf, covering the cloth with plastic, and rolling over it with a 25-lb roller. The cloth was then placed in a sample container, which was put in a cooler and transported to the laboratory. The dosimeter was then extracted with hexane. An aliquot of... 

Figure 6 Decline curve for the California site using the California roller method.

Dt50 = 9.5 days Dt90 = 1.5 days r2 = 0.88 Figure 8 Decline curve for the Florida site using the California roller method. 

State Turf clipping results (days) California roller results (days) ... 

Turf clipping results California roller results ... 

Property California roller Drag sled PUF roller Human hand press... 

Information relating to ease of nse, simplicity, time requirements and other criteria for each of the test methods was also obtained during the round-robin test by means of written subjective evaluations and critique by each volunteer. The drag sled and PUF roller methods were rated high in overall ease of use, while the California roller was rated low. 

Of the three techniques, the PUF roller most closely approximates the human hand press in the quantities of pesticide residues collected per unit area of surface sampled, although it collects several times as much as the dry palm of the hand. The pliable foam sampling material, especially when wetted, more closely resembles human skin than the cotton fabrics used by the drag sled and California roller. However, since the transfer rates for the latter two devices are much higher than that of the PUF roller, they are less prone to yield non-detectable results in the field. 

Fuller, R., D. Klonne, L. Rosenheck, D. Eberhart, J. Worgan, and J. Ross (2001). Modified California Roller for measuring transferable residues on treated turfgrass. Bull Environ. Contam. Toxicol, 67, 787-794. 

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