PUF roller

The PUF roller technique consists of placing a cylinder of polyurethane foam (PUF) onto a weighted, stainless steel roller and then rolling it over a defined area of treated turf. The turf is typically rolled over three times. The PUF is then pulled off the weighted, stainless steel roller, extracted, and analyzed for residues. 

RESIDENTIAL POST-APPLICATION PESTICIDE EXPOSURE MONITORING 81 PUF Roller... 

Figure 3.4 PUF roller (a) in position for sampling (b) axle cylinder/frame assembly...

Increasing the contact pressure exerted by the drag sled on a treated nylon plush carpet had relatively little effect on the transfer of chlorpyrifos residues to the cloth sampling medium (36 13 p.g at 2100 Pa, to 56 28 p.g at 4500 Pa, and to 43 10p.g at 15 600 Pa). Increasing the traverse speed of the drag sled reduced the amount of chlorpyrifos transferred from 56 28 Rg at 7 cm/s to 31 21p.g at 20 cm/s. The amount of transfer increased relatively uniformly with traverse distances up to 10 m. Static (3 s) transfer of chlorpyrifos to the sled averaged 0.6 p,g, or about half of that transferred to the PUF roller. The mean amounts transferred to the drag sled cloth increased from 4.2 p.g over the first 17 cm traversed, to 8.6 p,g over 92 cm, 124 p,g over 3 m, and 302 p.g over 10 m. 

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

Table 3.2 Comparison of transfer of fresh dried formulated pesticide residues from floor covering by drag sled, PUF roller and human hand presses...

Mean and standard deviation of transfer rates for single passes over floor covering surface using dry sampling media (contact areas of 930 cm for drag sled and 760 cm for PUF roller). 

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. 

For sample collection, the hand was pressed ten times on the carpet, progressing from one end to the other of a 10-cm x 100-cm area framed by the template (total area sampled, 640 cm ). The PUF roller was used to sample adjacent areas of similar size. After pressing in each of three areas of the carpeted room, the hand was carefully rinsed with 70 mL of pesticide-quality 2-propanol, which was collected in a clean sample bottle. Only one hand press was performed per day. 

In the first test, conducted in July under hot and relatively dry conditions, the grass was cut to 5 cm and raked prior to application of the chlorpyrifos/ chlorothalonil mixture. Deposition rates were determined by strategic placement of 10-cm X 10-cm cotton gauze coupons backed with aluminum foil. The test plot was allowed to dry for 4 h before sampling. The mean transfer efficiencies for chlorpyrifos were 2.37 ng/m (0.087%) for the PUF roller and 1.05 ng/m (0.039%) for the drag sled. The transfer efficiencies were much higher for... 

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). 

About I % of the 2,4-D in floor dust was dislodgeable (PUF roller wetted with acetonitrile phosphate buffer) and potentially available for dermal contact. 2,4-D residues on window sills and tables followed a similar traffic gradient, with surface loadings of 0.2 to 20 xg/m (none were detectable before application). In homes in which occupants removed their shoes at the entryway, 2,4-D loadings on floors were typically an order of magnitude lower than in those in which shoes were worn. 

Lu, C. and R.A. Fenske (1999). Dermal transfer of chlorpyrifos residues from residential surfaces Comparison of hand press, hand drag, wipe and PUF roller measurements... 

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