Vacuum cleaner sampling

The most frequently used methods for sampling indoor surface dust for SVOC/ POM analysis is simply to use dust from a vacuum cleaner dust bag, see for example, Krause, Chutsch and Englert (1989), or a special vacuum cleaner mouthpiece containing a filter, see for example, 0ie, Hersoug and Madsen (1997). Both the mouth-piece and the filter should be cleaned prior to use. It must be assured that the SVOCs and POMs of interest are quantitatively captured by the filter (e.g., phthalates are quantitatively captured by quartz fiber filters (Clausen and Wolkoffi 1997b)) and that the vacuum cleaner exhaust does not contaminate the samples with for example, phthalates. However, the vacuum cleaner sampling method is probably very dependent on the sampling conditions (e.g., carpet or hard floor... 

An empty 30 litre sample bag with a stainless steel pipe will be put into the container. The pipe is pushed through the cover. A PTFE tube will be fixed to the pipe to collect samples from different points. On the transparent cover a batteiy operated vacuum cleaner and a battery are mounted. Only by pressing a push button the sample is filled in about 10 seconds. By using this sampling device sampling doesn t make any problems. 

Another potential exposure route for children is through exposure to clothing and tracked-in dirt brought in by parents who work in factories that produce 3,3 -dichlorobenzidine. A public health assessment study conducted in Michigan in 1981 (ATSDR 1996) foimd the compoimd in the homes of 9 employees. Samples collected from vacuum cleaner bags had up to 10.5 ppm and dryer lint contained up to 0.74 ppm. If these homes have not been adequately cleaned, exposure could continue. 

To avoid the problems with vacuum cleaner surface dust sampling a special surface dust sampler, HVS-3, was developed (Roberts et al, 1991). The sampler consists of a nozzle that can be adjusted to a well defined distance to the surface, a cyclone that collects the dust particles, an air pump, and an exhaust filter to capture particles that are not retained in the cyclone. SVOCs may break through the cyclone as vapors and a PUF plug can be inserted after the cyclone. HVS-3 has been modified to ensure a more constant suction pressure and volume, and a known sampled area (Gyntelberg et al, 1994). The design and use of the HSV3 has now been standardized (ASTM, 1997, D 5438-94). 

Lewis et al. (1999) prepared a gross house dust sample by combing dust from four vacuum cleaner bags obtained from 25 middle-class homes. The composite dust was separated into seven size fractions ranging from <4 to 500 micrometer in diameter. Ten PAHs were analyzed. All of the ten target PAHs were detected... 

Indoor household dust samples gathered by a vacuum cleaner from rooms with furniture treated with a wood-preserving formulation were analyzed for CDDs (Christmann et al. 1989b). The wood-preserving... 

At the current time, it is not clear as to whether using vacuum cleaner bags or researcher-collected samples is more suitable. Allen etal. (2008b) compared concentrations of PBDEs in vacuum cleaner dust with researcher-coUected samples from 20 homes, finding only poor... 

Auother dust sampler that uses a haud-held vacuum cleaner but is capable of collectiug large dust samples was desigued by Rudel et al. (2001). The method employs a Eureka Mighty-Mite vacuum cleaner (8 A) (The Eureka Company, Bloomington, IL, USA) with the dust bag replaced by a 19-uun x 90-mm cellulose Soxhlet extraction thimble contained in a special PTFE sampling module. 

Colt, J.S., S.H. Zahm, D.E. Camann and P. Hartge (1998). Comparison of pesticides and other compounds in carpet dust samples collected from used vacuum cleaner bags and from a high-volume surface sampler. Environ. Health Perspec., 106, 721-724. 

Large samples can be extracted from bins or holds using a vacuum cleaner principle. Contamination is a problem when sampling below the surface, fines are extracted preferentially to coarse particles, and bias is a problem.f ... 

Concentrations of pesticides in indoor environments are dependent on their usage. Dust samples, for example, collected using vacuum cleaners, in households where wood preservatives were applied showed a median value of 13 mg g" of PCP, as compared with 0.008 mg g in samples from the control group [13]. 

Mostly pesticides in house dust are analyzed from floor dust taken with vacuum cleaners (or other suction devices). Even though there are standard protocols for sampling house dust [84, 90, 91] a great variety in sampling techniques has to be noted. These were reviewed by Butte and Heinzow [85] andMacher [92]. 

House dust serves as a reservoir for pesticides in households [85]. Dust ingestion scenarios show that exposures could also exceed the diazinon chronic reference dose [115]. Support for the thesis that household dust may not only be a direct exposure path but may serve as an indicator for all indoor exposure paths can be concluded from correlations between pesticides in dust and in samples of human origin. Regarding PCP, a semivolatile pesticide, concentrations in urine of women and children corresponded well with indoor dust samples from vacuum cleaner bags [13,136]. 

Upholstery and carpets are often treated with repellent finishes to minimize soiling during use. Since much of the soiling that occurs is due to dry soil, a test to evaluate dry soiling behavior is useful. AATCC Test Method 123-2000 can be used for upholstery and carpet samples. Either 10 g of actual vacuum cleaner soil or 10 g of a synthetic soil is rotated with pebbles in a rotary ball mill with two samples (3x7 inches) (7.6 x 18 cm) of the fabric to be tested. After a predetermined exposure time, the fabrics are removed, vacuumed and visually compared to previously soiled standards. 

Whereas the analytical part of the determination of biocides in dust displays only minor differences, samples referred to as household dust vary significantly. So far, no standard protocol for dust sampling has been reported. In the United States a High Volume Small Surface Sampler (HVS3) collecting dust samples of 2-100 g from carpets and bare floors in about 15 min has been developed (Roberts and Dickey, 1995). In Germany, predominantly dust samples from vacuum cleaner bags collected by commercial vacuum cleaners are used for evaluation of biocides in some cases samples were analyzed in passively deposited suspended particulate (PDSP) (Krause et al.. 

Support for the thesis that household dust leads to contamination comes from correlations between biocides in dust and in samples of human origin. This correlation was reported for PCP in the urine of women and children and dust from vacuum cleaner bags (Krause and Englert, 1980), and in PDSP and urine respectively (MeiBner and Schweinsberg, 1996). On the other hand, no correlation was observed between PCP in household dust and blood by Liebl et al. (1996). 

Dust may be regarded as the ideal material for detection and identification of indoor biocides and any of their residues still existing. Commercial vacuum cleaners ean be used for taking samples. Analysis using the < 63-pm fraction of dust lead to results that are more reproducible than those for any other fraction. Reliable results are only obtained under equilibrium conditions in rooms therefore there should be no cleaning for at least one week before dust samples are taken. Since the Umweltsurveys and two case control studies published recently are based on representative samples for household du.st of the German population (especially PCP, lindane and pyrethroids), the assessment of results is possible by comparison with reference values. 

The vacuum evacuation is effected by means of a vacuum pump (or even a simple vacuum cleaner appropriately connected ) via a vacuum probe, which is designed so that the excess resin will not enter into the vacuum pump to damage the machine. Vacuum evacuation can then commence. Typically evacuation down to 0.5 bars (about 50 kPa) would be sufficient. Pressurization of the sample is then effected by placing the whole configuration into an autoclave or any equivalent pressure vessel. If curing is to be done at elevated temperature, ensure that the temperature is rai.sed to the appropriate level before pressurization. The vacuum should be maintained at all times. The pressure is then raised to about 10 12 bars (100 120 kPa) and maintained until the sample is fully cured. For hot curing samples, it is usually advisable to cool the sample down. slowly to reduce residual stre.sses. 

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