Sampling indoor dust

There are also a number of approaches taken to sampling indoor dust. It is important to emphasise that the matrix under study is settled dust for which the exposure pathway is ingestion (usually accidental, but for a small number of individuals, particularly young... 

Brommer S, Harrad S, Van den Eede N, Covaci A (2011) Concentrations of organophosphate and brominated flame retardants in german indoor dust samples. Organohalog Compd 73... 

Garcia M, Rodriguez I, Cela R (2007) Microwave-assisted extraction of organophosphate flame retardants and plasticizers from indoor dust samples. J Chromatogr A 1152 280-286... 

Nagorka R, Conrad A, Scheller C, SfiBenbach B, Moriske H-J (2011) Diisononyl 1,2-cyclohexanedicarboxylic acid (DINCH) and di(2-ethylhexyl) terephthalate (DEHT) in indoor dust samples concentration and analytical problems. Int J Hyg Environ Health 214 26-35... 

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... 

Results for endocrine disrupting phenols in house dust as reported by Rudel et al. (2003) and Butte et al. (2001) are compiled in Table 11.1. Rudel et al. (2003) sampled indoor air in 120 homes as well. They analyzed both house dust and air for 89 organic chemicals identified as EDCs. The most abundant compounds in air included 4-nonylphenol and 4-t-butylphenol with typical concentrations in the range of 0.050-1.500ggm 3. Saito, Onuki and Seto (2004) collected air samples from houses, offices, and outdoor points. 4-t-butylphenol, 4-t-octylphenol and 4-nonylphenol were detected in both indoor and outdoor air. Concentrations and detection frequencies were higher in indoor air than outdoor air. The maximum levels of 4-t-butylphenol, 4-t-octylphenol and 4-nonylphenol in indoor air were 0.387, 0.0457 and 0.680 ggm 3, respectively. 4-t-butylphenol and 4-nonylphenol were detected with high frequencies (more than 97%) in the indoor air samples. Wilson, Chuang and Lyu (2001) reported a mean of 0.0007 gg m"3 Bisphenol A in the air of 10 child care centers and a mean of 0.203 gg m 3 for the sum of nonylphenol and its ethoxylates. 

DEHP has been detected in indoor dust samples. 0ie et al. (1997) reported that sedimented dust samples from 38 dwellings in Oslo, Norway contained an average of 640 g/mg sedimented dust (100 1,610 g/g), while suspended particulate matter from six dwellings contained an average of 600 g/g (24 94 g/g). 

Chemical leach tests on the bulk settled dust samples showed that the dusts are quite chemically reactive. Leach solutions have high alkali-nities, due to the rapid partial dissolution of calcium hydroxide from concrete particles. Indoor dust samples produced higher pH levels (11.8-12.4) and alkalinities (—600 mg CaCOa) than outdoor dusts (pH 8.2-10.4 alkalinity —30mgL CaCOa), indicating that outdoor dust samples had reacted with rainfall or other water prior to collection. Thurston et al (2002) found that the leachate pH of the dusts decreased with decreasing particle size. Some metals or metalloids in the dusts (aluminum, chromium, antimony, molybdenum, barium, copper, zinc, cobalt, nickel) are readily leached by deionized water many of these form oxyanion species or carbonate complexes that are most mobile at the alkaline pH s generated by the leachates. 

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]. 

Given that the SGV is driven by ingestion of soil and indoor dust, protocol 1 best reflects the likely exposure to cadmium in the potentially contaminated soil. Thus, it is very important to ensure that the correct sample pre-treatment protocol is adopted and that the end-user of this data understands this protocol and how the analysis is reported. Not all laboratories clearly specify the protocol that they use. It is also essential that the fraction of the sample discarded prior to sub-sampling for analysis is recorded in the analysis certificate. Also, details of any unusual artefacts or large debris that were removed prior to the analysis pre-treatment stages should be included in the analysis certificate. 

Matrix solid-phase dispersion (MSPD) integrates extraction and clean-up in a single step, and greatly speeds-up sample throughput. It has also been proposed for the isolation of several organophosphate esters, mainly flame retardants and plasticizers in indoor dust samples (Garcia et al. 2007). 

The use of ultrasounds to aid the extraction is another possibility. Phthalates (Abb et al. 2009) and perfluorinated alkanoic acid (PEA) (Kato et al. 2009) determinations have been reported. Ethyl acetate (phthalates) or formic acid with methanol (perfluoroalkyl chemicals) was added to the dust sample, and extraction was performed in an ultrasonic bath at room temperature for 10 min. In the case of phthalates an enrichment step was not carried out to avoid the risk of contamination. Pyrethroids and their metabolites can also been extracted from indoor dust samples by adding methylene chloride followed by sonication for 10 min (Starr et al. 2008). Another option is the combination of Soxhlet extraction with an ultrasonic treatment (Schecter et al. 2009). 

High resolution gas chromatography-high resolution mass spectrometry (HRGC/HRMS) also allows improving LODs. An example is PBDE determination in air, dust, and clothes dryer lint samples using this technique (Toms et al. 2009 Schecter et al. 2009). When C-labeled internal standards are added, analysis can be carried out by the isotope dilution technique. For example, PBDEs were analyzed in house indoor dust of different countries by GC/isotope dilution-HRMS (Sjodin et al. 2008). When volatiles are analyzed, another possibility is to use multidimensional GC/MS-olfactometry in a system equipped with a non-polar precolumn and polar column in series. This system was used to determine VOCs from swine barn particulate matter (Cai et al. 2006). 

Harrad et al. (2009) investigated the deeomposition of HBCDs stored in a well homogenised indoor dust sample at different conditions exposed to natural light, and kept in the dark. Calculated half-lives (ti/2) showed that HBCD concentrations decay faster in light-exposed samples (ti/2 = 12 weeks), than in light-shielded dust (ti/2 = 26 weeks). 

The results indicate that the amount of a single PFC in each sample is always lower than the threshold concentration given for PFOA and PFOS, and that TDI does not reach the threshold concentration. However, the results of the analyses also indicate that in practically all food samples considered, some or more PFCs have been found (even if each at low concentration). Also, considering the PFC ubiquitous presence in water, soil, atmosphere, indoor dust, and air, and their presence in so many products of our quotidian life (our clothes), we can say that we are surrounded by PFCs. Also taking into account their stability and their accumulation properties, the total PFC amount that can pass to humans can become enormous. 

Dust. As part of her study on the lead content in blood in Cd. Juarez, Chihuahua, Ordonez et al. (1976) carried out the analysis of lead in 70 samples of indoor dust accumulated in the homes of the children selected for the study. Samples of superficial soil in gardens, backyards, and orchards were also included. This study was motivated by the existence of a smelter at El Paso, Texas, U.S., whose emissions affect some socioeconomic marginal areas of Ciudad Juarez, Chihuahua, due to the prevalent winds. The average concentrations of lead found in the dust samples are shown in Figure 8. A positive correlation between the lead values in the dust and those in blood was found, with a significance of/ < 0.001. 

Information on the presence of TBBPA in indoor dust is scarce. Generally, TBBPA concentrations are at the low end of those found for PBDEs and HBCDs, which is consistent with TBBPA s primary usage as a reactive FR. Dodson et al. (2012) reported median TBBPA concentrations of 260 ng/g and 200 ng/g in dust samples from California homes in 2006 and 2011, respectively. Dust concentrations were signihcantly related to the age of electronics present, suggesting that new electronics may contain less TBBPA than older products. Twofold higher TBBPA concentrations were reported in dust sampled from Japanese homes in 2006 (520 and 490 ng/g) (Takigami et al. 2009). 

Outdoor lead dust was found to be a more potent contaminant of children s hands than indoor lead dust at day care centers in New Orleans boys, in general, had higher hand lead levels than girls. The conclusions were based on lead analysis of hand wipe samples taken before and after children played outdoors at four different day care centers (a private inner-city site, a private outer-city site, a public inner-city site, and a public outer-city site). The private inner-city site had a severely contaminated outdoor play area with measured soil lead concentrations ranging from 287 to 1,878 mg/kg. The outdoor play area at the public inner-city site, where children exhibited the lowest hand lead measurements of any site in the study, had been completely paved over with concrete or rubberized asphalt and had well-maintained equipment (Viverette et al. 1996). 

Measurements of actual house dust in sampled residences where people use lawn chemicals is more disturbing. Even if the immediate exposure to these chemicals-now clinging to boots, shirtsleeves, and socks-did not prove a risk, the chemicals that hitchhike with us indoors have a more complex fate. Now released from clothing and accumulating in the home, chemicals with purportedly short half-lives begin to become more persistent. By settling in house dust, and therefore on carpets, the highest level of exposure falls on those close to the floor, which includes pets, but more importantly, toddlers, infants, and small children, who are disproportionately sensitive to the possible effects of these chemicals. ... 

Settled dust Preliminary results on indoor and car dust show that levels of OPERs in dust collected in public buildings and cars are higher than the levels in dust collected from home environments [61, 68, 69]. There is also a shift in the OPER profile levels of TPP and TDC/PP increase moderately in the office dust, but a remarkable rise in TDC/PP levels is observed in car dust samples. Table 3 gives an overview of the sum of analyzed OPERs in the countries and the most dominant OPEs in the analyzed samples. Some of the aryl OPERs namely BDPP, DBPP, EHDPP were so far not detected in dust samples. There seems to be a region-specific consumption of OPERs as higher levels of, e.g., TPP and TDCiPP were observed in house dust from the USA and New Zealand ([15], [297]). 

Indoor air The most abundant OPFRs in indoor air samples from homes were TEP, T BP, TnBP, TCEP, and TC/PP, which are outlined in Table 3. Heavier OPERs such as TBEP, TPP, TCP, TDC/PP, and TEHP are usually present in low concentrations or even below the detection limit. However, in some work environments and cars high levels of TBEP and TDC/PP were observed [66, 68, 84]. The higher air concentrations were associated with a higher dust concentration... 

To evaluate human exposure to phthalates and their substitutes, the main approaches investigate either the levels of chemicals in matrices relevant for human exposure (indoor air, dust, food and packages, etc.) or the levels of parent and metabolite compounds in human samples (serum, urine, or breast milk). An overview of phthalate and nonphthalate plasticizers together with their metabolites commonly reported in literature is presented in Table 5. The half-lives for the most of these compounds are already established and therefore, by evaluating the levels of their metabolites in human urine, the levels of their parent compounds may be... 

Table 6 Literature survey on levels of most commonly used phthalates and their substitutes in house dust (median concentrations and in brackets P95 concentrations, results expressed in pg/g) and in indoor air samples (median concentrations, results expressed in ng/m )... 

Because of volatilization and leaching from their application in consumer and personal care products, phthalate esters are ubiquitous contaminants in indoor environment, and the levels found in dust from homes in different countries (Table 2), showed that the less volatile phthalates such as DEHP and BBP, are the predominant in dust samples [11,16, 74], and that the percentage of both carpet and plastic materials (furniture, decoration, and home electronics) could be associated with higher concentrations of BBP and DEHP in house dust [12, 74, 75]. The proportion of DiNP in house dust from Germany in 2009 [12], indicates that the... 

Table 2 Phthalate range (or median) concentrations in indoor and outdoor air (expressed in ng/m ) and home dust (expressed in pg/g dry weight) samples from different sites and countries... 

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