Mono-, di-, and trichlorinated biphenyls (PCB 1-PCB 39) in the indoor air of office rooms and their relevance on human blood burden.

Exposure to polychlorinated biphenyls (PCBs) from indoor air can lead to a significant increase in lower chlorinated congeners in human blood. Lower chlorinated congeners with short biological half-lives can exhibit an indirect genotoxic potential via their highly reactive metabolites. However, little is known about their occurrence in indoor air and, therefore, about the effects of possible exposure to these congeners. We analyzed all mono-, di-, and trichlorinated biphenyls in the indoor air of 35 contaminated offices, as well as in the blood of the 35 individuals worked in these offices for a minimum of 2 years. The median concentration of total PCB in the indoor air was 479 ng/m3 . The most prevalent PCBs in the indoor air samples were the trichlorinated congeners PCB 31, PCB 18, and PCB 28, with median levels of 39, 31, and 26 ng/m3 , respectively. PCB 8 was the most prevalent dichlorinated congener (median: 9.1 ng/m3 ). Monochlorinated biphenyls were not detected in relevant concentrations. In the blood samples, the most abundant congener was PCB 28; nearly 90% of all mono-, di-, and trichlorinated congeners were attributed to this congener (median: 12 ng/g blood lipid).

Quantification of all 209 PCB congeners in blood-Can indicators be used to calculate the total PCB blood load?

Polychlorinated biphenyls (PCBs) are a substance group of 209 theoretically possible compounds. The human body burden of PCBs is commonly calculated based on so-called indicator congeners such as PCB 138, PCB 153 and PCB 180, which are analyzed in human blood. The German "Human Biomonitoring (HBM) Commission" assumes that the sum of these indicator congeners multiplied by a factor of 2 represents the total PCB burden. This norm is based on data obtained from exposure studies after dietary intake. Data from indoor air shows a different congener pattern, which might lead to a relatively higher intake of lower chlorinated PCBs by inhalation. In two independent studies with adult participants from two regions in Germany, we measured all 209 PCB congeners in 44 whole blood and 42 plasma samples. Participants from the whole blood study group had additional exposure to PCBs via indoor air. With our analytical method, 141 individual PCB congeners, 27 coeluted pairs of PCB congeners and 2 records of 3 and 4 coeluted PCBs could be determined. Thus, 172 analysis results were reported per sample. In the whole blood samples, 50 congeners showed values below the limit of quantification (LOQ), whereas 94 congeners could not be detected in any of plasma samples. Total PCB concentrations (Σ 209 PCB congeners, incl. ½ LOQ) in the whole blood samples ranged from 99 to 2152ng PCB/g lipid (Median: 454ng/g lipid; 95th Percentile: 1404ng/g lipid). The sum of all 209 measured PCB (incl. ½ LOQ) in plasma samples showed levels between 52 and 933ng PCB/g lipid (Median: 226ng/g lipid; 95th Percentile: 642ng/g lipid). Our results show that the burden of PCBs on the human body is caused mainly by the three highly chlorinated indicator congeners PCB 138, PCB 153 and PCB 180. In median approximately 50% of the total PCB content in human whole blood or plasma samples can be attributed to these congeners. Total PCB, calculated by multiplying the sum of the three indicator congeners by 2, showed a strong and highly significant correlation to the sum of all 209 measured congeners for each sample. A slightly stronger correlation in the whole blood samples could be achieved by choosing six indicator congeners, including the lower chlorinated congeners (PCB 28, 52 and 101) into the calculation. Although this difference is very small, it must be considered that higher PCB levels in indoor air than those measured in the present study might be associated with a higher burden of indoor-air-related congeners in exposed individuals. For precautionary reasons, it could therefore be recommended that the assessment of individuals exposed to PCB via indoor air should be carried out based on the sum of the 6 indicator congeners PCB 28, PCB 52, PCB 101, PCB 138, PCB 153 and PCB 180 multiplied by a factor of 2.

Phthalates in German daycare centers: occurrence in air and dust and the excretion of their metabolites by children (LUPE 3).

Phthalates have been used for decades in large quantities, leading to the ubiquitous exposure of the population. In an investigation of 63 German daycare centers, indoor air and dust samples were analyzed for the presence of 10 phthalate diesters. Moreover, 10 primary and secondary phthalate metabolites were quantified in urine samples from 663 children attending these facilities. In addition, the urine specimens of 150 children were collected after the weekend and before they went to daycare centers. Di-isobutyl phthalate (DiBP), dibutyl phthalate (DnBP), and di-2-ethylhexyl phthalate (DEHP) were found in the indoor air, with median values of 468, 227, and 194ng/m(3), respectively. In the dust, median values of 888mg/kg for DEHP and 302mg/kg for di-isononyl phthalate (DiNP) were observed. DnBP and DiBP were together responsible for 55% of the total phthalate concentration in the indoor air, whereas DEHP and DiNP were responsible for 70% and 24% of the total phthalate concentration in the dust. Median concentrations in the urine specimens were 44.7µg/l for the DiBP monoester, 32.4µg/l for the DnBP monoester, and 16.5µg/l and 17.9µg/l for the two secondary DEHP metabolites. For some phthalates, we observed significant correlations between their concentrations in the indoor air and dust and their corresponding metabolites in the urine specimens using bivariate analyses. In multivariate analyses, the concentrations in dust were not associated with urinary metabolite excretion after controlling for the concentrations in the indoor air. The total daily "high" intake levels based on the 95th percentiles calculated from the biomonitoring data were 14.1µg/kg b.w. for DiNP and 11.9µg/kg b.w. for DEHP. Compared with tolerable daily intake (TDI) values, our "high" intake was 62% of the TDI value for DiBP, 49% for DnBP, 24% for DEHP, and 9% for DiNP. For DiBP, the total daily intake exceeded the TDI value for 2.4% of the individuals. Using a cumulative risk-assessment approach for the sum of DEHP, DnBP, and DiBP, 20% of the children had concentrations exceeding the hazard index of one. Therefore, a further reduction of the phthalate exposure of children is needed.

[The occurrence of plasticisers (phthalates) in communal facilities under special consideration of results from LUPE 3]. / Vorkommen von Weichmachern (Phthalaten) in Gemeinschaftseinrichtungen unter besonderer Bedeutung der Ergebnisse von LUPE 3.

Children are a very susceptible subgroup of the general population and therefore health authorities have a special interest to prevent them from health hazards. In a study of 3 German Bundesländer the indoor air and dust samples of altogether 63 German daycare centres were analysed for the presence of phthalate diesters in 2011/12 (LUPE 3 study). Inhalable dust and gas phases were collected with a glass fibre filter and polyurethane foam over approximately 6 h while children were attending these facilities. Settled dust was collected by vacuuming the floor of the room using an ALK dust sampler. Indoor air and dust were analysed using a GC/MS system. Median values in the dust samples were 888 mg/kg for di-2-ethylhexyl phthalate (DEHP), 302 mg/kg for diisononyl phthalate (DiNP), 34 mg/kg for diisodecyl phthalate (DiDP), 21 mg/kg for di-n-butyl phthalate (DnBP), and 20 mg/kg for diisobutyl phthalate (DiBP). For DEHP and DiNP maximum values of 10,086 mg/kg and 7,091 mg/kg were observed, respectively. DEHP and DiNP were responsible for 70% and 24% of the total phthalate concentration in the dust. In indoor air phthalates are found mainly in the particulate phase of the filters. Only the more volatile phthalates dimethyl phthalate and diethyl phthalate were found also in the gas phase. The median values in the indoor air were 470 ng/m³ for DiBP, 230 ng/m³ for DnBP, 190 ng/m³ for DEHP, and 100 ng/m³ for DiNP. DnBP and DiBP were together responsible for 55% of the total phthalate concentration in the indoor air. Overall, our study showed that the concentrations of phthalates in indoor air of daycare centers are slightly higher and in dust samples lower compared with schools.