Harald William Meyer

Polychlorinated biphenyls (PCBs) in indoor air originating from sealants in contaminated and uncontaminated apartments within the same housing estate

Twenty-four congeners of polychlorinated biphenyls (PCBs) were measured in 83 air samples and 20 elastic sealants samples of apartments with PCB-containing sealants. In addition, PCBs were measured in 21 air samples from reference apartments located in an uncontaminated section of the same estate. The PCB(tot) levels in the air of the contaminated section were 168-3843 ng m(-3) (mean: 1030 ng m(-3)), while the mean levels in the reference apartments were 6.03 ng m(-3). The sum of the 24 measured PCB congeners in sealants from the contaminated section was 187-221680 mg kg(-1). Principal component analysis revealed four groups among the sealant samples with different congener compositions, only two of which were clearly similar to known PCB mixtures, while two were not. Significant correlations and intercorrelations were observed between the lower chlorinated congeners in air and sealant, e.g. for PCB 28(air) and 28(seal) (p=0.04) and for PCB 28(air) and 52(air), 52(seal). However, no correlation was observed between the lower chlorinated congeners and the sums of PCB (∑PCB(6) or ∑PCB(24)) or the higher chlorinated congeners. Analysis of air concentrations in relation to questionnaire data indicated that the indoor air levels could be reduced by increased cleaning and airing frequencies.

Plasma polychlorinated biphenyls in residents of 91 PCB-contaminated and 108 non-contaminated dwellings-an exposure study.

BACKGROUND In the1950s-1970s polychlorinated biphenyls (PCBs) were used in several countries as plasticizers in elastic sealants in buildings. OBJECTIVE The primary objective was to study whether residents of PCB-contaminated dwellings had higher plasma levels of PCBs than their neighbours in non-contaminated dwellings. The secondary objective was to study possible associations between concentrations of PCBs in the indoor air and in the plasma of residents. METHODS Stratified cross-sectional study of residents of a housing estate with four sections, of which only one section had PCB-containing sealants. The determination of 27 PCB congeners in plasma was performed among 134 exposed and 139 non-exposed residents. Air measurements were conducted in 104 flats. RESULTS Significant differences in plasma PCBs between exposed versus non-exposed were found for most of the lower chlorinated and many of the higher chlorinated congeners. The median of sum of 27 PCBs was approximately four times higher in exposed compared with non-exposed residents. The elevated PCB concentrations persisted in multivariable analyses controlling for relevant cofactors. We found significant correlations between PCB indoor air concentrations and the PCB concentration in the plasma of the residents for ten of the lower chlorinated congeners. CONCLUSION Our study confirms that indoor air exposure to PCBs from PCB containing sealants may result in a considerable internal PCBs exposure of the residents. For the first time we were able to demonstrate that the internal exposure to low chlorinated PCBs is significantly associated with the indoor air concentration of these congeners.

Determinants of house dust, endotoxin, and β-(1→3)-D-glucan in homes of Danish children

Little is known about the geographic variation and determinants of bacterial endotoxin and β-(1,3)-D-glucan in Danish house dust. In a population of 317 children, we: (i) described loads and concentrations of floor dust, endotoxin, and β-(1→3)-D-glucan and (ii) their correlations and (iii) assessed their determinants; (iv) Finally, we compared our findings with previous European studies. Bedroom floor dust was analyzed for endotoxin content by the kinetic limulus amoebocyte lysate assay and for β-(1→3)-D-glucan by the inhibition enzyme immunoassay. The parents answered questions regarding potential determinants. We found: geometric means (geometric standard deviations) 186 mg/m(2) (4.3) for dust; 5.46 × 10(3) EU/m(2) (8.0) and 31.1 × 10(3) EU/g (2.6) for endotoxin; and 142 μg/m(2) (14.3) and 0.71 × 10(3) μg/g (7.3) for β-(1→3)-D-glucan. High correlations (r > 0.75) were found between floor dust and endotoxin and β-(1→3)-D-glucan loads, while endotoxin and β-(1→3)-D-glucan concentrations were moderately correlated (r = 0.36-0.41) with the dust load. Having a carpet was positively associated with dust load and with endotoxin and β-(1→3)-D-glucan concentrations. Pet keeping, dwelling type, and dwelling location were determinants of endotoxin concentrations. No other determinants were associated with β-(1→3)-D-glucan concentrations. Compared with other European studies, we found lower β-(1→3)-D-glucan loads and concentrations but higher endotoxin loads and concentrations suggesting a geographically determined different composition of Danish floor dust compared with other European regions.

Investigation of the importance of tertiary contamination, temperature and human behaviour on PCB concentrations in indoor air

High concentrations of polychlorinated biphenyls (PCBs) can still be measured in indoor air in many buildings built or renovated within the period from approximately 1950 until the late seventies. The increasing evidence of the importance of indoor exposure to PCBs has led to the initiation of remediation actions in many countries. Understandably, primary sources with original PCB content have been the main focus of the actions. However, removal of primary sources alone has shown to be insufficient in decreasing the high indoor PCB concentrations in contaminated buildings. The aim of this study was to investigate the importance of tertiary PCB sources to indoor air concentrations and identify predictors of PCB air concentrations in contaminated buildings. In this study, 24 PCB congeners were measured in the indoor air of 83 contaminated apartments as well as in sealants sampled in a random subset of 20 apartments. The sealants were identified to be the primary source containing the original PCBs. For total PCBs, the median air concentration was 859 ng/m3 and the median concentration in contaminated sealants was 16.5% by weight. Analyses performed in the present study indicate that the influence of tertiary sources on indoor air concentrations may be substantial and that removal of tertiary sources may be needed when performing PCB remediation in buildings.