Exposure to flame retardants in electronics recycling sites.

Waste electrical and electronic equipment (WEEE) contains various hazardous substances such as flame retardants (FRs). Inhalation exposures to many FRs simultaneously among WEEE recycling site workers have been little studied previously. The breathing zone airborne concentrations of five brominated FR compounds tetrabromobisphenol-A (TBBP-A), decabromodiphenylethane (DBDPE), hexabromocyclododecane, 1,2-bis(2,4,6-tribromophenoxy)ethane, hexabromobenzene, and one chlorinated FR (Dechlorane Plus®) were measured at four electronics recycling sites in two consecutive years. In addition, concentrations of polybrominated diphenyl ethers (PBDEs) and polybrominated biphenyls were measured. The three most abundant FRs in personal air samples were PBDEs (comprising mostly of deca-BDE), TBBP-A, and DBDPE, with mean concentrations ranging from 21 to 2320 ng m(-)(3), from 8.7 to 430 ng m(-3), and from 3.5 to 360 ng m(-3), respectively. At two of the sites, the emission control actions (such as improvements in ventilation and its maintenance and changes in cleaning habits) proved successful, the mean levels of FRs in personal samples being 10-68 and 14-79% of those from the previous year or alternatively below the limit of quantification. At the two remaining sites, the reductions in FR exposures were less consistent. The concentrations reported may pose a health hazard to the workers, although evaluation of the association between FR exposure and adverse health effects is hampered by lacking occupational exposure limits. Therefore, the exposures should be minimized by adequate control measures and maintaining good occupational hygiene practice.

Micronuclei, hemoglobin adducts and respiratory tract irritation in mice after inhalation of toluene diisocyanate (TDI) and 4,4'-methylenediphenyl diisocyanate (MDI).

Toluene diisocyanate (TDI) and 4,4'-methylenediphenyl diisocyanate (MDI), used in the production of polyurethane foam, are well known for their irritating and sensitizing properties. Contradictory results have been obtained on their genotoxicity. We investigated the genotoxicity and protein binding of inhaled TDI and MDI in mice by examining micronucleated polychromatic erythrocytes (PCEs) in bone marrow and peripheral blood and TDI- and MDI-derived adducts in hemoglobin. Male C57Bl/6J mice (8 per group) were exposed head-only to TDI vapour (mean concentrations 1.1, 1.5, and 2.4mg/m(3); the mixture of isomers contained, on the average, 63% 2,4-TDI and 37% 2,6-TDI) or MDI aerosol (mean concentrations 10.7, 20.9 and 23.3mg/m(3)), during 1h/day for 5 consecutive days. Bone marrow and peripheral blood were collected 24h after the last exposure. Inhalation of TDI caused sensory irritation (SI) in the upper respiratory tract, and cumulative effects were observed at the highest exposure level. Inhalation of MDI produced SI and airflow limitation, and influx of inflammatory cells into the lungs. Hemoglobin adducts detected in the exposed mice resulted from direct binding to globin of 2,4- and 2,6-TDI and MDI, and dose-dependent increases were observed especially for 2,4-TDI-derived adducts. Adducts originating from the diamines of TDI (toluene diamine) or MDI (methylene dianiline) were not observed. No significant increase in the frequency of micronucleated PCEs was detected in the bone marrow or peripheral blood of the mice exposed to TDI or MDI. The ratio of PCEs and normochromatic erythrocytes (NCEs) was reduced at the highest concentration of MDI, and a slight reduction of the PCE/NCE ratio, dependent on cumulative inhaled dose, was also seen with TDI. Our results indicate that inhalation of TDI or MDI (1h/day for 5 days), at levels that induce toxic effects and formation of TDI- or MDI-specific adducts in hemoglobin, does not have detectable genotoxic effects in mice, as studied with the micronucleus assay.

Protein adducts as biomarkers of exposure to aromatic diisocyanates in workers manufacturing polyurethane (PUR) foam.

This work was undertaken to investigate the usefulness of diisocyanate-related protein adducts in blood samples as biomarkers of occupational exposure to toluene diisocyanate (TDI; 2,4- and 2,6-isomers) and 4,4'-methylenediphenyl diisocyanate (MDI). Quantification of adducts as toluene diamines (TDAs) and methylenedianiline (MDA) was performed on perfluoroacylated derivatives by gas chromatography-mass spectrometry (GC-MS/MS) in negative chemical ionisation mode. TDI-derived adducts were found in 77% of plasma and in 59% of globin samples from exposed workers manufacturing flexible polyurethane foam. The plasma levels ranged from 0.003 to 0.58 nmol mL(-1) and those in globin from 0.012 to 0.33 nmol g(-1). The 2,6-isomer amounted to about two-thirds of the sum concentration of TDA isomers. MDI-derived adducts were detected in 3.5% of plasma and in 7% of globin samples from exposed workers manufacturing rigid polyurethane foam. A good correlation was found between the sum of TDA isomers in urine and that in plasma. The relationship between globin adducts and urinary metabolites was ambiguous. Monitoring TDI-derived TDA in plasma thus appears to be an appropriate method for assessing occupational exposure. Contrary to TDI exposure, adducts in plasma or globin were not useful in assessing workers' exposure to MDI. An important outcome of the study was that no amine-related adducts were detected in globin samples from TDI- or MDI-exposed workers, alleviating concerns that TDI or MDI might pose a carcinogenic hazard. Further studies are nevertheless required to judge whether diisocyanates per se could be such a hazard.