Christina Rosenberg

N-acetyltransferase genotypes as modifiers of diisocyanate exposure-associated asthma risk

We observed previously that polymorphisms in glutathione S-transferase (GST) genes modified allergic responses to diisocyanate exposure. Here, we extended the study to examine the possible role of N-acetyltransferase (NAT) genotypes in the development of diisocyanate-induced ill effects, both separately and in combination with the previously examined GSTM1, GSTM3, GSTP1 and GSTT1 genotypes. The study population comprised 182 diisocyanate-exposed workers, 109 of whom were diagnosed with diisocyanate-induced asthma and 73 of whom had no symptoms of asthma. The diisocyanates to which the workers had been exposed to were diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (HDI) and toluene diisocyanate (TDI). The NAT2 genotype did not have any significant effect on the risk of developing asthma, but the putative slow acetylator NAT1 genotypes posed a 2.54-fold risk of diisocyanate-induced asthma (95% confidence interval [CI] 1.32 to 4.91). The effect of the NAT1 genotype was especially marked for workers exposed to TDI, among whom the NAT1 slow acetylator genotypes posed a 7.77-fold risk of asthma (95% CI 1.18 to 51.6). Statistically significant increases in asthma risk were also observed among the whole study population for the concurrent presence of the GSTM1 null genotype and either NAT1 (odds ratio [OR] 4.53, 95% CI 1.76 to 11.6) or NAT2 (OR 3.12, 95% CI 1.11 to 8.78) slow acetylator genotypes, and of NAT1 and NAT2 slow acetylator genotypes (OR 4.20, 95% CI 1.51 to 11.6). The results suggest for the first time that in addition to GSTs, the NATs play an important role in inception of asthmatic reactions related to occupational exposure to diisocyanates.

Determination of airborne methyl isocyanate as dibutylamine or 1-(2-methoxyphenyl)piperazine derivatives by liquid and gas chromatography

The usefulness of a glass fibre filter method to collect airborne methyl isocyanate (MIC) was studied in laboratory experiments and in a workplace during manufacture of mineral wool insulation material. Filter collection was based on derivatisation in situ with 1-(2-methoxyphenyl)piperazine (2MP). 2MP impinger sampling was also evaluated in the workplace. Impinger sampling with dibutylamine (DBA) was used as an independent method. The samples were analysed by liquid and gas chromatography using various detection techniques: mass spectrometry, ultraviolet and electrochemical detection (LC-MS, LC-UV, LC-EchD and GC-MS). The sampling efficiency of 2MP filters for MIC varied with the origin of the glass fibre filter. Two Whatman filters (diameter 25 mm) with altogether 21 mumol of 2MP collected 100% of 9.8 micrograms of MIC during 30 min at an airflow rate of 1 l min-1. The workplace measurements were performed at two concentration levels, 0.003 and 0.09 mg m-3. The theoretical amounts of derivatisation reagent were 42 mumol (2MP filter), 52 mumol (2MP impinger) and 100 mumol (DBA). MIC concentrations were 20% lower by the 2MP methods compared with the DBA method (statistically significant difference). Breakthrough was 6% for the DBA method and 9% for the 2MP impinger method. To trap both MIC and isocyanic acid, which was also present in the workplace samples, a tenfold molar amount of 2MP reagent was used. The precision of sample preparation, expressed as relative standard deviation, was 3.5% (0.17 microgram ml-1, n = 6). The precision of sampling in the workplace was 15% (0.002 mg m-3, n = 6). The limit of quantification was 0.0006 mg m-3 for 30 l of air by the 2MP impinger method and 0.03-0.05 mg m-3 by the 2MP filter method. Hence, airborne MIC can be determined using 2MP as derivatisation reagent. Impinger sampling is preferable when low concentration levels are expected.

Determination in urine of diisocyanate-derived amines from occupational exposure by gas chromatography-mass fragmentography

Hexane-1,6-diamine was determined in the urine of car painters exposed to paint aerosols based on 1,6-bis(carbonylamino)hexane. The concentration of inhaled functional NCO groups during a 15-min exposure averaged 2.8 ± 0.8 µmol m–3(standard deviation, n= 5). The peak diamine concentration in urine of 63 ± 33 nmol (mmol creatinine)–1(standard deviation, n= 5) occurred 30 min after the end of exposure. The diamine was extracted from the urine with Sep-Pak silica gel cartridges and determined as the perfluoroamide derivative by capillary gas chromatography-mass fragmentography. The determination of diisocyanate-derived diamines in urine offers a selective and sensitive means of biological monitoring of occupational isocyanate exposure.

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.

Direct determination of isocyanates and amines as degradation products in the industrial production of polyurethane-coated wire

Isocyanates and amines were analysed in the workplace atmosphere during the production of polyurethane-coated wire. Toluene diisocyanate and phenyl isocyanate were identified as the isocyanate monomers in the experimental thermodegradation of four different polyurethane varnishes. The formation of amines was also studied with dynamic simulation of workplace conditions. Isocyanates and the corresponding amines were detected at 220 °C. The isocyanates were determined as N-(4-nitrobenzyl)propylamine derivatives by high-performance liquid chromatography with ultraviolet detection. Additional qualitative information was acquired by on-line ultraviolet analysis. The amines were determined as fluorinated amides by capillary gas chromatography with electron-capture detection or alternatively as free amines with thermionic specific detection and packed columns.The toluene diisocyanate and toluenediamine concentrations found during the different stages of the coating process varied from below 0.001 to 0.74 mg m–3 and from below 0.0005 to 4.9 mg m–3, respectively. Corresponding values for aniline were 0.0005 and 0.18 mg m–3. No phenyl isocyanate was detected in the factory samples. The capillary gas-chromatographic determination of electron-capturing derivatives for amines was highly specific and sensitive and thus suitable for their quantification in routine work. Gas chromatography-mass spectrometry of the derivatives confirmed this view.

Volatile organohalogen compounds from the bleaching of pulp - occurrence and genotoxic potential in the work environment

Abstract A softwood and hardwood kraft pulp mill, utilizing chlorine-containing bleaching agents, was monitored for 40 organohalogen compounds in the workplace air. Low levels of chloroform, carbon tetrachloride, tetrachloroethene, 1,1,1-trichloroethane, 1,4-dichlorobenzene, methanesulphonyl chloride, 2,5-dichlorothiophene and pentachlorophenol were detected. The workplace air at the bleaching plant was found to be slightly genotoxic in an on-site bacterial mutagenicity test.

Genotoxicity of kraft pulp spent liquors from different types of chlorination procedures

The genotoxicity of spent liquors from kraft softwood and hardwood pulp bleaching processes was studied using the Ames Salmonella test and the SOS chromotest. The induction of micronuclei, in vivo, was assayed in bone marrow erythrocytes of B6 mice treated with softwood first chlorination stage spent liquor. The softwood bleaching process used a combination of Cl2 and ClO2 at the first chlorination stage. During the study the amount of free chlorine at the first chlorination stage in the softwood bleachery was gradually decreased, although the amount of active chlorine remained the same. Enzymatic bleaching was also used in a softwood process together with chlorine (Cl2 + ClO2). The hardwood bleaching plant used only ClO2 at the first chlorination stage. A decrease in genotoxicity, corresponding to the decrease in Cl2, was observed in the Ames Salmonella assays of the softwood bleaching plant effluents. A similar decrease was observed in the SOS chromotest. The highest decrease in mutagenic activity was observed when enzymatic bleaching was used together with chlorine.

Characterization and Control of Terpene Emissions in Finnish Sawmills

This article describes an experimental study of terpene emission rates during fresh pine and spruce sawing and processing. Total terpene emission was determined by summing the product of the exhaust airflow rate and the mean concentration in the exhaust. Terpene concentrations were measured at fixed sampling points between the sawing lines. Terpene emission during pine sawing was found to be around 10 times greater than that during spruce sawing. The emission rates given here can be used to predict emission rates for various production rates. The predicted emission rates can be used in mass balance models to predict concentrations or required airflow rates to achieve the target concentration level.

Exposure of Workers to 2,3,7,8-Substituted Polychlorinated Dibenzo-p-Dioxin (PCDD) and Dibenzofuran (PCDF) Compounds in Sawmills Previously Using Chlorophenol-Containing Antistain Agents

The use of chlorophenol-containing antistain agents (e.g., Ky5, a wood preservative) ceased in Finland at the end of the 1980s, after 5 decades of use. Exposure of workers to the impurities in these agents (i.e., polychlorinated dibenzo-p-dioxins [PCDDs] and dibenzofurans [PCDFs]) was assessed at three sawmills at which personnel used a sodium chlorophenate product as an antistain agent. Given that compounds accumulate in body fat and their half-lives in humans are long, we could determine 2,3,7,8-substituted PCDDs and PCDFs 5-9 y after the last exposure occurred. We used high-resolution gas chromatography/high-resolution mass spectrometry to determine PCDDs/PCDFs in plasma from 39 Ky5-exposed workers and 18 nonexposed workers. The average total plasma concentration of PCDD/PCDF of the Ky5-exposed workers at the three sawmills were 1018, 945, and 1165 pg/g fat, and corresponding concentrations in the nonexposed workers were 743, 1124, and 844 pg/g fat, respectively. We found no significant differences in total levels between Ky5-exposed workers and nonexposed workers. However, concentrations of the 1,2,3,4,6,7,8-HpCDF isomer were significantly higher (p < .01) among the Ky5-exposed workers at all three sawmills (averages of 224, 99, and 148 pg/g fat) than among their respective nonexposed workers (averages of 43, 48, and 44 pg/g fat). These results indicate that workers had handled Ky5. When we expressed concentration levels in international toxic equivalents (I-TEQs), the mean total I-TEQ PCDD/PCDF of Ky5-exposed workers was significantly lower at one of the sawmills (average = 42 pg I-TEQ/g) than at the other two sawmills (averages of 64 and 62 pg I-TEQ/g)(p < .05). Nevertheless, total concentrations at the sawmills studied were within the range of background levels in the general population.

Airborne chlorinated dioxins and furans in a pulp and paper mill

Abstract The concentrations of airborne 2,3,7,8-substituted polychlorinated dibenzo- p -dioxins and dibenzofurans measured at a pulp and paper mill ranged from 0.04 to 1.9 pg/m 3 . The paper mill used softwood and hardwood pulp which was bleached with solely chlorine dioxinde in the first chlorination stage. The chlorinated furans dominated in all samples, while very few dioxins were detected. No 2,3,7,8-tetrachlorodibenzo- p -dioxin was detected. The highest concentration was measured for 1,2,3,4,6,7,8-heptachlorodibenzofuran, which was present in all samples. The toxic equivalent concentrations varied between 0.002 and 0.2 pg/m 3 using the international toxic equivalency factors. The congener profile of a paper dust sample was similar to that of the corresponding air samples.