Control banding assessment of exposure of offset printing workers to organic solvents.

OBJECTIVES: We aimed to assess the exposure of offset printing workers to hazardous substances in the rinsing processes of small-sized companies using a control banding method. METHODS: We obtained half-year amounts of hazardous substances purchased through a questionnaire survey and the hazardous information from the safety data sheets (SDSs) and related literature. RESULTS: The amount of petroleum kerosine and carbon hydride markedly increased in 2013 compared with that in 2010. In contrast, the amount of dichloromethane (DCM) decreased in 2013, and 1,2-dichloropropane (DCP) was not used in either 2010 or 2013. Mineral oil and xylene were allocated to Hazard Group D and judged to require Control Approach 3. In addition to DCM with Global Harmonization System's carcinogenic category 1, mildly treated mineral oil and solvent naphtha, allocated into Hazard Group E, are carcinogenic to humans and were judged to require Control Approach 4. There are two limitations of the control banding assessment: first, only limited and scarce hazard information could be obtained from SDSs, and second, safe-sided judgment for control technology for industrial hygiene. CONCLUSION: Small-sized enterprises are encouraged to implement control banding assessment for hazardous substances and to access expert advice available from Regional Industrial Health Centers. Easy access to appropriate expert advice is important to compensate for the limited and scarce hazard information and safe-sided judgment for control technology for Control Approaches 3 and 4.

Occupational exposure to N,N-dimethylformamide in the summer and winter.

We evaluated total body burden of N,N-dimethylformamide (DMF) taken through the lung and skin by personal exposure of workers to DMF and urinalysis of N-methylformamide (NMF) and N-acetyl-S(N-methylcarbamoyl)-cysteine (AMCC). A total of 270 workers were engaged in four different jobs in a workplace distant from main production lines emanating high levels of DMF. They were not required to wear any personal protective equipment including respirators or gloves. We found that log-transformed urinary levels of NMF and AMCC increased with an increase in log-transformed concentrations of exposure to DMF. Urinary levels of NMF and AMCC were significantly higher in the summer than the winter, although there was no significant seasonal difference in the concentrations of exposure to DMF. Our findings suggested that the increased urinary levels of NMF and AMCC in the summer resulted in increased skin absorption of DMF due to an increased amount of DMF absorbed by the moisturized skin under humid and hot conditions. Seasonal changes in the relative internal exposure index confirmed the present finding of enhanced summertime skin absorption of DMF. AMCC is thought to be a useful biomarker for assessments of cumulative exposure to DMF over a workweek and for evaluations of workers' health effects.

Seasonal difference in percutaneous absorption of N,N-dimethylformamide as determined using two urinary metabolites.

OBJECTIVE: We evaluated the percutaneous absorption of N,N-dimethylformamide (DMF) in DMF-exposed workers in the summer and winter by assessing their urinary levels of DMF metabolites. METHODS: Breathing-zone concentrations of DMF and workers' urinary levels of N-methylformamide (NMF) and N-acetyl-S-(N-methylcarbamoyl)-cysteine (AMCC) were simultaneously measured in the summer and winter in 193 male workers wearing a respirator and chemical protective gloves. RESULTS: The mean breathing-zone concentrations of DMF in both seasons were below the occupational exposure limit of 10 ppm. Although there was no significant seasonal difference in the breathing-zone concentrations of DMF, workers' urinary levels of NMF and AMCC were significantly higher in the summer than in the winter. Log-transformed urinary levels of the metabolites were significantly correlated with log-transformed breathing-zone concentrations of DMF in the summer, whereas no significant correlation between AMCC and DMF was found in the winter. The urinary levels of AMCC were dispersed more widely than those of NMF, suggesting that urinary AMCC reflected the cumulative exposure to DMF over a workweek. CONCLUSIONS: Percutaneous absorption was the principal route of exposure to DMF for the respirator-wearing workers. Increased urinary levels of NMF and AMCC in the summer were attributed to increased percutaneous absorption of DMF resulting from the increased amount of water-soluble DMF absorbed by sweaty skin caused by the increased summertime room temperature and humidity.

The effects of workplace occupational mental health and related activities on psychological distress among workers: a multilevel cross-sectional analysis.

OBJECTIVE: To investigate the association of workplace occupational mental health (OMH) and related activities with psychological distress of workers in Japan. METHODS: A total of 121 workplaces and their 3540 workers were surveyed using questionnaires assessing selected workplace OMH activities, demographic characteristics, psychological distress, and psychosocial work environment of the workers. A multilevel analysis was conducted. RESULTS: Promotion of communication correlated significantly and negatively with psychological distress among workers after adjusting for the covariates (P < 0.01). Occupational mental health activities correlated marginally significantly and negatively with psychological distress (P = 0.06). Their moderating effect for the worker-level association between psychosocial work environment and psychological distress was not significant. CONCLUSIONS: The findings suggest that promotion of communication in the workplace is associated with reduced psychological distress among workers. In addition, OMH activities may also be useful in reducing psychological distress.

Effects of weather variability and air pollutants on emergency admissions for cardiovascular and cerebrovascular diseases.

We examined the effect of ambient temperature, air pressure and air pollutants on daily emergency admissions by identifying the cause of admission for each type of stroke and cardiovascular disease using generalized linear Poisson regression models allowing for overdispersion, and controlling for seasonal and inter-annual variations, days of the week and public holidays, levels of influenza and respiratory syncytial viruses. Every 1°C decrease in mean temperature was associated with an increase in the daily number of emergency admissions by 7.83% (95% CI 2.06-13.25) for acute coronary syndrome (ACS) and heart failure, by 35.57% (95% CI 15.59-59.02) for intracerebral haemorrhage (ICH) and by 11.71% (95% CI 4.1-19.89) for cerebral infarction. An increase of emergency admissions due to ICH (3.25% (95% CI 0.94-5.51)), heart failure (3.56% (95% CI 1.09-5.96)) was observed at every 1 hPa decrease in air pressure from the previous days. We found stronger detrimental effect of cold on stroke than cardiovascular disease.

Mineral oil certified reference materials for the determination of polychlorinated biphenyls from the National Metrology Institute of Japan (NMIJ).

Four mineral oil certified reference materials (CRMs), NMIJ CRM 7902-a, CRM 7903-a, CRM 7904-a, and CRM 7905-a, have been issued by the National Metrology Institute of Japan, which is part of the National Institute of Advanced Industrial Science and Technology (NMIJ/AIST), for the determination of polychlorinated biphenyls (PCBs). The raw materials for the CRMs were an insulation oil (CRM 7902-a and CRM 7903-a) and a fuel oil (CRM7904-a and CRM 7905-a). A solution of PCB3, PCB8, and technical PCB products, comprising four types of Kaneclor, was added to the oil matrices. The total PCB concentrations in the PCB-fortified oils (CRM 7902-a and CRM 7904-a) are approximately 6 mg kg(-1). In addition, the mineral oils which were not fortified with PCBs were also distributed as CRMs (CRM 7903-a and CRM 7905-a). Characterization of these CRMs was conducted by the NMIJ/AIST, where the mineral oils and the PCB solution were analyzed using multiple analytical methods such as dimethylsulfoxide extraction, normal-phase liquid chromatography, gel permeation chromatography, reversed-phase liquid chromatography, and chromatography using sulfoxide-bonded silica; and/or various capillary columns for gas chromatography, and two ionization modes for mass spectrometry. The target compounds in the mineral oils and those in the PCB solution were determined by one of the primary methods of measurement, isotope dilution-mass spectrometry (ID-MS). Certified values have been provided for 11 PCB congeners (PCB3, 8, 28, 52, 101, 118, 138, 153, 180, 194, and 206) in the CRMs. These CRMs have information values for PCB homologue concentrations determined by using a Japanese official method for determination of PCBs in wastes and densities determined with an oscillational density meter. Because oil samples having arbitrary PCB concentrations between respective property values of the PCB-fortified and nonfortified CRMs can be prepared by gravimetric mixing of the CRM pairs, these CRMs can be used for validation of PCB analyses using various instruments which have different sensitivities.

Preparation of sulfoxide residue bonded silica stationary phase for separation of polychlorinated biphenyls from mineral oils.

In this study, a sulfoxide residue bonded silica stationary phase was prepared for the separation of polychlorinated biphenyls (PCBs) from mineral oils, and its properties were investigated. Organic sulfide was attached to a silica surface by an amide bond, and the bonded sulfide residues were oxidized to sulfoxide with hydrogen peroxide to afford sulfoxide and sulfone residues bonded to the stationary phases (0.84 and 0.63 mmol of sulfur bonded per gram, respectively). The oxidation states of sulfur atoms bonded on the stationary phases could be determined using high-resolution X-ray fluorescence spectra. The modified stationary phases, especially sulfoxide-bonded one, separated PCBs from mineral oils (paraffin-based transformer oils) more efficiently than aminopropyl silica or other polar stationary phases that have been used for the cleanup of PCBs. The chromatographic parameters for an aliphatic hydrocarbon (eicosane) and some PCB congeners indicated strong retention of highly chlorinated biphenyls by the sulfoxide-bonded silica compared with the aminopropyl silica. A cleanup procedure was established for simple determination of PCBs in mineral oil samples using the sulfoxide-bonded silica packed column fractionation. The analytical method was validated using a certified reference material and a PCB-fortified transformer oil sample.

Sediment certified reference materials for the determination of polychlorinated biphenyls and organochlorine pesticides from the National Metrology Institute of Japan (NMIJ).

Two marine sediment certified reference materials, NMIJ CRM 7304-a and 7305-a, have been issued by the National Metrology Institute of Japan in the National Institute of Advanced Industrial Science and Technology (NMIJ/AIST) for the determination of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs). The raw materials of the CRMs were collected from a bay near industrial activity in Japan. Characterization of these CRMs was conducted by NMIJ, where the sediments were analyzed using multiple analytical methods such as pressurized liquid extraction (PLE), microwave-assisted extraction (MAE), saponification, Soxhlet extraction, supercritical fluid extraction (SFE), and ultrasonic extraction; the target compounds were determined by one of the primary methods of measurements, isotope dilution-mass spectrometry (ID-MS). Certified values have been provided for 14 PCB congeners (PCB numbers 3, 15, 28, 31, 70, 101, 105, 138, 153, 170, 180, 194, 206, 209) and 4 OCPs (gamma-HCH, 4,4'-DDT, 4,4'-DDE, 4,4'-DDD) in both CRMs. NMIJ CRM 7304-a has concentrations of the contaminants that are a factor of 2-15 greater than in CRM 7305-a. Both CRMs have information values for PCB homolog concentrations determined by collaborative analysis using a Japanese official method for determination of PCBs. The total PCB concentrations in the CRMs are approximately 920 and 86 microg kg(-1) dry mass respectively.

Separation of polychlorinated biphenyls from mineral oil using alkylammonium ion-bonded silica stationary phases.

The potential of alkylammonium ion-bonded silica stationary phases for effective and simple pretreatment for determination of polychlorinated biphenyls (PCBs) in mineral oil samples is presented in this paper. The separation between PCBs and aliphatic hydrocarbons by normal phase chromatography was improved by using the alkylammonium ion-bonded silica stationary phases instead of alkylamine-bonded silica or other polar stationary phases. The number of alkyl residues bonded to the nitrogen atom was also an important factor of the separation.

Cytotoxic activity of Bacillus thuringiensis Cry proteins on mammalian cells transfected with cadherin-like Cry receptor gene of Bombyx mori (silkworm).

Cry1Aa, an insecticidal protein produced by Bacillus thuringiensis, has been shown to bind to cadherin-like protein, BtR175, in Bombyx mori (silkworm) midgut. We previously reported three variant alleles of BtR175 (BtR175a, b and c). When transiently expressed in COS7 cells, all the three BtR175 variants bound to Cry1Aa. We stably expressed BtR175b in HEK293 cells. These BtR175b-expressing cells swelled and died in the presence of activated Cry1Aa in a dose- and time-dependent manner, showing that BtR175b itself can impart Cry1Aa-susceptibility to mammalian cells. These cells were more susceptible to Cry1Aa than to Cry1Ab and Cry1Ac. Since dispersed B. mori midgut cells were reported to be highly susceptible to Cry1Ac, this result suggested that other Cry1Ac-specific receptor(s) were simultaneously working with BtR175 in the midgut cells. Advantages are also discussed of applying these transfected mammalian cells to toxicity assays of mutant Cry proteins.