Evaluation of personal exposure of workers to indium concentrations in total dust and its respirable fraction at three Japanese indium plants.

This study aimed to evaluate personal exposures of 27 workers to indium compounds as "total" dust and its "respirable" fraction in their breathing zones at 3 Japanese indium plants. Eight-hour time-weighted average (TWA) indium concentrations of personal exposure to dust collected in sampling periods of 6 h or longer were determined by ICP-MS. The arithmetic means of exposure concentrations were 0.

Quantitative assessment of occupational exposure to total indium dust in Japanese indium plants.

This study quantitatively assessed personal exposure of 86 workers to indium compounds as total dust at 11 Japanese indium plants. The personal exposures to indium concentrations in the breathing zone during an 8 h work-shift were determined by ICP-MS. The arithmetic mean indium concentration of all the workers was 0.

Control banding assessment of workers' exposure to indium and its compounds in 13 Japanese indium plants.

Objectives: This study aimed to assess workers' exposure to indium and its compounds in 55 indium-handling operations among 13 Japanese plants. The surveyed plants were selected from indium-manufacturing plants whose annual indium production exceeded 500 kg.

Methods: The Control of Substances Hazardous to Health (COSHH) Essentials control banding toolkit, which contains simple scales for hazard levels, quantities in daily use, and "dustiness" characteristics, was used to assess generic risks of indium-handling operations.

Assessment of workplace air concentrations of formaldehyde during and before working hours in medical facilities.

Workplace air concentrations of formaldehyde (FA) in medical facilities where FA and FA-treated organs were stored and handled were measured before and during working hours and assessed by the official method specified by Work Environment Measurement Law. Sixty-percent of the total facilities examined were judged as inappropriately controlled work environment. The concentrations of FA before working hours by spot sampling were found to exceed 0.

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.

A cross-sectional analysis of dioxins and health effects in municipal and private waste incinerator workers in Japan.

This cross-sectional study was intended to examine health effects of 678 male workers employed during an 8-yr period from 2000 to 2007 at 36 municipal and private waste incineration plants in Japan. Blood samples were obtained for analysis of concentrations of dioxins including coplanar polychlorinated biphenyls (coplanar PCBs) and evaluation of health effects. Health effects including diabetes were surveyed via a physician's interview or clinical data from blood samples.

Isomer pattern and elimination of dioxins in workers exposed at a municipal waste incineration plant.

The aim of this study was to clarify patterns of serum concentrations of dioxins in the employees of a waste incineration plant and to estimate elimination rates and half-lives of serum dioxin isomers, and the maximum serum concentrations of dioxin isomers at the time of plant shutdown. Sixteen subjects participating 3 times or more in annual health examinations during an 8-yr period from 2000 to 2007 were recruited for this study. Serum concentrations of dioxins expressed as TEQ/g lipid decreased gradually after plant shutdown with the highest decrease observed in polychlorinated dibenzofurans (PCDFs) followed by polychlorinated deibenzo-p-dioxins (PCDDs) and then coplanar PCBs.

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.

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.

Assessment of workplace air concentrations of indium dust in an indium-recycling plant.

Objectives: Suspended indium dust in an indium-recycling plant was quantified, in order to improve the work environment and to reduce workers' exposure to the dust.

Methods: Assessment of indium dust in the workplace air by multipoint area sampling and personal breathing zone sampling was conducted twice in 2004 and 2008.

Results: In 2004, all recycling processes except for purity analysis were classified into control class III according to the 2004 Notification.

Inhalation carcinogenicity and chronic toxicity of indium-tin oxide in rats and mice.

Objectives: Carcinogenicity and chronic toxicity of indium-tin oxide (ITO) were examined by inhalation exposure of rats and mice to ITO aerosol.

Methods: Fifty mice of both sexes were exposed to ITO at 0 (control), 0.01, 0.

Two- and 13-week inhalation toxicities of indium-tin oxide and indium oxide in rats.

Objectives: Two- and 13-week inhalation toxicities of indium-tin oxide (ITO) and indium oxide (IO) were characterized for risk assessments of workers exposed to ITO.

Methods: F344 rats of both sexes were exposed by inhalation to ITO or IO aerosol for 6 h/day, 5 day/wk for 2 wk at 0, 0.1, 1, 10 or 100 mg/m(3) or 13 wk at 0, 0.

Inhalation carcinogenicity and toxicity of 1,2-dichloropropane in rats.

The toxicity and carcinogenicity of 1,2-dichloropropane (DCP) were examined by inhalation exposure of male and female F344 rats to DCP for either 13 wk or 2 years. In the 13-wk study, the DCP concentrations used were 125, 250, 500, 1000, or 2000 ppm (v/v), and in the 2-year study the DCP concentrations were 80, 200, or 500 ppm (v/v). Thirteen-week exposure to DCP induced hyperplasia in the respiratory epithelium and atrophy of the olfactory epithelium at 125 ppm and above.

Characteristics of multiwall carbon nanotubes for an intratracheal instillation study with rats.

Much concern has been raised over the health consequences of workers exposed to carbon nanotubes. In order to characterize multi-wall carbon nanotubes (MWCNT) suspended in a phosphate-buffered saline containing 0.1% Tween 80 for an intratracheal instillation study.

Pulmonary toxicity of intratracheally instilled multiwall carbon nanotubes in male Fischer 344 rats.

In order to assess pulmonary toxicity of multiwall carbon nanotubes (MWCNT), male F344 rats were intratracheally instilled with MWCNT suspension at a dose of 40 or 160 μg/head or α-quartz particles as a positive control at a dose of 160 μg/head and sacrificed for lung histopathology and bronchoalveolar lavage (BAL) fluid analyses on Day 1, 7, 28 or 91 after instillation. Well-dispersed MWCNT brought about dose- or time-dependent changes in lung weight, total proteins, albumin, lactate dehydrogenase and alkaline phosphatase in the BAL fluid, and pulmonary lesions including inflammation, Type II cell hyperplasia, microgranulomas and fibrosis. Phagocytosed and free forms of MWCNT were found in both bronchiolar and alveolar spaces.

Genotoxicity and cytotoxicity of multi-wall carbon nanotubes in cultured Chinese hamster lung cells in comparison with chrysotile A fibers.

Objectives: The potential applications and industrial production of multi-wall carbon nanotubes (MWCNT) have raised serious concerns about their safety for human health and the environment. The present study was designed to examine the in vitro cytotoxicity and genotoxicity of MWCNT and UICC chrysotile A (chrysotile).

Methods: Cytotoxicity using both colony formation and lactate dehydrogenase (LDH) assays and genotoxicity including chromosome aberration, micronucleus induction and hgprt mutagenicity were examined by exposing cultured Chinese hamster lung (CHL/IU) cells to MWCNT or chrysotile at different concentrations.

Two-year inhalation study of carcinogenicity and chronic toxicity of 1,4-dioxane in male rats.

Carcinogenicity and chronic toxicity of 1,4-dioxane were examined by inhalation exposure of 50 male F344 rats to 1,4-dioxane vapor at 0 (clean air), 50, 250, or 1250 ppm (v/v) for 6 h/day, 5 days/wk, and 104 wk. Survival rates of 250 and 1250 ppm-exposed groups were decreased near the end of the 2-yr exposure period, due probably to the occurrence of malignant tumors. A statistically significant but marginal decrement of terminal body weight (<10%) was found in the 1250 ppm-exposed group, suggesting slight systemic toxicity.

Oral carcinogenicity and toxicity of 2-amino-4-chlorophenol in rats.

Objectives: This study was carried out to clarify the subchronic and chronic toxicity, and carcinogenicity of 2-amino-4-chlorophenol(ACP).

Methods: Carcinogenicity, and chronic and subchronic toxicity of ACP were examined by feeding 10 rats of both sexes ACP-containing diet at a dose level of 0 (control), 512, 1,280, 3,200, 8,000 or 20,000 ppm (w/w) for 13 wk and 50 rats of both sexes at a dose level of 0, 1,280, 3,200 or 8,000 ppm for 2 yr.

Results: The 13-wk oral subchronic toxicity of ACP was characterized by proliferative lesions leading to development of tumors in the forestomach and urinary bladder and by erythrocyte toxicity as evidenced by decreases in red blood cell counts, hemoglobin and hematocrit and concurrent increases in methemoglobin levels and reticulocyte counts.

Enhanced hepatocarcinogenicity by combined inhalation and oral exposures to N,N-dimethylformamide in male rats.

N,N-Dimethylformamide (DMF), a ubiquitous contaminant in living and working environments, enters the human body by inhalation, as well as by oral and dermal routes of exposure. In order to provide bioassay data for carcinogenic risk assessment of humans exposed to DMF by multiple routes of exposure, hepatocarcinogenic effect of combined inhalation and oral exposures of rats to DMF was examined. A group of 50 male F344 rats, 6-week-old, was exposed by inhalation to 0 (clean air), 200, or 400 ppm (v/v) of DMF vapor-containing air for 6 hr/day and 5 days/week during a 104-week period, and each inhalation group was given ad libitum DMF-formulated drinking water at 0, 800 or 1,600 ppm (w/w) for 104 weeks.

An improved system for exposure of cultured mammalian cells to gaseous compounds in the chromosomal aberration assay.

A gas exposure system using rotating vessels was improved for exposure of cultured mammalian cells to gaseous compounds in the chromosomal aberration assay. This system was composed of 12 square culture vessels, a device for preparation of air containing test gas, and positive and negative control gases at target concentrations and for supplying these gases to the culture vessels, and a roller apparatus in an incubator. Chinese hamster lung cells (CHL/IU) were grown on one side of the inner surface of the square culture vessel in the MEM medium.