Titanium dioxide dust was analyzed using a hand-held X-ray fluorescence analyzer (HHXRF). Titanium dioxide powders were suspended in 1-butanol, and the suspended solutions were filtered through membranes. The titanium masses on the membrane filters were measured using XRF through the conventional procedure and our newly proposed procedure. In the new method, the membrane filter samples were shifted to a copper plate and analyzed using an HHXRF analyzer designed for metal alloys. Titanium was regarded as an impurity in the copper plate, and the HHXRF device used the fundamental parameter (FP) program for the analysis. The values obtained through this method were nearly equal to those obtained by the benchtop X-ray fluorescence analyzer. There were some differences between the values obtained for the PVC membrane filter sample and PTFE membrane filter sample. However, the measured values were independent of the crystal structures and the primary sizes of the titanium dioxide powders. According to our proposed method, 25 µg of titanium was found in the filter sample. Our results indicate that a sampling period of only 33 min is sufficient to assess whether the airborne concentration of nano titanium dioxide is above its recommended OEL (0.3 mg/m3); and therefore, this method is effective as a screening technique for nano titanium dioxide.
A number of recent workplace health problems have resulted from very low-dose chemical substances. Low concentrations of organic solvents at a no observed adverse effect level (NOAEL) generate a specific smell. Health effects, including high sensitivity and adverse physical conditions, occur in response to the smell and are thought to result from the chemicals. One hypothesis that explains the mechanisms underlying the reactions to the smells of these substances is aversive conditioning by an odor stimulus. The hypothesis postulates that the smell is associated with pain and/or fear. Unpleasant reactions are induced when the same smell is experienced later, even when the concentration of the substance is lower than NOAEL. However, no experiments have been conducted to test this hypothesis. In the present study, we examined if aversive conditioning can be established in rats by using a low-dose organic solvent as a conditioned stimulus (CS). The organic solvent functioned as a CS, and aversive conditioning was established with the odor stimulus. In a future study, we are planning to examine the effects of unknown chemicals with the procedure used in the present study. In addition, we will examine modifications in odor threshold after the establishment of the conditioned taste aversion.
In Japan, a number of fall accidents have been associated with equipment such as stepladders. In this study, industrial accident cases were investigated to understand the incidence of accidents caused by stepladders. A total of 34,195 industrial accidents resulting in at least a 4-day absence from work in 2006 (25.5% of the total industrial accidents) were analyzed based on casualty reports from the Japanese Ministry of Health, Labour and Welfare. Each accident was classified by industry type, accident type, the number of absent days, and victim's age, sex, employment period, injury or disease type, and injured or disease-affected part. There were 992 stepladder-related accidents (6 were fatal accidents). The estimated annual number of stepladder-related accidents was 3,896 (24 were fatal accidents, 95% confidence interval [CI]: 3,657–4,135), which accounted for 2.9% of all accidents (95% CI: 2.7–3.1). Based on industry type, 45.5% of the stepladder-related accidents occurred in the construction industry, 15.5% in the manufacturing industry, and 12.3% in the commercial industry. Most of these accidents occurred among >49 years male workers in the construction and manufacturing industries, whereas two-third of these workers in the commercial industry were aged <49 years. A total of 68.6% of the workers sustained a fracture. The most commonly affected body parts were the lower (34.7%) and upper limbs (21.4%), and 64.9% of workers took a leave of absence for >31 days. For 18.4% of workers, the duration of employment at the time of the accident was <1 year; 27.6% of workers were employed for ≥20 years. These results indicate that further research should focus on the conditions that cause these accidents so that prevention strategies can be implemented to reduce the incidence of industrial accidents related to stepladders.
On February 22, 2011, an epicentral a 6.1 moment magnitude (Mw) earthquake with a seismic center near Lyttelton occurred in the suburb of Christchurch, New Zealand, at 12 : 51 p.m. local time, 17 days before the Great East Japan Earthquake struck off the coast of Tohoku. The authors visited and exchanged opinions with Work Safe NZ, a New Zealand government organization, the Canterbury Rebuild Health and Safety Programme (CRHSP), and Site Safe, a nonprofit construction organization, for the purpose of collecting information regarding the safety and health efforts made by the New Zealand government and its pertinent agencies, as well as understanding the current status of rebuilding and recovery efforts after the Canterbury Earthquake (which started as almost in tandem with recovery efforts in the wake of the Great East Japan Earthquake). Results show that there was little difference between New Zealand's countermeasures on safety and similar efforts made in Japan. However, there were some beneficial activities in New Zealand, such as an update to the system of qualifications; use of a tender system (based on an evaluation of safety and health); and partnerships between clients, contractors, and regulatory agencies. These activities should be implemented Japan to improve the nation's construction industry regarding safety and health.