Yukio Fujiki

Estimating amounts of toluene inhaled by workers with protective mask using biological indicators of toluene

Personal air samplers were attached to workers wearing protective masks to determine the levels of toluene vapor in the breathing zone. Concentrations of toluene in exhaled air, blood and urine; and hippuric acid and o-cresol concentrations in the urine of the workers were determined. Subsequently, toluene concentrations in the air inhaled by workers with and without gas masks were estimated by single and multiple regression equations. Analysis of single regression equations revealed that, compared with toluene concentrations in air, masks decreased the concentrations of the four biological exposure indicators: toluene in exhaled air, urinary toluene, urinary hippuric acid and urinary o-cresol by about 29% in average. Analysis by multiple regression equations showed a decrease of 38% in four biological indicators. Since average exposure to toluene in the shop was relatively low, the workers wore the masks only during high concentrations of toluene; they were, however, exposed to direct inhalation when the masks were removed in lower concentrations.

Passive Sampling of Inorganic Mercury Vapor by Charcoal Tube

A liquid absorption method with potassium permanganate (IMP method) is generally used for determining inorganic mercury in a working environment. Previously the authors reported the usefulness of a solid absorption method with activated carbon with dithzone added. Improving this method, we tried to develop a passive sampler for mesuring exposure of individual to inorganic mercury. By modifying a passive tube for the vapor of organic solvents marketed by Shibata Kagaku Kikai Kougyo Inc., we succeeded in inventing a passive sampler for inorganic mercury. The data obtained with the passive samplers were compared with those obtained by an active sampling method (AS method). The results revealed that the data of this method were compatible with the sampling rate calculated from the diffusion coefficient values reported in the literature. The measurement of individual personal exposure to inorganic mercury has therefore been possible at a relatively low cost and with only a light physical burden on the examinee.

Biological Monitoring of Inorganic Mercury in Workers in a Fluorescent Lamp Plant.

Biological Monitoring of Inorganic Mercury in Workers in a Fluorescent Lamp Plant. Masako Iden, et al. Matsushita Electronics Corp., Okayama Factory—The level of mercury in urine is measured as an exposure monitoring of mercury, and the activity of urinary N‐acetyl‐β‐D‐glucosaminidase (NAG) is used as an index of adverse effects of mercury on human kidneys. Here we examined the validity of these procedures by comparing the urinary total mercury (U‐Hg) level and NAG activity in both 75 male workers exposed to inorganic mercury and age‐matched unexposed male workers in a fluorescent lamp plant. To investigate factors affecting the levels of U‐Hg, 12 items were selected in relation to oral intake and excretion of mercury: consumption of 1) soft drink, 2) coffee or tea, 3) milk and 4) alcohol; 5) habit of drinking tap water at the work place; frequency of 6) eating fish and 7) alcohol intake; 8) smoking; 9) use of dental amalgam; 10) eating of home grown rice; 11) exercise habit and 12) age. The U‐Hg level and NAG activity were adjusted by creatinine levels. Personal exposure levels of inorganic mercury in air (A‐Hg) and the U‐Hg level correlated well (p< 0.001) in the exposed group but neither the exposed nor unexposed group showed a correlation between the U‐Hg level and NAG activity. Although the mean level of U‐Hg in the exposed group was higher than that in the unexposed (p< 0.001), no difference was observed in the mean level of NAG activity. A multiple regression analysis followed by a one‐way ANOVA revealed that only the frequency of eating fish per week contributed to increase the level of U‐Hg. The results suggest that oral intake of mercury from fish is a possible confounding factor in the exposure monitoring of inorganic mercury in the work place.

ヘッドスペース・ガスクロマトグラフ(HS・GC)法による尿中アセトン,メタノール,およびメチルエチルケトンの定量

Using HS.GC, We have succeeded in simultaneous determination of Ac, MeOH and MEK in urine without any complicated pretreatment or correction by internal standard. Moreover, in order to lower the detection limits of these materials, study was made on the salting out effect using 14 kinds of salts. As pretreatment, 2.0 ml of urine, 3.0 g of sodium sulfate and small sized magnetic stirrer are put into vial, which is sealed by septum. This is then heated for 10 min in warm bath of 50 degrees C. In order to dissolve the added salts as much as possible, the specimen is stirred by the stirrer. After cooling the liquid to room temperature, the specimen is analysed by HS.GC. The results showed that sodium sulfate was excellent synthetically. 1) Using the urine of workers not exposed to organic solvents three kinds of urine having specific gravity of 1.010, 1.024 and 1.034 were prepared and mixed standard organic solvents (Ac, MeOH and MEK) were added. Recovery percentages and coefficients of variation were calculated. The results showed that recovery percentages ranged from 92.0 to 101.7% and coefficients of variation from 0.2 to 4.6%. 2) The regression equations of standard curves were satisfactory with y = 9053x - 200(r = 0.999, n = 12) for Ac, y = 801x - 400 (r = 0.999, n = 12) for MeOH, and y = 15488x - 277 (r = 0.999, n = 12) for MEK. 3) The detection limits calculated by IUPAC formula were 0.0092 mg/l for Ac, 0.11 mg/l for MeOH and 0.0063 mg/l for MEK. These results indicated that this method is superior to other methods because the pretreatment is very simple, specificity is excellent, analysis by standard curves is possible, and this method is not affected by specific gravity of the urine.