Determination of organic and inorganic mercury compounds and of metallic mercury in the air was studied by using 0.1% _L-cystein aqueous solution as absorbent with the atomic absorption spectrometry. The results obtained were as follows.
1. To catch mercury compounds, impingers were employed. 0.1% _L-cystein aqueous s. was used in the first and the second catching bottles. Into third and fourth bottles, 5% H₂SO₄ aqueous s. and KMnO₄ 0.5% aqueous s. were poured respectively. Organic and inorganic mercury compounds were caught in the first two bottles, while metallic mercury was caught in the last two quantitatively with perfect selection.
2. Organic compounds were twice extracted from _L-cystein aqueous s. by benzene. From benzene layer, organic mercury compounds wers extracted in _L-cystein aqueous s. again. After organic and inorganic mercury compounds and metallic mercury contained in the sample had been decomposed by H₂SO₄ and KMnO₄, they were reduced to metallic mercury by SnCl₂ to be determined separately by the atomic absorption spectrometry. By this procedure, analytical processes became very simple and acurate results were obtained.
3. Analytical sensitivity of this method was 0.1μg Hg/m³ air at the minimum.
4. In a workshop where phenyl mercuric acetate was being synthesized, mercury in the indoor air was determined by this method, and it was recognized that detected organic mercury was less than 20% and inorganic and metallic mercury were 72.9-76.3% and 6.9-13.6% of the total mercury.

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The scale of management and the number of super markets having been expanded rapidly, the number of operators conducting the operation of cash registers have increased as accordingly. It is said that many kinds of industrial ill health and disease such as “shoulder-arm-neck-syndrome” have appeared in these operators.
Health examinations of 27 cash register operators and evaluation of the work loads thereby were performed.
The results were as follows :
1. Most of the operators contracted “shoulder-arm-neck-syndrome” in less than 2 years of their experiences.
2. The performances of the operators consisted of recognizing the small size letters and numerals on the labels pasted down each goods, and pressing the keyboards of cash registers as fast as possible. These performances required strong muscle activity and strict accuracy. The operators had to press the keyboards without releasing all fingers from the “home position” except the finger under pressing.
3. It is considered that their work loads consist of the followings :
(1) The loads of local muscles of fingers, hands, arms, shoulders and necks being used to press the keyboards and to move goods.
(2) The nervous and mental loads in recognizing various kinds of goods, pressing the keyboards without turning eyes on, in conducting the affairs of cash without errors, in receiving the customers and in cooperating with the sacker.
(3) The increased mental and physical loads by small working space, standing posture for many hours, unadjustable height and angle of the work desks and of the cash registers, body twisting motions and the environment.
4. The fatigue caused by the above mentioned work loads may be stored, fixed, and advanced to the stage of chronic, irreversible fatigue, and finally to diseases. It is necessary for cash register operators that a systematic management have to be done for the prevention of the occupational disease. Especially it is highly desirable to establish relevant administrative safty and hygiene standards for the registering work using cash registers.

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Atmospheric concentrations of cyanides in various kinds of plating workshops were determined, and it was cleared that there was an intimate relation between the atmospheric concentration of cyanides and pH of the plating solutions. The more alkaline the solution, the less became the concentration of cyanides. Cyanides contained in the overflowed solution from the plating bath changed to hydrogen cyanide gas while the solution dried up spontaneously, and this gas diffused into the workshop.
For sampling cyanides in the air, impinger should be used. The sampling ability of the sampling solution was closely related with its alkalinity. If the aqueous solution of sodium hydroxide is used as the sampling solution, the alkalinity of the solution should be more than 0.2 normal for long time bubbling and more than 0.02 normal for short time bubbling. During the bubbling procedure, the alkalinity of the sampling solution decreased gradually. And the solution should not be used for sampling cyanides if its alkalinity is less than 0.001 normal. If the alkalinity of the sampling solution is exhausted, this solution can not preserve the captured cyanides any more.

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