Abstract: Measurement of Concentrations of Thio- glycolic Acid, Dithiodiglycolic Acid and Ammonia in Indoor Air of a Beauty Salon:

Permanent waving treatments for hair have been popularly carried out for many decades. The chemical process occurring in perm treatments consisting of hair reduction and subsequent oxidation involves the reactions mainly concerning thiol (SH) and disulfide (SS). A permanent waving solution (PWS) is commonly used for chemical waving for hair styles, and the major ingredient of PWS is thioglycolic acid (TGA, CAS. No. 68-11-1) added as ammonium salt. In the reduction process, TGA works as a reducing agent to cleave the disulfide bonds of cysteine residues in keratin proteins of hair, i.e., cleavage of crosslinks between an intermediate filament and matrix keratin protein (KAP) and between KAP-KAP components. TGA is a colorless and water soluble liquid with 1.3 kPa of vapor pressure at 18°C. Although the odor threshold for TGA is presently not available, TGA vapor usually becomes the source of the specific pungent odor of the permanent waving treatment. Meanwhile, exposure to TGA has been known to damage organs or systems in animals and potentially cause adverse effects on human health as reported as follows. Rotenberg et al. reported its acute oral toxicity in the rat and mouse, acute inhalation toxicity in the mouse, acute dermal toxicity in the rabbit and chronic inhalation toxicity in rats. Epidemiological studies conducted by Fenton, Blatter and Zielhuis, Kersemaekers et al. 8) and Gan et al. suggested the risk of reproductive disorders in hairdressers tended to increase with exposure to chemicals used for hair treatments. Gan et al. focused on the effect of TGA-containing PWS on the health of human populations of female hairdressers and school teachers in China. The results suggested reproductive function in Abstract: Measurement of Concentrations of Thioglycolic Acid, Dithiodiglycolic Acid and Ammonia in Indoor Air of a Beauty Salon: Daisuke OIKAWA, et al. Kankyo Research Co., Ltd.—Objectives: Among the many chemicals used in a hair salon, exposure to thioglycolic acid (TGA) used for permanent waving solutions (PWS) potentially causes adverse health effects. However, no report has been previously published on the indoor air concentrations of TGA in a beauty salon that contributes to assessment of exposure to TGA of hairdressers and their customers. This study aimed to demonstrate the present concentration levels of TGA in indoor air of a beauty salon where the PWS containing ammonium thioglycolate was actually used for perm treatments. Methods: A field measurement of TGA, dithiodiglycolic acid (DTDGA, a reaction product of TGA and cysteine residues of hair keratin) and ammonia was carried out in a beauty salon located at Tokyo, Japan, from June 30 to July 2. Both TGA and DTDGA were collected in water using an impinger and determined by high performance liquid chromatography (HPLC). Results: The indoor air concentrations of TGA were below the limit of detection of 0.008 mg m−3 at every event and much lower than occupational safety guideline levels set by the NIOSH and ACGIH. Meanwhile, the concentrations of ammonia ranged from 0.15 to 0.87 mg m−3, and relatively higher concentrations were found during perm events and in samples collected near stations used for perm treatments. Concentrations of DTDGA varied from <0.026 mg m−3 to 0.75 mg m−3. Conclusions: There was a different emission process of TGA and ammonia from PWS, and airborne TGA is not important as a possible exposure route for hairdressers and customers in this beauty salon. (J Occup Health 2012; 54: 370–375) Measurement of Concentrations of Thioglycolic Acid, Dithiodiglycolic Acid and Ammonia in Indoor Air of a Beauty Salon