Retrospective quantitative risk assessment of skin sensitization caused by an antimicrobial agent used in a consumer product: 2,3,5,6-Tetrachloro-4-(methylsulfonyl) pyridine.

BACKGROUND: Serious cases of allergic contact dermatitis (ACD) caused by exposure to 3,5,6-tetrachloro-4-(methylsulfonyl)pyridine (TCMSP; CAS no. 13108-52-6) used as an antimicrobial agent for desk mats have been reported in Japan. OBJECTIVE: A quantitative risk assessment (QRA) of TCMSP contained in desk mats was performed retrospectively. MATERIALS AND METHODS: A local lymph node assay (LLNA): BrdU-ELISA was conducted to determine a reliable EC1.6 value for TCMSP. The acceptable exposure level (AEL) for TCMSP was derived from the EC1.6 value by applying sensitization assessment factors (SAFs). The exposure level was estimated based on the assumption referring to the use conditions of thiabendazole in the same purpose. Then, the estimated exposure level was compared with the AEL to evaluate the skin sensitization risk. RESULTS: The AEL was calculated as 0.00458 µg/cm2 based on the EC1.6 value (0.011%, 2.75 µg/cm2 ) by applying a composite SAF of 600. The estimated TCMSP exposure level from the desk mat was 500 times greater than the AEL, indicating a serious skin sensitization risk. CONCLUSIONS: Assessments of skin sensitization potencies of chemicals to be used in consumer products are strongly recommended, and QRAs should be performed at the pre-marketing stage to avoid the skin sensitization risk in consumers.

Safety evaluation of recycling process used to produce recycled pulp for adult paper diapers.

Eight contaminants were used to perform a surrogate contamination test to evaluate safety of the process for producing recycled pulp for adult paper diapers. We performed a safety evaluation of the recycling process for producing recycled pulp following the European Food Safety Authority safety assessment for polyethylene terephthalate (PET) bottles using recycled PET. We also compared the first tier safety limit established on the basis of TTC (Climit) in the pulp that contained recycled pulp with residual contaminant concentrations (Cres). If Climit > Cres, there is no concern regarding safety of the recycling process. Climit was determined to be 0.46 mg/kg-pulp based on the human exposure threshold of 0.15 µg/person/day using the scenario in which a bedridden senior citizen uses four adult paper diapers manufactured with pulp containing 10% recycled pulp per day. Cres was derived from the initial concentration in used pulp (0.17 mg/kg-pulp), and decontamination rate was obtained from the surrogate contamination test. The Cres of the eight contaminants were between 0.0017 and 0.10 mg/kg-pulp, which were all below the Climit of 0.46 mg/kg-pulp. These results indicated there was no safety problem regarding this process for producing recycled pulp for adult paper diapers.

Investigation of the amount of transdermal exposure of newborn babies to phthalates in paper diapers and certification of the safety of paper diapers.

A risk assessment study of seven phthalates in paper diapers for newborn babies produced in Japan was performed. The diapers were purchased and the contents of the seven phthalates were determined and estimated amounts of exposure were calculated based on the eluted rate into artificial medium of urine or sweat, average weight of infants, and frequency of use. Di-2-ethylhexyl phthalate and di-n-butyl phthalate were detected in the topsheets and determined to be 0.6 µg/g and 0.2 µg/g, respectively. The daily estimated exposure volume was calculated to be in the range of 1.86 × 10(-10)-2.98 × 10(-6) mg/kg/day as follows: content of seven phthalates in the topsheet (0.1-1 µg/g) × eluted rate of phthalates into artificial sweat (0.0006-2.4%) × weight of the topsheet of a diaper (1.5 g) × the number of diapers used per day (12 sheets) × skin absorption rate (0.005-0.1)/average body weight (2.9 kg). For hazard assessment, we used 0.2-300 mg/kg/day for the seven phthalates based on the data available at international agencies. The margin of exposure to the seven phthalates was 6.71 × 10(4)-1.99 × 10(11), indicating that the risk of exposure to phthalates from the diapers produced in Japan was negligible.

Risk assessment study of dioxins in sanitary napkins produced in Japan.

A risk assessment study of dioxins in sanitary napkins produced in Japan was performed. The daily estimated exposure volume to dioxins was compared with the tolerable daily intake (TDI). The concentrations of dioxins such as polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (DL-PCBs) in seven sanitary napkins were measured using gas chromatography and mass spectroscopy analytical methods. Among the seven napkins, a range of 0.0044-0.076pg TEQ/g dioxins was measured. Daily estimated exposure volume from sanitary napkins was calculated as follows: (dioxin volumes in a sanitary napkin (0.0044-0.076pg TEQ/g)×pulp weight in a sanitary napkin (11.2g)×used napkin numbers/d (7.5)×the number of days/month that women use sanitary napkins (7)×skin absorption rate (0.03)×used years (40))/(average body weight of women (50kg)×the number of days in the month (30)×life years (86)). Daily exposure volumes were estimated to be 0.000024-0.00042pg TEQ/kg/d. For hazard assessment, we used 0.7pg TEQ/kg/d which was the lowest level of TDI among TDI values reported by international agencies. When the daily exposure volume was compared with the TDI, the former was approximately 1666-29,166 times less than the latter. This fact indicated that the risk of exposure to dioxins from sanitary napkins produced in Japan was negligible.