Detection and toxicity assessment of nitrosamines migration from latex gloves in the Chinese market

Nitrosamines are potent carcinogens and have been found in latex products. In 2007, twenty-seven natural latex gloves including sterile gloves, examination gloves and household use gloves were sampled from the Chinese market. This study monitored the migration of nitrosamines and nitrosatable substance from these gloves, and evaluated their mutagenicity using a Salmonella typhimurium mutation assay (Ames assay) with the strains TA98, TA97, TA100 and TA102 and by a micronucleus test (MN test) using ICR mice. In addition, the cytotoxicity of these compounds was determined by a MTT assay. N-nitrosodimethylamine (NDMA), N-nitrosodiethylamine (NDEA) and N-nitrosodibutylamine (NDBA) were all found in samples treated with artificial sweat for 4 h at 37 °C, and total nitrosamines varied from 18.89 to 244.51 μg/Kg. The nitrosamine mixture of NDMA, NDEA and NDBA was used in both the Ames assay and the MN test. The proportion of NDMA, NDEA and NDBA (1:10:20) was selected according to the proportion of nitrosamines migration from sample E05. In the Ames assay, the lowest dose (1.98×10−3 μg per plate) produced a positive result in the TA98 strain, corresponding to nitrosamines migration from sample E05 of 0.016 g (the total nitrosamines migration from glove E05 was 122.55 μg/kg). The TA100 strain responded positively at a dose of 4.96×10−2 μg per plate, corresponding to nitrosamines migration from glove E05 of 0.040 g. The MN test showed nitrosamine migration of 3.04 mg from 2066 pairs of sample E05 and could induce micronuclei in one mouse weighing 28 g (average weight of one E05 glove was 6 g). Extracts from gloves were found to be cytotoxic and there was a significant correlation between cytotoxicity (IC50) and the release level of nitrosamines. In conclusion, in view of the high content of nitrosamines in latex gloves and the potential toxicity of nitrosamines migration from these gloves, it is suggested that both an effective and feasible detection method and prescribed limits should be imposed.