2-Nitroanisole. Documentation of occupational exposure limits (OELs)

Abstract

2-Nitroanisole is a colorless to yellowish liquid poorly soluble in water. It is used primarily to o-anisidine and o-dinisidine synthesis, which are precursors of azo dyes. 2-Nitroanisole has harmonized classification in the European Union: Carc. 1B 4 – carcinogenic, 1B category; H350 – may cause cancer after exposure trough the respiratory tract or skin; Acute Tox. 4 – acute toxicity 4; H302 – it acts adversely after swallowing. Occupational exposure to this compound occurs during its production and application. In Poland in 2016 203 workers were exposed to 2-nitroanisole. No data on 2-nitroanisole toxicity in humans were found in the available literature. In rodents 2-nitroanisole did not demonstrate large toxicity after administration in a single dose. In these animals repeatedly treated with this compound an increase in parenchymatous organ weights, decrease in body weight and also methemoglobinemia and hemolytic anemia were observed. 2-Nitroanisole was mutagenic in bacterial tests, induced gene mutations, chromosomal aberrations and sister chromatid exchange, and also damaged DNA (positive commet test). In rodents 2-nitroanisole induced both preneoplastic and neoplastic alterations mainly in urinary bladder, kidneys, and large intestine. The maximum admissible concentration (MAC) value for 2-nitroanisole has been calculated on the basis of the results of a short term experiment performed on rats. The critical effects observed were an increase in both liver and spleen weight and hemolytic anemia. On the basis of the NOEL value at the level of 8 mg/kg bw./day and uncertainty factors of 36, a MAC value at the level of 1.6 mg/m3 was obtained. On basis of literature data urinary bladder cancer risk associated with 1.6 mg/m3 concentration of 2-nitroanisole and a lifetime occupational exposure (40 years) was calculated at 2 × 10-3, which may be recognized as acceptable risk. The MAC has ”Carc. 1B” notation (carcinogenic substance, 1B category).