Nitrosamines and nitrosamine precursors in foods from Linxian, China, a high incidence area for esophageal cancer.

Nitrosamines and precursor secondary amines were assayed in foods from families in four villages of the esophageal cancer high incidence area of Linxian, Henan Province, People's Republic of China. Amines (as tosylamides) and nitrosamines were readily detected at p.p.m. and p.p.b. levels, respectively, in all samples. In this small preliminary survey (25 families, four villages), however, there were no strong correlation between the levels of the carcinogenic nitrosamines or the precursor secondary amines with the incidence of esophageal cancer in the individual families. The success of the analytical procedures suggests that a more extensive study is warranted.