[Investigation on nitrosamines in the diets of the inhabitants of high-risk area for esophageal cancer in the southern China and analysis of the correlation factors].

Nan'ao County in Guangdong Province was an esophageal cancer high-risk area in the southern China. Of the suspected etiological factors in the environment, N-nitrosamines and their precursors have been received the most attention. 55 samples of the diets ingested by the inhabitants were collected and tested for volatile N-nitroso compounds and for their precursors by GC-TEA. Five kinds of N-nitrosamines (NDMA, NDEA, NPYR, NPIP and NMBzA) were detected in the samples. The average level of them was 312.0 micrograms/kg(median). The day intake of the nitrosamines was 286.5 micrograms/head/day. By the computerized stepwise regression analysis and curve fitting, we studied the correlation among the nitrosamines, the precursors and the major food items. It demonstrated that a relatively high content of volatile N-nitrosamines was present in the diets collected in the area.