[Reference value of urinary arsenic for nonoccupational exposed subjects in Henan]

Urinary arsenic levels of 2065 nonoccupational exposed subjects in Henan were determined by spectrophotometric analysis. The results showed: (1) The difference was not significant among Zhengzhou, Luoyang, Anyang, Xinyang and Shangqiu (0.01 < P < 0.025). (2) The difference was not significant among different ages(0.01 < P < 0.025) and between sexes(P > 0.05). (3) The distribution was positive skewness. The median of urinary arsenic was 17.8 micrograms/L. The arithmetic mean was 20.7 micrograms/L. The standard deviation was 15.2 micrograms/L. The geometric mean was 17.3 micrograms/L. (4) It is suggested that the reference upper limit value of urinary arsenic for nonoccupational exposed subjects in Henan in 56 micrograms/L.