Seasonal variation in exposure frequency and concentration levels of aflatoxins and ochratoxins in urine samples of boys and girls.

Urine samples from children in Sierra Leone (134 boys and 110 girls), were collected during the dry season. During the rainy season samples were collected from 97 boys and 93 girls. Analysis of the dry season samples, revealed that, with the exception of one boy, all children had detectable amounts of aflatoxins and/or ochratoxins in their urine. Similarly, with the exception of four children (two from each sex), rainy season urine samples also contained these two mycotoxins. There were significant differences in the frequency of exposure to some mycotoxins: ochratoxin A (OTA), p < 0.01; 4-hydroxyochratoxin A (4R-OTA), p < 0.002; aflatoxin M1 (AFM 1), p < 0.04; aflatoxicol (AFL), p < 0.03; aflatoxin B2 (AFB2), p < 0.04. There were also significant differences in the levels of aflatoxin B1 (AFB1), (p < 0.05) and AFB2, (p < 0.02) detected in dry season samples. Stratification of these results according to season and sex, has indicated significant differences with respect to 4R-OTA (p < 0.04) and AFB1 (p < 0.02). The results of this study show that in Sierra Leone, children are frequently and constantly exposed to both aflatoxins and ochratoxins.