Urinary Mercury Excretion, Baseline Study in Guatemalan Dental Students

Methods: A total of 318 students were recruited. Then a 24-hour pooled urinary sample was taken from each subject. Iced transportation conditions were used. 200 ml of the urinary sample were frozen and stored for double checking. Then another 100 ml of the urinary sample were taken and processed with the Kaye method, which was used to establish mercury levels in urine.

Results: Means and standard deviations obtained (µg Hg/l urine) by year of study were as follow: first year (n=133) 3.282 ± 2.909 µg/l; second year (n=37) 7.056 ± 6.790 µg/l; third year (n=52) 5.484 ± 5.327 µg/l; fourth year (n=43) 4.234 ± 2.657 µg/l; fifth year (n=34) 3.438 ± 1.763 µg/l; and sixth year (n=19) 5.173 ± 4.606 µg/l. Furthermore, only 5 subjetcs (1.57%) exhibited 19 µg/l in their own pooled urinary sample. Statistical analysis with ANOVA indicated significant means differences among groups (p<0.00001).

Conclusion: We conclude that the sampled students presented normal levels of mercury excretion in urine for exposed subjects(≤20 µg/l), however a closer follow up should be taken with those students with the highest scores and possible exposition sources should be established.