Rapid measurement of total mercury in human blood, hair, and milk

Fish consumption, particularly of predatory marine species, is the primary route of human methylmercury exposure. Pregnant and lactating women can transport mercury through the placenta and breast milk to their offspring, adversely affecting neurological development. Assessment of maternal mercury dosages can be useful in determining infant and fetal exposure. Unfortunately, traditional methods of measuring mercury are time consuming and expensive. Thermal decomposition, amalgamation/absorption atomic spectroscopy (TDA/AAS) has emerged as an alternative technology for rapid analysis and high throughput of large numbers of samples. The objectives of this research were to develop and validate rapid methods to measure total mercury in human blood and milk, as well as to explore the relationship between different biomarkers of mercury exposure. A method of measuring total mercury in whole blood using TDA/AAS was identified and applied to a study of women with elevated hair mercury levels (above 0.75 ppm). Hair and blood samples were collected and changes in hair to blood ratio over a three month period of mercury withdrawal were examined; no significant effect of duration since the start of withdrawal on the correlation was observed. The whole blood method was also evaluated for its usefulness in measuring mercury concentrations in human milk and validated by measuring mercury concentrations in Asian women\u27s milk. Mean mercury concentration in milk was 0.38 ppb. An equivalent infant dosage was calculated assuming daily milk consumption of 150 g/kg body weight-day. Approximately 10% of the women had mercury concentrations in their breast milk that would lead to infant dosages comparable to the EPA RfD of 0.1 &mgr;g/kg body weight-day. In summary, a rapid method for measuring mercury in human whole blood and milk was developed and validated for use in clinical research studies or exposure assessment