ICMGP - Conference Presentation

Abstract Information :

Human exposure to monomethylmercury (MMHg) is predominately through consumption of aquatic organisms and rice in Asia, but it is still challenging to accurately distinguish and quantify these two exposure sources in human body. Here we innovatively utilized MMHg compound specific stable isotope analysis (MMHg-CSIA) in hair to quantify human MMHg sources in coastal and inland area of China where aquatic organisms and rice are routinely consumed. We found that aquatic organisms and rice MMHg exposure end-members have significantly different (p < 0.05) ?199HgMMHg values in both coastal and inland areas. Hair ?199HgMMHg is more similar to aquatic organisms than to rice ?199HgMMHg. Additionally, significant differences (p < 0.05) in ?202Hg versus ?199Hg were detected between MMHg and inorganic Hg (IHg) in human hair, which distinguished the different sources of MMHg and IHg in human body. Suggesting using total mercury (THg) isotope in hair with low MMHg fraction may contain uncertainties confounded by IHg. A binary mixing model based on pseudorandom number generation function was developed to estimate human MMHg exposure from aquatic organisms and rice using ?199HgMMHg data. Model results suggest that human MMHg exposure was mostly (>80%) from aquatic organisms consumption and only a small portion from rice consumption in coastal and inland areas. This study demonstrates that the MMHg-CSIA method can provide unique information for tracking human MMHg exposure sources by excluding the deviations from dietary surveys, individual MMHg absorption or demethylation efficiency, and confounding of IHg.