Exposure Assessment for Methylmercury From Seafood for Consumers in the United States

摘要

An exposure model was developed to relate seafood consumption to levels of methyl mercury (reported as mercury) in blood and hair in the U.S. population, and two subpopulations defined as children aged 2 to 5 and women aged 18 to 45. Seafood consumption was initially modeled using short-term (3 day) U.S. consumption surveys that recorded the amount of fish eaten per meal. Since longer exposure periods include more eaters with a lower daily mean intake, the consumption distribution was adjusted by broadening the distribution to include more eaters and reducing the distribution mean to keep total population intake constant. The estimate for the total number of eaters was based on long-term purchase diaries. Levels of mercury in canned tuna, swordfish, and shark were based on FDA survey data. The distribution of mercury levels in other species was based on reported mean levels, with the frequency of consumption of each species based on market share. The shape distribution for the given mean was based on the range of variation encountered among shark, tuna, and swordfish. These distributions were integrated with a simulation that estimated average daily intake over a 360-day period, with 10000 simulated individuals and 1000 uncertainty iterations. The results of this simulation were then used as an input to a second simulation that modeled levels of mercury in blood and hair.