Survey of total mercury in total diet food composites and an estimation of the dietary intake of mercury by adults and children from two Canadian cities, 1998-2000

Total mercury was measured in 259 total diet food composites from two Canadian cities. Levels were generally low, with 46% of the composites having concentrations below the limit of detection, which ranged from 0.026 to 0.506 ng g^-1. The fish category contained the highest mercury concentrations, which averaged 67 ng g^-1 and ranged from 24 to 148 ng g^-1. All composites were below the Canadian guideline for total mercury in fish of 0.5 ppm. Dietary intakes of mercury averaged 0.022 μg kg^-1 body weight/day (μg kg^-1 day^-1), and ranged from 0.012 μg kg^-1 day^-1 for females over 65 years old to 0.062 μg kg^-1 day^-1 for 0-1-month-old infants. For fish consumers, fish contributed to more than half of the ingested mercury. All intakes were well below Joint FAO/WHO Expert Committee on Food Additives Provisional Tolerable Weekly Intakes, expressed on a daily basis, of 0.71 μg kg^-1 day^-1 total mercury and 0.47 μg kg^-1 day^-1 methyl mercury, and also below a recent Health Canada recommended maximum methyl mercury intake of 0.2 μg kg^-1 day^-1 for children and women of child-bearing age.