ABSTRACT
Total mercury was measured in 156 composites prepared from 936 samples of canned tuna sold in Canada in 2006. Each composite comprised a single brand. Yellowfin tuna contained the lowest concentrations, averaging 0.066 mg/kg. Skipjack tuna contained slightly higher concentrations, averaging 0.132 mg/kg. The highest average concentration was found in the Albacore tuna: mean 0.325 mg/kg, range 0.174-0.507 mg/kg. The second highest concentration among the 49 albacore composites was 0.469 mg/kg. There were 72 composites for which the type of tuna was not specified. The mercury in these averaged 0.095 mg/kg and ranged from 0.016 to 0.237 mg/kg.
Subject(s)
Diet , Environmental Exposure/analysis , Food Contamination/analysis , Mercury/analysis , Seafood/analysis , Tuna , Water Pollutants/analysis , Animals , Canada , CommerceABSTRACT
Total mercury (Hg) was measured in 150 infant formula products (as sold) and oral electrolyte solutions purchased in Canada in 2003. Results less than the limit of detection (LOD) were reported as the numeric value of the LOD. Electrolytes contained the lowest concentrations, averaging 0.026 ng/g. Average levels in milk-based ready-to-use, concentrated liquid and powdered concentrate were 0.028, 0.069 and 0.212 ng/g, respectively. In soy-based formulae, the respective mean concentrations were 0.049, 0.101 and 0.237 ng/g. These concentrations cannot be considered on an absolute basis because 76% of sample concentrations fell below the limit of detection. Despite the inability to measure many of the actual background concentrations, the method was sufficiently sensitive to identify clear cases of low-level Hg contamination (up to 1.5 ng/g) of individual lots of powdered formula. Also, all the different lots of one brand of concentrated liquid infant formulae had significantly higher concentrations of Hg than those of all other concentrated liquid products. After dilution with preparation water, the Hg concentrations in all products would be lower than the Canadian Drinking Water Guideline for Hg of 1 ng/mL and too low to impact on health.
Subject(s)
Drug Contamination , Electrolytes/chemistry , Food Contamination , Infant Formula/chemistry , Mercury/analysis , Poisons/analysis , Rehydration Solutions/chemistry , Administration, Oral , Electrolytes/administration & dosage , Electrolytes/economics , Electrolytes/standards , Food Handling , Food Inspection , Guideline Adherence , Health Policy , Health Promotion , Humans , Infant , Infant Formula/standards , Limit of Detection , Ontario , Quebec , Rehydration Solutions/administration & dosage , Rehydration Solutions/economics , Rehydration Solutions/standards , Reproducibility of Results , Soy Foods/analysis , Soy Foods/economicsABSTRACT
A cold vapor atomic absorption spectrometric method was developed for the subnanogram-per-gram determination of total Hg in a wide variety of foods. Foods were weighed into 50 mL polypropylene centrifuge tubes and dried without charring at 55 degrees C in a circulating oven. Samples were then digested at 58 degrees C with HNO3, HCl, and H2O2. After matrix modification with solutions of 2% Mg(NO3)2, 0.01% Triton X-100, and Cu(II) at 10 microg/mL, samples were analyzed by using a CeTAC Technologies M-6000A dedicated Hg analyzer. Based on a 2 g sample weight, the detection limit of the method over 12 batches averaged 0.30 ng/g wet weight and ranged from 0.03 to 0.6 ng/g. Recoveries of Hg added to 17 different foods, analyzed in a routine manner, averaged 97%, and individual recoveries ranged from 77 to 107%. Accuracy was confirmed by analysis of 7 biological reference materials from the National Research Council of Canada and the National Institute of Standards and Technology. Stabilization of low concentrations of Hg in solutions containing no sample was required to prevent loss of Hg from blanks. In a comparison of NaCl, potassium dichromate, and Au(II), chloride was much more effective for stabilization than the other two, and HCl was used for subsequent stabilization.
