Methylmercury and inorganic mercury in canned seafood : April 1, 2015, to March 31, 2016

Abstract

Mercury is a naturally occurring metal that can be present in the environment through natural sources such as volcanoes, soils, undersea vents, and mercury-rich geological zones. It can also be released through human activities like combustion and industrial processes (such as coal-fired power generation, mining, smelting, and waste incineration). The use of mercury in batteries, fluorescent tube lighting, thermometers, and other manufactured items is also a source of mercury release into the environment. Mercury is considered a global contaminant due to its toxicity, its ability to persist in the environment, and its ability to be transported long distances within the atmosphere. Exposure to methylmercury can cause harmful effects on the digestive, immune, and nervous systems, particularly in children and foetuses, whereas inorganic mercury is corrosive to skin and eyes, and toxic to kidneys. This targeted survey generated baseline surveillance data on the levels of methylmercury and inorganic mercury in domestic and imported canned seafood products on the Canadian retail market. The CFIA sampled and analyzed 300 products, including 207 fish samples, 62 mollusk samples and 31 crustacean samples. Methylmercury was detected in 38% of samples and inorganic mercury was detected in 23% of samples tested. The levels of methylmercury and inorganic mercury in this targeted survey were comparable to those previously found in CFIA surveys and reported in literature. Only 2 samples of the 50 canned albacore tuna samples analyzed in this survey contained methylmercury concentrations (0.74 and 0.67 ppm) that were above Health Canada’s ML for total mercury in retail fish of 0.5 ppm. There are no regulations in Canada for mercury or methylmercury in the other products tested. Health Canada determined that none of the samples analyzed for metals in this survey posed a concern to human health.