John West canned tuna is routinely tested and monitored for mercury and other potential environmental contaminants. The levels of mercury we are able to detect are very low and well within the maximum levels permitted under EU/UK legislation. The UK Food Standards Agency advice is that people should eat at least 2 portions of fish a week, one of which should be an oily fish. (Canned tuna is not considered an oily fish). They do make the additional recommendation that if you are trying for a baby or are pregnant, then you should eat no more than the equivalent of 4 cans of tuna a week. (These figures are based on medium-sized cans with a drained weight of about 130 -140g per can). You can read more on this subject at: www.food.gov.uk