Mercury concentrations in wet and dry cat and dog food

Given that mercury (Hg) concentrates in fish, and this is an important ingredient in pet food, we hypothesized that Hg concentrations could be of concern. To address this hypothesis, total Hg concentrations were measured in a variety of brands of cat (n = 47) and dog (n = 54) food. Since most of the Hg in fish is methylmercury, we assume that this is the form in the pet food. However, this still needs to be tested. Mercury concentrations ranged from 1 to 604 ng g−1. There are no standards for pet food, so values were compared to available consumption advisories: 300-1000 ng g−1 for humans, 30 ng g−1 for kingfishers (fish eating birds), small mammals (70 ng g−1), and river otters (100 ng g−1). Thirty one of the pet food samples had concentrations >30 ng g−1, and 14 > 100 ng g−1. More studies are necessary to understand the health implications of Hg concentrations observed.