Individual and Combined Contamination of the Heavy Metals in Commercial Cat and Dog Food

Abstract As the long-term accumulation of heavy metals in food poses significant health risks to pets, there is a growing concern among people regarding heavy metal contamination in pet food. In order to investigate the heavy metals levels in pet food in China, we collected a total of 93 imported cat and dog food from the Chinese market produced in 2021–2022, comprising 45 cat food and 48 dog food, and determined the concentrations of lead (Pb), cadmium (Cd), chromium (Cr), mercury (Hg) and arsenic (As) in them. Cr and As were detected in all samples, followed by contamination rate of Hg. In cat food, Cr and As were the most prevalent heavy metals, and Cr and Hg were found in all dog food. Pb was not detected in canned foods, while Cr, As, Hg, and Cd had contamination rates of 100%, 100%, 85.71%, and 34.18% respectively. Dry food in cat and dog foods, with Cr, Hg, and As having the highest contamination rates at 100%. Some samples exceed the limits set by Hygienical Standard for Pet Feed of China (Announcement No. 20 of 2018) regarding Pb and Cr, while other heavy metals remained within acceptable limits. Canned food, however, met all regulatory limits for heavy metals. Across all types of pet food, Cr, Hg, and As were consistently the most prevalent combined contaminants. Analysis of the aHI values showed that Cr posed the highest risk, exceeding safety thresholds significantly. Pb and As also posed risks, with differing impacts between cats and dogs. This study underscores the extensive presence of heavy metal contamination in pet foods, posing a significant risk to pet health due to ongoing exposure to multiple heavy metals.