Analysis of Toxic Trace Metals in Pet Foods Using Cryogenic Grinding and Quantitation by ICP-MS, Part I

摘要

The purpose of this study was to examine pet foods from a variety of sources to determine if potentially toxic elements were present in the foods. A range of "budget" to "premium" grade pet food samples were donated by pet owners or purchased in several different stores. The food samples were ground in a cryogenic freezer mill (dry samples) or blender (wet samples), digested with concentrated nitric acid, and analyzed for trace metal content by inductively coupled plasma-mass spectrometry (ICP-MS). Results were then compared to both Environmental Protection Agency Reference Dose (RfD) values and World Health Organization Tolerable Daily Intake (TDI) values, which are considered the daily oral exposure limits for the human population. Many of the pet foods sampled showed significant concentrations of various toxic metals. In many cases, the concentrations exceeded the extrapolated human limit values calculated to pet-size dosages. Part I of this article focuses on the raw materials that are used in pet food manufacturing processes and all the potential sources of contamination. Part II of the article will discuss how the data relate to the dietary exposure of toxic metals in those pet foods when calculated for the daily intake of an average-sized dog and cat. To get a better understanding of the impact on the health of the pets, the daily intake of toxic metals will be compared to EPA and WHO human risk assessment guidelines.