Development of a New Biomonitoring Technique Using Domestic Pets as Sentinel Species

Abstract

The goal of this research project was to develop a new way of investigating residential exposure to environmental contaminants. Specific objectives were to 1) develop a new method of monitoring biological exposure, 2) test the method in the field, and 3) develop a technique for analyzing the data. Domestic pets were chosen as the sentinel species, and the protocol involved collection of hair samples with subsequent analysis using inductively coupled plasma-mass spectrometry (ICP-MS). The method was tested using~ 100 pets residing in the Butte area, and a new technique was devised that defines hazard quotients and hazard indices commonly employed in the field of risk assessment to identify pets of concern (POCs) and elements of concern (EOCs). In the field campaign, 76 percent of hair samples had arsenic concentrations ≥ the reference concentration of 0.02 mg percent. Twenty-five pets were identified as POCs based on pet hazard indices (HIj ) ≥ 1.0, and only 10 of the 25 POCs resided within the Butte Priority Soils Operable Unit (BPSOU), a boundary set by the EPA to represent the bulk of residential contamination in Butte. We also identified the following elements as EOCs based on element hazard indices (HIi) ≥ 1.0: sodium, copper, manganese, selenium, boron, molybdenum, arsenic, lead, aluminum, lithium, and zirconium. The new biomonitoring technique was designed as a screening-level tool for studying residential exposure to environmental contaminants, but pets are companion animals and results may have implications for human health risk assessment.