An exposure assessment of 27 quaternary ammonium compounds in pet dogs and cats from New York State, USA

Benzylalkyldimethylammonium (BACs), dialkyldimethylammonium (DDACs), and alkyltrimethylammonium compounds (ATMACs) are quaternary ammonium compounds (QACs) used widely as biocides, disinfectants, and sanitizers. Owing to their toxicity, human exposure to this class of chemicals is a concern. Pet animals are sentinels of human exposure to several indoor environmental chemicals. For the first time, we measured 7 BACs, 6 DDACs, 6 ATMACs, and 8 metabolites of BACs in urine and feces of pet dogs and cats from New York State, USA. We found widespread occurrence of QACs in feces, with median concentration of n-ary sumation All (sum concentration of all 27 QAC analytes) at 9680 and 1260 ng/g dry weight (dw) in dog and cat feces, respectively. BACs were the most abundant compounds among the four types of QACs, accounting for 64 % and 57 % of n-ary sumation All in dog and cat feces, respectively, followed by DDACs (33 % and 34 %, respectively), ATMACs (4 % and 9 %, respectively), and BAC metabolites (0.2 % and 0.3 %, respectively). However, in urine, only omega-carboxylic acid metabolites of BACs were found at median concentrations at 2.08 and 0.28 ng/mL in dogs and cats, respectively. Samples collected from animal shelters contained elevated levels of QACs than those from homes of pet owners. A significant positive correlation was found among the four types of QACs analyzed, which suggested usage of these chemicals in combination as mixtures. Based on the concentrations measured in feces, and through a reverse dosimetry approach, the median cumulative daily intakes (CDIs) of QACs were estimated to be 49.4 and 4.75 mu g/kg body weight (BW)/day for dogs and cats, respectively. This study provides first evidence that pet dogs and cats are exposed to QACs at significant levels that warrant further attention.