Estimated Tris(1,3-dichloro-2-propyl) Phosphate Exposure Levels for US Infants Suggest Potential Health Risks

Tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) has been widely used as a flame retardant and is commonly detected in environmental samples. Biomonitoring studies relying on urinary metabolite levels [i.e., bis(1,3-dichloro-2-propyl) phosphate (BDCIPP)] demonstrate widespread exposure, but TDCIPP intake is unknown. Intake data are critical components of meaningful risk assessments and are needed to elucidate the potential health impacts of TDCIPP exposure. Using biomonitoring data, we estimated TDCIPP intake for infants aged 2-18 months. Children were recruited from central North Carolina (n = 43, recruited in 2014 and 2015), and spot urine samples were analyzed for BDCIPP. TDCIPP intake rates were estimated using daily urine excretion in urine. Daily TDCIPP intake estimates ranged from 0.01 to 15.03 mu g kg(-1)day-1 for children included in our assessment, with some variation depending on model assumptions. The U.S. Consumer Products Safety Commission previously established an acceptable daily intake of 5 mu g kg(-1)day(-1) for non-cancer health risks. Depending on modeling assumptions, we found that 2-9% percent of infants had TDCIPP intake estimates above this threshold. Our results indicate that current TDCIPP exposure levels could pose health risks for highly exposed infants.