UC Santa Barbara

For most humans, environmental exposure to toxicants begins as early as the moment of conception and accrues differently based on where a person lives, the nature of their work, and a variety of other socio-economically linked behaviors. A toxicant of particular interest are phthalates – the chemicals used to make plastics flexible and durable. They are found in clothes, furniture varnishes, toys, pharmaceuticals, food containers, and personal care products - to name just a few sources of exposure. Phthalates can make their way into bodies through ingestion, inhalation, and dermal absorption, and the breakdown of them within bodies can be measured as phthalate metabolites in urine. The specific physiological mechanisms linking phthalate exposure to health outcomes are still being deciphered, although it is abundantly clear that they pervade all aspects of the environment and our bodies, resulting in negative health outcomes. We study the level of the metabolite, mono-ethyl phthalate (MEP), in urine samples of children and adult participants in the National Health and Nutrition Examination Survey (NHANES), years 2001-2016. We have chosen mono-ethyl phthalate as our biomarker indicating exposure to phthalates because it is one of the most abundant phthalate metabolites present in human urine; it is the primary metabolite of diethyl phthalates (DEP). We ask which socio-demographic characteristics are associated with higher phthalate levels in urine within children and adults. Socio-demographic characteristics we examine include: age, gender, education, race/ethnicity, family income to poverty level, citizenship status. We expect that socio-demographically disadvantaged groups will have the highest levels of phthalate exposure. Factors such as education, SES, and gender influence where people live, (and their built environment exposures), their time-use patterns, their occupation, their treatment at healthcare facilities, and their purchasing patterns. Those factors (where people live, time-use patterns, occupation, etc.) shape phthalate exposure. Consequently, we expect some of these groups to have more phthalates in their bodies than other groups. This research contributes to understanding health experiences outside of clinical definitions, drawing attention to structural vulnerabilities and the way that environmental toxicants are embodied in individuals and populations.