Phthalate exposures in California over 2007-2018: estimates from municipal wastewater discharge reports Open Access

Rodgers, Jackson (Spring 2019)

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Phthalates are a useful group of chemicals with over 470 million pounds produced or imported in the United States each year. Phthalates primary applications are as plasticizers (making plastics soft). Some phthalates are even used in personal care products like fragrances or cosmetics. However, some phthalates like di(2-ethylhexyl) phthalate were shown to produce adverse health effects in male infants. Due to the ubiquitous use and potential health effects, it is of public health importance to estimate population level exposures to phthalates. To efficiently estimate population wide exposures to phthalates, this paper uses wastewater discharge reports. Contaminants measured in wastewater is made publicly available by the United State Environmental Protection Agency. 6 phthalates were considered in this analysis – butyl benzyl, di-n-octly, di (2-ethylhexyl), dibutyl, diethyl, and dimethyl phthalate as these are listed on the United States Environmental Protection Agency’s list of 126 priority pollutants. Restricted maximum likelihood mixed-effects linear regression models were utilized to explain temporal and spatial heterogeneity. Butyl benzyl phthalate per-capita geometric mean mass discharge appears to increase. Decreases in per-capita geometric mean masses were seen in di(2-ethylhexyl) phthalate and diethyl phthalate over the 11-year period.  

Table of Contents


Materials and Methods

Wastewater data


Biomonitoring California

Data analysis and model fitting

Restricted maximum likelihood mixed-effects linear regression model of log-per capita municipal wastewater facility phthalate discharges regressed on year

Inverse variance-weighted fixed-effects meta-regression of Biomonitoring California reported geometric means for phthalates

Results and Discussion




Wastewater and Biomonitoring Trends




Population calculations

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