Modeling Human Exposure to Phthalate Esters: A Comparison of Indirect and Biomonitoring Estimation Methods

Abstract

Humans are potentially exposed to phthalate esters (PEs) through ingestion, inhalation, and dermal contact. Studies quantifying exposure to PEs include “biomarker studies” and “indirect studies.” Biomarker studies use measurements of PE metabolites in urine to back-calculate exposure to the parent diester, while indirect studies use the concentration of the PE in each medium of exposure and the rate of intake of that medium to quantify intake of the PE. In this review, exposure estimates from biomarker and indirect studies are compiled and compared for seven PEs to determine if there are regional differences and if there is a preferred approach. The indirect and biomarker methods generally agree with each other within an order of magnitude and discrepancies are explained by difficulties in accounting for use of consumer products, uncertainty concerning absorption, regional differences, and temporal changes. No single method is preferred for estimating intake of all PEs; it is suggested that biomarker estimates be used for low molecular weight PEs for which it is difficult to quantify all sources of exposure and either indirect or biomarker methods be used for higher molecular weight PEs. The indirect methods are useful in identifying sources of exposure while the biomarker methods quantify exposure.

Determination of contamination pathways of phthalates in food products sold on the Belgian market

“…For example, some phthalates and their metabolites have been reported to adversely affect the male reproductive system (Meeker et al, 2009) and to have the potential to alter androgen-responsive brain development in humans (Swan et al, 2010). Of all exposure pathways, food intake is the most important one for phthalates, followed by dust ingestion and indoor air inhalation (Clark et al, 2011;Fromme et al, 2007b;Rudel and Perovich, 2009;Wormuth et al, 2006).…”

An integrated exposure assessment of phthalates for the general population in China based on both exposure scenario and biomonitoring estimation approaches

“…Given that there are large variations in the monitoring concentrations and calculated EDIs of phthalates, median values of them are normally used to indicate the slight difference of those representative levels (Clark et al, 2011;Lee et al, 2014). Following this commonly used method, we conducted our evaluation by comparing the median values of the calculated EDIs as well, which also made it feasible to make any possible parallel comparison with existing relevant studies in different regions of the world.…”

“…Because phthalates are not chemically bound to polymers, they are easily released from products into the environment and are therefore becoming ubiquitous environmental contaminants (Wittassek et al, 2011;Cheng et al, 2013). Humans are exposed to phthalates in numerous ways, such as inhalation of indoor and outdoor air, dermal contact of soil and dust, ingestion of food, dust and soil (Clark et al, 2011). The wide range of uses, possible adverse health effects and various exposure pathways have made phthalate exposure a general concern.…”

“…analyzed concentrations of phthalate metabolites in three cities in China and estimated the daily intake of phthalates in the Chinese population based on a biomonitoring estimation approach that determined specific phthalate metabolites in the human body (e.g., urine, blood, breast milk, saliva, semen) as biomarkers of exposure and back-calculated exposure to the parent diester utilizing physiological excretion constants (Clark et al, 2011). also detected concentrations of phthalates in eight categories of foodstuffs collected from two cities in China and calculated the estimated daily dietary intake of phthalates (EDI diet ).…”

Remediation of phthalates in river sediment by integrated enhanced bioremediation and electrokinetic process

“…Humans get exposed to phthalates via multiple exposure pathways including inhalation, dietary intake and dermal absorption (Clark et al, 2011). After PAEs reach natural environment, these compounds may have health risks to human due to their xenoestrogenic effects (Nielson and Larsen, 1996), and carcinogenic and mutagenic effects (Nielson and Larsen, 1996).…”