Case Study on Screening Emerging Pollutants in Urine and Nails.

Area of Science:

• Environmental Chemistry
• Toxicology
• Human Biomonitoring

Background:

• Alternative plasticizers and flame retardants (FRs) are increasingly used as replacements for banned chemicals.
• Limited data exists on the human metabolism and occurrence of these emerging compounds.

Purpose of the Study:

• To identify metabolites of alternative plasticizers and FRs in vitro and in vivo.
• To investigate the presence of these compounds and their metabolites in human urine and fingernails.
• To assess the utility of in vitro assays and fingernails for human biomonitoring.

Main Methods:

• In vitro metabolism studies were conducted for four alternative plasticizers (ATBC, DPHP, DEHTP, DEHA) and one FR (V6).
• Liquid chromatography-electrospray ionization-Orbitrap mass spectrometry (LC/ESI-Orbitrap-MS) was used to analyze urine and fingernail samples from a Norwegian cohort.
• Detection frequencies and relative proportions of metabolites in different matrices were determined.

Main Results:

• Metabolites of ATBC, DEHTP, and DEHA were detected in human urine and fingernails, with varying frequencies.
• V6, a flame retardant, was identified in fingernails for the first time.
• Two DEHTP metabolites were highly detected in urine (97% DF) and found in fingernails; no DPHP metabolites were detected in vivo.
• In vitro metabolite profiles largely corresponded to in vivo findings, supporting the reliability of in vitro assays.

Conclusions:

• In vitro assays can effectively mimic in vivo metabolic processes for alternative plasticizers and FRs.
• Fingernails represent a promising, non-invasive matrix for biomonitoring past exposure to certain organic contaminants, including FRs.
• Further validation is required to establish fingernails as a routine biomonitoring tool.