Fluorinated surfactants
From Opasnet
- The text on this page is taken from an equivalent page of the IEHIAS-project.
- A very diverse group, which all share an extreme persistence towards degradation.
- Major groups are perfluoroalkylsulfonic acids (e.g. PFOS), perfluorinated carboxylic acids (e.g. PFOA) and fluorotelomers.
Contents
Fluorinated surfactants as biomarkers
Sample collection and storage
Matrix:
- Perfluorinated alkyl substances (PFAS) are often associated with plasma albumin binding, which makes blood a suitable matrix.
- Few studies have shown significant concentrations of PFAS in human milk
- Cord blood may be a good indicator matrix as well.
Kinetics:
- The major exposure pathway of PFAS in by food
- Also exposure through inhalation of particle-bound PFAS has been observed
- PFAS are generally very inert and not likely to degrade
- Serum elimination half-life in occupationally exposed workers is estimated to be 8.7 years.
Sampling conditions:
- Blood samples can be taken using standard procedures, and are stored frozen at -20°C.
- Fluorotelomers are more volatile and need special attention.
Sample measurement
Analytical aspects:
- Because of the ubiquitous nature of PFAS, avoiding contamination of the samples is a major challenge.
- Analysis is usually performed using GC/MS or LC/MS techniques
- Detection limits depend on which matrix and compound is analysed
Performance characteristics:
- A first worldwide interlaboratory study highlighted that there are large differences in analytical performance
- Variations are mainly due to extraction and clean-up procedures.
Validation:
No particular guidelines for PFAS analysis in human tissues are available
Confounding factors:
Only gender has been illustrated to be a confounder, with higher serum concentrations of PFOS in males.
Data interpretation
Concentrations reported in literature:
| PFOS Female | PFOS Male | PFHxS Female | PFHxS Male | PFOA Female | PFOA Male | PFOSA Female | PFOSA Male | |
| Maximum (ng/ml) | 81 | 72 | 3,3 | 3,4 | 30,9 | 38,1 | 5,8 | 5,8 |
| Minimum (ng/ml) | 2,5 | 1,3 | 0,2 | 0,2 | 2,4 | 3,5 | 0,7 | 1 |
Dose-response/effect relationships:
- Most toxicological data is available for rodents,
- Very little epidemiological data for humans is available
- The NOAEL for males and females was considered to be around 0,03 mg/kg/day and 0,15 mg/kg/day respectively.
Time trend, geographical variation, susceptibel groups:
- Substantial increases of PFAS concentrations in the environment have been reported over the last decades.
- With the voluntary production stop of PFOS, concentrations are expected to decrease in the future.
