Alkylphenols

The text on this page is taken from an equivalent page of the IEHIAS-project.

APs are used as additives in plastics and as surface-active ingredients in industrial detergents and emulsifiers. Several APs such as nonylphenol (NP) are persistent, toxic, endocrine-disrupting chemicals.

Alkylphenols as biomarkers

Sample collection and storage

Matrix:

Human blood serum, cord blood serum and breast milk have been described as a suitable matrix for APs, though comparisons of AP levels in maternal blood and breast milk are missing so far.

Kinetics:

• APs are ubiquitously present in food and are also detected in water and air samples
• Other routes of exposure include absorption through skin and inhalation or ingestion from pesticide sprays
• APs generally are rapidly metabolized
• In fish, biological half lives are estimated to be around 10-15 hours

Sampling conditions:

Both blood and breast milk sampled can be gathered and stored using standard procedures. Samples are stored at -20°C

Sample measurement

Analytical aspects:

• Standard measurement methods include combinations of GC, LC, MS and HPLC techniques;
• ELISA methods have been developed for APs in the range of 5-500 ppb;
• Detection limit of LC/MS of<0.5 ng/ml serum;
• Detection limit of RP-HPLC with coulometric-array detection is 0.5-1 ng/ml.

Performance characteristics:

• Reproducibility in breast milk is around 2.5-5% using GC/MS
• In blood samples, relative standard deviations of 10% are found using LC/MS

Validation:

Analytical methods have been validated for a wide variety of matrices

Confounding factors:

No correlations between APs and confounding factors are so far described

Data interpretation

Concentrations reported in literature:

• Nonylphenol in breast milk: 0.3 mg/kg
• NP in umbilical cord blood: N.D. – 15.17 ng/ml
• NP in blood serum: 0.58-16 ng/g serum (The Netherlands), 14-222 ng/g serum (Japan)

Dose-response/effect relationships:

Dose-response relationships are observed in rats:

• Dose 0–60-90-120 mg/kg body weight: dose-response with uterine weight, expression of progesterone and estrogen receptors.
• Dose 0-50-100-200 mg/kg body weight: dose-response with testes and prostate weight, daily sperm production and sperm counts

Time trend, geographical variation, susceptibel groups:

No clearly defines groups with increased susceptibility, this may depend on exposure situations.