Dialkyl phosphates in meconium as a biomarker of prenatal exposure to organophosphate pesticides: A study on pregnant women of rural areas in Crete, Greece

Abstract

1. The authors developed a sensitive analytical method for the determination of dialkyl phosphates (DAPs) in meconium. This method was applied to determine the DAPs, which are non-specific metabolites of the organophosphate pesticides (OPs), in meconium of newborns by mothers who live in rural areas in Crete, Greece. DAPs are considered as biomarkers of exposure to OPs. Meconium is produced in the foetus at approximately 16 weeks of gestation and it acts as a repository of many xenobiotics. The determined organophosphate metabolites were dimethylphosphate (DMP), diethylphosphate (DEP), dimethylthiophosphate (DMTP), diethylthiophosphate (DETP), and diethyldithiophosphate (DEDTP).

2. The DAPs were extracted from meconium by liquid–solid extraction, derivatized, and analysed by gas chromatography-mass spectrometry (GC-MS). The mean percentile recoveries were 76.9%, 65.2%, 94.1%, 109.4%, and 107.2% for DMP, DEP, DMTP, DETP, and DEDTP, respectively. The percentage of positive samples was 92.1% for DMP, 36.8% for DEP, 60.5% for DMTP, 63.2% for DETP, and 57.9% for DEDTP. Mean (± standard deviation) and the range concentrations of the positive samples (ng g⁻¹) were 126.74 ± 142.73 (10.64–739.45), 11.46 ± 20.43 (1.50–79.14), 215.05 ± 187.34 (8.54–662.16), 4.92 ± 5.09 (1.25–19.04), and 1.84 ± 2.07 (0.5–8.04) for DMP, DEP, DMTP, DETP, and DEDTP, respectively.

3. Statistical analysis revealed no significant difference in meconium levels between high- and low-risk groups of exposure of pregnant women. However, the results of this study demonstrate that DAPs in meconium may be considered as a potential biomarker for the assessment of foetal exposure to organophosphate pesticides.

Keywords::

• Meconium
• dialkyl phosphates
• prenatal exposure
• gas chromatography-mass spectrometry (GC-MS)
• pesticides
• pregnancy

Acknowledgements

The authors would like to express their gratitude to Koukoura Ourania, MD, and Sigelaki Argiro, midwife; to the staff at the Department of Obstetrics and Gynecology, University Hospital of Heraklion, Crete; to the students Eleutheria Theodoropoulou and Mathaios Kabalakis for their help in the collection and preparation of the meconium samples; and to Thanasis Alegakis, PhD, for his useful advice on the statistical part of the manuscript. The study was co-funded by the Prefecture of Heraklion and the University of Crete Program Code (Grant Number ELKE UC n2197) and grants from the Toxicology Laboratory, University of Crete Research Committee (Grant Numbers ELKE UC n2600 and n2598). The paper is dedicated to retired Professor Dr Koumantakis Eugenios for his long-lasting interest for this kind of research.

Declaration of interest: The authors report no conflicts of interest.