Pentachlorophenol, polychlorodibenzodioxin and polychlorodibenzofuran in eggs from hens exposed to contaminated wood shavings

Abstract

Laying hens may be exposed to pentachlorophenol (PCP) present in bedding materials derived from treated timber. As a result, this chemical and its contaminants or degradation products, such as polychlorodibenzodioxins (PCDDs) and polychlorodibenzofurans (PCDFs), may be present in eggs. The litter-to-eggs transfer and depletion of these compounds were studied in a flock of laying hens reared on contaminated wood shavings. PCP determination was carried out via high resolution gas chromatography coupled to low resolution mass spectrometry/mass spectrometry (HRGC–LRMS/MS); PCDDs and PCDFs were quantified by HRGC–HRMS (SIM). After substitution of the litter contaminated with PCDDs and PCDFs at an average of 50 pg WHO-TE g⁻¹ and with PCP at 15 µg g⁻¹, pooled eggs from six selected hens were sampled twice a month for the depletion study. At steady state, PCDDs and PCDFs showed a transfer ratio of 0.9; for PCP it was 0.03. PCP concentration in eggs (500 ng g⁻¹ whole weight) fell sharply the second week after exposure withdrawal; for PCDDs and PCDFs (47 pg WHO-TE g⁻¹ fat, at day 0), the overall TEQ half-life was estimated at an average of 3.8 weeks. Due to differences in toxicokinetics (a faster depletion), PCP does not appear to be a suitable marker of PCDD and PCDF violative levels. However, the prominent analytical contribution of H₇CCD and O₈CCD in the contamination profile may help to trace the source of contamination. Among congeners, 2,3,7,8 T₄CDF exhibited a different depletion pattern, indicating a possible mechanism of active transport.

Keywords:

• eggs
• hen
• pentachlorophenol
• dioxins
• bedding material
• depletion

Acknowledgements

This study was funded by Italian Ministry of Health (ARACNA project). We thank Dr Massimo Amadori from National Animal Welfare Reference Center (Brescia, Italy) for animals housing and sampling, Dr Antonella Pilozzi for administrative assistance and Fabiola Ferri for graphical assistance.