While routine monitoring poultry meat was obtained from breeding hens, dioxins contaminations were detected in Portugal. Levels of 430.9 pg PCDD/F-WHO-TEQ/g 1 were found, which are higher than the official limits legally allowed for this matrix (1.75 pg PCDD/F-WHO-TEQ/g). To identify the magnitude of the contaminations, 60 samples were collected from poultry farms and different matrices, namely: feed, water, wood shavings from the litters, muscle of the breeding hens, hatching eggs collected in the positive farm and muscle collected from broilers farms supplied by the positive breeding farm. The comparison of the dioxins congeners profiles showed that there was a coincidence of peaks of higher relative concentrations in the wood shavings, with the peaks of the highest relative concentration in the hatching eggs, especially the relative concentrations of the congeners 1,2,3,4,6,7,8-HpCDD and OCDD, which may be explained by the role of VLDLy in the delivery of triglycerides to the oocyte, where they will be used as the energy source for the developing embryo. The comparison of the dioxins congeners profiles of the breeding hens muscle with the poultry muscle, showed a coincidence of peaks of higher relative concentrations in the con- geners 1,2,3,7,8-PeCDD, 1,2,3,6,7,8-HxCDD, 1,2,3,4,6,7,8-HpCDD and OCDD which may indicate a dechlorination pathway "in vivo". Results allowed concluding that those wood shavings, improperly used as poultry litters, were certainly the source of contamination of the food chain.

This work describes the treatment of Pinus pinaster wood with four different industrial wood preservatives (two anti-bluing or fungicide and two fungicide/pesticide) and the detection and quantification of the dioxin contamination profile in the wood shavings. The samples were collected from poultry liters during three contamination incidents of poultry meat. Two methods used were, both nonpressure: one by immersing the wood samples in the preservative solution and the other by impregnation of the preservative solution into the wood, with vacuum. It was concluded that there is no difference in terms of contamination profile, caused by the different industrial wood treatment preservative products in study. A clear correlation between the commercial products used in wood treatment and the contamination profile of wood shavings that have been used as bedding material in poultry production was detected.

During 2016, following the implementation of a dioxin contamination monitoring in poultry meat (ducks) in a slaughterhouse, a positive sample was found. The investigation identified the wood shavings used as bedding material in the duck farm as the possible source of contamination of these animals. In this episode, contamination profiles of higher and lower concentrations, seem to be very similar, being OCDD, OCDF and 1,2,3,4,6,7,8-HpCDD responsible for 74.4% of the total contamination of those animals. The study revealed a reduction of poultry contamination after the removal of the source of contamination, with an average daily depletion percentage level ranging between 1.43% and 4.35%.

During 2006 and 2011, following the implementation of dioxin contamination monitoring in poultry meat, levels higher than legally allowed in meat from poultry slaughtered for human consumption, were found. The wood shavings used as bedding material in the poultry farm showed considerable high contaminations, indicating that these materials were the likely source of contamination of the animals. Wood shavings samples (n = 23), used as poultry litters in intensive farms of broilers, were analysed. In both episodes, contamination profiles of higher and lower concentrations, seem to be very similar, being OCDD, OCDF,

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