Ricardo Fernández-González

A Critical Review about Human Exposure to Polychlorinated Dibenzo-p-Dioxins (PCDDs), Polychlorinated Dibenzofurans (PCDFs) and Polychlorinated Biphenyls (PCBs) through Foods

Dioxins include polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and part of polychlorinated biphenyls (PCBs). Only the compounds that are chlorinated at the 2,3,7, and 8 positions have characteristic dioxin toxicity. PCDDs, PCDFs and PCBs accumulate in the food chain due to their high lipophilicity, high stability, and low vapor pressure. They are not metabolized easily; however their hydroxylated metabolites are detected in feces. They cause a wide range of endocrine disrupting effects in experimental animals, wildlife, and humans. Endocrine related effects of PCDDs, PCDFs and PCBs on thyroid hormones, neurodevelopment and reproductive development were referenced. In addition, some studies of contamination of foods, bioaccumulation, dietary exposure assessment, as well as challenges of scientific research in these compounds were reviewed.

Searching ingredients polluted by polycyclic aromatic hydrocarbons in feeds due to atmospheric or pyrolytic sources

The primary aim of the proposed work is to propose the potential sources of pollution by polycyclic aromatic hydrocarbons (PAHs) in feeds and ingredients. To reach this propose the development of a simple, fast, quantitative and economic method for determining PAHs using liquid-liquid extraction (LLE), clean-up and detection by liquid chromatography with fluorescence detection (LC-FD) in polluting feeds and ingredients was developed. The overall method quantification limits range from 0.020 to 4.0μg/kg and analyte recoveries are between 70% and 105% with relative standard deviations (RSD) lower than 20%. Molecular patterns of PAHs were used to study their distribution in the selected samples by cluster analysis, separating them in two groups: contaminated by atmospheric or pyrolytic sources. In order to find a relationship between the nutritional composition (protein, fibre, ash and fat content), and the hypothetical toxicity of selected feeds, a partial least squared (PLS) analysis was used, showing that fibre was a major contributor. Moreover, the complete data set of 27 feed samples and 25 feed ingredients x 13 PAH concentrations were analysed by PCA to find out what ingredients were controlling PAH pollution.

A Critical Review about the Health Risk Assessment of PAHs and Their Metabolites in Foods

Polycyclic aromatic hydrocarbons (PAHs) are a family of toxicants that are ubiquitous in the environment. These contaminants generate considerable interest, because some of them are highly carcinogenic in laboratory animals and have been implicated in breast, lung, and colon cancers in humans. Dietary intake of PAHs constitutes a major source of exposure in humans. Factors affecting the accumulation of PAHs in the diet, their absorption following ingestion, and strategies to assess risk from exposure to these hydrocarbons following ingestion have received very little attention. This review, therefore, focuses on concentrations of PAHs in widely consumed dietary ingredients along with gastrointestinal absorption rates in humans. Metabolism and bioavailability of PAHs in animal models and the processes, which influence the disposition of these chemicals, are discussed. Finally, based on intake, disposition, and tumorigenesis data, the exposure risk to PAHs from diet is presented. This information is expected to provide a framework for refinements in risk assessment of PAHs.

Inputs of polychlorinated biphenyl residues in animal feeds

Animal nutrition constitutes an important issue for the animal production industry. Products intended for animal feed may contain undesirable substances which could endanger animal health or, because of their presence in livestock products, human health or the environment. In this sense, several incidents related with the presence of persistent organic pollutants, particularly with polychlorinated biphenyls (PCBs), have happen in food and feed additives. Animal feed and feed components are challenging matrices for the determination of residues and contaminants. The variability of these matrices is enormous. It ranges from relatively simple ones like those based on wheat to all kinds of by-products from agro and food industry, such as cereal oils. Firstly, this article reviews and addresses the extraction efficiency of ultrasonic assisted solvent extraction (UASE) and focused ultrasonic solvent extraction (FUSE) for determining selected PCBs in animal feed and ingredients. Detection of these pollutants was carried out by gas chromatography (GC) coupled to electron capture detection (ECD); tandem mass spectrometry (MS/MS) was used as confirmatory technique. Recoveries ranged from 70% to 98% by UASE and from 75% to 106% by FUSE with estimated quantification limits between 0.11 and 0.3 μg/kg in feeds and ingredients and between 0.2 and 0.75 μg/kg in fats. Once the method was optimised, it was applied to 18 feed samples as well as 16 ingredients. PCBs were detected in almost all the selected samples. As expected, the samples of animal origin as shell powder and fish oil showed the highest concentrations of 56 and 29 ng/g, which are equivalent to toxicological concentrations of 123 and 18 ng WHO-TEQDL-PCBs/kg, respectively. Feeds and ingredients from vegetable origin ranged from non-detected to 7.1 μg/kg. PCB 77 and 169 were the discriminant congeners in the selected samples of feed and ingredients. Samples showed that the pattern of PCBs depends on the sources of contamination.

Optimization of purification processes to remove polycyclic aromatic hydrocarbons (PAHs) in polluted raw fish oils

Fish oils are one of the main sources of health promoting nutrients such as n-3 fatty acids in animal and human diet. Nevertheless, they could be an important source of persistent organic pollutants (POPs). Different strategies of decontamination processes to reduce polycyclic aromatic hydrocarbon (PAH) levels in fish oils, such as solvent extraction (ethanol) and adsorbent extraction using commercially available (activated carbon) and sustainable adsorbents (mussel shell and wood ashes), were compared. Adsorption conditions were evaluated and optimized by an experimental design and the experimental results were adjusted to response surfaces. In this way, PAH removals increased with increasing of individual PAH molecular weight and they range from 80% to 100% using activated carbon and from 10% to 100% using wood ashes. Pine wood ashes showed similar removal rates to activated carbon (87%-100%) excluding F (51%) and P (42%). No PAH removal was observed using mussel shell ashes. Ethanol extraction was also optimized and showed a good performance in the extraction of PAHs. However, it does affect their ω-3 fatty acid contents. Finally, real oil samples from different fishing areas: Spain, South America, and North Europe were selected for the decontamination experiments under experimental conditions previously optimized.

Feed Ingredients Mainly Contributing to Polycyclic Aromatic Hydrocarbon and Polychlorinated Biphenyl Residues

Animal nutrition constitutes an important issue for the animal production industry. Products intended for animal feed may contain undesirable substances which could endanger animal health or, because of their presence in livestock products, human health or the environment. In this sense, several incidents related with the presence of persistent organic pollutants, particularly with polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs), have happen in food and feed additives. Simple, fast, quantitative, and economic methods for determining PAHs and PCBs in potentially polluting feed ingredients were developed and evaluated. The methods involved liquid-liquid extraction (LLE), clean-up, and detection by liquid chromatography with fluorescence detection (LC-FD) for PAHs and gas chromatography (GC) coupled to electron capture detection (ECD) for PCBs, using tandem mass spectrometry (MS/MS) as confirmatory technique. The overall method quantification limits range from 0.020– 4.0 μg/Kg for PAHs and from 0.20–0.75 μg/Kg for PCBs, analyte recoveries are between 70 and 105% with relative standard deviations (RSD) lower than 20%. Once the method was optimized, it was applied to 25 feed ingredients considered as potential candidates for feedstuff. As expected, the samples of animal origin as shell powder and fish oil showed the highest PCB concentrations of 56 and 29 ng/g, which are equivalent to toxicological concentrations of 123 and 18 ng WHO-TEQDL-PCBs/Kg, respectively. Opposite results were obtained with PAHs and the highest PAH4 levels were detected alfalfa (47 μg/Kg), calcium phosphate (27 μg/Kg), and palm oil (23 μg/Kg) used as feed ingredients.

Feeds and Corresponding Footprints of Residual Polycyclic Aromatic Hydrocarbons and Polychlorinated Biphenyls Based on Their Constituents

Food safety is central to any society, having important economic, social, and environmental implications. International comparisons have shown that the European Union is the worlds largest producer of food and drink products. It is not surprising therefore that the Agro-food sector has major importance/influence on the economy of Europe. The first link in the agro-food chain is animal feed, and therefore the risks associated to them, as is the case of the distribution of carcinogenic polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs), are of paramount importance. Simple, fast, quantitative, and economic methods for PAHs and PCBs potentially polluting feeds were developed. The PAHs were detection by liquid chromatography with fluorescence detection (LC-FD) and the PCBs by gas chromatography (GC) coupled to electron capture detection (ECD), using tandem mass spectrometry (MS/MS) as confirmatory technique. The complete data set of 27 feed samples x 13 PAH and PCB concentrations were analyzed by Principal Component Analysis (PCA) to find out what feeds were controlling PAH and PCB contamination.

Decontamination solutions for polychlorinated biphenyls (PCBs) in raw fish oils from environmentally contaminated sea fishes

Fish oil has been identified as one of the most important contributors to the levels of polychlorinated biphenyls (PCBs) in food and feed products. In this study, PCB adsorption from fish oil onto activated carbon (AC), other sustainable adsorbents (mussel shell and wood waste ashes) and organic solvent such as ethanol were compared and optimized. Regarding to adsorbents, PCBs were extracted from fish oil by a 2.0% adsorbent material dose, during 6.0 h at 25 °C. Solvent extraction was carried out using 2 × 5.0 mL ethanol by manually stirring for 3.0 min, and then by Ultrasound-Assisted Solvent Extraction (UASE) for 5.0 min. The results showed that removal rates obtained by using adsorbent materials ranged from 0.0 to 10% for marker PCBs, from 0.0 to 37% for mono-ortho-PCBs, from 0.0 to 74% for PCB11 and from 0.0 to 95% for non-ortho-PCBs. Regarding to solvent extraction, ethanol was used by manually stirring and then by Ultrasound-Assisted Solvent Extraction (UASE). The samples were then centrifuged (2000 rpm/10 min) and the alcoholic phase was removed. With this method, removal efficiencies were much better (85-116%); nevertheless, high eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) removal rates (70-78 and 71-79%, respectively) were detected. We can conclude that adsorption with adsorbents depends on the geometry of PCB congeners, as well as both type of adsorption material and their origin, and that several sorption cycles are needed. Adsorption with ethanol could be the most effective methodology but nutritional quality was impaired, what makes necessary to look for other not so polar removal solvents.

Atmospheric pollutants in fog and rain events at the northwestern mountains of the Iberian Peninsula

Atmospheric polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) are persistent organic pollutants (POPs) and exist in gas and particle phases, as well as dissolved or suspended in precipitation (fog or rain). While the hydrosphere is the main reservoir for PAHs, the atmosphere serves as the primary route for global transport of PCBs. In this study, fog and rain samples were collected during fourteen events from September 2011 to April 2012 in the Xistral Mountains, a remote range in the NW Iberian Peninsula. PAH compounds [especially of low molecular weight (LMW)] were universally found, but mainly in the fog-water samples. The total PAH concentration in fog-water ranged from non-detected to 216 ng·L(-1) (mean of 45 ng·L(-1)), and was much higher in fall than in winter. Total PAH levels in the rain and fog events varied from non-detected to 1272 and 33 ng·L(-1) for, respectively, LMW and high molecular weight (HMW) PAHs. Diagnostic ratio analysis (LMW PAHs/HMW PAHs) suggested that petroleum combustion was the dominant contributor to PAHs in the area. Total PCB levels in the rain and fog events varied from non-detected to 305 and 91 ng·L(-1) for, respectively, PCBs with 2-3 Cl atoms and 5-10 Cl atoms. PCBs, especially those with 5-10 Cl atoms, were found linked to rain events. The occurrence of the most volatile PCBs, PCBs with 2-3 Cl atoms, is related to wind transport from far away sources, whereas the occurrence of PCBs with 5-10 Cl atoms seems to be related with the increase of its deposition during rainfall at the end of summer and fall. The movement of this fraction of PCBs is facilitated by its binding to air-suspended particles, whose concentrations usually show an increase as the result of a prolonged period of drought in summer.