Dissertation committee:
Εμμανουήλ Δασενάκης, Καθηγητής, Τμήμα Χημείας, ΕΚΠΑ
Αναστάσιος Οικονόμου, Καθηγητής, Τμήμα Χημείας, ΕΚΠΑ
Ευάγγελος Μπακέας, Καθηγητής, Τμήμα Χημείας, ΕΚΠΑ
Νικόλαος Καλογερόπουλος, Καθηγητής, Τμήμα Επιστήμης Διαιτολογίας & Διατροφής, Χαροκόπειο Πανεπιστήμιο Αθηνών
Σωτήριος Καραβόλτσος, Επίκουρος Καθηγητής, Τμήμα Χημείας, ΕΚΠΑ
Λεόντιος Λεοντιάδης, Ερευνητής Α’ Βαθμίδας, ΕΚΕΦΕ «Δημόκριτος»
Ειρήνη Βασιλειάδου, Ερευνήτρια Β’ Βαθμίδας, ΕΚΕΦΕ «Δημόκριτος»
Summary:
The extensive release and distribution of chemical pollutants in the atmospheric air, in seawater, surface and underground water and soil along with their accumulation in the living organisms, results in their trophic transfer through the food chain along with the consequent prolonged exposure of many species, including humans. After entering the body, these pollutants may express their toxic action and cause significant adverse effects on health, such as developmental problems, damages to the reproductive, immune and endocrine systems, induction of carcinogenesis etc.
Polycyclic Aromatic Hydrocarbons (PAHs) are a large group of organic compounds. Some of them have proved to be toxic, harmful pollutants and are considered as a "threat" to humans and other living organisms. Sixteen of them are designated as High Priority Pollutants by the US-Environmental Protection Agency (EPA), while the European Food Safety Authority (EFSA) and the other European authorities have identified 15 PAHs as mutagenic, toxic and carcinogenic and benzo[g,h,i]perylene as mutagenic and toxic (15+1 PAH).
Their presence in food items and the dietary exposure to PAH is evaluated by various Organizations. The European Union recommends the continuous monitoring of levels of 15+1 PAHs in food, while the use of the sum of 4 PAHs (benz[a]anthracene, chrysene, benzo[a]pyrene, benzo[b]fluoroanthene) is proposed as an indicator of the presence of carcinogenic PAHs in food. The EU has established maximum limits for the presence of benzo[a]pyrene, the most dangerous PAH and the sum of 4 PAHs in certain food categories, for the protection of public health. A large number of studies has been conducted in various countries, in order to estimate the exposure of general population on PAHs, through food consumption.
In this context, the present Doctoral Thesis aims at the monitoring of PAHs’ concentration levels in food, in order to estimate the overall intake through food consumption for assessing the potential exposure risk of the Greek population.
For this purpose, a highly selective and sensitive analytical method of isotopic dilution using labeled internal standards, in combination with the use of an optimized Gas Chromatography-Tandem Mass Spectrometry (GC-MS/MS) technique was developed and validated, for the determination of PAHs at the background level. The method is in compliance with the requirements of the relevant European Commission Regulations and was found suitable for the monitoring of PAHs levels in food, even in trace concentrations, a necessary action for the protection of public health. Twenty six PAHs were determined, including the EU 15+1 PAHs, the EPA 16 PAHs, as well as benzo[e]pyrene and perylene.
The method was initially applied to 51 samples of bivalve molluscs, which are considered as environmental indicators. Sampling of the molluscs was conducted in Central Macedonia Region, from aquacultures in the Thermaikos and Strymonikos Gulf, in three sampling periods. PAHs were detected in all mussel samples, the Low Molecular Weight PAHs being the predominant in all samples. The average concentrations for the total of 26 PAHs ranged from 1.37 to 25.59 μg kg-1 wet weight, while none of the samples exceeded the established EU limit for PAHs levels in bivalve molluscs. Mussels from winter sampling period had the highest average concentration levels for the sum of PAHs, while no significant difference in the concentration levels was observed between the three sampling sites.
Subsequently, concentration levels of PAHs were determined in dietary food samples, collected with the help of volunteers and according to the Duplicate diet/portion study protocol method. This method was selected, since the determination of the pollutants is conducted in the final meal that someone consumes, taking into account the burden of PAHs contributed by cooking and maintenance techniques. The sum of the 26 PAHs in the analyzed samples ranged from 4.43 to 15.11 μg kg-1, while levels of benzo[a]pyrene and the sum of 4 PAHs did not exceed the maximum limits established for all food groups, in any of the samples. The diagnostic ratios and distribution patterns of PAHs in the samples, showed that PAHs’ profile in dietary food samples is directly related to the type of participants’ diet.
For the general population of Greece, the mean upper daily intake of 26 PAHs was estimated at 7.16 μg day-1 and the exposure at 101.47 ng kg-1 body weight day-1, of the 4 PAHs at 0.25 μg d-1 and 3.46 ng kg-1 b.w. d-1 and of benzo[a]pyrene at 0.05 μg d-1 and 0.63 ng kg-1 b.w. d-1, respectively. The daily dietary exposure for male participants was higher than that of women, while the exposure was directly related to the type and amount of food consumed.
Additionally, the dietary exposure of the Greek population was calculated based on the national nutritional consumption data and the concentrations of PAHs in various European food items, reported in the EFSA’s Report of 2008. In this approach, the mean upper daily exposure was estimated at 18,83 ng kg-1 b.w. d-1 for the sum of 4 PAHs and at 3.51 ng kg-1 b.w. d-1 for benzo[a]pyrene, with the corresponding values obtained from the Duplicate Diet approach fluctuating at lower levels.
The Duplicate Diet method was found suitable for the estimation of dietary exposure to PAHs, despite the possible slight underestimation of the result. On the contrary, the method based on consumption and concentration data, resulted in high level values and overestimation of the exposure.
The calculated Margins of Exposure (MOE) did not indicate a possible risk to PAHs from food consumption, for the general Greek population. The calculated dietary exposure seemed to be in lower levels compared to those determined for the population of other countries, a fact that is attributed to the limited environmental pollution, the type of food that is consumed, the cooking practices, but also to the sensitive and selective analytical methodology that was used.
