Monitoring of polycyclic aromatic hydrocarbons in vegetables in "Land of Fires" area and assessment of benzo(a)anthracene bioavailability in vitro and soil cultivation

Abstract

PAHs are a class of toxic, lipophilic chemicals widely spread in the environment. Humans are exposed to PAHs through different pathway, but the dietary source represents the major route of exposure to PAHs in non-smokers and in non-occupationally exposed people. Food can be contaminated from environmental sources especially anthropogenic sources without exclude natural ones. PAHs can enter the food chain by deposition from air or by deposition and transfer from soil and water. The aim of this study was to verify the diffusion of six PAHs (benzo(a)anthracene [BaA], benzo(a)pyrene [BaP], benzo(b)fluoranthene [BbF], benzo(k)fluoranthene [BkF], crysene [Cry] and dibenzo(a,h)anthracene [dBahA]) in the vegetable foods from the Campania region collected in three-year period 2014-2016. Moreover, the study also aimed to understand the origin of the widespread contamination of BaA, in particular the kind of adsorption process involved (leaves, root adsorption etc.). Therefore, turnip (Brassica rapa) and tomato (Solanum lycopersicum) were grown in the presence of the BaA both in a controlled environment (in vitro) and in a more complex system as soil (in vivo). In both the approach two BaA rates were applied (50 e 100 mg kg-1) by exceeding contamination level reached in other studies. The results of monitoring activity indicated that PAH contamination in plant matrices was a definitely spread phenomenon with the lower contamination when compared with those found in other food matrices (smoked meat and smoked or not fish products). In fact, although most of the analyzed samples showed PAH values below the limit of quantification (<0.2 g kg-1), few cases sporadically occurred (artichokes, broad-leaved vegetables, wheat, corn, strawberries) with exceeding values. The study carried out on the contamination in vivo and in vitro of turnip and tomato demonstrated that the two species differently responded to the BaA presence and the response depended on the BaA concentration. The BaA translocation occurred in turnip roots and just in negligible amounts in shoots. Conversely, tomato seedlings showed larger capacity to adsorb BaA in roots. Therefore, the overall results demonstrated that the contamination of turnip and tomato plants could occur if the matrix where plants live is strongly contaminated by BaA, although real data on edible parts are missing. The bioavailability of BaA affected strongly the translocation of contaminant molecules in plant tissues and hence whatever action addressed to limit the BaA mobility should be desirable.