Lead and cadmium in foods/drinking water from Slovenian market/taps: Estimation of overall chronic dietary exposure and health risks.

Approximately 3000 food samples from the Slovenian market and 2500 drinking (tap) water samples in the period 2011 - 2016 were evaluated for the presence of toxic elements lead (Pb) and cadmium (Cd) and the overall chronic dietary exposure was assessed for each element. The highest mean concentrations were found for Pb in products for special nutritional use - dietary supplements (0.383 mg/kg) and for Cd in fish and seafood (0.117 mg/kg). The consumption data were obtained from the national study of the household budget and from the European Food Safety Authority (EFSA) summary statistics. Chronic dietary exposure was estimated deterministically. The average Pb and Cd intakes from food and drinking (tap) water ranged for children from 0.90 to 1.021 µg/kg bw/day and 4.65 to 5.65 µg/kg bw/week, respectively, and for adults, including adolescents, from 0.40 to 0.53 µg/kg bw/day and 1.98 to 2.82 µg/kg bw/week, respectively. The high consumption of cereal-based foods and vegetables contributed most to overall Pb and Cd intake in the majority of the age groups. The exposure to Pb was generally lower and that to Cd was higher compared to the average EU values. The most exposed were children, as the health-based guidance values were exceeded for both elements, which indicates a health concern. An important contribution to Cd exposure can be attributed to grains and potatoes grown in Slovenia, where the soil contains more Cd than that in other EU countries. Further efforts to reduce Pb and Cd intake are required to minimize potential health risks.

Prediction of cadmium concentration in selected home-produced vegetables.

Soil contaminated with cadmium presents a potential hazard for humans, animals and plants. The latter play a major role in the transfer of cadmium to the food chain. The uptake of cadmium and its accumulation by plants is dependent on various soil, plants and environmental factors. In order to identify soil properties with statistically significant influence on cadmium concentration in vegetables and to reduce the collection of data, time and costs, regression models can be applied. The main objective of this research was to develop regression models to predict the concentration of cadmium in 9-vegetable species: zucchini, tomato, cabbage, onion, potato, carrot, red beet, endive and chicory, based on soil properties. Soil samples were collected from 123 home gardens of the Municipality of Celje and 59 of these gardens were also included in vegetable sampling. The concentration of elements (e.g. arsenic, cadmium, copper, lead, and zinc) in the samples was determined by Inductively Coupled Plasma Mass Spectrometry. Single (for cabbage, potato, red beet and chicory) and multiple (for tomato, onion, carrot and endive) linear regression models were developed. There was no statistically significant regression model for zucchini. The most significant parameter for the influencing the cadmium concentration in vegetables was the concentration of cadmium in soil. Other important soil properties were the content of organic matter, pH-value and the concentration of manganese. It was concluded that consuming carrots, red beets, endives, onions, potatoes and chicory which are grown in gardens with Cd concentrations (mgkg(-1) DW) above 2.4, 3.2, 6.3, 7.9, 8.3 and 10.9, respectively, might represent an important contribution to dietary Cd exposure.

Remarkable effect of water on functionalization of the phenyl ring in methyl-substituted benzene derivatives with F-TEDA-BF4.

Various N-F reagents reacted with hexamethylbenzene (1) forming side chain substituted alkoxides or esters in protic solvents, Ritter type side chain functionalization was observed in acetonitrile in the presence of trifluoroacetic acid, while in aqueous acetonitrile solution phenyl ring transformation took place, starting with ipso attack of water and further rearrangement of the methyl group as the main process. Rearranged 2,3,4,5,6,6-hexamethylcyclohexa-2,4-dienone (7) was transformed to 5-fluoro-2,3,5,6,6-pentamethyl-4-methylenecyclohex-2-en-1-one (8) or 5-hydroxy-2,3,5,6,6-pentamethyl-4-methylenecyclohex-2-en-1-one (9). 1,2,3,4,5,6-Hexamethyl-bicyclo[2.2.0]hexa-2,5-diene reacted with F-TEDA-BF4 in the presence of water and 7 was formed in high yield. Durene (12) followed similar ipso attack of water as 1, but on the other hand 1,2,3,4-tetramethylbenzene displayed different regioselectivity and 2,3,4,5-tetramethylphenol was formed, further transforming to 4-fluoro-2,3,4,5-tetramethylcyclohexa-2,5-dienone. The functionalizations of methylbenzenes obeyed a second-order rate equation v = d[N-F]/dt = k2[N-F][substrate], and DeltaG# values between 77 and 94 kJ/mol were determined. The presence of water did not significantly influence DeltaG# but considerably affected DeltaS# and positive values were found where methyl group migration was the dominant process (9.1 J/(mol K) for 1 and 0.5 J/(mol K) for 12). A higher reactivity of durene than mesitylene (k2(MES)/k2(DUR) = 0.23) was found, supporting the assumption that single electron transfer (SET) is the dominant process in the functionalizations of methyl-substituted benzene derivatives with F-TEDA-BF4.