Concentration of potentially toxic elements in various berries grown in allotment gardens of Riga city, Latvia

Concentration of trace and major elements is an important indicator of nutritional value of food, also regarding cultivated food crops like fruits, berries, and vegetables. Concentration of elements differs regionally and is influenced by various factors. Nevertheless, some chemical elements (As, Cd, Hg, Ni, Pb, Zn, etc.) are known as environmental pollutants and may affect the quality and safety of crops and food products. The aim of the study was to determine the concentration of potentially toxic elements like Cd, Cr, Cu, Fe, Ni, Pb, and Zn in samples of berries grown in allotment gardens of Riga city. Dried and homogenised samples of raspberries, strawberries, red currants, black currants, gooseberries, and cherries were mineralised in a solution of concentrated HNO₃/H₂O₂ by heating on a thermoblock. Quantitative analysis of sample solutions was performed using atomic absorption spectroscopy. Potentially toxic elements were in concentrations as follows: Fe > Zn > Cu > Ni > Pb > Cr > Cd. Mean concentrations of the elements of the major concern were: Ni 0.54 mg/kg, Pb 0.20 mg/kg, Cr 0.10 mg/kg, and Cd 0.03 mg/kg. Results indicated significant variability of element concentration among the species.