Determination of Lead, Cadmium, and Persistent Organic Pollutants in Wild and Orchard-Farm-Grown Fruit in Northeastern Poland

Abstract

The concentrations of the heavy metals lead (Pb) and cadmium (Cd) were determined in berries (blackberry, raspberry, bilberry, wild strawberry), and hazelnuts picked from plants in the wild as well as in fruit (blackberry, raspberry, blueberry) and hazelnuts picked from orchard-farmed plants in northeastern Poland. The levels of seven congeners of polychlorinated biphenyls (PCB₇), γ isomer of hexachlorocyclohexane (γ-HCH), and sum of dichlorodiphenyl trichloroethane and its metabolites (ΣDDT) were also measured in plants and nuts. In addition, the concentrations of Pb, Cd, PCB_7, γ-HCH, and ΣDDT were determined in the surface samples of soil from the sites of fruit picking. The highest acceptable concentrations based upon Polish standards for Pb and Cd were not exceeded in forest fruit. In wild berries, Pb occurred at a level below the detection limit, whereas the concentration of Cd ranged from 6 to 49 μg/kg fresh weight. The levels were Cd 72 μg/kg fresh weight and Pb 290 μg/kg fresh weight in raspberries from orchard plants and exceeded the maximal acceptable limit of 50 μg/kg for Cd and 200 μg/kg for Pb. The level of Pb at 210 μg/kg fresh weight in hazelnuts from orchard plants also exceeded maximal acceptable limits. Individual samples of fruit, regardless of their origin, were found to contain trace amounts of organic pollutants such as 1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene (p,p'–DDE) and PCB congeners 101 and 118. All soil samples contained from 3.2 to 14.9 mg/kg dry weight concentrations of Pb and most soil samples also contained Cd. Further, individual soil samples were found to contain high levels of ΣDDT (145 μg/kg), including p,p'-DDT at a concentration of 67 μg/kg. The concentrations of persistent organic pollutants (POP) in wild and orchard-farm-grown fruit in northeastern Poland were generally below threshold permissible limits, and no correlation was found between levels of contaminants in soils and POP concentrations in fruit.

This work was supported by funds from the Polish Ministry of Science and Higher Education (grants BST 0704-806 and 0706-802).