Waste as a potential source of heavy metals in vegetables

Human activities such as agriculture, traffic, industry, discharge of wastewater as well as inadequate waste disposal negatively influence the environment in which significant amounts of heavy metals have been introduced. Since plants have the ability to accumulate heavy metals from the environment with larger or smaller extent, there is possibility that vegetables we eat, due to pollution of soil where it was cultivated, contains heavy metals in concentration which exceeds prescribed limits. In this work heavy metals were analysed in common vegetable species obtained in northern- west part of Croatia, such as: red and white potato, onion, carrot, bean, lettuce and cabbage. From every species of vegetables four samples were collected. The following heavy metals were determined: arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), manganese (Mn), mercury (Hg), nickel (Ni) and zinc (Zn). For determination of heavy metals atomic absorption spectrometry was used. The results have shown that from 28 collected samples, in five of them the excess of maximal allowed values of heavy metals prescribed by Ordinance on maximal allowed concentrations of particular contaminants in food (OG 146/12) was observed. From the mentioned five samples in each of them the excessive values for lead (two samples of red potato, two samples of bean and one sample of carrot) were recorded, and in one the excessive value for cadmium (a sample of red potato) was recorded. The pollution present in vegetables is probably the result of pesticide and mineral fertilizers use in agricultural production. Beside that the pollution might have the origin in disposed waste, floods, traffic and other sources of pollution located nearby.