Effect of various enhancers on the bioavailability of heavy metals and their accumulation in lettuce (Lactuca sativa L.)

Nikolai Dinev, Vesselin Kutev, Mariana Hristova, Ivanka Mitova, Ana Katzarova

Abstract: A vegetation experiment was carried out. Various ameliorants (manure water extract, modified zeolite, mineral fertilizers, mineral fertilizers plus straw or mineral fertilizers plus natural zeolite) applied to contaminated soil from the area of Kremikovtzi steel plant on lettuce growth were tested. Ameliorants have a specific effect on the changes of soil toxicity. It was found that although in low concentrations, cadmium has the maximum negative impact on the sanitary qualities of the lettuce biomass. It was confirmed high mobility of cadmium ions and their easy migration into the aboveground parts. This explains the lack of positive effect from the application of various ameliorants. The uniform content of cadmium in the aboveground part is also impressive. The results of metal extraction with EDTA show a high degree (twice) of extraction of all elements in the variants with mineral fertilizers and straw or zeolite. BCR sequential distributed of the order of bioavailability Cd> Zn> Cu> Pb, as the most mobile and accessible element for plants is cadmium. These effects are not duplicated in the recalculation of heavy metal exports in plant biomass, where the yield obtained has a significant impact. It is highest in the variants with application of mineral fertilizers and especially in the application of mineral fertilizers plus straw.

Keywords: contaminated soil; food safety; heavy metals; risk assessment

Date published: 2021-09-03