Abstract
Due to the presence of heavy metals in sewage sludge, their use for the fertilization of vegetables is of environmental and health significance. The objective was to investigate the non-carcinogenic and carcinogenic indices of lead (Pb), for children and adults, in the greenhouse vegetables fertilized with sewage sludge. The experiment was a factorial with three replicates, in which five levels of sewage sludge (0 (L1), 1.5 (L2), 3.0 (L3), 4.5 (L4) and 6% (L5)) were tested on spring onion (Allium fistulosum L.), radish (Raphanus satvius L.), cress (Lepidium sativum L.), basil (Ocimum basilicum), purslanes (Portulaca sp.), and summer savory (Satureja sp.). The effects of sewage sludge, vegetable type, and their interaction significantly affected the morphological properties of vegetables, average daily doses (ADD), hazard quotient (HQ), and cancer risk (CR) (P ≤ 0.01) in both children and adults. The highest and the least ADD was resulted by cress and savory. The L3 level increased HQ by 32% compared with control, which is five times higher than the safety level. Cress had the highest CR for children (0.0115) and adults (0.0037). According to the results the occurrence of cancer, which was likely for both children and adults, due to the consumption of vegetables, fertilized with sewage sludge, was three times higher for children. If the use of sewage sludge is desirable for the production of agricultural and horticultural crops, finding methods, which may decrease the concentration of heavy metals in sewage sludge is of outmost significance.