Effects of Sewage Sludge and Chemical Fertilizers on Pb and Cd

Background: Reprocessing of sewage sludge to agricultural land is preferred to disposal through landfill or incineration due to its potentially beneficial effects on soil fertility from organic matter and plant nutrients, such as N and P, present in the sludge. Therefore, this study was conducted to investigate the impact of sewage sludge and chemical fertilizers on Pb and Cd accumulation in fenugreek, Trigonella gracum. Methods: The experiment was carried out in earthen pots, 30 cm in diameter and 30 cm in depth. The study was done on five groups- control, S1: sewage sludge (50 tone/ha), S2: sew-age sludge (50 tone/ha)+heavy metals [85 ppm of Cd(Cl)2; 840 ppm of Pb(NO3)2], F1: chemi-cal fertilizer (250 kg/ha), and F2: chemical fertilizer (250 kg/ha)+ heavy metals [85 ppm of Cd(Cl)2; 840 ppm of Pb(NO3)2]- in three replicates. Results: The results showed that total Pb concentrations ranged from 0.05 to 2 mg/kg, with the maximum level in the sewage sludge treatment (S2) while Cd concentrations in the plant ranged from 0.07 to 1.1 mg/kg with the maximum content in the chemical fertilizer treatment (F2). The concentrations of Pb and Cd in vegetables were significantly higher than the permis-sible limits. Conclusion: This study highlights the potential risks involved in the cultivation and consump-tion of vegetables on plots irrigated with sewage sludge, a practice which may endanger the health of urban populations that consume these vegetables.