Cadmium Accumulation in Soil and in Some Vegetable Crops induced by Phosphate Fertilizer

Abstract

To evaluate the impact of four levels of phosphorus fertilizer on cadmium (Cd) accumulation in soil and in the vegetative parts of tomato (Lycopersicum esculentum L.), lettuce (Lactuca sativa L.) and radish (Raphanus sativus L.), three field experiments using loamy sandy soil, in West Al-Nubaria area, Abu-El-Atta Village, were conducted in 2004 and 2005 winter seasons. The levels of triple superphosphate fertilizer (45-47% P 2 O 5 ) used were 0, 100, 200, and 300 kg P 2 O 5 /fed (fed = fedan =4200 m 2 ). Different rates of triple super-phosphate had significant effects on Cd concentration in the plant tissues of the three studied crops. Phosphate increased Cd accumulation in plant parts, with more evident effect with the highest rate. The range of Cd concentration in tomato fruit juice (0.08-0.12 mg kg -1 ) was higher than that in tomato fruit flesh (0.009-0.020 mg kg -1 ). Cd concentration in radish ranged between 0.65-0.76 mg kg -1 which was higher than that in lettuce 0.12 -0.24 mg kg -1 or in tomato fruits ( 0.100 -0.176 mg kg -1 ) at the applied levels of phosphate fertilizer. In lettuce plants, the Cd concentration in root was higher than that of shoots while the opposite was found in radish plants. Soil available cadmium and phosphorus levels after harvest increased significantly with increasing application rates of phosphorus in the three experiments.The application of phosphate fertilizer, although it had notable benefits to soil fertility, it was associated with possible negative effects due to increased P availability and Cd accumulation which affect both soil water quality and soil ecology.