The Identification of Cadmium Pollution in Arable Land and the Selection of Soil Amendments and Vegetable Cultivars to Remediate Cadmium Contamination of Vegetables in Yangtze River Delta

This study collected 274 soil samples and 188 soil-crop paired samples in moderately Cd contaminated farmland dominated by vegetables in suburbs of Yangtze River Delta. In addition, this study conducted field trials of soil amendment and cultivar selection using Luhao as the target crop. The mean Cd concentrations of soils and various crops were 0.29 mg kg -1 and 66.1 μg kg -1 , respectively, and the Cd concentration in soils and crops exceeded their respective thresholds were 23.7% and 3.7%. Cadmium concentration of Luhao was 101.8 μg kg -1 , and 6.8% of samples exceeded the threshold, with Cd-contaminated to the greatest extent compared to other crops. The Cd concentration across all crops and Luhao decreased by increased soil pH rather than by decreased soil Cd concentration. Three combinations, i.e. lime and sodium sulfide, lime with sodium sulfide and mushroom residue, and lime with sodium sulfide and cow manure, were efficient to remediate Cd pollution in Luhao in an acidic soil, indicated by the decreased concentration of soil CaCl 2 extractable Cd by 22.1-25.0%, and Cd concentration in Luhao by 31.6-33.2%. Cadmium concentration in edible portions of either green or Kunming Luhao were 21.7% and 34.7%, less than red Luhao when grown in an acidic soil. However, the same trend was not observed when Luhao grown in a neutral soil. The amendments of lime and organic fertilizer jointly decreased Cd concentration in Luhao by 50.5%, increased soil pH by 12.3%, and increased the yield by 51.5% when applied at a large scale, i.e. 200 ha. In conclusion, soil pH was the critical factor to remediate crop Cd pollution, and that the amendments of lime and organic matter, and Green Luhao and Kunming Luhao of lower Cd accumulation were critical and emergent strategies to remediate Cd pollution in vegetables