RESUMEN
Phosphorus (P) plays an important role in immobilizing heavy metals (HMs), thereby preventing their accumulation, especially in edible parts of crops. In this study, vermicompost (VM) and chemical fertilizers (CFs) were used as soil amendments to increase the available P concentration in soil contaminated with cadmium (Cd) and nickel (Ni), with the aim of reducing their bioavailability, uptake, and bioaccessibility. Using CF and VM as soil amendments substantially increased the available P and exchangeable potassium concentrations in the soil. Furthermore, VM addition led to an increase in OM content and in exchangeable calcium and magnesium, resulting in the improved growth of lettuce. It also reduced the uptake of Cd and Ni in the two lettuce cultivars tested in the study. However, CF addition boosted the accumulation of Cd and Ni by increasing the soil acidity. CF addition, and especially VM addition, altered the chemical forms of Cd and Ni from active to inactive. Overall, the results of this study underscore the positive impact of using VM as a soil amendment on lettuce growth and the prevention of HM accumulation in edible parts of lettuce. VM addition led to decreased bioavailability, uptake, and bioaccessibility of HMs in soil, which could improve food safety and reduce potential risks associated with HM contamination.
Asunto(s)
Disponibilidad Biológica , Lactuca , Metales Pesados , Fósforo , Contaminantes del Suelo , Suelo , Contaminantes del Suelo/metabolismo , Lactuca/metabolismo , Lactuca/crecimiento & desarrollo , Suelo/química , Fertilizantes , Cadmio/metabolismo , Níquel , Compostaje/métodosRESUMEN
(1) Background: Trace metal (TM) contamination of farmland soil in Taiwan occurs because factories dump wastewater into irrigation ditches. Since vermicompost affects the bioavailability of TMs, the objective of this study was to evaluate its effects on the accumulation of growth of TMs in leafy vegetables. (2) Methods: Two TM-contaminated soils and different types of pak choi and lettuce were used and amended with vermicompost. Besides soil properties, the study assessed vermicompost's influence on the growth, accumulation, and chemical forms of TMs and on the health risks posed by oral intake. (3) Results: Vermicompost could increase the content of soil organic matter, available phosphorus, exchangeable magnesium, and exchangeable potassium, thus promoting the growth of leafy vegetables. The accumulation of four TMs in crops under vermicompost was reduced compared to the control, especially for the concentration of cadmium, which decreased by 60-75%. The vermicompost's influence on changing the chemical form of TMs depended on the TM concentrations, type of TM, and crop species; moreover, blanching effectively reduced the concentrations of TMs in high-mobility chemical forms. Although vermicompost mostly reduced the amount of cadmium consumed via oral intake, cadmium still posed the highest health risk compared to the other three TMs.
Asunto(s)
Metales Pesados , Contaminantes del Suelo , Cadmio/análisis , Metales Pesados/análisis , Suelo , Contaminantes del Suelo/análisis , Taiwán , VerdurasRESUMEN
(1) Background: Even in croplands with a low concentration of cadmium (Cd), there is still a risk for planting crops because of the high accumulation capacity of some leafy vegetables. (2) Methods: In this study, water spinach was planted in four main soil series (Wa, Eh, Tk, and Yu) in central Taiwan, which were spiked with Cd. The soil available phosphorous content was increased to 10-17 mg/kg, and the accumulation and developed chemical forms of Cd were analyzed. (3) Results: The experimental results showed that addition of phosphorous to Wa and Eh promoted the growth of water spinach. Accumulation and upward translocation of Cd were also increased in the phosphorus treatment compared with the control. The addition of phosphorus increased the percentage of Cd compartmentalized in undissolved Cd phosphate, which revealed that the mobility and toxicity of Cd were reduced in the phosphorus treatment. However, most of the water spinach was not edible because the vegetable-induced hazard quotient, which was calculated using three methods, showed hazardous potential in general.