|
| Phosphate passivation of lead and cadmium in soil and their leaching characteristics under simulated acid rain |
| Received:April 25, 2022 |
| View Full Text View/Add Comment Download reader |
| KeyWord:phosphate|passivate|acid rain leaching|lead|cadmium |
| Author Name | Affiliation | E-mail | | YAO Zhenhui | School of Environmental and Safety Engineering, Changzhou University, Changzhou 213164, China | | | ZHOU Huiping | School of Environmental and Safety Engineering, Changzhou University, Changzhou 213164, China
Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment, Nanjing 210042, China | zhouhp@cczu.edu.cn | | TU Lida | School of Environmental and Safety Engineering, Changzhou University, Changzhou 213164, China | | | PANG Zhongzheng | School of Environmental and Safety Engineering, Changzhou University, Changzhou 213164, China | |
|
| Hits: 819 |
| Download times: 750 |
| Abstract: |
| To explore the passivation effect of phosphate on soil lead（Pb）and cadmium（Cd）under different water conditions and the risk of heavy metal leaching caused by remediation under acid rain leaching, paddy soil contaminated by Cd and Pb surrounding a mining area in Tongling, Anhui Province was selected as the research object. The remediation effect of diammonium hydrogen phosphate（DAP）and tricalcium phosphate（TCP）on Cd and Pb under different amounts and soil water content was compared, and the effect of phosphorus containing passivator on Cd and Pb after application under simulated acid rain conditions was discussed. The results showed that the application of two kinds of phosphorus fertilizer could reduce available Cd and Pb in soil. DAP reduced the content of available Cd in soil by 41.87%-65.62%, and the content of available Pb by 38.83%-76.98%. Under TCP treatment, the content of available Cd and Pb decreased by 39.55%-56.17% and 37.52%-66.46% respectively. Under 75% maximum field capacity, available Cd content decreased by 21.22%（TCP）and 23.45%（DAP）; while available Pb content decreased by 14.22%（TCP）and 9.28%（DAP）, respectively. The fixation effect of phosphorus fertilizer on Cd and Pb decreased with an increase in the amount of acid rain leached. The average concentrations of Pb in the soil under two phosphorus fertilizer treatments were 47.23 mg·kg-1（DAP）and 53.21 mg·kg-1（TCP）, respectively, at a depth of 5-55 cm. The change rate of Pb content in the soil treated with phosphorus fertilizer under different acid rain conditions was 3.12%-13.53%. The research shows that DAP and TCP can effectively inactivate Cd and Pb in the soil under different application rates, and the passivation effect on Pb is better than that of Cd. Additionally, the passivation effect is positively related to the application rate. After the application of phosphorus fertilizer, the content of Cd and Pb in the 15-45 cm soil layer solution decreases significantly, and the content of Cd and Pb in the soil layer solution below 45 cm changes slightly. With an increasing in acid rain leaching, DAP reactivates Cd and Pb in the deep soil solution. Under strong acid rain conditions, phosphate fertilizers can effectively limit the migration of Cd and Pb in the soil at different depths, such that most of the Cd is fixed in the 0-15 cm soil layer, while the distribution of Pb in the soil at different depths is similar. |
|
|
|
