連續施用鎘砷同步鈍化劑的稻米鎘砷含量降低效果分析?

摘 要：選擇湖南典型鎘砷復合污染稻田，通過2018—2020年連續3 a的大田定位試驗對10個鎘砷同步鈍化產品進行效果驗證，為鎘砷同步鈍化產品連續施用的持續效果及鎘砷復合污染稻田產品的選擇提供參考。結果表明：10個鈍化劑產品均具有同步降低稻米鎘砷含量的效果，但不同鈍化劑的稻米降鎘、降砷效果不同，稻米降鎘效果最好的是T9處理，3 a平均稻米降鎘率為52.42%；其次是T4和T3，3 a平均稻米降鎘率分別為42.62%和40.96%；稻米降砷效果較好的為T7和T4處理，3 a平均稻米降砷率分別為34.15%和33.32%；整體上，鈍化劑降低稻米鎘含量的效果高于降砷的效果，且鈍化劑的連續施用對稻米降鎘和降砷皆具有一定的累加效應；另外，連續施用3 a鈍化劑在一定程度上提升了土壤的pH值，且2018—2020年稻米鎘含量皆與土壤pH值呈顯著負相關，表明施用鈍化劑提升了土壤pH值，并抑制了水稻對鎘的吸收積累。綜合考慮認為，T4、T8、T7和T10處理的鈍化劑產品適用于鎘砷復合污染土壤的修復治理，T9等其他處理的鈍化劑產品適用于單鎘污染耕地的修復治理。

關鍵詞：鎘；砷；鎘砷同步鈍化劑；水稻；重金屬污染耕地修復

中圖分類號：S511；X829 文獻標識碼：A 文章編號：1006-060X（2023）06-0043-06

Abstract：Typical Cd-As co-contaminated paddy soil in Hunan Province， in this study， was chosen to verify the continued application efficacy of 10 kinds of Cd-As synchronous passivation products through a three-consecutive-year field experiment from 2018 to 2020， thus providing reference for selecting optimum products to remediate Cd-As co-contaminated paddy soil. The results illustrated that the 10 kinds of Cd-As synchronous passivation products all could decrease Cd and As concentration in rice grain， however， the reduction efficacy of different Cd-As synchronous passivation products was dissimilar; compared to CK， T9 displayed the most remarkable Cd reductive efficacy in rice grain during the three years （52.42% on average）， followed by T4 （42.62%） and T3 （40.96%）. T7 and T4 led to the largest diminution of As in rice grain， averagely reaching 34.15% and 33.32%， respectively. On the whole， the achievement of Cd-As synchronous passivation products on reducing rice grain Cd concentration was better than on As， moreover， with three years of continuous application of Cd-As synchronous passivation products， a certain cumulative effect on decreasing Cd and As in rice grain emerged. Furthermore， the three years of continuous application increased the soil pH to a certain extent， and the Cd content in rice grain presented a significantly negative correlation with the soil pH from 2018 to 2020， indicating that the application of passivators increased the soil pH and inhibited the absorption and accumulation of Cd by rice grain. All the results suggested T4， T8， T7 and T10 were suitable for remediating Cd-As co-contaminated paddy soil， while T9 and other passivation products were appropriate for the treatment of Cd alone contaminated paddy soil.

Key words：cadmium; arsenic; Cd-As synchronous passivator; rice; remediation of heavy mental contaminated farmland

鎘砷復合污染是我國南方稻田重金屬污染的主要形式[1]，由于鎘砷相反的化學行為特征以及水稻對鎘砷吸收積累的差異[2]，淹水或施用石灰等農田降鎘技術往往引起水稻對砷的積累[3]，從而在鎘砷復合污染稻田的修復治理過程中顧此失彼[4-5]。施用鎘砷同步鈍化劑是當前鎘砷復合污染稻田修復治理最有效的方法。……