Ding Fenghua, Wang Guo, Liu Shuxin, He Zhenli L
Institute of Ecology, Lishui University, Lishui, Zhejiang 323000, China.
Department of Resources and Environmental Sciences, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China.
Heliyon. 2023 Sep 6;9(9):e19905. doi: 10.1016/j.heliyon.2023.e19905. eCollection 2023 Sep.
Arsenic (As) toxicity threshold values (TTVs) for plants are fundamental to both establishing regional As reference values in soil and performing risk assessment. However, TTVs vary with plant species and soil types. In this study, a hydroponic experiment with 16 plant species was conducted to screen the most As-sensitive plant species. The results showed that the EC (available As concentration at which shoot biomass or height is inhibited by 20%) values were 1.38-104.4 mg L for shoot height and 0.24-42.87 mg L for shoot fresh biomass. Rice was more sensitive to As toxicity than the other species. Therefore, it was chosen as the ecological receptor in the pot experiment on As phytotoxicity in nine types of soils collected from Fujian Province in South China. The EC and EC with respect to rice shoot height were 3.72-29.11 mg kg and 7.12-45.60 mg kg, respectively. Stepwise regression analysis indicated that free iron oxide concentration is the major factor that affects As bioavailability in soil, and EC ( = 10, 20, and 50) of soil available As for shoot height was positively related to free iron oxide concentration in soil. In addition, soil cation exchange capacity, clay (<0.002 mm) content, and exchangeable magnesium content are also important factors influencing As phytotoxicity in acidic soils. The regression models can be used to predict As phytotoxicity in acidic soils.
植物的砷（As）毒性阈值（TTVs）对于确定土壤中的区域As参考值和进行风险评估都至关重要。然而，TTVs因植物种类和土壤类型而异。在本研究中，进行了一项针对16种植物的水培实验，以筛选对As最敏感的植物种类。结果表明，对于地上部高度，EC（地上部生物量或高度被抑制20%时的有效As浓度）值为1.38 - 104.4 mg/L，对于地上部鲜生物量，EC值为0.24 - 42.87 mg/L。水稻对As毒性比其他物种更敏感。因此，在从中国南方福建省采集的9种土壤上进行的As植物毒性盆栽实验中，选择水稻作为生态受体。水稻地上部高度的EC和EC分别为3.72 - 29.11 mg/kg和7.12 - 45.60 mg/kg。逐步回归分析表明，游离氧化铁浓度是影响土壤中As生物有效性的主要因素，土壤有效As对于地上部高度的EC（ = 10、20和50）与土壤中游离氧化铁浓度呈正相关。此外，土壤阳离子交换容量、黏土（<0.002 mm）含量和交换性镁含量也是影响酸性土壤中As植物毒性的重要因素。这些回归模型可用于预测酸性土壤中的As植物毒性。
