Guangdong-Hongkong-Macao Joint Laboratory of Collaborative Innovation for Environmental Quality, Macao Environmental Research Institute, Macau University of Science and Technology, Macao 999078, China; National Observation and Research Station of Coastal Ecological Environments in Macao, Macau University of Science and Technology, Macao 999078, China.
Guangdong-Hongkong-Macao Joint Laboratory of Collaborative Innovation for Environmental Quality, Macao Environmental Research Institute, Macau University of Science and Technology, Macao 999078, China; National Observation and Research Station of Coastal Ecological Environments in Macao, Macau University of Science and Technology, Macao 999078, China.
J Hazard Mater. 2022 May 15;430:128430. doi: 10.1016/j.jhazmat.2022.128430. Epub 2022 Feb 4.
There is uncertainty in quantifying the toxic effects of total chromium (Cr) in the environment by modeling the toxicity of individual Cr(III) or Cr(VI). In the present study, the effects of Cr(III) and Cr(VI) on barley root elongation were investigated in a hydroponic system where Cr(III) and Cr(VI) combination dose-response experiments under monotoxicity concentration, single-dose addition, and fixed concentration ratios were designed to identify and quantify their combined phytotoxicity of one element with various valences. The results show that the calculated mixed toxicity unit values for 50% inhibition (TU) ranged from 1.06 to 1.45, indicating the weak antagonism effects of Cr(III) and Cr(VI) on barley root toxicity. Also, the single-dose group experiment has proved that the EC of Cr(VI) was increased from 71.2 μM to 119.9 μM with Cr(III) addition, which suggested that Cr(III) has antagonism on the toxicity of Cr(VI). While EC of Cr(III) was not affected by Cr(VI) addition. After introducing the expansion coefficient of Cr(III) on Cr(VI) toxicity, both the extended concentration addition model (e-CA) based on the log-logistic and Weibull equations and the extended independent action model (e-IA) could more accurately predict the barley root elongation under Cr(III) and Cr(VI) interaction. The e-CA model based on the Weibull equation had almost the best correlation coefficient (R) and lowest root mean square error (RMSE) between the measured and predicted values. Finally, the combined toxicity and antagonism of the same element with co-existing different valences simultaneously were successfully and firstly identified and quantified in the present study.
在环境中定量评估总铬（Cr）的毒性效应时，通过对单个 Cr(III) 或 Cr(VI) 的毒性建模存在不确定性。在本研究中，在水培系统中研究了 Cr(III) 和 Cr(VI) 对大麦根伸长的影响，其中设计了 Cr(III) 和 Cr(VI) 组合剂量反应实验，在单毒性浓度、单一剂量添加和固定浓度比下，以确定和量化不同价态的一种元素的混合植物毒性。结果表明，50%抑制（TU）的计算混合毒性单位值范围为 1.06 至 1.45，表明 Cr(III) 和 Cr(VI) 对大麦根毒性的弱拮抗作用。此外，单剂量组实验证明，Cr(III) 的添加使 Cr(VI) 的 EC 从 71.2 μM 增加到 119.9 μM，表明 Cr(III) 对 Cr(VI) 的毒性具有拮抗作用。而 Cr(III) 的 EC 不受 Cr(VI) 添加的影响。引入 Cr(III) 对 Cr(VI) 毒性的扩展系数后，基于对数逻辑和威布尔方程的扩展浓度加和模型（e-CA）和扩展独立作用模型（e-IA）都可以更准确地预测 Cr(III) 和 Cr(VI) 相互作用下的大麦根伸长。基于威布尔方程的 e-CA 模型具有几乎最佳的相关系数（R）和最低的实测值和预测值之间的均方根误差（RMSE）。最后，本研究首次成功地识别和量化了具有共存不同价态的同种元素的联合毒性和拮抗作用。
