It has not been well understood that the influences of pH and accompanying anions on the toxicity of selenate (Se(VI)). The influences of pH and major anions on Se(VI) toxicity to wheat root elongation were determined and modeled based on the biotic ligand model (BLM) and free ion activity model (FIAM) concepts. Results showed that EC50[Se(VI)]_T values increased from 162 to 251 μM as the pH values increased from 4.5 to 8.0, indicating that the pH increases alleviated the Se(VI) toxicity. The EC50{SeO₄²⁻} values increased from 133 to 203 μM while the EC50{HSeO₄⁻} values sharply decreased from 210 to 0.102 nM with the pH increasing from 4.5 to 8.0. The effect of pH on Se(VI) toxicity could be explained by the changes of Se(VI) species in different pH solutions as SeO₄²⁻ and HSeO₄⁻were differently toxic to wheat root elongation. The toxicity of Se(VI) decreased with the increasing activities of H₂PO₄⁻ and SO₄²⁻ but not for NO₃⁻ and Cl⁻ activities, indicating that only H₂PO₄⁻ and SO₄²⁻ had competitive effects with Se(VI) on the binding sites. An extended BLM was developed to consider effects of pH, phosphate and sulphate, and stability constants of SeO₄²⁻, HSeO₄⁻, H₂PO₄⁻ and SO₄²⁻ to the binding sites were obtained: log$K_{Se{O}_{4}BL}$ = 3.45, log$K_{HSe{O}_{4}BL}$ = 5.98, log$K_{H_{2}P{O}_{4}BL}$ = 2.05, log$K_{S{O}_{4}BL}$ = 1.85. Results implied that BLM performed much better than FIAM in the wheat root elongation prediction when coupling with toxic species SeO₄²⁻ and HSeO₄⁻, and the competitions of H₂PO₄⁻ and SO₄²⁻ for the binding sites while developing the Se(VI)-BLM.

尚未完全了解pH值和相关阴离子对硒酸盐（Se（VI））毒性的影响。基于生物配体模型（BLM）和自由离子活性模型（FIAM）的概念，确定并建模了pH和主要阴离子对Se（VI）对小麦根伸长的毒性的影响并进行了建模。结果表明，随着pH值从4.5升高到8.0，EC50 [Se（VI）] _T值从162增加到251μM，表明pH值增加减轻了Se（VI）的毒性。EC50 {SeO ₄ ^2- }值从133μM增加到203μM，而EC50 {HSeO ₄ ⁻}值从210急剧降低至0.102 nM，pH从4.5升高至8.0。（VI）在不同的pH的溶液作为物种的SeO pH对硒（VI）的毒性的影响可以通过Se构成的变化来解释₄ ^2-和HSeO ₄ ^-是对小麦根伸长不同的毒性。硒的毒性（VI）与H的增加活性下降₂ PO ₄ ^-和SO ₄ ^2-而不是NO ₃ ^-和Cl ^-的活动，这表明只有ħ ₂ PO ₄ ^-和SO ₄ ^2-与Se（VI）在结合位点上具有竞争作用。延长的BLM的开发是为了考虑pH值，磷酸盐和硫酸盐，和SEO的稳定常数的效果₄ ^2-，HSeO ₄ ^-，H ₂ PO ₄ ^-和SO ₄ ^2-，获得的结合位点：日志${ķ}_{\mathrm{小号}Ë{Ø}_4乙\mathrm{大号}}$ = 3.45，记录${ķ}_{H\mathrm{小号}Ë{Ø}_4乙\mathrm{大号}}$ = 5.98，记录${ķ}_{H_{2}P{Ø}_4乙\mathrm{大号}}$ = 2.05，记录${ķ}_{\mathrm{小号}{Ø}_4乙\mathrm{大号}}$ = 1.85。结果暗示，在BLM的小麦根伸长预测与联接时进行比FIAM好得多有毒物种的SeO ₄ ^2-和HSeO ₄ ^- ，和H的比赛₂ PO ₄ ^-和SO ₄ ^2-的结合位点在开发Se（VI）-BLM。