Departamento de Química Analítica, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510, México, D.F., Mexico.
Departamento de Química Analítica, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510, México, D.F., Mexico.
Chemosphere. 2017 Mar;171:435-445. doi: 10.1016/j.chemosphere.2016.12.083. Epub 2016 Dec 19.
The environmental bioavailability of zinc (II), i.e., the uptake of the element by an organism, was determined using two microalgae species, Scenedesmus acutus and Pseudokirchneriella subcapitata, and estimated using hollow fiber supported liquid membrane (HF-SLM) device as the chemical surrogate. Several experimental conditions were studied including the presence of organic matter, inorganic anions and concomitant cations and pH. The results show strong positive correlation coefficients between the responses given by the HF-SLM and the microalgae species (r = 0.900 for S. acutus and r = 0.876 for P. subcapitata) in multivariate environments (changes in pH, calcium, humic and citrate concentrations). The maximum amount of zinc (II) retained by the HF-SLM (4.7 × 10 mol/cm) was higher than those for P. subcapitata and S. acutus (9.4 × 10 mol/cm and 6.2 × 10 mol/cm, respectively). The variation in pH (pH 5.5-9) was the variable with the greatest effect on zinc internalization in all systems, increasing approximately 2.5 times for P. subcapitata and 5.5 times for S. acutus respect to pH = 5.5, while the presence of humic acids did not affect the response. The species' concentration analysis of the experimental design at pH = 5.5 indicated that the amount of internalized zinc (II) by the HF-SLM and both microalgae species is strongly dependent on the free zinc concentration (r = 0.910 for the HF-SLM, r = 0.922 for S. acutus and r = 0.954 for P. subcapitata); however, at pH = 9.0, the amount of internalized zinc (II) is strongly dependent on the sum of free zinc and labile species (r = 0.912 for the HF-SLM, r = 0.947 for S. acutus and r = 0.900 for P. subcapitata). The presence of inorganic ligands (chloride, sulfate, phosphate, carbonate, and nitrate) and metal ions (cobalt (II), copper (II), nickel (II), chromium (VI), lead (II) and cadmium (II)) produced different behaviors both in the chemical surrogate and the biological references. The results showed that the synthetic device can mimic biological uptake in the presence of humic acids, nitrate, sulfate, and phosphate, and pH within the range 5.5-9 when S. acutus was used as the biological reference, considering the simultaneous contribution of the Zn and ZnOH labile species depending on the chemical composition of the medium.
采用两种微藻（Scenedesmus acutus 和 Pseudokirchneriella subcapitata），利用中空纤维支撑液膜（HF-SLM）装置作为化学替代物，测定锌（II）的环境生物有效性（即元素被生物体吸收的情况）。研究了几种实验条件，包括有机物、无机阴离子和伴随的阳离子以及 pH 的存在。结果表明，在多变量环境下（pH、钙、腐殖质和柠檬酸盐浓度变化），HF-SLM 与微藻物种（S. acutus 的 r=0.900 和 P. subcapitata 的 r=0.876）之间的响应呈强正相关系数。HF-SLM 保留的最大锌（II）量（4.7×10-5mol/cm）高于 P. subcapitata 和 S. acutus 的最大量（分别为 9.4×10-5mol/cm 和 6.2×10-5mol/cm）。pH（pH 5.5-9）的变化是所有系统中对内化锌影响最大的变量，与 pH=5.5 相比，P. subcapitata 增加了约 2.5 倍，S. acutus 增加了 5.5 倍，而腐殖酸的存在并不影响响应。在 pH=5.5 下的实验设计的物种浓度分析表明，HF-SLM 和两种微藻物种内化的锌（II）量强烈依赖于游离锌浓度（HF-SLM 的 r=0.910，S. acutus 的 r=0.922 和 P. subcapitata 的 r=0.954）；然而，在 pH=9.0 时，内化的锌（II）量强烈依赖于游离锌和可利用物种的总和（HF-SLM 的 r=0.912，S. acutus 的 r=0.947 和 P. subcapitata 的 r=0.900）。无机配体（氯、硫酸盐、磷酸盐、碳酸盐和硝酸盐）和金属离子（钴（II）、铜（II）、镍（II）、铬（VI）、铅（II）和镉（II））在化学替代物和生物参考物中均产生了不同的行为。结果表明，当使用 S. acutus 作为生物参考物时，在 pH 5.5-9 范围内，在存在腐殖酸、硝酸盐、硫酸盐和磷酸盐的情况下，以及在 pH 范围内，合成装置可以模拟生物吸收，同时考虑到根据介质的化学成分，Zn 和 ZnOH 可利用物种的同时贡献。
