Department of Chemistry, Tshwane University of Technology, Arcadia 0001, Pretoria, Republic of South Africa. ndibewup@ tut.ac.za
J Toxicol Environ Health A. 2010;73(4):261-71. doi: 10.1080/15287390903249164.
The objective of this study was to (1) measure the concentration of four anions (Cl(-), F(-), [image omitted], and [image omitted]) and nine other elements (Al, Ba, Ca, K, Mg, Mn, Fe, Ni, and Si) in two nontraditional biopolymeric chemical stabilizers (EBCS1 and EBCS2), (2) investigate consequent environmental toxicity risk implications, and (3) create awareness regarding environmental health issues associated with metal concentration levels in enzyme-based chemical stabilizers that are now gaining widespread application in road construction and other concrete materials. Potential ecotoxicity impacts were studied on aqueous extracts of EBCS1 and EBCS2 using two thermodynamic properties models: the Pitzer-Mayorga model (calculation of the electrolyte activity coefficients) and the Millero-Pitzer model (calculation of the ionic activity coefficients). Results showed not only high concentrations of a variety of metal ions and inorganic anions, but also a significant variation between two chemical stabilizing mixtures. The mixture (EBCS2) with the lower pH value was richer in all the cationic and anionic species than (EBCS1). Sulfate (SO(2-)(4)) concentrations were found to be higher in EBCS2 than in EBCS1. There was no correlation between electrolyte activity and presence of the ionic species, which may be linked to a possible high ionic environmental activity. The concentrations of trace metals found (Mn, Fe, and Ni) were low compared to those of earth metals (Ba, Ca, K, and Mg). The metal concentrations were higher in EBCS1 than in EBCS2. Data suggest that specific studies are needed to establish "zero" permissible metal ecotoxicity values for elements and anions in any such strong polyelectrolytic enzyme-based chemical stabilizers.
（1）测量两种非传统生物聚合化学稳定剂（EBCS1 和 EBCS2）中四种阴离子（Cl(-)、F(-)、[图像省略]和[图像省略]）和其他九种元素（Al、Ba、Ca、K、Mg、Mn、Fe、Ni 和 Si）的浓度；（2）调查由此产生的环境毒性风险的影响；（3）使人们意识到与酶基化学稳定剂中金属浓度水平相关的环境健康问题，这些稳定剂目前在道路建设和其他混凝土材料中得到了广泛应用。使用两种热力学性质模型：Pitzer-Mayorga 模型（电解质活度系数的计算）和 Millero-Pitzer 模型（离子活度系数的计算），研究了 EBCS1 和 EBCS2 的水提取物的潜在生态毒性影响。结果不仅显示了各种金属离子和无机阴离子的高浓度，而且还显示了两种化学稳定剂混合物之间的显著差异。pH 值较低的混合物（EBCS2）比（EBCS1）含有更多的阳离子和阴离子。EBCS2 中的硫酸盐（SO(2-)(4)）浓度高于 EBCS1。电解质活度与离子物种的存在之间没有相关性，这可能与可能的高离子环境活性有关。与地球金属（Ba、Ca、K 和 Mg）相比，发现的痕量金属（Mn、Fe 和 Ni）浓度较低。EBCS1 中的金属浓度高于 EBCS2。数据表明，需要进行特定研究，为任何此类强聚电解质酶基化学稳定剂中的元素和阴离子建立“零”可允许的金属生态毒性值。
