Olajire A A, Oluyemi E A, Ayodele E T, Fawole O O
Department of Pure and Applied Chemistry, Ladoke Akintola University of Technology, Ogbomoso, Nigeria.
Int J Environ Health Res. 2005 Apr;15(2):151-8. doi: 10.1080/09603120500061997.
The potential risk of soil, surface and ground water contamination by trace metals leached from highway construction solid wastes is a major environmental concern. The objectives of this study were to evaluate trace metal leachability, toxicity of the leachate to aquatic organism and environmental impacts of highway construction solid waste (HCSW). Potential leachability, defined as the maximum metal pool that may become available for leaching at a constant pH 4 decreased in the following order: Zn > Ni > As > Pb > Cu. Potential metal leachability was controlled mainly by solid phase distribution of metals in wastes. The kinetics of metal release were determined using the cascade leaching test (CLT) with water at pH 4. With the exception of zinc in the first fraction, metal concentrations in all consecutive leaching fractions remained below the maximum permissible level in water for human consumption. The result of toxicity test showed that the leachates were in concentrations that did not exceed toxic concentrations for aquatic toxicity tests. The results indicate low risk of surface and ground water contamination resulting from highway construction solid wastes.
公路建设固体废物中微量金属的浸出对土壤、地表水和地下水造成污染的潜在风险是一个重大的环境问题。本研究的目的是评估微量金属的浸出性、浸出液对水生生物的毒性以及公路建设固体废物（HCSW）对环境的影响。潜在浸出性定义为在恒定pH值为4时可能用于浸出的最大金属量，其顺序为：锌>镍>砷>铅>铜。潜在金属浸出性主要受废物中金属的固相分布控制。使用pH值为4的水通过级联浸出试验（CLT）确定金属释放动力学。除了第一部分中的锌外，所有连续浸出部分中的金属浓度均低于人类饮用水中允许的最大水平。毒性试验结果表明，浸出液的浓度未超过水生毒性试验的有毒浓度。结果表明公路建设固体废物对地表水和地下水造成污染的风险较低。
