Kinetics and toxicological potential of heavy metal leaching from asphalt pavements

Fuliao Zou; Zhen Leng; Zhifei Tan; Danning Li; Meizhao Han; Guoyang Lu; Anand Sreeram

doi:10.1016/j.scitotenv.2023.169193

Kinetics and toxicological potential of heavy metal leaching from asphalt pavements

Sci Total Environ. 2024 Feb 20:912:169193. doi: 10.1016/j.scitotenv.2023.169193. Epub 2023 Dec 11.

Authors

Fuliao Zou¹, Zhen Leng², Zhifei Tan¹, Danning Li¹, Meizhao Han¹, Guoyang Lu³, Anand Sreeram⁴

Affiliations

¹ Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
² Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong; Research Centre for Resources Engineering towards Carbon Neutrality, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong. Electronic address: zhen.leng@polyu.edu.hk.
³ Department of Architecture and Civil Engineering, City University of Hong Kong, Kowloon Tong, Kowloon, Hong Kong.
⁴ Department of Engineering, University of Cambridge, Trumpington Street, Cambridge, United Kingdom; Nottingham Transportation Engineering Centre, Department of Civil Engineering, University of Nottingham, Nottingham, United Kingdom.

PMID: 38092218
DOI: 10.1016/j.scitotenv.2023.169193

Abstract

The leaching of heavy metals from asphalt pavement has attracted increasing attention due to its associated environmental risks. Comprehending the leaching process is crucial for ensuring the safe utilization of asphalt pavement. This study investigates heavy metal leaching kinetics from asphalt pavements using tank-leaching tests and dynamic simulations employing both first and second-order kinetic models. Furthermore, this study reveals the toxicological potential of heavy metal leaching from asphalt pavement by assessing its temporal metal accessibility based on the obtained kinetic attributes. Six distinct asphalt mixtures were prepared and tested, each exhibiting two different gradations. The findings demonstrated that both kinetic models effectively elucidated the leaching process. Notably, the relatively stable final leaching stages primarily adhered to first-order kinetics, while the second-order kinetics provided a superior description of the more intricate initial leaching stages. In terms of toxicological potential, the results indicated that recycled waste-incorporated asphalt pavements, specifically bottom ash-incorporated asphalt and asphalt rubber, exhibited excessive heavy metal leaching for varying durations, ranging from several days to months under specific conditions. This study has provided valuable insights into the metal leaching kinetics of asphalt pavements and their associated toxicological impact, significantly advancing the current understanding of the consequences of heavy metal leaching from asphalt pavements.

Keywords: Asphalt pavement; Kinetic modeling; Metal leaching; Toxicological potential.