New perspective on human health risk from polycyclic aromatic hydrocarbons (PAHs) on surfaces of structures and buildings for industrial legacy before and after remediation

Abstract

Industrial legacies are gradually becoming an important asset for urban regeneration. Coking plants, as one of the important industrial legacies, emit large amounts of polycyclic aromatic hydrocarbons (PAHs) in production, and the health risks of PAHs in the atmosphere and soil around coking plants have been fully recognized, but not much attention has been paid to the health risks of PAHs adsorbed on the surfaces of buildings. Therefore, we evaluated the health risks of PAHs adsorbed on the surfaces of buildings before and after the remediation and relocation of a legacy coking plant in China. Remediation was done in three steps: (1) mechanical grinding, (2) high-pressure blasting, and (3) surfactant washing. The concentration of total PAHs and the distribution of PAHs before remediation were different for each structure. The average total PAHs concentration before remediation was found to be between 0.16 mg m−2 and 329.77 mg m−2. The risk posed by the PAHs concentrations before and after remediation in each structure was quantified. For workers, surrounding residents, and tourists, the calculated carcinogenic risk ranged from 1.08 × 10−6 to 6.84 × 10−4, 9.00 × 10−6 to 4.89 × 10−3, and 7.44 × 10−6 to 3.22 × 10−3, respectively. After remediation, total PAHs concentrations ranged from non-detect to 1.15 g m−2. Our research has shown that PAHs adsorbed on the surface of coking plant buildings can pose serious health risks to human and require remediation before reuse. Mechanical grinding, high-pressure blasting, and surfactant cleaning can effectively remove PAHs adsorbed on the surface of buildings. The above results would provide different perspectives for the site risk assessment and remediation before the industrial legacies were reused.