Migration risk of Escherichia coli O157:H7 in unsaturated porous media in response to different colloid types and compositions. (15th April 2023)

• Record Type: Journal Article
• Authors: Li, Shuxin; Zhang, Wenjing; Zhang, Dayi; Xiu, Wei; Wu, Shengyu; Chai, Juanfen; Ma, Jincai; Jat Baloch, Muhammad Yousuf; Sun, Simiao; Yang, Yuesuo
• Is Part Of: Environmental pollution. Volume 323(2023)
• Publication Date: 2023-04-15
• Subjects: porous media -- Pathogen -- Multiple colloids -- Migration mechanism; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2023.121282
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: The vadose zone is a critical zone for microbial entry into the subsurface environment, and various types of inorganic and organic colloids can affect the migration of pathogenic bacteria. In the study, we explored the migration behavior of Escherichia coli O157:H7 with humic acids (HA), iron oxides (Fe2 O3 ) or their mixture, uncovering their migration mechanisms in the vadose zone. The effect of complex colloids on the physiological properties of E. coli O157:H7 was analyzed based on the measured particle size, zeta potential and contact angle. HA colloids significantly promoted the migration of E. coli O157:H7, where Fe2 O3 was opposite. The migration mechanism of E. coli O157:H7 with HA and Fe2 O3 is obviously different. Multiple colloids dominated by organic colloid will further highlight its promoting effect on E. coli O157:H7 under the guidance of electrostatic repulsion due to the influence of colloidal stability. Multiple colloids dominated by metallic colloid will inhibit the migration of E. coli O157:H7 under the control of capillary force due to the restriction of contact angle. The risk of secondary release of E. coli O157:H7 can be effectively reduced when the ratio of HA/Fe2 O3 is ≥ 1. Combining this conclusion with the distribution characteristics of soil in China, an attempt was made to analyse the migration risk of E. coli O157:H7 on a national scale. In China, from north to south, the migration capacity of E. coli O157:H7 gradually decreased, and the risk of secondary release gradually increased. These results provide ideas for the subsequent study of the effect of other factors on the migration of pathogenic bacteria on a national scale and provide risk information about soil colloids for the construction of pathogen risk assessment model under comprehensive conditions in the future. Graphical abstract: Image 1 Highlights: Migration of E. coli with complex colloids was promoted to varying degrees. Secondary release risk of E. coli was reduced when HA/Fe2 O3 ≥1 in unsaturated zone. HA mainly promotes migration due to electrostatic repulsion when HA/Fe2 O3 ≥1. Fe2 O3 inhibits migration under the control of capillary force when HA/Fe2 O3 ＜1. Providing ideas for the building of pathogen risk models under integrated condition.