Browsing by Author "Song, Xin"

Now showing 1 - 4 of 4
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    Co-occurrence of PFASs, TPHs, and BTEX in subsurface soils: impacts on native microbial communities and implications for bioremediation
    (Elsevier, 2025-02-15) Zhang, Zhuanxia; Liu, Zeliang; Coulon, Frederic; Luo, Gubai; Wang, Qing; Gao, Xinyu; Li, Zhongyuan; Song, Xin
    This study investigates the co-occurrence of per- and polyfluoroalkyl substances (PFASs), petroleum hydrocarbons (TPHs) and benzene, toluene, ethylbenzene, and xylene (BTEX) and their effects on the indigenous microbial communities in soils at a contaminated site with a history of petroleum refinery operations. PFASs concentrations were in the range of 5.65–6.73 ng/g, and fluorooctane sulfonate (PFOS) and perfluorobutane sulfonic acid (PFBS) were the dominating compounds. No significant difference was observed in the PFASs concentration profiles between the site and background locations, indicating that PFASs detected in the soil samples were mainly contributed from non-point sources, due to the long-distance transport of PFASs in the region. The concentrations of TPHs and BTEX ranged from 227 to 72,360 mg/kg and 0.06–2109.77 mg/kg, respectively, mainly contributed by the historical refinery activities. The presence of PFASs, TPHs, and BTEX significantly impacted soil microbial community diversity and abundance, altering microbial compositions and enriching bacteria with higher resistance or metabolic capabilities against contamination. Strong correlations were observed between TPHs and its degraders such as Pseudomonas, Azoarcus, and Polaromonas. Significant positive relationship between PFASs and Trichlorobacter implied the potential defluorination capabilities of Trichlorobacter, warranting further investigation. Moreover, the higher energy metabolism including carbon, nitrogen and sulfur metabolisms and higher abundance of metabolic enzymes for alkane, cyclohexane and toluene in the refinery site revealed the potential occurrence of natural biodegradation of contaminants with indigenous microbial community. These findings highlight the complexity of sites contaminated with a mixture of traditional and emerging contaminants, providing valuable insights into the potential for biodegradation of mixed contaminants and underscoring the need for integrated approaches in environmental remediation strategies. This study contributes to understanding the ecological impacts of co-occurring contaminants and emphasizes the importance of considering multiple contaminant types in environmental risk assessments and remediation efforts.
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    Understanding microplastic presence in different wastewater treatment processes: removal efficiency and source identification
    (Elsevier, 2024-06-15) Ma, Min; Huo, Mingxin; Coulon, Frederic; Ali, Mukhtiar; Tang, Zhiwen; Liu, Xin; Ying, Zhian; Wang, Bin; Song, Xin
    Municipal effluents discharged from wastewater treatment plants (WWTPs) are a considerable source of microplastics in the environment. The dynamic profiles of microplastics in treatment units in WWTPs with different treatment processes remain unclear. This study quantitatively analyzed microplastics in wastewater samples collected from different treatment units in two tertiary treatment plants with distinct processes. The influents contained an average of 15.5 ± 3.5 particles/L and 38.5 ± 2.5 particles/L in the two WWTPs with in the oxidation ditch process and the integrated fixed-film activated sludge process, respectively. Interestingly, microplastic concentrations in the influent were more influenced by the population density in the served area than sewage volume or served population equivalent. Throughout the treatment process, concentrations were reduced to 1.5 ± 0.5 particles/L and 1.0 ± 1.0 particles/L in the final effluents, representing an overall decrease of 90% and 97%, in WWTPs with the oxidation ditch process and integrated fixed-film activated sludge process, respectively. A significant proportion of the microplastics were removed during the primary treatment stage in both WWTPs, with better performance for foam, film, line-shaped and large-sized microplastics. Most microplastics were accumulated in activated sludge, indicating its key role as the primary sink in WWTPs. The multiple correspondence analysis identified laundry washing and daily necessities such as packaging and containers as the major contributors to microplastics in WWTPs. The study proposed recommendations for upgrading WWTPs, modifying designs, and implementing strategies to reduce microplastic sources, aiming to minimize the release of microplastics into the environment. These findings can shed lights on the sources of microplastics in WWTPs, and advance our understanding of the mechanisms for more effective microplastic removals in wastewater treatment technologies in future applications.
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    Unveiling complete natural reductive dechlorination mechanisms of chlorinated ethenes in groundwater: insights from functional gene analysis
    (Elsevier, 2024-05-05) Zhang, Zhuanxia; Ali, Mukhtiar; Tang, Zhiwen; Sun, Qi; Wang, Qing; Liu, Xin; Yin, Lipu; Yan, Song; Xu, Minmin; Coulon, Frederic; Song, Xin
    Monitored natural attenuation (MNA) of chlorinated ethenes (CEs) has proven to be a cost-effective and environment-friendly approach for groundwater remediation. In this study, the complete dechlorination of CEs with formation of ethene under natural conditions, were observed at two CE-contaminated sites, including a pesticide manufacturing facility (PMF) and a fluorochemical plant (FCP), particularly in the deeply weathered bedrock aquifer at the FCP site. Additionally, a higher abundance of CE-degrading bacteria was identified with heightened dechlorination activities at the PMF site, compared to the FCP site. The reductive dehalogenase genes and Dhc 16 S rRNA gene were prevalent at both sites, even in groundwater where no CE dechlorination was observed. vcrA and bvcA was responsible for the complete dechlorination at the PMF and FCP site, respectively, indicating the distinct contributions of functional microbial species at each site. The correlation analyses suggested that Sediminibacterium has the potential to achieve the complete dechlorination at the FCP site. Moreover, the profiles of CE-degrading bacteria suggested that dechlorination occurred under Fe3+/sulfate-reducing and nitrate-reducing conditions at the PMF and FCP site, respectively. Overall these findings provided multi-lines of evidence on the diverse mechanisms of CE-dechlorination under natural conditions, which can provide valuable guidance for MNA strategies implementation.
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    Unveiling the truth of interactions between microplastics and per- and polyfluoroalkyl substances (PFASs) in wastewater treatment plants: microplastics as a carrier of PFASs and beyond
    (American Chemical Society, 2025-02-04) Ma, Min; Coulon, Frederic; Tang, Zhiwen; Hu, Zhiyuan; Bi, Ye; Huo, Mingxin; Song, Xin
    Microplastics (MPs) and per- and polyfluoroalkyl substances (PFASs) are ubiquitous contaminants in environments, yet their co-occurrence and interactions remain insufficiently understood. In this study, we confirmed the concurrent presence of MPs and PFASs and their distinct distribution patterns in a wastewater treatment plant (WWTP) through a comprehensive sampling and analysis effort. Significant correlations (p < 0.05) were observed between specific types of MPs and PFASs, suggesting their shared sources. Moreover, MPs were identified as carriers of PFASs, with PFAS concentration ranging between 122 and 166 ng/g, predominantly consisting of perfluorooctanoic acid (PFOA) and perfluorobutanoic acid (PFBA). The laboratory verification experiment revealed that PFASs could be leached from MPs in aqueous environments, in which commercial MPs exhibited higher leaching potential, with the highest combined concentration of perfluorooctanesulfonate (PFOS), PFOA, and PFBA reaching 10.4 ng/mL. PFOS demonstrated a desorption efficiency exceeding 120% in sorption/desorption experiments, confirming its release from the MPs themselves. These results highlighted the dual roles of MPs as both carriers and sources of PFASs. The identified contaminant profiles and correlations between MPs and PFASs across different matrices in WWTP provide valuable insights and form a basis for further research into proactive measures to effectively mitigate their environmental contamination.