Polybrominated diphenyl ethers (PBDEs) are persistent organic pollutants commonly found in e-waste recycling sites, posing severe environmental risks due to their toxicity and persistence. Previous studies have identified colloid-facilitated transport as a key mechanism in the subsurface migration of these contaminants. However, the influence of transient flow conditions on this process remains poorly understood. Based on these challenges, it is crucial to conduct in-depth research on the effects of these conditions on PBDE mobility.
Researchers from Nankai University, published a study (DOI: 10.1016/j.eehl.2024.03.002) in Eco-Environment & Health on 26 March 2024, examining how dry-wet and freeze-thaw cycles affect the release of BDE-209 from soil at an e-waste site in Taizhou, China. The study employed undisturbed soil core leaching tests to simulate these transient flow conditions, providing new insights into the behavior of PBDEs in contaminated environments.
The study revealed that both dry-wet and freeze-thaw cycles significantly influence the release of BDE-209 from soil, with colloids playing a crucial role in this process. During dry-wet cycles, the drying period induced differential capillary stress, promoting colloid generation through soil pore wall cracking. This led to higher concentrations of BDE-209 in the colloids compared to those from freeze-thaw cycles. Conversely, freeze-thaw cycles caused mechanical stress from water expansion and contraction, resulting in the formation of inorganic colloidal particles with lower BDE-209 content. The researchers found that the drying duration and intensity of the cycles directly affected the amount and type of colloids mobilized, thereby impacting the concentration of BDE-209 in the leachate. These findings emphasize the importance of considering transient flow conditions in assessing the environmental risks of PBDEs at contaminated sites.
Dr. Chuanjia Jiang, the lead author, stated, “Our findings underscore the critical role of transient flow conditions in the mobility of hydrophobic contaminants like BDE-209. Understanding these mechanisms is essential for developing effective strategies to mitigate the spread of such pollutants in the environment, especially in areas impacted by e-waste recycling activities.”
This research provides valuable insights for environmental scientists and policymakers working on contamination management at e-waste sites. By highlighting the effects of transient flow conditions on PBDE release, the study suggests that hydrological intervention measures, such as controlled drying and freeze-thaw management, could be developed to limit the mobilization and spread of these harmful contaminants, ultimately protecting groundwater quality and reducing human exposure risks.
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References
DOI
Original Source URL
https://doi.org/10.1016/j.eehl.2024.03.002
Funding information
This work was supported by the National Key Research and Development Program of China (2019YFC1804202), the National Natural Science Foundation of China (22276101 and 22020102004), the Fundamental Research Funds for the Central Universities (63233056), and the Ministry of Education of China (T2017002).
About Eco-Environment & Health
Eco-Environment & Health (EEH) is an international and multidisciplinary peer-reviewed journal designed for publications on the frontiers of the ecology, environment and health as well as their related disciplines. EEH focuses on the concept of “One Health” to promote green and sustainable development, dealing with the interactions among ecology, environment and health, and the underlying mechanisms and interventions. Our mission is to be one of the most important flagship journals in the field of environmental health.
