The impacts of humic substances (HS) on the aquatic stability and toxicity of nano‑cerium dioxide (nCeO) to three organisms with different exposure characteristics were investigated. Addition of HS to suspensions of nCeO lowered the surface zeta potential of the particles, reduced their hydrodynamic size, and increased the energy barrier as indicated by the total potential energy profile. This resulted in a more stable suspension compared to suspensions without HS added. Moreover, a higher concentration of HS further stabilized nCeO in the suspension. Acute toxicity of the suspensions to the unicellular green alga Raphidocelis subcapitata and to the crustacean Chydorus sphaericus was lower as compared to exposure without HS added. The acute toxicity of nCeO suspensions to the zebrafish (Danio rerio) eleutheroembryo was on the other hand significantly enhanced (additive and synergistic) upon increasing HS concentration. Our findings emphasize that HS is important to stabilize the nano-suspensions and that its impact on nCeO toxicity differs across different aquatic organisms. Emphasizing the exposure characteristics of each of the organisms selected from the trophic levels can explain how particle stability impacts particle toxicity.
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http://dx.doi.org/10.1016/j.scitotenv.2021.146583 | DOI Listing |
Water Sci Technol
January 2025
China Construction Fifth Engineering Division Co., Ltd, Changsha, Hunan 410004, China.
Road runoff underwent treatment using a filter filled with sludge from drinking water treatment plants to assess its capacity for removing dissolved organic matter (DOM). This evaluation utilized resin fractionation, gel permeation chromatography, three-dimensional excitation-emission matrix fluorescence spectroscopy, and UV-Visible spectroscopy. The filter demonstrated enhanced efficiency in removing dissolved organic carbon, achieving removal rates between 70 and 80%.
View Article and Find Full Text PDFEco Environ Health
March 2025
College of Natural Resources and Environment, Northwest A & F University, Xianyang 712100, China.
The interactions of nanoplastics (NPs) with natural organic matters (NOMs) dominate the environmental fate of both substances and the organic carbon cycle. Their binding and aggregation mechanisms at the molecular level remain elusive due to the high structural complexity of NOMs and aged NPs. Molecular modeling was used to understand the detailed dynamic interaction mechanism between NOMs and NPs.
View Article and Find Full Text PDFJ Appl Microbiol
January 2025
Centre for Environmental and Marine Studies (CESAM) and Department of Biology, University of Aveiro, Aveiro, Portugal.
Aims: In the present study, we tested if terrestrially-derived humic substances (HS) could mitigate the adverse effects of elevated temperature and UVB radiation on the bacterial communities of two hard corals (Montipora digitata and Montipora capricornis), one soft coral (Sarcophyton glaucum), sediment and water. We also examined the impact of temperature, UVB radiation and HS supplementation on coral photosynthetic activity, a proxy for coral bleaching.
Methods And Results: We performed a multifactorial experiment using a randomized-controlled microcosm setup.
J Hazard Mater
January 2025
Research Institute for Farm Animal Biology, Dummerstorf, Germany.
Human activities and climate change have significantly increased humic substances in freshwater ecosystems over the last few decades. This increase is particularly concerning during seasonal changes or after heavy rainfall, when concentrations can easily increase up to tenfold. This phenomenon, known as "browning," has unknown consequences for aquatic organisms.
View Article and Find Full Text PDFEnviron Res
January 2025
Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment (MEE), Nanjing, 210042, PR China.
Recently, thallium (Tl) contamination at trace levels has gained worldwide attention, particularly in the remote ore-smelting regions of China. To effectively eliminate the residual target Tl(I) ions, one of the best strategies is to develop novel adsorbents with high selectivity. In this study, we selected silicate mineral waste (SMW) and chitosan (CTS) to synthesize a low-cost composite adsorbent for the removal of trace Tl(I).
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