ABSTRACT Heavy metal contamination of aquatic ecosystems is a pathway of risk to human health. This study measured cadmium (Cd) and lead (Pb) concentrations in the water, muscles and gills of Epinephelus chlorostigma from Saudi Arabian Dammam and Jubail regions. It also examined DNA and RNA concentrations and their ratio in these tissues to evaluate the associated genetic effect. Cd and Pb were slightly higher in Jubail. Cadmium was significantly lower in gill for Dammam (p<0.01) compared to Jubail. Jubail samples showed insignificant increase in DNA concentration and the RNA/DNA ratios in gill with decreased RNA level compared to Dammam. Conversely, muscles showed higher DNA, RNA contents and RNA/DNA ratio (p<0.05) for Dammam compared to Jubail. Histopathological changes were shown in tissues due to heavy metal exposure. In general, heavy metals concentrations, compared to the permissible edible limits set by FAO/WHO, suggest that some health concerns should be taken into consideration.

ABSTRACT Groundwater contamination by emerging contaminants (ECs) such as pharmaceuticals, pesticides, microplastics, and endocrine-disrupting compounds is a significant global issue that poses serious risks to human health, ecological balance, and water security. This review offers a comprehensive overview of the sources and pathways of ECs, their environmental impacts, and the health risks they pose to humans. It further evaluates remediation strategies, highlighting their effectiveness and limitations. This review highlights the potential of artificial intelligence and machine learning in real-time monitoring, predictive modeling, and adaptive groundwater management.

ABSTRACT Nanoplastics (NPs) and tetrabromobisphenol A (TBBPA) are emerging contaminants in the aquatic system. However, their combined effects on primary producers remain poorly understood. Therefore, this study aimed to investigate the effects of NPs, TBBPA, and their combination on the freshwater microalgae Scenedesmus obliquus. This study employed field emission scanning electron microscopy, liquid chromatography‒mass spectrometry, Fourier Transform Infrared Spectroscopy, dynamic light scattering, and zeta potential analysis to characterize the materials and assess their interactions. The mixture of NPs with TBBPA showed enhanced growth inhibition, oxidative stress, and antioxidant activity while reducing photosynthetic pigment levels compared to pristine TBBPA. Collectively, these findings provide critical insights into the co-exposure of NPs and TBBPA, highlighting the ecotoxicological risk to primary producers in freshwater ecosystems.

ABSTRACT Thiamethoxam (TMX), a neonicotinoid pesticide, poses environmental risks due to its mobility in soil. This study investigates the effect of co-applying biochar and iron-based materials (ZVI, Fe₃O₄) on TMX degradation in peanut field soils. Field experiments showed that while biochar alone delayed TMX degradation, its combination with iron powder significantly reduced bioavailable TMX (from 79% to 25.5%) and kernel residues. Co-application enhanced Fe(II) and amorphous iron oxides, promoting TMX breakdown, especially with straw biochar and ZVI. It also improved soil properties and peanut yield. These findings support using biochar–iron composites for TMX-contaminated soil remediation.

ABSTRACT Greenhouse gases trap heat, contributing to global warming. Tractors, essential for modern agriculture, emit CO₂ due to fossil fuel consumption. Reducing these emissions is crucial for environmental sustainability. Land consolidation, which merges small and fragmented plots into larger, more efficient farms, can optimize tractor use and lower fuel consumption. This study examined how farm size, number of plots, aspect ratio and distances affect CO₂ emissions.Scenarios were created and grouped for all parameters. The results showed that increasing the number of plots and plot distances in small farms led to higher emissions per unit area. High emissions were not observed in medium and large farm size scenarios. The study concluded that planning small farm plots as close as one piece and limiting medium and large farms to a maximum of 4-5 plots significantly reduced emissions. Effective land consolidation planning can significantly reduce CO2 emissions from tractor use in agriculture.

ABSTRACT This study examines the impact of technical barriers to trade (TBT) on air pollution levels within China, utilizing a robust dataset from the Enterprise-Level Pollution Emission Database and the Customs database, covering the period from 2002 to 2013. A two-way fixed effects econometric model is employed to rigorously assess the relationship between TBT and air pollutant emission intensities in Chinese industrial firms. Our findings reveal a definitive correlation between increased TBT and elevated emission levels of key pollutants. Specifically, each 1% increase in TBT correlates with rises in emission intensities: 0.025% for sulfur dioxide (SO2), 0.024% for soot, 0.076% for industrial dust, and 0.012% for nitrogen oxides (NOx). The analysis highlights that restrictions on imported intermediates, as opposed to final goods, are primarily responsible for these increased emissions. This research underlines the critical environmental implications of trade policies and advocates for a balanced approach to promoting environmental health through the strategic importation of eco-friendly products and technologies.

ABSTRACT Phycoremediation, employing microalgae, effectively treats Palm Oil Mill Effluent (POME) by removing pollutants, curbing eutrophication, and yielding valuable substances. Microalgae utilize photosynthesis and their high surface area to convert carbon dioxide into biomass, reducing pollutant concentrations and enhancing water body oxygenation. This dual mechanism acts as a natural biofilter, addressing environmental concerns while bolstering the economic potential of the palm oil industry. The integrated system of biogas production and phycoremediation covers crucial aspects such as cultivating microalgae on POME, producing valuable compounds, and biogas upgrading. This approach harmonizes POME treatment, resource recovery, and renewable energy production, showcasing environmental and economic advancements.

ABSTRACT Enrofloxacin (ENR) is widely used in aquaculture due to its broad-spectrum activity against a large number of pathogenic bacteria. However, ENR exhibits strong adsorption and a low biodegradation rate in the environment. This study proposes a new method for degrading ENR, which combines dielectric barrier discharge (DBD) with advanced oxidation of peroxymonosulfate (PMS, HSO5 −) and the use of nitrilotriacetic acid (NTA) combined with Fe(III) activator to improve reaction efficiency. The effects on the degradation efficiency were experimentally investigated by adjusting the internal process parameters and adding coexisting substances. The ESR and free radical scavenging experiments showed that both hydroxyl and sulfate radicals contributed to the degradation of the pollutant ENR. Based on the identified intermediates, and three possible degradation pathways were suggested. And the intermediates were less harmful. In conclusion, the Fe(III)-NTA/PMS/DBD system may be an efficient, environmentally friendly and new technology with development potential.

ABSTRACT Cyanobacterial outbreaks seriously affect drinking water safety. Therefore, developing effective algal removal technologies is urgently needed. The study aims to investigate the effects of pH, electrode distance, current density, and initial algal concentration on electrochemical algae collection. Consequently, we loaded nanoscale zero-valent iron (nZVI) on activated carbon fiber/nickel foam (ACF/Ni) to form an ACF/nZVI/Ni composite cathode using the liquid phase reduction method and used titanium-based platinum plating (Pt/Ti) as the anode to construct a novel Pt/Ti- ACF/nZVI/Ni electrochemical system. The results showed that on pH of 6.0, the electrode distance was 10 mm, the current density was 75 mA/cm2, and the initial algal concentration was OD680 = 0.100; the algal cell removal rate was 94.20% after electrolysis for 30 min. This paper provides an efficient and environmentally friendly electrochemical algal removal technology for protecting the safety of drinking water and dealing with cyanobacterial outbreaks.

ABSTRACT Meadow soils are one of the important agricultural soil types, biochar is a good soil amendment, whereas the studies on the effects of biochar additions on carbon and nitrogen contents, as well as bacterial communities of meadow soils, were seldom carried out. The effects of one nitrogen addition rates (no addition, 0.2% addition) and two biochar addition patterns (no addition, 1% addition, 3% addition) on the carbon and nitrogen contents, as well as bacterial communities of meadow soils, were investigated by conducting a one-year indoor incubation experiment. Biochar addition increased the relative abundance of Proteobacteria, Chloroflexi and Bacteroidota. The combination of biochar and nitrogen source significantly increased the total organic carbon, ammonium nitrogen, nitrate nitrogen and total nitrogen content of the meadow soil. Therefore, the addition of moderate amounts of biochar to meadow soils can contribute to sustainable ecological agriculture as a form of soil improvement.