Managing eutrophic waterbodies produced large quantity of cyanobacterial sludge (CS), a biomass rich in nitrogen (N) that can be recycled through composting. However, how this management affects the compost fertility and ammonia (NH3) volatilization is little known. This study used a chicken manure and wheat straw mixture with struvite, as the control composting treatment (CK). Subsequently, 10%, 20%, 30%, and 40% of the chicken manure was substituted with CS at the initiation of composting, which were named CS10%, CS20%, CS30%, and CS40%, respectively. The results showed that compost pH decreased by 0.2–0.5 units, while total N content significantly increased by 10.4–20.8% under all CS amended treatments compared to the CK. Furthermore, cumulative NH3 volatilization in the CS amended treatments increased with higher CS substitution rates, showing a significant increase of 21.3–110.0%. In CS amended treatments, the initial contents of microcystin–RR and –LR were 82.0–328.0 μg kg−1 and 48.0–192.0 μg kg−1, respectively, which were degraded by 35.7–79.5% and 30.2–77.8%, peaking at 30% CS substitution. Notably, the CS40% treatment showed degradation rates dropping to 62.3% and 60.7%, accompanied by a significant increase in microcystin content. Meanwhile, the heavy metals (total arsenic, cadmium, chromium, mercury, and lead) contents of all composts complied with organic fertilizer standard (NY/T 525–2021) of China. Interestingly, the CS10% had significantly lower heavy metal concentrations compared to the CK, thus enhancing compost safety. In conclusion, 10% was an optimal CS incorporating ratio to improve the quality of compost derived from chicken manure, wheat straw and struvite, while reducing NH3 emissions, which provided a feasible technical pathway for recycling the CS.

Effect-based toxicity assessments are crucial for evaluating the risks of disinfection byproducts (DBPs), particularly unknown species, generated during drinking water chlorination. However, the accuracy of this approach is highly dependent on unbiased sample extraction. Conventional methods often employ single, low-pH extraction, which may fail to recover pH-sensitive amphoteric DBPs derived from amphoteric precursors (e.g., nitrogenous compounds). This study investigated how extraction pH affects the measured biotoxicity of DBPs formed from three model precursors: biopterin (Bip), cytosine (Cyt), and tryptophan (Trp). Under excess chlorine conditions, all three precursors degraded rapidly. The formation of aliphatic DBPs followed the order Trp > Cyt > Bip, and the maximum toxicity of the non-volatile extracts, assessed via a Vibrio fischeri bioassay, followed the reverse order: Bip > Trp > Cyt. This toxicity profile was significantly influenced by extraction pH, with maximum toxicity observed for Bip at around pH 4.0, under weakly acidic conditions for Trp, and under neutral to alkaline conditions for Cyt. For all precursors, the total organic carbon concentration remained constant throughout chlorination, indicating negligible mineralization and the predominant formation of non-aliphatic, likely heteroaromatic, products. These findings demonstrate that conventional extractions at a single low pH can lead to the incomplete recovery of toxic DBPs from amphoteric precursors. Therefore, pH-optimized extraction protocols are necessary for a more accurate risk assessment of chlorinated drinking water.

Under the global climate change, variations in climatic elements such as temperature, precipitation, and sunshine duration significantly impact the growth, development, and yield formation of winter wheat. A precise understanding of the impact of climate change on winter wheat growth and the scientific use of meteorological resources are crucial for ensuring food security, optimizing agricultural planting structures and agricultural sustainability. This study uses statistical methods and focuses on the Beijing–Tianjin–Hebei region, utilizing data from 25 meteorological stations from 1961 to 2010 and winter wheat yield data from 1978 to 2010. Twelve refined indicators encompassing temperature, precipitation, and sunshine duration were constructed. Path analysis was employed to determine their weights, establishing a comprehensive climate indicator model. Results indicate: Temperature indicators in the region show an upward trend, with accumulated temperature of the whole growth period increasing at a rate of 61.1 °C·d/10a. Precipitation indicators reveal precipitation of the whole growth period rising at 3.9 mm/10a and pre-winter precipitation increasing at 4.2 mm/10a. Sunshine duration exhibits a declining trend, decreasing at 72.7 h/10a during the whole growth period. Comprehensive climate indicators decrease from south to north, with the southwest region exhibiting the highest tendency rate (18.41), while the central and southern regions show greater variability. This study provides scientific basis for optimizing winter wheat planting patterns and rational utilization of climate resources in the Beijing–Tianjin–Hebei region. It recommends prioritizing cultivation in western southern Hebei and improving water conditions in the central and northern areas through irrigation technology to support sustainable crop production.

Iron (hydr)oxides are key reactive components in soil, governing the fate and transport of organic pollutants. This study aims to elucidate how different iron (hydr)oxides affect microbial degradation.The impact of four iron (hydr-) oxides on the microbial degradation of benzo[a]pyrene (BaP) by Paracoccus aminovorans HPD-2 was investigated. Interactions between the HPD-2 cells and minerals were probed using Extended-DLVO theory, scanning electron microscopy (SEM), and electron paramagnetic resonance (EPR) analysis. Notably, the addition of all four iron (hydr-) oxides markedly inhibited BaP degradation, compared to the control treatment (without added iron oxides, CK). The degree of inhibition followed the order: ferrihydrite > goethite > hematite > magnetite, with degradation efficiencies of 19.8%, 21.8%, 31.0%, and 47.1% over a 7-day period, respectively. These differential effects are primarily driven by the intrinsic properties of the iron oxides; higher zeta potential values correlated strongly with greater inhibition of HPD-2 cells. Furthermore, certain amorphous and secondary iron minerals exhibited higher catalytic activity and free radical production than their crystalline counterparts, which significantly hindered BaP degradation. These findings clarify the complex interactions between iron (hydr)oxides, bacteria, and organic pollutants during biodegradation. This work provides a foundation for enhancing the bioremediation of contaminated soils in field applications.