The increasing discharge of textile dyes into water bodies poses significant environmental and public health challenges. This study developed and evaluated a synergistic system to remove Direct Blue 71 (DB71), a recalcitrant triazo dye, from aqueous solutions by combining biosorption onto tamarind shell (Tamarindus indica, TS) with biodegradation by Phanerochaete chrysosporium (Pc) immobilized on TS. Both individual and combined systems (TS+Pc) were assessed in batch and continuous fixed-bed column configurations. FTIR and SEM-EDS analyses confirmed that TS has a porous, heterogeneous surface rich in hydroxyl, carboxyl, carbonyl, and amino functional groups; post-adsorption detection of sulfur, absent in the untreated material and attributable only to the dye's sulfonate groups, provided direct evidence of DB71 binding. The pseudo-second-order model best described biosorption kinetics. Maximum DB71 removal (69%) was achieved at pH 3 with a biosorbent dose of 20 g/L, with ~54% still removed at near-neutral pH 7, indicating effective operation without strong acidification. The equilibrium data in the concentration range studied were best fitted by the Freundlich model at 25 and 35 °C and by the Langmuir model at 40 °C, in line with adsorption on an energetically heterogeneous surface. Since no saturation plateau was obtained, the fitted Langmuir Q_o (13.66 mg/g at 25 °C and 15.73 mg/g at 40 °C) represents an operational capacity for this range rather than a monolayer capacity. Thermodynamic analysis indicated a spontaneous process (ΔG° = −33.3 to −35.5 kJ/mol), with uptake increasing with temperature. P. chrysosporium successfully colonized TS within 6–7 days and decolorized DB71 on both nutrient-rich and nutrient-free solid media. In batch experiments, the TS+Pc system achieved decolorization efficiencies of 98%, 76%, and 67% at DB71 concentrations of 10, 50, and 100 mg/L, respectively, substantially outperforming the fungus alone (68%, 49%, and 16%). In fixed-bed columns, inoculation of TS with Pc extended the breakthrough time from 25 to 82 min and increased the bed capacity at breakthrough from 2.51 to 8.39 µg/g, a 3.3-fold gain, with the Yoon-Nelson model providing an adequate operational description of the column dynamics (R² = 0.9928). These results demonstrate that tamarind shell functions simultaneously as a primary biosorbent and a nutrient-rich substrate that sustains fungal ligninolytic activity, yielding a synergistic, low-cost, and sustainable approach for treating azo dye–contaminated textile wastewater.

Heavy metal transport between the water column and sediment is commonly described using linear or empirical relationships, which may not capture nonlinear feedback mechanisms and abrupt changes in contamination states. In this study, we proposed a nonlinear cubic equilibrium model for describing metal partitioning between water and sediment and for identifying critical transition conditions associated with bifurcation behavior. The proposed model established a nonlinear relationship between the input metal concentration in water I_i and the accumulated sediment concentration C_i. Using experimental data for copper (Cu) and nickel (Ni) transport from the literature data, model parameters were estimated by the least-squares method. The obtained response curves exhibited an S-shaped structure, indicating the existence of multiple equilibrium states, bistability, and hysteresis. Fold points obtained from the condition d I_i/d C_i=0 defined critical thresholds at which saddle-node bifurcations occur and abrupt transitions between contamination states become possible. The bifurcation analysis with respect to the nonlinear parameter p_i further identified critical values separating bistable and monostable regimes. The results demonstrated that Cu and Ni systems may exhibit history-dependent behavior, where the sediment contamination level is not determined solely by the current pollution input but also by the previous evolution of the system. The proposed framework extends conventional pollutant transport models by incorporating nonlinear dynamics, multistability, and regime-shift mechanisms. It provides a mathematical basis for identifying tipping points in water-sediment contamination systems and offers a potential tool for assessing environmental risks associated with sudden changes in metal accumulation. The main contribution of this work is the demonstration that nonlinear bifurcation analysis provides insight into critical states, multistability, hysteresis, and regime transitions in water-sediment contamination systems, extending conventional concentration-based approaches toward a deeper understanding of nonlinear environmental dynamics.

In this systematic review, we synthesized research on the application of the precautionary principle to the complex environmental and ecological risks associated with hydraulic fracturing. Following PRISMA guidelines, the search was conducted across five major academic databases, resulting in the analysis of thirteen high-quality, peer-reviewed studies and authoritative reports. The findings indicated a significant and persistent gap between the formal legal adoption of the precautionary principle and its practical implementation within regulatory frameworks. Evidence showed that although some jurisdictions have incorporated the principle into legislative mandates, they often rely on traditional, hazard-based risk assessments in practice. In contrast, other regions exhibit varied applications of the principle, shaped by enforcement capacities, political contexts, and governance structures. Furthermore, the analysis suggests that the precautionary principle is frequently employed as a strategic tool in contentious public debates, serving more as a rhetorical device than as a binding legal standard. This instrumental use complicates its function within evidence-based policy. In conclusion, effective precautionary governance requires more than legislative commitments. Managing technologies characterized by significant environmental uncertainty requires developing robust institutional capacity, enhancing transparency in decision-making, and implementing proactive measures such as comprehensive, long-term baseline environmental monitoring. Transitioning from symbolic legal declarations to operationalized, science-informed oversight enables authorities to better mitigate the ecological risks of hydraulic fracturing and promote resilient environmental protection strategies.

Autotrophic denitrification has garnered increasing attention as it eliminates the dependency on external organic carbon sources. Addressing the challenge of elevated nitrate levels in the tailwater of urban wastewater treatment plants (WWTPs), we proposed a sodium thiosulfate-siderite autotrophic denitrification (STSAD) biofilter for advanced nitrogen removal. The optimal operational parameters were an influent pH of 7.0, a temperature of 30°C, a hydraulic retention time (HRT) of 2 hours, and a sodium thiosulfate dosage equivalent to 1.5 times the theoretical requirement. Under these conditions, the system achieved a nitrate (NO₃^--N) removal rate of 100% and a total nitrogen (TN) removal efficiency exceeding 95%. Microbial analysis revealed significant biofilm enrichment on the ceramsite and siderite media, with Thiobacillus and Ferritrophicumidentified as the predominant denitrifying genera. This ensured that effluent TN and COD levels comply with discharge standards.

The coexistence of antibiotics, heavy metals, and antibiotic resistance genes (ARGs) in antibiotic-containing wastewater poses a coupled challenge for membrane bioreactors (MBRs): Treatment performance must improve without shifting environmental risk elsewhere in the system. In this review, we examined how metal-based functional interfaces influence antibiotic removal, membrane fouling, and antibiotic-resistance risks in MBRs. Metal ions, iron-based particles, functionalized membranes, and electrochemical or bioelectrochemical interfaces can enhance pollutant removal and operational stability through coagulation and adsorption, redox reactions, electron transfer, and regulation of membrane-surface interactions. However, lower concentrations of parent antibiotics or lower ARG abundances in the effluent do not necessarily reflect genuine degradation or reduced environmental risk. Pollutants and resistance determinants may accumulate in sludge, cake layers, and membrane biofilms, while metal-induced selection can favor co-resistance and cross-resistance and trigger co-regulatory responses. We proposed an integrated assessment framework that considers pollutant transformation, membrane operation, metal release, the spatial distribution of resistance determinants, and their potential for dissemination. This framework provides a basis for evaluating the long-term safety of metal-based functional interfaces in MBRs.

The destruction of narcotics evidence through open burning has the potential to generate air pollutants that adversely affect environmental quality and human health. Although this method is widely used for evidence disposal, limited studies have evaluated the characteristics of pollutant emissions and their environmental impacts. This study aimed to analyze the effects of air pollution resulting from the open burning of narcotics evidence in South Sulawesi and to identify mitigation strategies based on an industrial ecology approach. A field experimental study with a spatial–temporal design was conducted by measuring five air pollutants (SO₂, NO₂, O₃, NH₃, and CO) using an Impinger Gas Sampler. Measurements were performed at three observation periods (before, during, and after burning) and three monitoring distances (0, 100, and 200 m). Differences in pollutant concentrations across observation periods were analyzed using the Friedman test, while simple linear regression was applied to evaluate the relationship between monitoring distance and pollutant concentrations. The Friedman test demonstrated significant differences in pollutant concentrations across observation periods(P < 0.05), with concentrations increasing markedly during burning and declining afterward, although remaining above baseline levels. Linear regression analysis revealed a strong negative relationship between distance and pollutant concentrations (R² = 0.750 – 0.993), indicating that pollutant levels decreased with increasing distance. Dispersion modeling estimated that O₃ and NO₂ could travel approximately 1384 and 1337 m, respectively, whereas NH₃ dispersed over approximately 412 m. These findings indicate that emissions from narcotics burning may affect both local and regional air quality. From an industrial ecology perspective, open burning is inconsistent with closed-loop system principles because it releases unmanaged atmospheric emissions. Open burning of narcotics evidence significantly contributes to air pollution and may impact surrounding communities beyond the burning site. The adoption of environmentally sustainable destruction technologies, such as controlled incineration equipped with emission filtration systems, is recommended to reduce pollutant emissions and support environmentally responsible evidence disposal.