Asian Journal of Chemical Sciences

Management of Dioxins and Furans from Plastic Combustion: A Critical Narrative Review of Formation, Control and Residue Strategies Across Engineered and Uncontrolled Settings

Le Thi Thuy Duong, Tran Ngoc Bao Luan, Tran Thi Van Trinh — Wed, 29 Jul 2026 00:00:00 +0000

Polychlorinated dibenzo-p-dioxins and dibenzofurans, together with their brominated and mixed analogues, are unintentionally produced persistent organic pollutants of exceptional toxicity, and the combustion of plastics is a globally significant source. This review integrates the chemistry of dioxin formation from plastics with the full hierarchy of management options across both engineered incineration and uncontrolled open burning, a pairing that existing reviews have addressed only in part. Drawing on accessible peer-reviewed and institutional literature identified through scholarly indexes and appraised critically, the review examines formation mechanisms, feedstock and operating determinants, secondary abatement, residue management, and the governance framework. The evidence indicates that dioxins form predominantly by heterogeneous reactions in the post-combustion temperature window, that chlorine from poly(vinyl chloride) and bromine from flame retardants supply the halogen dioxins require, and that combustion quality and flue-gas cleaning, rather than feedstock halogen content, govern emissions wherever effective control exists. In engineered facilities the combination of good combustion, rapid quenching, sorbent injection and catalytic destruction has cut air emissions by two to three orders of magnitude, shifting the residual burden to dioxin-laden fly ash whose mature management routes immobilise rather than destroy the pollutant. Open burning, the fate of a large share of the world’s plastic waste, emits dioxins at factors thousands of times higher and delivers exposure to the most vulnerable populations, yet lies almost wholly outside the reach of the control technologies and standards that dominate the literature. Brominated and mixed halogenated dioxins remain under-recorded relative to their likely importance. The principal unresolved questions concern the quantification and prevention of open-burning emissions, the regulatory incorporation of brominated congeners, and the maturation of destruction-based residue treatment. The central conclusion is one of proportion: technical effort remains concentrated on the setting that already emits least.

Seasonal Assessment of the Physicochemical Parameters of Groundwater in the Town of Houndé, Burkina Faso

Corneille Bakouan, Césard Millogo, Regie Dimanche Ouédraogo, Issan Ki — Tue, 11 Aug 2026 00:00:00 +0000

Groundwater is the principal source of drinking water for many residents of Houndé, Burkina Faso. This study examined the physicochemical and hydrochemical quality of groundwater in the Houndé region, Burkina Faso, where residents relied heavily on wells and boreholes for their drinking-water supply. Five (05) water sources, comprising two (02) boreholes and three (03) wells, were analysed during two sampling campaigns: one in the rainy season (August 2024) and the other in the dry season (March 2025). The measured parameters included temperature, pH, electrical conductivity, turbidity, total dissolved solids (TDS), hardness, major ions, and several trace metals. The presence of these parameters in water originating from geological formations is a characteristic of groundwater observed in most regions of Burkina Faso. Temperatures varied little, ranging from 26.1°C to 26.8°C throughout the year. Sample pH ranged from 5.4 to 7.8, with nearly 60% of the values within the WHO range of 6.5–8.5. The remaining 40% showed slightly acidic pH values, although this did not significantly affect water quality. Electrical conductivity was higher in the boreholes (292–397 µS/cm) than in the wells (21.3–67.9 µS/cm), while remaining below the WHO standard of 1,000 µS/cm. The conductivity values observed in the boreholes could be associated with human activities near these water sources and inadequate protective measures, which may have contributed to the infiltration of dissolved substances. Turbidity was generally low, except in wells 2 and 3, where values exceeded the WHO threshold of 5 NTU, possibly indicating an influence from human activities. Nitrate concentrations were low (3.54–18.3 mg/L). Metal concentrations were generally low, with a temporary exceedance of the WHO guideline value for total iron (0.3 mg/L). The ionic balance error remained below 10%, in accordance with WHO recommendations, thereby supporting the validity of the analyses. The Water Quality Index (WQI) ranged from 13.97 to 45.18, placing all samples in the excellent category for human consumption. The Piper and Schoeller–Berkaloff diagrams revealed predominantly calcium bicarbonate and calcium–magnesium hydrochemical facies, indicating that mineralisation was primarily influenced by water–rock interactions.

Prediction of the Molecular Lipophilicity of an Alkylphenol Family Using Quantum Chemistry and QSPR Methods

Fatogoma Diarrassouba, Kafoumba Bamba, Nahossé Ziao — Thu, 20 Aug 2026 00:00:00 +0000

This study examined the relationship between the water/octanol partition coefficient of eighteen alkylphenols and molecular descriptors derived from quantum-chemical calculations using a quantitative structure-property relationship (QSPR) approach. The experimental database was divided into a training set of fourteen compounds and a test set of four compounds. Three descriptors, the electronic energy (E_T), the energy of the Lowest Unoccupied Molecular Orbital (E_LUMO) and the energy gap (ΔE_gap) were used to develop a multiple linear regression model. The model showed a strong association between the experimental lipophilicity values and the selected descriptors, with R = 0.9850, R² = 0.9703, a standard deviation of 0.0853, and F = 108.9532. Internal validation using leave-one-out cross-validation and property randomisation, together with external validation using the test set and the Tropsha criteria, was applied to assess model stability and predictive performance. The applicability domain was evaluated using a Williams plot. Within the studied dataset and the defined applicability domain, the model showed close agreement between experimental and predicted water/octanol partition coefficients. The reported validation results indicate that the selected quantum-chemical descriptors can be used to model lipophilicity within this alkylphenol series. Predictions for additional alkylphenols should, however, remain restricted to compounds that fall within the model’s defined applicability domain.

Comparative Chemical Characterisation of Produced Water from Onshore and Offshore Oil Fields in the Niger Delta, Nigeria

Sat, 22 Aug 2026 00:00:00 +0000

Background: Produced water is the largest waste stream generated during petroleum exploration and production and may contain chemical constituents that can cause adverse environmental impacts if inadequately managed.

Aim: This study comparatively characterised the chemical composition of produced water from selected onshore and offshore oil fields in the Niger Delta, Nigeria, and evaluated compliance with environmental discharge standards.

Materials and Methods: Twenty-four produced water samples were collected from eight oil fields, comprising four onshore and four offshore production facilities. Physicochemical parameters, major ions, heavy metals, total petroleum hydrocarbons (TPH), oil and grease, and polycyclic aromatic hydrocarbons (PAHs) were determined using standard analytical methods. Water Quality Index (WQI), Pollution Index (PI), Pearson correlation analysis, Principal Component Analysis (PCA), and Hierarchical Cluster Analysis (HCA) were employed to evaluate produced water quality, contamination patterns, and relationships among the measured parameters. Comparative statistical analyses were performed to determine differences between onshore and offshore produced water.

Results: The pH ranged from 6.66 to 7.34, while electrical conductivity and total dissolved solids ranged from 34,628 to 47,426 µS/cm and from 22,874 to 33,184 mg/L, respectively. Sodium (7,964–11,248 mg/L) and chloride (12,246–17,462 mg/L) were the dominant dissolved ions. Iron (3.86–8.42 mg/L) exhibited the highest heavy metal concentration, whereas cadmium ranged from 0.01 to 0.06 mg/L. Total petroleum hydrocarbons varied between 46.82 and 138.46 mg/L, oil and grease ranged from 18.64 to 62.84 mg/L, and total PAHs ranged from 16.50 to 58.62 mg/L, with consistently higher concentrations recorded in offshore produced water. Water Quality Index values ranged from 381.8 to 706.4, classifying all samples as unsuitable for direct environmental discharge. Strong positive correlations were observed between electrical conductivity and total dissolved solids (r = 0.996) and between oil and grease and TPH (r = 0.981). Principal Component Analysis explained 88.64% of the total variance, while Hierarchical Cluster Analysis grouped the oil fields into three distinct chemical clusters.

Conclusion: Offshore produced water exhibited significantly higher contaminant concentrations than onshore produced water, with several parameters exceeding regulatory discharge limits. These findings underscore the need for improved produced water treatment technologies, continuous environmental monitoring and stricter compliance with petroleum wastewater discharge regulations in the Niger Delta.