Kashif Rasool

Emerging contaminants (ECs), including pharmaceuticals, endocrine disruptors, pesticides, PFAS, and microplastics, are increasingly detected in aquatic environments due to their persistence, bioactivity, and limited removal by conventional treatment processes. These challenges are intensified in hyper-arid regions where desalination and wastewater reuse dominate water supply, concentrating contaminants and creating unique exposure pathways. The Arabian Gulf is one of the most environmentally stressed marine systems, characterized by hypersalinity, extreme temperatures, dense coastal development, and strong petrochemical influence. Despite its major role in global petrochemical and plastic production, the region lacks coordinated monitoring and regulatory frameworks, creating significant gaps in understanding EC occurrence, fate, and risks. Treatment systems designed for temperate climates often underperform under Gulf conditions, enabling contaminants to persist, accumulate in sediments, and enter marine food webs. This review examines the occurrence, behaviour, and removal challenges of ECs in the Gulf, where concentrations frequently exceed international benchmarks due to wastewater reuse, desalination brine discharge, maritime activities, and oil-related pollution. Regional factors such as hypersalinity, high temperatures, and petrochemical interactions further influence contaminant persistence and toxicity. Conventional treatments show reduced efficiency, while alternatives such as halophyte-based wetlands and brine valorisation show promise. However, key gaps remain in nanoplastics, PFAS speciation, and cumulative exposure, requiring coordinated monitoring and unified GCC regulations.

Food waste valorization through Anaerobic Digestion (AD) represents a sustainable and circular approach to managing organic residues by converting them into valuable bioenergy and biobased products. Despite a growing body of literature on food waste AD, a critical methodological gap persists in which existing reviews largely treat reactor-level performance, life cycle assessment (LCA), and techno-economic analysis (TEA) as discrete fields, leaving the spreading of high-rate reactor uncertainties into integrated LCA/TEA scaling decisions largely unresolved. This review directly bridges that gap by systematically linking process-level performance metrics to sustainability and economic outcomes within a cohesive analytical framework. The biochemical composition of food waste is examined first, emphasizing carbohydrate, protein, and lipid content influence digestion efficiency and methane yields. Recent technological advancements in high-rate digestion systems are critically analyzed, including Upflow Anaerobic Sludge Blanket (UASB), Expanded Granular Sludge Bed (EGSB), and Internal Circulation (IC) reactors with particular attention to operational bottlenecks such as granule stability, inhibitory compound accumulation, and scale-up constraints that limit real-world performance relative to laboratory benchmarks. Two-stage AD (TSAD) configurations and membrane bioreactor (MBR) innovations are assessed for their capacity to enhance CH₄ yields and improve biomass retention, though at the cost of increased capital expenditure and process complexity. Substrate pretreatment strategies are assessed for their effectiveness in enhancing biodegradability and biogas production by 25–80%, combined with the energy penalties and reagent costs that frequently offset these gains on a commercial scale. These process-level trade-offs are carried forward into a structured synthesis of co-digestion approaches are examined for synergistic benefits. Whereas LCA studies confirm that AD reduces environmental impacts across multiple impact categories relative to landfilling and incineration. Critically, TEA findings reveal that economic viability remains sensitive to feedstock heterogeneity. The integration of AD within sustainable food systems supports nutrient recovery, decentralized waste management, and renewable energy generation. However, realizing these co-benefits at scale requires resolving constant uncertainties in digestate quality standards, gate fee structures, and carbon accounting methodologies from most TEA framework. Thus, these findings advance the transition toward a circular bioeconomy by providing a coherent, critically grounded framework that connects high-rate reactor design to real-world sustainability performance.

This study provides a thorough examination of ambient air bioaerosols in Qatar, specifically delving into the environmental aspects of bacteria, fungi, and viral diversity. The main objective is to elucidate the public health implications related to airborne superbugs and viruses in Qatar's unique arid climate, focusing on the urban areas of Doha. Bioaerosol samples were meticulously collected from eight distinct urban sites in Qatar throughout the year, covering diverse climatic conditions. Employing advanced methodologies, such as classical microbiology and next-generation sequencing, the samples underwent analysis to identify a wide range of pathogens, including bacteria, fungi, and viruses. The results obtained during the spatial-seasonal characterization of bacterial and fungal concentration in ambient air throughout the year reveal that bacterial and fungal diversity was higher in the summer (hot-dry) and winter seasons, respectively. The highest average concentration of total ambient bacteria and fungi was observed to be 130 CFU/m3 during the summer (dry-hot) and 40 CFU/m3 during the winter season, respectively. Notably, high bacterial concentration occurred in 80% of locations during the summer (dry-hot) season, while for fungi, it was 70% of locations during winter seasons. Fungal concentration was reported to be low during the summer (humid-hot) season. Culturable bacterial and fungal species were identified through detailed biochemical and microscopic analysis. Health-significant microorganisms identified include bacteria (Pseudomonas, Pasteurella, Pantoea, Proteus, Myroides, Chryseobacterium, Yersinia, Ochrobactrum, Sphingomonas, Vibrio) and fungi (Alternaria, Aspergillus, Fusarium, Rhizopus, Penicillium). The study detected the strongest antibiotic resistance during the summer (humid-hot) season, with all samples exhibiting resistance to Metronidazole, a common treatment for bacterial vaginosis and other inflammatory diseases. The investigation also yielded significant findings in two additional crucial areas: (i) Antibiotic Resistance Genes (ARG): Identification of critical and high-priority antibiotic-resistant strains, such as Acinetobacter baumannii and Staphylococcus aureus, indicating a significant public health concern for urban air quality. Temporal and spatial variations in ARG profiles further emphasized the complexity of the issue. (ii) Viral Diversity: A comprehensive array of viruses, including zoonotic and plant viruses, were detected. The presence of human pathogens like Escherichia coli and Orthohepevirus A (Hepatitis E virus) highlighted the potential for airborne disease transmission. This study underscores the intricate interplay between human, animal, and environmental health in urban ecosystems, aligning with previous research findings. The results emphasize the critical need for integrated surveillance to comprehensively understand bioaerosol composition and associated public health risks, especially in the context of Qatar's distinctive climatic conditions, where dust storms can significantly influence bioaerosol dynamics. The study advocates for heightened awareness and proactive public health measures to mitigate the risks associated with airborne pathogens and antibiotic resistance, aligning with recommendations from various health experts.

The improper disposal of agricultural food waste (AFW) and its associated plastic packaging significantly exacerbates environmental degradation, including pollution, greenhouse gas emissions, and loss of valuable resources, while imposing substantial economic burdens. These pressing challenges have spurred advancements in bioplastics as sustainable and eco‐friendly alternatives to conventional plastics. Here, the potential of AFW, rich in biopolymers such as starch and cellulose, as a renewable feedstock is examined for bioplastics such as polylactic acid, polybutylene succinate, and polyhydroxyalkanoates. It explores the characteristics of these bioplastics, focusing on production techniques such as extraction‐based processes, microbial fermentation, fermentation combined with polymerization, and synthesis from volatile fatty acids. Additionally, the role of AFW pretreatment methods, including physical, chemical, biological, and enzymatic approaches, in enhancing conversion efficiency is analyzed. Here, it is highlighted that recent advancements in bioplastic production have improved efficiency, biodegradability, and scalability, offering a viable substitute for traditional plastics. These findings demonstrate that valorizing AFW not only addresses plastic and food waste challenges but also promotes sustainability and circular economy principles, paving the way for greener industries and reduced ecological impact.