Ecotoxicological impacts of landfill sites: Towards risk assessment, mitigation policies and the role of artificial intelligence.

Waste disposal in landfills remains a global concern. Despite technological developments, landfill leachate poses a hazard to ecosystems and human health since it acts as a secondary reservoir for legacy and emerging pollutants. This study provides a systematic and scientometric review of the nature and toxicity of pollutants generated by landfills and means of assessing their potential risks. Regarding human health, unregulated waste disposal and pathogens in leachate are the leading causes of diseases reported in local populations. Both in vitro and in vivo approaches have been employed in the ecotoxicological risk assessment of landfill leachate, with model organisms ranging from bacteria to birds. These studies demonstrate a wide range of toxic effects that reflect the complex composition of leachate and geographical variations in climate, resource availability and management practices. Based on bioassay (and other) evidence, categories of persistent chemicals of most concern include brominated flame retardants, per- and polyfluorinated chemicals, pharmaceuticals and alkyl phenol ethoxylates. However, the emerging and more general literature on microplastic toxicity suggests that these particles might also be problematic in leachate. Various mitigation strategies have been identified, with most focussing on improving landfill design or leachate treatment, developing alternative disposal methods and reducing waste volume through recycling or using more sustainable materials. The success of these efforts will rely on policies and practices and their enforcement, which is seen as a particular challenge in developing nations and at the international (and transboundary) level. Artificial intelligence and machine learning afford a wide range of options for evaluating and reducing the risks associated with leachates and gaseous emissions from landfills, and various approaches tested or having potential are discussed. However, addressing the limitations in data collection, model accuracy, real-time monitoring and our understanding of environmental impacts will be critical for realising this potential.

Abundance, characteristics, and risk assessment of microplastics in indigenous freshwater fishes of India.

Microplastic (MP) pollution has pressing concerns regarding environmental health and the availability of safe food for humans. Information on the occurrence of MP in freshwater biota in the Indian scenario is currently lacking. The present study examined MP contamination in edible and non-edible tissues of widely consumed freshwater fishes. All the fish species (n = 35/species) analyzed had microplastic contamination with the highest MP abundance of 7.86 ± 2.0 items/individual in Channa punctatus followed by Labeo rohita (4.17 ± 0.6 items/individual) and Labeo bata (3.03 ± 0.4 items/individual); whereas MP abundance in small indigenous fishes (SIF) such as Salmostoma bacaila and Puntius amphibius accounts for 0.83 ± 0.13 and 0.77 ± 0.2 items/individual respectively. The principal component analysis results showed a 77.434% variance from two components identified for MP distribution. Fibre type MP was the most dominant type besides fragments and pellets that opined the type of MP required for ecotoxicity assessment, the need of the hour. Raman spectroscopy analysis confirms high-density and low-density polyethylene-type polymers. Evidence of MP in edible tissue indicates the translocation phenomenon resulting in human exposure through the consumption of biota contaminated with MP. Risk assessment revealed a low risk of MP based on its abundance while polymer type indicates a high risk for the fish species investigated. A thorough investigation of the level of adsorbed organic contaminants in the MP is warranted to address the interactive effects on biota. To the best of our knowledge, this is the first detailed report on MP contamination and its risk assessment in Indian freshwater fishes.