RESUMO
This is the first attempt that investigate the abundance of plasticizers in leachate sediment in the scientific literature, alongside the debut effort to explore the abundance of microplastics and plasticizers in landfill leachate and sediment in Sri Lanka. Microplastics in sizes ranging from ≥2.0-5.0, ≥1.0-2.0, and ≥ 0.5-1.0 mm were extracted from the leachate draining from ten municipal solid waste open dump sites and sediment samples covering seven districts. Microplastics were extracted by density separation (Saturated ZnCl2) followed by wet peroxide digestion and the chemical identification was conducted by Fourier Transform Infrared spectroscopy. Plasticizers were extracted to hexane and analyzed by high-performance liquid chromatography. The total mean microplastic abundance in leachate was 2.06 ± 0.62 mg/L whereas it was 363 ± 111 mg/kg for leachate sediments. The most frequently found polymer type was polyethylene (>50%), and white color was dominant. The average concentration of bisphenol A (BPA), benzophenone (BP) and diethyl-hydrogen phthalate (DHEP) in leachate was 158 ± 84.4, 0.75 ± 0.16 and 170 ± 85.8 µg/L respectively. Furthermore, BP and DHEP in leachate sediment was 100 ± 68.3 and 1034 ± 455 µg/kg respectively. As landfill leachate is directly discharged into nearby surface and groundwater bodies that serve as sources of drinking water, the study highlights the potential concerns of microplastic and plasticizer exposure to the surrounding Sri Lankan community through consumption of contaminated drinking water. Therefore, there is a timely need of develop the effective waste management and pollution control measures to minimize the possible threats to both the environment and human health.
RESUMO
Properly selecting landfill sites for waste disposal is crucial for mitigating environmental and public health risks. Geographic Information Systems (GISs) and Artificial Intelligence (AI) techniques have emerged as valuable tools for identifying suitable landfill locations. This study presents a systematic mapping study (SMS) that investigates the usage of GIS and AI in landfill site selection. We searched six databases (IEEE Xplore, ACM Digital Library, Science Direct, Emerald Insight, Taylor & Francis Online and Web of Science) using predefined keywords related to landfills, GIS and AI. From 858 initially retrieved articles, we selected 48 relevant articles for in-depth analysis. Our research aimed to answer various questions, such as publication trends, the geographic distribution of case studies, criteria for assessing landfill suitability, tools and techniques employed, preliminary site screening methods, decision-making processes, limitations and future research directions. We used bubble charts, bar charts and tables to visualize the results. The findings of our study highlight the growing interest in using GIS and AI for landfill site selection and emphasize the importance of incorporating multi-criteria decision-making techniques. Furthermore, the results reveal the need for developing more advanced AI models, addressing the limitations of current approaches and exploring novel visualization techniques for enhancing landfill site selection processes. This study provides valuable insights for researchers and practitioners in waste management, environmental science and geoinformatics. It sets the groundwork for future research on improving GIS- and AI-based landfill site selection methodologies.
RESUMO
Plastic wastes deposited in landfills eventually break down and degrade into microplastics by physical, chemical, and biological forces. Though microplastics in leachate pose significant threats to the environment, the leachate generated from landfills has not received much attention as a possible source of environmental microplastics. A descriptive and systematic investigationof the global distribution of microplastics in landfill leachate does not exist to date. Therefore, this attempt is to provide a concise scientometric review of the studies on the presence of microplastics in landfill leachate. The present review revealed that the global trend in research on microplastics in leachate has increased exponentially after 2018 and China is the leading country. Different geographical regions have reported different microplastic abundances with the highest of 291.0 ± 91.0 items/L from a landfill in Shanghai. The use of novel sampling techniques to detect small microplastics (20-100 µm) has led to the high abundance of microplastics in landfill leachate in Shanghai. Due to its widespread usage, polyethylene is the most typically encountered polymer type in landfill leachate around the world. However, it is quite challengingto compare the results among studies due to the use of different size categories and extraction techniques. The removal of microplastics by the current leachate treatment facilities is still mostly unexplored, thus it is crucial to develop novel technologies to treat the microplastics in landfill leachate. Further investigations on the transport of microplastics in landfill leachate are urgently required to have a better understanding of potential human exposure and health implications.
