RESUMEN
This study aims to identify continuous water quality changes and identify fluorescence properties from urban rivers to marine zones. Various types of natural and anthropogenic sources derived dissolved organic matter (DOM) have been identified in this study. These include soil-derived DOM, plant remnants, and soluble particles produced when organic material partially decomposes and is released by microorganisms, such as bacteria, algae, and plants. DOM was characterized using a three-dimensional excitation-emission matrix (3DEEM), parallel factor analysis (PARAFAC), and water quality parameters from the Buriganga River, Dhaka to Patenga Seaport, Chittagong, along with the Shitalakshya River, a small portion of the Padma River, and the Meghna River. To better understand the data analysis, the study area was divided into three central regions: urban industrial rivers, industrial estuarine rivers, and marine zones. In the urban industrial river, 3DEEM and PARAFAC identified five fluorophores (peaks: A, C, M, T, and Tuv) with five components: detergent-like, fulvic-like, tryptophan or protein-like, fulvic-like (C-type), and protein-like, which might originate from the industrial activities and sewage pollution. In the industrial estuarine river zone, three fluorophores have been identified (peaks: A, C, Tuv) with two known components, namely, fulvic acid (A-type) and fulvic acid (C-type), with an unknown photoproduct at Ex/Em = 295/368 (peak Tuv). Components in the industrial river zone may originate from terrestrial sources, indicating vegetation along the river. In the marine zone, four fluorophores have been identified (peaks: Tuv, A, T, C) with two components, that is, protein- or tryptophan-like and humic acid-like from coral origin. The intensities of both fulvic-like and protein-like substances were high in urban industrial river water owing to industrial activity and sewage pollution. SUVA254 suggests high aromaticity in all three regions, whereas the optical properties suggest that terrestrial and microbial components are present in the urban industrial and estuarine rivers. This further indicates that urban industrial river water quality is highly polluted. The lowest degradation potential index (DPI) in the marine zone might result from the presence of the highest number of dissolved solids in the water, and the highest DPI of industrial estuarine rivers explains the comparatively high presence of terrestrial-derived humic (A)- and humic (C)-like components in the ratio to the unknown photoproduct of mid-wavelength. PRACTITIONER POINTS: This study's uniqueness is a 220-km cruise from an urban river to a coastal seaport to analyze fluorescence properties. The study found that most water parameters were within the DoE standards, except for DO, which was consistently low. 3DEEM-PARAFAC identified five fluorophores linked to detergent, fulvic, and protein-like substances from sewage and industrial sources. Our study concludes that microbial and terrestrial sources dominate dissolved organic matter in urban, estuarine, and marine regions.
Asunto(s)
Monitoreo del Ambiente , Ríos , Calidad del Agua , Ríos/química , Compuestos Orgánicos/análisis , Contaminantes Químicos del Agua/análisis , Fluorescencia , CiudadesRESUMEN
This study focused on the current situation and management after the end-of-life solar photovoltaic (PV) module in Bangladesh. The solar PV cells have a lifetime to serve properly, which is about 15-25 years from installation. Solar PV cell has recycling potentiality as well as the risk of producing hazardous wastes. After the end-of-life, the solar panel would turn into waste, specifically e-waste, which might be an environmental concern in the long run. Thus, it is crucial to estimate the waste production and to delineate the environment-friendly management. Therefore, this study aims to visualize the present status of solar PV cells, potential waste generation, and their management perspectives in Bangladesh. We also studied the existing policy of waste management. This study followed a mixed methodological approach, including the key informant interview (KIIs), synthesis of existing literature-based findings, stakeholder consultation and secondary data inventory. From the results, it was found that Bangladesh has huge potential to generate solar PV-based e-waste in the near future that needs to be tackled with high priority. A total about 33205.36 tonnes of potential e-waste can be generated from installed PV cells. A suitable management system might be able to recover materials such as glass (24,468 tonnes), aluminium (2,656.43 tonnes), silicon (1404. 92 tonnes), and copper (49.89 tonnes) from the PV cells wastes. As there is an excellent opportunity to recover resources from the waste panels, there is also scope to grow enterprise for recycling of waste panels. Unfortunately, such policy or plan from the government is yet to be taken into account. However, a long-term national plan is required to manage this waste, maintaining the high standard based on in-depth research.