Department of Environmental Science, Bangladesh University Professionals, Dhaka, 1216, Bangladesh.
Department of Environmental Science and Resource Management, Mawlana Bhashani Science and Technology University, Santosh, Tangail, 1902, Bangladesh.
Environ Monit Assess. 2024 Nov 26;196(12):1252. doi: 10.1007/s10661-024-13419-y.
Urban lakes are vital to ecosystems, providing essential services and recreational spaces in densely populated megacities. However, rapid urbanization and anthropogenic activities, particularly eutrophication driven by macronutrient accumulation, severely threaten these water bodies. This study underscores the critical need for continuous trophic state monitoring to sustain fish, wildlife, and plant ecosystems. The trophic status of Dhanmondi, Gulshan, and Banani Lakes in Dhaka City, Bangladesh, was assessed using Carlson's Trophic State Index (CTSI) and Burn's Trophic Level Index (BTLI), based on chlorophyll a (Chl-a), total phosphorus (TP), Secchi disc depth (SD), and total nitrogen (TN). Water samples from five sites per lake were analyzed for physicochemical parameters from June 2023 to May 2024, revealing monthly and seasonal variations. The study revealed that Dhanmondi Lake's CTSI ranged from 69.3 to 79.5 (June 2023 to March 2024), indicating initial "Eutrophic" conditions progressing to "Hypereutrophic." Gulshan Lake consistently showed "Hypereutrophic" conditions, with CTSI values between 84.1 and 97.3. Banani Lake was "Eutrophic" in June and July 2023, transitioning to "Hypereutrophic" from August 2023 to May 2024 (84.1-97.7). The Trophic Level Index (TLI) showed the "Hypereutrophic" status with a progressive monthly escalation for all the lakes. The Water Quality Index (WQI) categorized the lakes as "Poor" to "Very Poor" from June to August 2023, becoming "Unsuitable" from September 2023 to May 2024, indicating significant anthropogenic stress. Principal component analysis (PCA) identified nutrient infiltration, soil erosion, waste discharge, and organic residue accumulation as key pollution drivers. The study advocates for a multi-sectoral strategy to regulate nutrient loading and mitigate eutrophication, emphasizing best management practices for urban lake conservation.
城市湖泊对生态系统至关重要，为人口密集的特大城市提供了必要的服务和娱乐空间。然而，快速的城市化和人为活动，特别是由大量营养物质积累引起的富营养化，严重威胁着这些水体。本研究强调了持续进行营养状态监测以维持鱼类、野生动物和植物生态系统的迫切需要。本研究使用卡尔森营养状态指数（CTSI）和伯恩营养级指数（BTLI）评估了孟加拉国达卡市的 Dhanmondi、Gulshan 和 Banani 湖的营养状态，这些指数基于叶绿素 a（Chl-a）、总磷（TP）、塞氏盘深度（SD）和总氮（TN）。从 2023 年 6 月到 2024 年 5 月，从每个湖泊的五个地点采集水样，分析理化参数，揭示了月际和季节性变化。研究表明，Dhanmondi 湖的 CTSI 范围在 69.3 到 79.5 之间（2023 年 6 月至 2024 年 3 月），表明最初的“富营养化”条件逐渐发展为“过营养化”。Gulshan 湖一直处于“过营养化”状态，CTSI 值在 84.1 到 97.3 之间。Banani 湖在 2023 年 6 月和 7 月处于“富营养化”状态，从 2023 年 8 月到 2024 年 5 月（84.1-97.7）过渡到“过营养化”。营养级指数（TLI）显示所有湖泊的“过营养化”状态逐月升级。从 2023 年 6 月到 8 月，水质指数（WQI）将这些湖泊分类为“差”到“很差”，从 2023 年 9 月到 2024 年 5 月，WQI 为“不适宜”，表明存在严重的人为压力。主成分分析（PCA）确定了营养物质渗透、土壤侵蚀、废物排放和有机残留物积累是关键的污染驱动因素。本研究提倡采取多部门战略来调节营养负荷和减轻富营养化，强调城市湖泊保护的最佳管理实践。
