Characteristics, Sources, and Seasonal Variability of Dissolved Organic Matter (DOM) in the Ganges River, Bangladesh

Characterizing the effects of stormwater runoff on dissolved organic matter in an urban river (Jiujiang, Jiangxi province, China) using spectral analysis

“…This result indicates that rainwater runoff contained substantial amounts of organic matter, and the DOM of the river was mainly in uenced by terrestrial DOM inputs. This nding is consistent with the results reported for aquatic ecosystems, for which the DOM concentrations in water were observed to increase as a result of increased rainfall and runoff (Zhou et al 2015, Niloy et al 2021.…”

Contrasting seasons and land uses alter riverine dissolved organic matter composition

“…5c), suggesting that the sharp increase of these forms downstream is explained by a non-agricultural, but rather urban, source. A component similar to our C4 (λEx/λEm = 345/452), Peak W, has previously been identified in detergents and whitening agents (Mostofa et al, 2010;Niloy et al, 2021), which is coherent with an urban point source. However, C4 was not particularly dominant in the WWTP effluent (15.8% in effluent vs 21.9% in the downstream mainstem), suggesting that if the source of C4 is urban in our study, it may originate from overland flow rather than from the WWTP point source.…”

Biogeochemistry of the dissolved organic matter (DOM) in the estuarine rivers of Bangladesh–Sundarbans under different anthropogenic influences

“…HIX varied between 5.8 and 9.3 (mean = 7.1, σ = 1.5), implying that DOM components were intermediately humified, predominantly terrestrial derived, aromatic, matured, and contained high carbon in their composition ( Table 3 ). HIX values in the SMF-Bangladesh were higher than two major rivers in Bangladesh, the Ganges (2.7–7.8) and the Brahmaputra River (1.5–4.1) ( Niloy et al., 2021a , 2022 ).…”

“…SUVA 254 varied between 1.9 and 10.03 L/mg-m (mean= 4.3 L/mg-m, σ= 2.9), showing maximum and minimum values at Harbaria and Dublar char sampling stations in the SMF-Bangladesh ( Table 3 ). SUVA 254 in the SMF-Bangladesh were higher than the Ganges (1.2–5.5 L/mg-m) and the Brahmaputra River (0.3–1.5 L/mg-m) indicating having higher aromaticity than the two major rivers in Bangladesh ( Niloy et al., 2021a , 2022 ). SUVA 254 values were >3 L/mg-m at Kotka, Hiron point, and Mongla, and >6 L/mg-m at Harbaria, confirming that DOM at these sampling stations contained strong terrestrial signatures ( Table 3 ).…”

“…Hiron point and Dublar char contained the maximum and minimum S R values and thus suggesting the presence of comparatively low (LMW) and high molecular weight (HMW) DOM components in the SMF-Bangladesh ( Table 3 ). S R values between 0.04 and 0.9 in the Ganges River ( Niloy et al., 2021a ), 0.76 and 1.79 in the wetlands ( Helms et al., 2008 ), 0.7 and 2.4 in the lake water ( Zhang et al., 2010 ) were comparatively lower and thus confirmed the presence of higher molecular weighted DOM components than in the SMF-Bangladesh. Photo-degradation and microbial activity play vital roles in decreasing and increasing the molecular weight of DOM fractions, respectively ( Hansen et al., 2016 ).…”