Influence of upstream land use on dissolved organic matter and trihalomethane formation potential in watersheds for two different seasons

Abstract

Different land uses of upstream catchments may affect the quantity and the quality of dissolved organic matter (DOM) in watersheds, but the influence may differ by season. In this study, we examined concentrations and selected spectroscopic properties of DOM and the propensity to form trihalomethanes (THMs) for 19 different middle-sized watersheds across the Han River basin in Korea. Sampling was conducted for non-storm events during pre-monsoon (May) and monsoon seasons (July). The anthropogenic land uses including agricultural and residential areas occupied 2.3 to 49.4% of the upstream catchments of the watersheds. Non-aromatic, labile, and less condensed DOM structures were more abundant in the monsoon season. Parallel factor analysis (PARAFAC) modeling with fluorescence data demonstrated that a combination of three different fluorescence components could explain the seasonal and the spatial distributions of DOM characteristics. Terrestrial humic-like fluorescence was the most abundant component for all the DOM samples, while protein-like fluorescence became more pronounced for the monsoon season. THM concentrations did not differ between the two seasons. Observed seasonal differences in the concentrations and the characteristics of DOM suggested a greater contribution of groundwater to the streams in watersheds in the monsoon versus the pre-monsoon season. Significant correlations among anthropogenic land use, microbial humic-like fluorescence, and the propensity to form THMs were found only for the pre-monsoon season. Principal component analysis (PCA) demonstrated that, regardless of the season, anthropogenic land uses increased the concentrations of DOM and nutrients but that their effects on the DOM properties were not evident for the monsoon season.

Hydrochemistry, water quality and land use signatures in an ephemeral tidal river: implications in water management in the southwestern coastal region of Bangladesh

“…Anthropogenic activities are increasing day by day leading towards conversion of pristine lands, increasing urban residences, surface water runoff, wastewater input and dwindling forested lands and wetlands. Literatures suggest the practice of land use changes has an impact spanning from local to global scale (e.g., Wilson and Weng 2010;Yang et al 2012;Hur et al 2014;Roy et al 2015, etc. ), ranging from changes in the global carbon cycle (e.g., Pielke et al 2002;Kalnay and Cai 2003;Don et al 2011;Poeplau et al 2011, etc.…”

Recognition of spatial framework for water quality and its relation with land use/cover types from a new perspective: A case study of Jinghe Oasis in Xinjiang, China

“…Accurate information on the spatial distribution of surface water quality is imperative for assessment of environmental monitoring, land surface water management as well as watershed changes (NRC, 2008;Sun et al, 2012). Land use/cover change in drainage basins significantly influences water quality in rivers, lakes, river mouths, and coastal areas (Huang et al,2013a;Bu et al,2014;Hur et al,2014). Surface water resources, through runoff or infiltration, will always carry a huge amount of pollutants (Swaney et al,2012).…”

Advanced Residuals Analysis for Determining the Number of PARAFAC Components in Dissolved Organic Matter

“…DOM has many important functions in natural and engineered systems, such as: providing shelter, energy, and nutrients for microbes; [1][2][3] regulating the mobility and toxicity of heavy metals and other pollutants; [4][5][6] and generating carcinogenic disinfection by-products during water purification. [7][8][9] Fluorescence excitation-emission matrices (EEMs) are produced by aligning fluorescence emission scans measured at several excitation wavelengths. 10 Parallel factor (PARAFAC) analysis models the variation in fluorescence across a set of EEMs by minimizing the least-squares error in a tri-linear regression of correlated excitationemission (Ex/Em) pairs.…”