Spatiotemporal variability and key influencing factors of river fecal coliform within a typical complex watershed

Abstract

a b s t r a c tFecal coliform bacteria are a key indicator of human health risks; however, the spatiotemporal variability and key influencing factors of river fecal coliform have yet to be explored in a rural-suburban-urban watershed with multiple land uses. In this study, the fecal coliform concentrations in 21 river sections were monitored for 20 months, and 441 samples were analyzed. Multivariable regressions were used to evaluate the spatiotemporal dynamics of fecal coliform. The results showed that spatial differences were mainly dominated by urbanization level, and environmental factors could explain the temporal dynamics of fecal coliform in different urban patterns except in areas with high urbanization levels. Reducing suspended solids is a direct way to manage fecal coliform in the Beiyun River when the natural factors are difficulty to change, such as temperature and solar radiation. The export of fecal coliform from urban areas showed a quick and sensitive response to rainfall events and increased dozens of times in the short term. Landscape patterns, such as the fragmentation of impervious surfaces and the overall landscape, were identified as key factors influencing urban non-point source bacteria. The results obtained from this study will provide insight into the management of river fecal pollution.

Spatiotemporal variations of DOM in a typical multi-source watershed in northern China: A fluorescent evidence

“…Tryptophan-like component C3 (280/290 ~ 350nm) was a kind of biodegradable protein-like substance, associating with the aromatic ring structure of amino acids in DOM. Fluorescence peaks of C3 (280/290 ~ 350nm) appeared in a region with a shorter wavelength of emission (λ Em < 380nm) (Zhang et al, 2020). The component was closely related to the organic matter in sewage, which was regarded as anthropogenic or produced from plankton action over anthropogenic organics (Meng et al, 2013).…”

“…What's more, the ultraviolet fulvic acid-like component (235-250/385-430nm) contained a large number of phenolic hydroxyl carbonyl groups and other functional groups. And these humic-like uorescence peaks both have connections with its hydroxyl and carboxyl groups in the structure (Zhang et al, 2020). Humic-like C1 (230, 335/400nm) and C2 (260, 360/450nm) usually indicated terrestrial humus and anthropogenic activities that came from forest streams (Derrien et al, 2018), agricultural basins (Williams et al, 2013), stormwater (Graeber et al, 2012), sewage (Fuss et al, 2017).…”

“…The composition and spatiotemporal variations of DOM can exhibit the nutritional status of the river, and also directly affect the nutrient cycle and material exchange in the surface water ecosystem (Fellman et al, 2010;Hu et al, 2021;Li et al, 2020b). Besides, spatiotemporal characteristics of DOM are of great signi cance to adjust the capacity of pollutant endurance and sustainable safety (Zhang et al, 2020). Moreover, complex sources are crucial factors in river pollution.…”

“…However, with the rapid economic development and the intensi cation of human activities, water pollution in the North Canal River watershed has become increasingly serious. In recent years, researches on the North Canal River watershed have focused on the concentration and risk of heavy metals, pharmaceuticals, and personal care products, polycyclic aromatic hydrocarbons, microbial diversity, and different nitrogen and phosphorous in water and sediment (Dai et al, 2015;Guo et al, 2020;Liu et al, 2019a;Qiao et al, 2020;Zhang et al, 2020). For all this, the composition and source of DOM in the North Canal River watershed and its relationship with water quality are still lacking.…”

Characteristics of runoff pollution in a highly urbanized region: A case study in the Dongguan City

“…Also, large amounts of pollutants are transported to drainage systems and downstream water bodies during rainfall events, causing severe runoff pollution [1]. Some research has shown that this pollution can lead to serious deterioration of urban water quality and greatly affect the health of both human beings and aquatic organisms [2]. It is of great importance to systematically analyse the characteristics of runoff pollution in some typical highly urbanized regions considering landscape patterns and rainfall events.…”