Multivariate analyses of the effect of an urban wastewater treatment plant on spatial and temporal variation of water quality and nutrient distribution of a tropical mid-order river

Abstract

Freshwater resources are increasingly scarce due to human activities, and the understanding of water quality variations at different spatial and temporal scales is necessary for adequate management. Here, we analyze the hypotheses that (1) the presence of a wastewater treatment plant (WWTP) and (2) a polluted tributary that drains downstream from the WWTP change the spatial patterns of physicochemical variables (pH, turbidity, dissolved oxygen, and electrical conductivity) and nutrient concentrations (reactive soluble phosphorus, total phosphorus, nitrogen series, total nitrogen, and total dissolved carbon) along a mid-order river in SE Brazil and that these effects depend on rainfall regime. Six study sites were sampled along almost 4 years to evaluate the impacts of human activities, including sites upstream (1-3) and downstream (5-6) from the WWTP. The impacts were observed presenting an increasing trend from the source (site 1) towards Água Quente stream (site 4, the polluted tributary), with signs of attenuation at site 5 (downstream from both WWTP and site 4) and the river mouth (site 6). Input of nutrients by rural and urban runoff was observed mainly at sites 2 and 3, respectively. At sites 4 and 5, the inputs of both untreated and treated wastewaters increased nutrient concentrations and changed physicochemical variables, with significant impacts to Monjolinho River. Seasonal variations in the measured values were also observed, in agreement with the pluviometric indexes of the region. Univariate analyses suggested no effect of the WWTP for most variables, with continued impacts at sites downstream, but non-parametric multivariate analysis indicated that these sites were recovering to chemical characteristics similar to upstream sites, apparently due to autodepuration. Therefore, multivariate methods that allow rigorous tests of multifactor hypotheses can greatly contribute to determine effects of both point and non-point sources in river systems, thus contributing to freshwater monitoring and management.

Ecosystemic Assessment of Surface Water Quality in the Virilla River: Towards Sanitation Processes in Costa Rica

“…Untreated wastewater discharges are the main source of surface water pollution in urban areas [7][8][9][10]. They reduce the quality of the water body and stimulate the proliferation of pathogenic organisms that can cause severe diseases concerning public health [11][12][13].…”

Non-Lactobacillus-Dominated Vaginal Microbiota Is Associated With a Tubal Pregnancy in Symptomatic Chinese Women in the Early Stage of Pregnancy: A Nested Case–Control Study

“…Principal component analysis (PCoA) was applied to further discover the community structure using statistical analysis of metagenomic profiles (STAMP). Analysis of similarities (ANOSIM) with 999 permutations was done using PRIMER-e 7.0 (www.primer-e.com/) to test the significant separation between groups in PCoA (Barrenha et al, 2017).…”

Aspectos del contexto socioambiental que inciden en la contaminación del recurso hídrico en un cantón urbano

“…Nota: Fuentes potenciales de contaminación al recurso hídrico por vertidos actividades comerciales, productivas y de vivienda que en estos se desarrollan, así como las consecuencias ocasionadas por efectos de impermeabilización y escorrentía de los suelos (de Mello et al, 2020;Song, Song, Shao y Hu, 2020). Así mismo, estudios han demostrado una relación entre aumento de contaminación del agua superficial con respecto al aumento de poblacional (Barrenha et al, 2018;Calvo-Brenes & Mora-Molina, 2012).…”