RESUMO
In this work, we present the water quality assessment of an urban river, the San Luis River, located in San Luis Province, Argentina. The San Luis River flows through two developing cities; hence, urban anthropic activities affect its water quality. The river was sampled spatially and temporally, evaluating ten physicochemical variables on each water sample. These data were used to calculate a Simplified Index of Water Quality in order to estimate river water quality and infer possible contamination sources. Data were statistically analyzed with the opensource software R, 4.1.0 version. Principal component analysis, cluster analysis, correlation matrices, and heatmap analysis were performed. Results indicated that water quality decreases in areas where anthropogenic activities take place. Robust inferential statistical analysis was performed, employing an alternative of multivariate analysis of variance (MANOVA), MANOVA.wide function. The most statistically relevant physicochemical variables associated with water quality decrease were used to develop a multiple linear regression model to estimate organic matter, reducing the variables necessary for continuous monitoring of the river and, hence, reducing costs. Given the limited information available in the region about the characteristics and recovery of this specific river category, the model developed is of vital importance since it can quickly detect anthropic alterations and contribute to the environmental management of the rivers. This model was also used to estimate organic matter at sites located in other similar rivers, obtaining satisfactory results.
Assuntos
Monitoramento Ambiental , Rios , Qualidade da Água , Rios/química , Argentina , Monitoramento Ambiental/métodos , Análise Multivariada , Cidades , Poluentes Químicos da Água/análise , Análise de Componente PrincipalRESUMO
The continuous discharge of pharmaceutical compounds into the aquatic environment has raised concerns over the contamination of water resources. Urban activities and intensive animal breeding are important sources of contamination. The accumulation of antibiotics may lead to the transfer or alternatively maintain the presence of resistance genes in natural microbial communities existing in epilithic biofilms. The objective of this study was to evaluate the pharmaceutical contamination levels and the presence of resistance genes in biofilms from a South Brazilian watershed. The Guaporé watershed exhibits a high diversity of land use, including agricultural and urban areas with differing levels of anthropogenic pressure. Seventeen sites along the Guaporé watershed were monitored. Biofilm samples were collected in two seasons (winter and summer), and the pharmaceutical concentration and quantity of resistance genes were analyzed. All monitored sites were contaminated with pharmaceuticals. Agricultural activities contribute through transferring pharmaceuticals derived from the application of animal waste to agricultural fields. The most contaminated site (pharmaceuticals and bacterial resistance genes) was located in an urban area exposed to high pressure. Decreases in the contamination of biofilms were also observed, exemplifying processes of natural attenuation in the watershed. The quality of the biofilms sampled throughout the watershed served as a useful tool to understand and monitor environmental pollution.
Assuntos
Rios , Poluentes Químicos da Água , Animais , Rios/microbiologia , Monitoramento Ambiental , Poluentes Químicos da Água/toxicidade , Poluentes Químicos da Água/análise , Biofilmes , Preparações FarmacêuticasRESUMO
Parabens are preservatives widely used by industry since these compounds have antifungal properties, relative low cost, and stability over a wide pH range. This study aims to quantify and assess the environmental risks of methylparaben (MP), ethylparaben (EP), propylparaben (PP), and butylparaben (BP) in surface water from a Brazilian River, Mogi Guaçu. The State of São Paulo, including the Mogi Guaçu River region, suffered from a period of intense drought and high temperatures, which caused anomalies in river flows and water supply problems. The water samples were collected from 14 locations, along 300 km of river extension, at four different seasons. Samples were previously extracted and pre-concentrated by dispersive liquid-liquid microextraction (DLLME) and later analyzed by ultra-performance liquid chromatography coupled with electrospray ionization in tandem with mass spectrometry (UPLC-ESI-MS/MS) detector. During the sampling period, PP was detected in 89.3% of the water samples, MP in 87.5%, EP in 73.2%, and BP in 48.2%. The sum of parabens' average levels was 42.2 µg L-1 in Winter, 41.5 µg L-1 in Summer, 36.6 µg L-1 in Autumn, and 31.5 µg L-1 in Spring. These levels can be attributed to the smaller dilution effect caused by the drought period. Also, ecological risk assessment indicated that parabens could take a low, medium, and high risk for target organisms in the measured aquatic environments, especially considering Pimephales promelas where 15% of the samples do not present potential risk, 84% of samples can present medium risk and only 1% have low risk. Besides, the risks for BP are also considerably higher, when almost 40% presents for high risks and 60% for medium risks. The present study indicates worrisome threats to the water source and to allegedly protected biodiversity and, therefore, urgent actions are needed to effectively protect.