scholarly journals Multivariate statistical evaluation of dissolved heavy metals and a water quality assessment in the Lake Aha watershed, Southwest China

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9660
Author(s):  
Shilin Gao ◽  
Zhuhong Wang ◽  
Qixin Wu ◽  
Jie Zeng

Heavy metals are of public concern in aquatic ecosystems due to their growing release from industries and mining activities. This study investigated the sources, temporal-spatial distributions and water quality of dissolved heavy metals (Mn, Co, Al, Ni, Ba, V, Sb, Fe, Sr) in the Lake Aha watershed, an area under the influence of sewage and acid mining drainage. These heavy metals displayed significant spatial and temporal variabilities. The water quality index results (WQI values ranged from 3.21 to 15.64) and health risk assessment (all hazard indexes are below 1) indicated that dissolved heavy metals in this study pose a low risk for human health. Correlation analysis and principal component analysis indicated that Fe and Sr mainly presented a natural geological feature in the study area, and Mn, Co, Al and Ni were influenced by the acid coal mine drainage, whereas Ba, V and Sb were under the impact of local industrial or medical activities. This study provides new insights into the risk assessment of heavy metals in small watersheds.

2021 ◽  
Vol 11 (14) ◽  
pp. 6592
Author(s):  
Ana Moldovan ◽  
Maria-Alexandra Hoaghia ◽  
Anamaria Iulia Török ◽  
Marius Roman ◽  
Ionut Cornel Mirea ◽  
...  

This study aims to investigate the quality and vulnerability of surface water (Aries River catchment) in order to identify the impact of past mining activities. For this purpose, the pollution and water quality indices, Piper and Durov plots, as well vulnerability modeling maps were used. The obtained results indicate that the water samples were contaminated with As, Fe, Mn, Pb and have relatively high concentrations of SO42−, HCO3−, TDS, Ca, K, Mg and high values for the electrical conductivity. Possible sources of the high content of chemicals could be the natural processes or the inputs of the mine drainage. Generally, according to the pollution indices, which were correlated to high concentrations of heavy metals, especially with Pb, Fe and Mn, the water samples were characterized by heavy metals pollution. The water quality index classified the studied water samples into five different classes of quality, namely: unsuitable for drinking, poor, medium, good and excellent quality. Similarly, medium, high and very high vulnerability classes were observed. The Durov and Piper plots classified the waters into Mg-HCO3− and Ca-Cl− types. The past and present mining activities clearly change the water chemistry and alter the quality of the Aries River, with the water requiring specific treatments before use.


2021 ◽  
pp. 56-77
Author(s):  
Thyego Silva ◽  
Mariucha Lima ◽  
Teresa Leitão ◽  
Tiago Martins ◽  
Mateus Albuquerque

A hydrochemical study was conducted on the Quaternary Aquifer, in Recife, Brazil. Groundwater samples were collected in March–April 2015, at the beginning of the rainy season. Conventional graphics, ionic ratios, saturation indices, GIS mapping, and geostatistical and multivariate statistical analyses were used to water quality assessment and to characterize the main hydrochemical processes controlling groundwater’s chemistry. Q-mode hierarchical cluster analysis separated the samples into three clusters and five sub-clusters according to their hydrochemical similarities and facies. Principal Component Analysis (PCA) was employed to the studied groundwater samples where a three-factor model explains 80% of the total variation within the dataset. The PCA results revealed the influence of seawater intrusion, water-rock interaction, and nitrate contamination. The physico-chemical parameters of ~30% groundwaters exceed the World Health Organization (WHO) guidelines for drinking water quality. Nitrate was found at a concentration >10 mg NO3−/L in ~21% of the wells and exceeded WHO reference values in one. The integrated approach indicates the occurrence of the main major hydrogeochemical processes occurring in the shallow marine to alluvial aquifer as follow: 1) progressive freshening of remaining paleo-seawater accompanying cation exchange on fine sediments, 2) water-rock interaction (i.e., dissolution of silicates), and 3) point and diffuse wastewater contamination, and sulfate dissolution. This study successfully highlights the use of classical geochemical methods, GIS techniques, and multivariate statistical analyses (hierarchical cluster and principal component analyses) as complementary tools to understand hydrogeochemical processes and their influence on groundwater quality status to management actions, which could be used in similar alluvial coastal aquifers.


Water ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2078
Author(s):  
Jie Zeng ◽  
Guilin Han ◽  
Mingming Hu ◽  
Yuchun Wang ◽  
Jinke Liu ◽  
...  

Dissolved heavy metals (HMs), derived from natural and anthropogenic sources, are an important part of aquatic environment research and gain more international concern due to their acute toxicity. In this study, the geochemistry of dissolved HMs was analyzed in the upper Three Gorges Reservoir (TGR) of the Yangtze River (YZR) watershed to explore their distribution, status, and sources and further evaluate the water quality and HM-related risks. In total, 57 water samples were collected from the main channel and tributaries of the upper TGR. The concentrations of eight HMs, namely V, Ni, Cu, Zn, As, Mo, Cd, and Pb, were measured by ICP-MS. The mean concentrations (in μg/L) of eight HMs decreased in the order: As (1.46), V (1.44), Ni (1.40), Mo (0.94), Cu (0.86), Zn (0.63), Pb (0.03), and Cd (0.01). The concentrations of most HMs were 1.4~8.1 times higher than that in the source area of the YZR, indicating a potential anthropogenic intervention in the upper TGR. Spatially, the concentrations of V, Cu, As, and Pb along the main channel gradually decreased, while the others were relatively stable (except for Cd). The different degrees of variations in HM concentrations were also found in tributaries. According to the correlation analysis and principal component (PC) analysis, three PCs were identified and explained 75.1% of the total variances. combined with the concentrations of each metal, PC1 with high loadings of V, Ni, As, and Mo was considered as the main contribution of human inputs, PC2 (Cu and Pb) was primarily attributed to the contribution of mixed sources of human emissions and natural processes, and Zn and Cd in PC3 were controlled by natural sources. Water quality assessment suggested the good water quality (meeting the requirements for drinking purposes) with WQI values of 14.1 ± 3.4 and 11.6 ± 3.6 in the main channel and tributaries, respectively. Exposure risk assessment denoted that the health effects of selected HMs on the human body were limited (hazard index, HI < 1), but the potential risks of V and As with HI > 0.1 were non-negligible, especially for children. These findings provide scientific support for the environmental management of the upper TGR region and the metal cycle in aquatic systems.


2021 ◽  
Vol 14 (2) ◽  
pp. 694
Author(s):  
Micael De Souza Fraga ◽  
Laura Thebit de Almeida ◽  
Marcel Carvalho Abreu ◽  
Felipe Bernardes Silva ◽  
Guilherme Barbosa Reis ◽  
...  

No estado de Minas Gerais, as campanhas de coleta e análise da qualidade da água nos corpos hídricos contemplam até 51 variáveis, o que dificulta a análise e interpretação desse conjunto de dados e a identificação das variáveis determinantes para a qualidade da água. Diante disso, o objetivo deste trabalho foi identificar as principais fontes de poluição, bem como o comportamento da qualidade da água ao longo do tempo de monitoramento, por meio de diferentes análises estatísticas na circunscrição hidrográfica do rio Piranga. Pelos resultados obtidos, a análise fatorial/análise de componentes principais apontou a alta susceptibilidade que a bacia apresenta à erosão do solo, a contaminação pelo lançamento de efluentes domésticos e a variabilidade da qualidade das águas em virtude dos metais pesados. As variáveis Escherichia coli, ferro dissolvido, fósforo total e manganês total apresentaram os valores de violação da classe de enquadramento mais críticos. A análise de tendência mostrou padrões diferentes para o índice de qualidade da água e para as variáveis mais relevantes para a qualidade da água. Dentre as variáveis que compõe o índice, destacam-se as tendências de aumento de nitrato em todas as estações analisadas. De maneira geral, os resultados mostraram que a qualidade da água na área de estudo varia em função da erosão do solo, do alto grau de contaminação por efluentes domésticos, da poluição difusa advinda das áreas agrícolas e dos metais pesados, sendo as variáveis de qualidade da água vinculadas a estes fatores as mais importantes. Surface water quality assessment in the hydrographic region of the Piranga River using multivariate and non-parametric statistical analysis ABSTRACTIn the state of Minas Gerais, campaigns to collect and analyze water quality in water bodies include up to 51 variables, which makes it difficult to analyze and interpret this data set and to identify the determining variables for water quality. Therefore, the objective of this work was to identify the main sources of pollution, as well as the behavior of water quality over the monitoring time, through different statistical analyzes in the hydrographic region of the Piranga River. Based on the results obtained, the factor analysis/principal component analysis out the high susceptibility that the hydrographic region presents to soil erosion, contamination by the release of domestic effluents and the variability of water quality due to heavy metals. The variables Escherichia coli, dissolved iron, total phosphorus and total manganese presented the most critical values of violation of the framework class. The trend analysis showed different patterns for the water quality index and for the most relevant variables for water quality. Among the variables that make up the index, the trends of nitrate increase in all analyzed stations stand out. In general, the results showed that the water quality in the unit varies depending on soil erosion, the high degree of contamination by domestic effluents, the diffuse pollution from agricultural areas and heavy metals, with water quality variables being linked to these factors the most important.Keywords: environmental analysis, Minas Gerais, water pollution, water resources.


Author(s):  
Bin Liang ◽  
Guilin Han ◽  
Jie Zeng ◽  
Rui Qu ◽  
Man Liu ◽  
...  

Dissolved heavy metals are not only the essential micronutrients, but also the toxic elements for human bodies. To investigate the heavy metal sources and assess the water quality of the Lancangjiang River, dissolved Cr, Ni, Cu, Zn, Mo, and Pb were detected in this study. The results show that dissolved Ni and Mo, Cr and Pb, and Cu and Zn were similarly distributed within the drainage basin. The correlation analysis exhibited that dissolved Ni and Mo had correlation with water parameter, and dissolved Cu was weakly correlated with Ni, indicating that they might be affected by natural processes. The principal component analysis explained 68.342% of the total variance for three principal components, of which dissolved Ni, Mo, and Cu were controlled by natural inputs; dissolved Cu and Cr were affected by anthropogenic activities; and dissolved Zn was influenced by agricultural activities in the downstream. The water quality showed that the water in upstream was worse than in midstream and downstream, and the whole drainage basin had water of excellent quality. Water within the drainage basin poses no risks to human bodies via daily diets and dermal routes. Dissolved Zn, Cu, and Mo occupied the major proportion of heavy metals transporting into the Mekong River. The agricultural inputs of dissolved Zn might pose potential risks to the Mekong River.


Sign in / Sign up

Export Citation Format

Share Document