Evaluation of Water Quality and Heavy Metals in Wetlands along the Yellow River in Henan Province

Abstract

Assessing spatiotemporal variation in water quality and heavy metals concentrations in wetlands and identifying metal contamination source are crucial steps for the protection and sustainable utilization of water resources. Using the water quality identification index (Iwq), heavy metal pollution index (HPI), hierarchical cluster analysis (HCA) and redundancy analysis (RDA), we evaluated spatiotemporal variation in water quality and heavy metals concentrations, and their interrelation in wetlands along the middle and lower Yellow River. The average Iwq was highest during flood season but the average HPI was lowest in the same season. Meanwhile, the trend in mean HPI across three hydrological seasons was the opposite to that of mean Iwq. There was significant variation in wetlands water pollution status across seasons. During the flood season, the wetlands in the affected area with hanging river were seriously polluted. In other seasons, pollution in the artificial wetlands was even more severe. Moreover, serious pollution of wetlands in belt transect #03 (Yuanyang-Zhongmu) was more frequent. Dissolved oxygen and chemical oxygen demand strongly influenced heavy metal concentrations, while other water quality parameters had different influences on heavy metal concentrations in different hydrological seasons. The causes of water pollution were divided into natural factors and human disturbance (with potential relationships between them). The polluted wetlands were greatly affected by the Yellow River during the flood season while they were more impacted by agricultural and domestic sewage discharge in other seasons. However, heavy metal deposition and leaching into riparian wetlands were still affected by diverse channel conditions. If this trend is allowed to continue unabated, wetlands along the middle and lower Yellow River are likely to lose their vital ecological and social functions.

Modification of the Water Quality Index (WQI) Process for Simple Calculation Using the Multi-Criteria Decision-Making (MCDM) Method: A Review

“…), but few of them reported that they directly used the formula for water quality assessment (CCMEWQI) [20]. Furthermore, the WQI method has been applied for different purposes, but mainly for surface water quality (especially for river water) [21][22][23][24][25][26][27][28][29], groundwater quality [1,[30][31][32][33][34][35][36], and wetland [37][38][39][40][41][42] across the world. Moreover, the Environmental Protection Agency (EPA) of the Republic of Serbia also utilizes WQI to inform about the overall status of the river water system [43].…”

Heavy Metals and Related Human Health Risk Assessment for River Waters in the Issyk−Kul Basin, Kyrgyzstan, Central Asia

“…The statistical characteristics of hydrochemical data including major ions and heavy metals (Table 2) cannot explain the relationship between various chemical proxies, so we used the hierarchical cluster analysis (HCA) [49] to clarify the possible influences on heavy metals in the river waters of the Issyk−Kul Basin [50][51][52][53]. The chemical compositions of the river waters were analysed at different periods using HCA.…”

Hydrochemical composition and potentially toxic elements in the Kyrgyzstan portion of the transboundary Chu-Talas river basin, Central Asia

“…Factors influencing the chemical composition of river waters in the Chu-Talas Basin. Cluster analysis [35][36][37][38][39] was used to reveal the differences between potentially toxic elements and major ions, and differences among water samples from the Chu-Talas Basin. The method of Euclidean distance was used in the cluster analysis for the similarity measure, and the method of Ward's minimum variance was used for the clustering of variables and row dendrograms.…”