Zheming Shi

Distributions, Sources, and Species of Heavy Metals/Trace Elements in Shallow Groundwater Around the Poyang Lake, East China

The shallow groundwater in the Poyang Lake area is one of the important sources of drinking water. However, there has been no systematic assessment on the groundwater quality associated with human consumptions. Here, we reported the concentrations and distributions of heavy metals/trace elements in the groundwater. Geographic Information System, ions relationship, and geochemical modeling program PHREEQC were used to investigate the distributions, sources, and chemical species of heavy metals/trace elements. The results showed that most of the shallow groundwater samples in the Poyang Lake area were in neutral or slightly acidic and oxidizing environment. The concentrations of Fe, Cr, Se, Cu, Zn, As, and Cd in most of the shallow groundwater samples were not significant in the area. However, the concentrations of Mn, Al in a few of samples and Pb in half of samples exceeded the limits, which makes the water unsuitable for drinking. The chemical components of shallow groundwater originated mainly from the dissolution of minerals and the input of anthropogenic activities. The concentrations and distributions of Pb, Mn, Al in groundwater largely depended on the dissolution of silicate and carbonate minerals, as well as the influence of human activities, as some of samples with high concentrations were found near industrial and domestic sites. The dissolution of minerals dominated the concentration distributions of Sr, Si, and Li. The concentrations of Al and Si in groundwater were also affected by pH. Chemical species of heavy metals/trace elements were also analyzed in this study. The data evaluation methods and results of this study could be useful to the water resource management and utilization in the area and other similar areas.

Tectonically Induced Anomalies Without Large Earthquake Occurrences

In this study, we documented a case involving large-scale macroscopic anomalies in the Xichang area, southwestern Sichuan Province, China, from May to June of 2002, after which no major earthquake occurred. During our field survey in 2002, we found that the timing of the high-frequency occurrence of groundwater anomalies was in good agreement with those of animal anomalies. Spatially, the groundwater and animal anomalies were distributed along the Anninghe–Zemuhe fault zone. Furthermore, the groundwater level was elevated in the northwest part of the Zemuhe fault and depressed in the southeast part of the Zemuhe fault zone, with a border somewhere between Puge and Ningnan Counties. Combined with microscopic groundwater, geodetic and seismic activity data, we infer that the anomalies in the Xichang area were the result of increasing tectonic activity in the Sichuan–Yunnan block. In addition, groundwater data may be used as a good indicator of tectonic activity. This case tells us that there is no direct relationship between an earthquake and these anomalies. In most cases, the vast majority of the anomalies, including microscopic and macroscopic anomalies, are caused by tectonic activity. That is, these anomalies could occur under the effects of tectonic activity, but they do not necessarily relate to the occurrence of earthquakes.

Hydrogeochemical Characteristics and Evolution of Hot Springs in Eastern Tibetan Plateau Geothermal Belt, Western China: Insight from Multivariate Statistical Analysis

The eastern Tibetan Plateau geothermal belt is one of the important medium-high temperature geothermal belts in China. However, less work has been done on the hydrochemical characteristic and its geological origin. Understanding the chemical characteristics and the hydrochemical evolution processes is important in evaluating the geothermal energy potential in this area. In the present study, we discussed the hydrochemical properties and their origins of 39 hot springs located in the eastern Tibetan Plateau geothermal belt (Kangding-Litang-Batang geothermal belt). Cluster analysis and factor analysis are employed to character the hydrochemical properties of hot springs in different fault zones and the possible hydrochemical evolution processes of these hot springs. Our study shows that the hot springs can be divided into three groups based on their locations. The hot springs in the first group mainly originate from the volcanic rock and the springs in the second group originate from the metamorphic rock while the springs in the third group originate from the result of mixture of shallow water. Water-rock interaction, cation exchange, and the water environment are the three dominant factors that control the hydrochemical evolution process in the eastern Tibetan Plateau. These results are also in well agreement with the isotopic and chemical analysis.