Jincui Wang

Response of Groundwater to Climate Change under Extreme Climate Conditions in North China Plain

The North China Plain (NCP) is one of the water shortage areas of China. Lack of water resources restricted the economic and social development of North China area and resulted in deterioration of ecosystem and natural environment. Influenced by the climate change and human activities, the water circulation of NCP was largely changed and the crisis of water resources was aggravated. Therefore, it is important to study the features of the extreme climate and the response mechanism of groundwater to climate change. We analyzed the trend of climate change and extreme climate features in the past 60 years based on the monitoring data of meteorological stations. And then the response characteristics of groundwater to climate change were discussed. The average temperature of NCP was in an obviously upward trend. The overall precipitation variation was in a downward trend. The climate change in this area showed a warming-drying trend. The intensity of extreme precipitation displayed a trend of declining and then increasing from north to south as well as declining from eastern coastal plain to the piedmont plain. Grey correlation degree analysis indicated that groundwater depth had a close relationship with precipitation and human activities in NCP. The response of groundwater level to precipitation differed from the piedmont alluvial-pluvial plain to the coastal plain. The response was more obvious in the coastal plain than the piedmont alluvial-pluvial plain and the middle plain. The precipitation influenced the groundwater depth both directly and indirectly. Under the condition of extreme precipitation, the impact would aggravate, in the forms of rapid or lag raise of groundwater levels.

Distribution and Mobility of Heavy Metals in Soil of Sewage Irrigation Area in Pearl River Delta, China

The research reveals the mobility and distribution of heavy metals (Cd, Cu, Zn, Mn, Ni, and Cr) in soil of sewage irrigation area in Pearl River Delta. Samples were collected from topsoil (0-10cm) and subsoil (30-40cm), and the total concentration and available concentration of heavy metals were extracted by HNO3–HF–HClO4 and DTPA respectively. The mean total concentrations for all of the heavy metals in topsoil are higher than that in subsoil in study area. Cd has the best mobility in soil of study area due to soil has lower retention for Cd than for other metals, while Ni has the poorest mobility in soil of study area. The total concentrations of Zn, Cu and Cd decrease with the depth of soil profile, while the total concentrations of Cr and Ni have little change with the depth of soil profile, only the total concentration of Mn has a little decrease at first and then increased rapidly with the depth of soil profile.

Natural background levels of chemical components in groundwater of Hutuo River catchment area, North China Plain

ABSTRACT Natural background levels (NBLs) are commonly used to serve as references when assessing the contamination status of groundwater units. In this study, a methodology based on hydrogeochemistry and statistics was proposed to derive NBLs. A comprehensive understanding of the evolution of groundwater chemistry was acquired and the impact of natural and anthropogenic factors was analyzed based on a total of 93 groundwater samples. The hydrogeochemical plots and the Pau Ta criterion were applied to define the anomalies of the monitoring data by calculating the corresponding Mahalanobis distance. The NBLs were defined for the remaining groundwater samples of the three aquifers after excluding the anomalies with certain percentiles such as median and 90% percentile by means of cumulative frequency plots. Analysis of the hydrochemical data shows that for the aquifers studied, rock weathering dominates the evolution of groundwater chemistry in conjunction with cation exchange, and the dissolution of calcite and silicate weathering are responsible for the major chemical constituents of the groundwater. The NBLs established in the present study showed a difference in groundwater among three aquifers due to the distinct geological conditions. The background of nitrate in the groundwater of the unconfined aquifer was acquired according to the cumulative frequency plot. Deeper insight into the geochemical evolution of groundwater and the establishment of NBLs can be beneficial to improve groundwater management for sustainable development in rapidly urbanizing areas.

Study on Application of Two-stage Bio-contact Oxidation Technology in Municipal Wastewater Treatment in Alpine Region

Following the introduction of characteristic of wastewater and correlated project in the Alpine Region, the problems were pointed out which should be noticed in wastewater treatment process selection in this specific area. Some suggestions about key design parameters were proposed, and the Two-stage Bio-contact Oxidation Technology was been selected and applied in wastewater treatment plant in north suburb of Dongsheng District, Erdos City. Through project application, it was indicated that when average value of COD, BOD5 and SS was 483.2mg/L, 244.4mg/L and 258.4mg/L respectively during 10 days at about 12 ° in influent wastewater, average value in effluent water reached up to 57.1mg/L, 23.8mg/L and 26.5mg/L and removal rate of each contaminant was up to 88.2%, 90.3% and 89.7% respectively. It gained preferable results and this successful project also provided references for other similar wastewater treatment plant for future.

A New Automatic On-Situ Sampling and Monitoring Method for Water

In view of the fact that some difficulties exist in automatic and depthset sampling and monitoring for water, a new sampling system is developed. Firstly, the future sampler design ingredients are analyzed. Then the sampling system structure and operating principles are introduced in detail. A model machine is designed and several experiments have been carried on. The results indicate that this sampling system can perform automatic sampling effectively and efficiently; it could sample water as deep as 30m, and the depth error is less than 0.5m; water parameters such as temperature, pH and electrical conductivity (EC) can be measured on-site and the accuracy is 0.1∘C, 0.01 and 1μS/cm respectively. Besides, the sampler can reduce volatile organic components loss effectively and is also suitable to collect water sample for inorganic component analysis.

Characteristic and Speciation of Beryllium in Shallow Groundwater in the Pearl River Delta

The Distribution of shallow groundwater containing beryllium were summarized and the major factors influencing beryllium enrichment were discussed in this paper, based on chemical data of Be, aluminum and pH from more than 900 groundwater samples in the Pearl River Delta. The results show that Be concentration ranges from less than 0.02µg•L-1 to 40.3µg•L-1, with the majority less than 0.05µg•L-1 and the mean Be content of 0.66µg•L-1. The samples of Be content exceeding the upper limit for drinking water in China were scatteredly found in Guangzhou, Shenzhen, Dongguan, Foshan and Huizhou, with the over proof rate of 2.24%. The distribution of Be contamination in groundwater is characterized by local punctate type. The pH and Al are the major factors influencing distribution of beryllium in groundwater. Acidic and high Al content in groundwater and soil provide favorable conditions for migration of Be. Rock weathering and natural soil formation is one of the origins of Be in groundwater, and pollution caused by human activities is the other important source of Be in groundwater, especially in the severely contaminated sites.

Distribution of Heavy Metals in Groundwater of Sewage Irrigation Area in Guangdong Province, China

The research reveals the distribution and correlation of heavy metals in groundwater of sewage irrigation area in Guangdong province. 14 groundwater samples were collected in August 2008, and the groundwater samples were filtrated through 0.45 µm membranes and acidified in the field. Determinations of Cd, Cu, Zn, Pb, Ni, and Cr in all the samples were performed using ICP-OES, and determinations of As and Se in all the samples were performed employing HG-AFS. The result shows that the groundwater of sewage irrigation area has been contaminated with As and Ni, whereas the concentrations of other heavy metals (Pb, Zn, Cu, Cr, Cd, Se) in groundwater did not reach the upper limit for drinking water in China. High As concentrations in groundwater may due to the weak alkaline character of groundwater in sewage irrigation area, because groundwater with weak alkaline is beneficial to enrichment of As. According to correlation and cluster analysis, it is shown that Ni, Se, Zn and Cd may have the common source (sewage irrigation) or by chemical similarity in groundwater, Pb and Cu may have the similar environmental geochemical behavior in groundwater since they are chalcophile elements, whereas As is out of other heavy metals due to the pH of groundwater, because groundwater with weak alkaline is beneficial to enrichment of As, in contrast, for Pb, Cu, Zn etc. In addition, weak correlation relationships between pH and heavy metals concentrations in groundwater of study area suggest that heavy metals concentrations in groundwater of sewage irrigation area are not governed by simple relationships with pH.