王杰

Abstract：Groundwater is an important part of the water cycle and is also widely used as sources of drinking water. With the increasing development of groundwater exploitation， the pollution is becoming more and more serious. This paper talks about the main research directions of groundwater pollution， the detection， the remediation and some conclusions.

Key Words：：groundwater； pollution； detection； remediation

Chapter1：Introduction

Groundwater is an important part of the water cycle. it is one of the important sources of drinking water， and is also widely used for water supply in North China plain. As it is buried under the ground， groundwater pollution is difficult to find and control. According to the classification on hydraulics， groundwater polution can be roughly divided into four categories： the intermittent infiltration type，the continuous infiltration type，the transfluence，type and the radial flow type.

According to the monitoring results of 195 cities in China， 97% of their ground water has been polluted. Using polluted groundwater causes hazards to public health or the spread of disease. Due to the feeble degree of groundwater alternation and poor self-purification ability， pollution detection and remediation is of great importance.

Chapter2：Detection of Groundwater pollution

In our country， there have developed considerable research directions about the detection of groundwater pollution， concluding pollution sources， organic pollution and monitoring methods， etc. At the same time， numerous cutting-edge technology has been applied and developed. The following is about two prominent technology.

2.1 Applications of electrical prospecting

In recent years， a lot of foreign researches have showed that electrical prospecting can be successfully applied to the investigation of the groundwater pollution. Through applications of different geophysical methods， different problems can be solved： the first is to use resistivity method to identify scope of groundwater pollution and prospect groundwater in coastal environment； the second is to use frequency spectrum induced polarization method to detect state of the conductive plume and finally delineate groundwater pollution areas； the third is to use the spectral induced polarization method to detect organic chemical contamination. Also corresponding geophysical methods can also be taken for different purposes， such as search of pollution sources， detection of the effects of industrial effluents and so on.

2.2 Applications of Environmental isotopes

As the most advanced techniques currently in the world， isotope techniques play an important role in the study of groundwater. Isotopes are composed by stable isotopes and radioisotopes and the latter have radioactive decay. When applied in the study of groundwater， both of them play the role of age determination and marking. Generally， the isotopes with a longer half-life （14C， 36Cl， 39 Ar and 81 Kr） are used to determine the age of ancient groundwater ， while isotopes with a shorter half-life （3 H， 32 Si， 37 Ar and 85 Kr and 222 Rn） are used to determine the age of the younger groundwater. When a stable isotope of compounds is replaced by a radioactive isotope， the migratory paths and processes of the compounds can be revealed clear. Currently， 3 H and 14C are the radioactive isotopes widely used in China.

Chapter3：Remediation of Groundwater

Pollutants and contaminants can be removed from ground water by applying various techniques thereby making it safe for use. Ground water treatment （or remediation） techniques span biological， chemical， and physical treatment technologies. Most ground water treatment techniques utilize a combination of Technologies. Some of the biological treatment technique include bioaugmentation， bioventing， biosparging， bioslurping， and phytoremediation. Some chemical treatment techniques include ozone and oxygen gas injection， chemical precipitation， membrane separation， ion exchange， carbon absorption and surfactant enhanced recovery. Physical treatment techniques include， but are not limited to， pump and treat， air sparging， and dual phase extraction.

Conclusion

（1） As an important part of water resources， the groundwater is of great significance in water supply of north China. Therefore， detection of groundwater would pave the way for the sustainable development of water resources. With a large number of contaminated sites， groundwater pollution is very serious. However， due to the complexity of polluting mechanism， the control and remediation methods would be various and need quantities of researches. Also， control and remediation would face more practical demand.

（2） Its of great importance to carry out corresponding management of groundwater pollution on the basis of the researches. First， the investigation of groundwater pollution sites should be carried out. Second， the monitoring network of groundwater pollution should be set up to conduct periodic analysis. Third， the warning system is necessary for the control of ground water pollution. Last but not least， Active research of the remediation of groundwater pollution should be promoted.

（3） In developed countries， the detection and remediation of groundwater pollution has became the forward position of research and practice， as well as a heated topic. In our country， research of this field has just started and urgently need to carry out the research work with the experience of developed countries. Briefly， The control and remediation of groundwater pollution need joint development of hydrogeology， environmental engineering， environmental chemistry， etc.

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