**5. Acknowledgements**

The authors would like to thank the Earth Sciences department at the University of Gothenburg, Sweden for access to the electronic library. The authors thanks the anonymous reviewers who reviewed the paper.

#### **6. References**


groundwater aquifers will be contaminated where prolonged use of pesticides is practiced.In the case where ephemeral rivers flow throughirrigated land, they serve as a mechanism to re-distribute pesticides in the groundwater aquifers. Where flooding is frequent, the same mechanism of redistribution of pesticides occurs. The long-term effects pesticides in groundwater are much more long lived, and are difficult to remove from the aquifers. Hence their effects will be cumulative on the communities using the aquifers.The effects of pesticides on human health has now been shown to have several health effects

The authors would like to thank the Earth Sciences department at the University of Gothenburg, Sweden for access to the electronic library. The authors thanks the anonymous

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**24** 

*China* 

**Transport of Carbon Tetrachloride in a Karst** 

Carbon tetrachloride (CCl4) has been used as a grain fumigant, pesticide, solvent for oils and fats, metal degreaser, fire extinguisher and flame retardant, and in the production of paint, ink, plastics, semi-conductors and petrol additives (Agency for Toxic Substances and Disease Registry (ATSDR), 1994). Its properties are shown in Table 1. CCl4 is classified by the International Agency for Research on Cancer (IARC) and the US Environmental Protection Agency as a Group B2 carcinogen and also listed on the CERCLA Priority List of Hazardous Substances maintained by the Agency for Toxic Substances and Disease Registry (ATSDR, 2008). CCl4 is a common contaminant in soil and groundwater. CCl4 is found in approximately 20% of the US Superfund National Priority List sites (Ferguson & Pietari, 2000). But, there are limited published case studies of CCl4 contamination in karst aquifer. Karst aquifers are distinguished by an abundance of large subsurface openings and are therefore especially vulnerable to chlorinated-solvent contamination (CCl4, TCE, PCE). The release of chlorinated solvents into karst aquifers presents a difficult challenge to environmental scientists, managers, and regulators. The importance of karst aquifers to

Molecular weight 153.8 g/mol Density(25 °C) 1.594 g/mL Vapor pressure at 20 °C 12.2 kPa Boiling point at 101.3kPa 76.72 °C Melting point at 101.3kPa 22.92 °C Critical pressure 4.6 Mpa Critical temperature 283.2 °C Solubility in water at 25 °C 785 mg/L

Henry's law constant at 24.8 °C 2.3×10-2 atm·m3/mol

Heat of evaporation 194.7 kJ/kg

Table 1. Physical properties of carbon tetrachloride (Fouw, 1999)

LogKow 2.64 LogKoc 2.04

**1. Introduction** 

Baoping Han1,2, Xueqiang Zhu2, Zongping Pei2 and Xikun Liu3

**Aquifer in a Northern City, China** 

*3Management Department of Urban Water Resource of Xuzhou,* 

*1Xuzhou Institute of Technology,* 

*2China University of Mining and Technology,* 

