The west plain region of Jilin province of northeast China is one of the typical endemic fluorosis areas caused by drinking water for many years. Investigations of hydrogeological and ecoenvironmental conditions as well as endemic fluorosis were conducted in 1998. Results show that the ground water, especially, the water in the unconfined aquifer is the main source of drinking water for local residents. The fluoride concentration in groundwater in the unconfined aquifers is higher than that in the confined aquifer in the west plain of Jilin province. The fluoride concentration in the unconfined aquifer can be used to classify the plain into fluoride deficient area, optimum area and excess area, which trend from west to east. High fluoride (>1.0 mg L(-1)) in drinking water resulted in dental and skeletal fluorosis in local residents (children and pregnant women). There exists a positive correlation between fluoride concentration in the drinking water and the morbidities of endemic fluorosis disease (r1 = 0.781, r2 = 0.872). Health risks associated with fluoride concentration in drinking water are assessed. It has been determined that fluoride concentration in excess of 1.0 mg L(-1) exposes residents to high health risks based on risk identification. The study area is classified into five health risk classes as shown in Figure 4. The risk indexes of this area more than 1.0 are accounted for 68% of the total west plain region.

Many existing risk assessment methodologies heavily rely on complex physical models and probabilistic concepts, which are difficult to use and not suitable for a first-cut analysis. Meanwhile, most groundwater pollution risk assessment indices generally are solely based on groundwater vulnerability and ignore the consideration of the hazard of pollution source. In this paper, we developed a simple groundwater pollution risk index approach, which can be easily utilized in many developing countries. The approach is developed according to vulnerability of the aquifers and pollution source index, which is based on landfill treatment technology. Applications of this risk index approach to 22 formal landfill sites in Beijing show that 1, 2, 4, 10, 5 landfill sites can be classified as of high, medium high, medium, medium low, low risk level respectively. These results demonstrate that vulnerability assessment alone is not sufficient to groundwater pollution risk assessment. This simple risk assessment method is most suitable for a comparative assessment of a large number of pollution sources at a regional scale due to its lower cost and easy operability. It also allows prioritizes landfills for reclamation interventions and recommendation of required actions such that an efficient management of landfills could be accomplished.

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Abstract Traditional indicators of water resource utilization degree and efficiency cannot show the stressed relationship between the level of water resource utilization and economic development level in a region. Therefore, this manuscript proposes a generalized index of socio-economic consumption level of water resources. The definition of the index is the ratio of water consumption change for GDP growth per unit, and the potential of water resources exploitation and utilization. The theoretical curve of this index has a rise period, a high value period, and a decline period, which correspond to the take-off period, bottleneck period and maturity period of the regional economic development, respectively. This index can help us find the turning point of water resources restricting economy. The indexes of each year are calculated respectively from 1994 to 2010 of Beijing and Hebei province of China as example. The result shows that both two provinces are in the transitional period from high value period to the decline period. This example shows the universality of Generalized Index of Regional Socio-economic Consumption Level of Water Resources. Setting a target Generalized Index of Regional Socio-economic Consumption Level of Water Resources is consistent with the sustainable development level of regional economy which could promote both regional economic development and water resources protection.

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The layered ground under the excitation of a harmonic magnetic field will generate a secondary magnetic field. On the condition of low induction number, the apparent conductivity can be obtained by using the normalized secondary field measured by the instrument directly. By discretizing the integral of relative response function density, the expression of contribution value of conductivity of each layer to the apparent conductivity can be obtained. By using multiple sets of transceiver distance, we can obtain different apparent conductivity observation equations, then the conductivity and thickness of each layer can be solved by Gauss-Newton method. A three-layer medium model containing a V-shaped tunnel is designed for inversion simulation calculations. The results show that the higher the SNR of observed signal, the more stable the inversion result. The maximum relative error of thickness is about 10%.