Research on the expansion mechanism of the ground pollution and its preventive measures in Thailand

本研究的目的是掌握泰国地面污染的实际情况，阐明其扩展机制，调查预防措施。特别是从排水渠周边土壤性质和水分蒸发排放对污染物的转移机理等方面进行了研究。到目前为止，几乎没有类似的研究。本研究的主要结果如下：与发达国家相比，泰国的地面污染管理标准相对宽松。造成地面污染的原因有两种类型。一种是工业废液、矿山、养虾、盐场等以及发达国家的人工污染，另一种是岩盐等自然污染。在前者的情况下，有一些调查和测量实际上正在进行。即使做了，也有很多不向公众开放的情况，污染的实际情况也不能完全掌握。测定了水的蒸发和排放，明确了污染物的运动机制。蒸发和排放对地表和植物的影响较大，在地理特征变化不大的地区，污染物浓度明显增高。也就是说，被污染的河水和地面中的污染物由于水力梯度而渗入地下，污染扩大。由于地表水分的蒸发，污染物在地表附近变得高浓度。由此可见，曼谷平原的地面污染是河水、地下水和土壤的复合型污染。缅甸、老挝、柬埔寨等国在不久的将来都会出现这种复合型污染，必须立即采取对策。在防止污染扩大方面，首先要切断污染源。污染浓度高的区域应采用不透水材料进行封闭，以防止污染物的移动。之后，污染区域被净化。少

Purposes of this study are grasp of the actual condition of the ground pollution, elucidation of its expansion mechanism and investigation of prevention measures in Thailand. Especially, the study is carried out from the viewpoint of the soil properties around drainage canal and the transfer mechanism of the pollutant with evaporation and emission of the moisture. So far, similar research is hardly done. The main results by this research is as the following.Standards for the regulation of the ground pollution in Thailand are comparatively loose contents in comparison with the advanced country. There are 2 types on the cause of the ground pollution. One is be artificial of industrial liquid wastes, mines, shrimp culture, salt farm, etc. as well as the advanced country, and another one is the natural contamination by rock salt, etc. In the case of former, there are a few cases that investigation and measurement are actually being done. Even if they are being done, there are almost cases … More of un-opening to the public, and the actual condition of the pollution cannot be grasped fully.The evaporation and emission of water was measured to clear the movement mechanism of the pollutant. An evaporation and emission had an influence from the surface of the earth side and the plant greatly, and it is clear that a pollutant becomes high concentration in the area of a little change of geographical features. In other words, polluted river water and pollutant in the ground seepage into the ground for the hydraulic gradient, and pollution expands. And the pollutant becomes high concentration around the ground surface caused by the evaporation of water from the surface. Therefore, it becomes clear that the ground pollution in Bangkok plain is the pollution of the compound type of the river water, the groundwater and the soil. The pollution of this compound type must do a countermeasure immediately because it will occur in Myanmar, Laos Cambodia and so on in the near future.As for prevention of expansion of the pollution, it is the first to break off pollution source. The polluted area which became high concentration should be confined by impervious material to prevent the movement of the pollutant. After that, the polluted area is purified. Less