Nitrata pollution of groundwater arising from agricultural practices, and some technologies to conrol the polluion

为了弄清宫康诺河流域地下水的硝酸盐污染情况，连续数年测定了约800份井水的硝酸盐氮含量。12%的样品硝酸盐氮含量超过10 ppm。动物粪便被认为是该地区墙水中硝酸盐- n的主要来源之一。利用壳聚糖及壳聚糖衍生物对硝酸盐阴离子进行了去除和分离。其中，具有仲胺基的壳聚糖衍生物对硝酸盐阴离子的选择性高于氯离子和硫酸盐阴离子。以硝酸阴离子为模板的壳聚糖衍生物在pH值接近中性时对硝酸阴离子有较高的吸附能力。以氮肥为核心材料，采用乙烯烯-二乙烯苯共聚法制备了以氮肥为核心材料的微胶囊，在各种条件下控制了核心材料的释放，并具有防止地下水污染的能力。孔的形状和直径以及颗粒的大小受制备条件的控制。制备了含80%核心材料的微胶囊。

To clarify the nitrate pollution of groundwater in Miyakonozyo basin, nitrate-N content of some 800 of wall-water was measured for several years. Twelve% of total samples exceeded 10 ppm nitrate-N.Animal waste was considered to be one of main sources of nitrate-N in wall-water in this region.Removal and separation of nitrate anion were carried out using chitosan and chitosan derivatives. Among these, the chitosan derivatives having the secondary amine group showed the high selectivity for nitrate anion over chloride and sulfate anions. The chitosan derivative with the template of nitrate anion exhibited a high adsorption of nitrate anion at pH value around neutrality.Microcapsule containing nitrogen fertilizer as a core-material were prepared using stirene-di-vinylbenzene co-polymerization for various conditions, in which they control the release of the core-materials and have a ability of prevention of groundwater pollution. Shapes and diameters of the pore and the particle sizes were found to be controlled by the preparation conditions. The microcapsule containing 80% of core-materials was found to be prepared in the study.