元阳梯田区全福庄小流域水质分析与评价

Water quality analysis and evaluation in Quanfu Village Basin of Yuanyang Terrace

以全福庄小流域为研究对象，在对元阳梯田区农业生产和环境现状调查的基础上，根据《地表水环境质量标准》（GB3838．2002），通过科学的采集水样，结合当地农业生产实际情况和实验室条件，选取pH、COD、总氮、总磷、硝氮、氨氮、正磷酸盐等七项水质指标，严格按照国家标准进行实验测定，并采用综合指数法对选取的元阳梯田区五处采样点（森林水源地、梯田出水口、梯田入水口、全福庄小寨、河流入水口）的水质进行综合评价。分析结果为：五个采样点的pH指标处于I～V类之间；其COD、氨氮、硝氮等指标均处于I～II类之间；梯田出水口总磷超过V类标准，其他采样点指标等级均处于I～III类之间；梯田出水口总氮超过II类标准，其他采样点指标等级均处于I～II类之间。评价结果为：研究区水质总体处于I～II类之间，这是由于梯田灌区的水历经森林、土壤、甚至岩层的净化作用，整体水质较好，其中梯田出水口水质达NIII类水，属轻度污染。

Quanfu Village Basin was selected as a research object, and the survey on agricultural production and the environment of terraced area was conducted. Water samples were collected scientifically. According to ＂Surface Water Quality Standards ＂（GB3838-2002）, and based on the actual situation of local agricultural production and laboratory conditions, parameters of pH, COD, total nitrogen, total phosphorus, nitrate nitrogen, ammonia nitrogen, phosphate, etc were chosen. The experimental determination was according to national standards strictly. Comprehensive evaluation was used to evaluate the water quality of five selected sampling sites, which were forest water source, terrace inlet, terrace outlet, Quanfu Village, and river inlet. The results showed that pH indicators of the five sampling sites were in classes I - V. COD, ammonia nitrogen, nitrate nitrogen indicators were in classes I - II. Total phosphorus of terrace outlet was over class V. Indicators of other sampling points were in classes I -III. Total nitrogen of terrace outlet was over class II ; indicators of other sampling points were in classes I - II .The results indicated that the water quality was generally in classes I - II. The overall water quality was good, due to the water purification of forest, soil and rock. The water in terrace outlet reached III, suggesting that the water was polluted lightly.