为了评价贵州草海水质状况,分别于2016年1,4,7,10月对草海阳关山和草海中部各3个样点的11项水体理化指标进行了监测,运用综合营养状态指数法(TLI)并结合《地表水环境质量标准》(GB 3838—2002)对监测区水质进行了评价,同时应用主成分分析(PCA)分析了水质的污染程度和主要影响因子。结果显示:①11项参数在2个区域均有显著的季节差异,其中透明度(SD)和溶氧(DO)为冬季最优,悬浮物(SPM)在秋季最高,pH几乎均呈弱碱性(除秋季);TN,TP,NH₄⁺-N,COD_Mn全年的水平分别为0.58～2.27,0.032～0.072,0.059～0.364,4.28～6.79 mg/L,Chl.a水平为5.62～9.95 mg/m³,其中TN在秋季最高,TP在秋冬季较高,COD_Mn和Chl.a在夏秋季较高。②TLI评价结果表明,阳关山和中部水体TLI值在秋季略超过50,为轻度污染状态,其他季节TLI值均为30～50,为中营养状态;《地表水环境质量标准》(GB 3838—2002)评价结果表明阳关山全年主要为Ⅱ—Ⅲ类水质,而中部较差,全年主要为Ⅱ— Ⅳ类水质,影响水质类别的主要因子是TN和COD_Mn,TP和NH₄⁺-N全年为Ⅱ类水平。③PCA结果显示阳关山水质最主要的影响因子包括离子、氮素、有机质、DO和Chl.a,而中部则包括Chl.a,NH₄⁺-N,SD,EC,TP,DO,WT,SPM。总之,氮素和有机质是影响草海阳关山和中部水质的最主要因子和根本原因,控制外源性的氮和有机质输入是管理和改善草海水质的关键所在。

Eleven indicators of water quality in two areas of the Caohai Lake (Yangguanshan and the middle part) in Guizhou Province were measured seasonally in 2016. Trophic state index (TLI) and Surface Water Quality Standard (GB 3838—2002) were used to evaluate the trophic status of water quality, and principal component analysis (PCA) was conducted to assess the pollution level and main influential factors. Results demonstrated that: (1) The eleven indicators in both areas displayed significant seasonal variations, among which transparency and dissolved oxygen (DO) were highest in winter; while suspended solids (SPM) was highest in autumn. Except that in autumn, pH remained at about 8. TN, TP, NH₄⁺-N and COD_Mn were in 0.58-2.27, 0.032-0.072, 0.059-0.364 and 4.28-6.79 mg/L, respectively and Chl.a ranged from 5.62 to 9.95 mg/m³, with the highest TN in autumn, the highest TP in autumn and winter, and highest COD_Mn and Chl.a in summer and autumn. (2) The TLI of both areas were slightly higher than 50 in autumn, indicating slight pollution, while in other seasons, the TLI ranged between 30 and 50, implying medium trophic state. Evaluation results from GB 3838—2002 show that the water quality in Yangguanshan belonged to class Ⅱ and Ⅲ, except for a few occasions; whereas in the middle part, the water quality was mainly class Ⅱ and Ⅳ. TN and COD_Mn were major influential factors, while TP and NH₄⁺-N were at level Ⅱ throughout the year. (3) Principle component analysis revealed that the most important influencing factors of water quality in Yangguanshan were ions, nitrogen, organic matter, DO and Chl.a, while in the middle part were Chl.a, NH₄⁺-N, SD, EC, TP, DO, WT and SPM. In conclusion, nitrogen and organic matters are the most important influencing factors and the fundamental causes of water quality in Yangguanshan and the middle part of Caohu Lake. Controlling the inputs of external nitrogen and organic matters would be the key to improving the water quality in Caohai Lake.