珠三角地区密养淡水鱼塘水质状况分析与评价

Assessment of water quality of intensive ponds in the Pearl River Delta region

池塘养殖是珠三角地区淡水渔业生产的主要形式。2012年5月～12月对草鱼（Ctenopharyngodon idellus）、云斑尖塘鳢（Oxyeleotris marmoratus）、大口黑鲈（Micropterus salmoides）和乌鳢（Channa argus）等该地区几种主要密养淡水品种鱼塘水质进行监测,分析水体理化环境因子,并选取pH、溶解氧（DO）、非离子氨（NH3）、氨氮（NH4^＋-N）、硝酸盐氮（NO3^--N）、亚硝酸盐氮（NO2^--N）、总氮（TN）、总磷（TP）、高锰酸盐指数（CODMn）和透明度等10项因子,采用单项污染指数和负荷比对监测参数进行单项评价,用综合污染指数法对各池塘水质进行整体评价。结果表明4种密养淡水鱼塘营养盐负荷高问题突出,NH3、NO3^--N、NO2^--N、TN和TP为池塘中的主要污染因素;草鱼池塘主要污染物为NH3和TN,其污染负荷合计为37.58%;云斑尖塘鳢池塘主要污染物为NH3、NO3^--N和TN,其污染负荷达59.37%;大口黑鲈池塘的主要污染物为NH3、TN、NO3^--N和NO2^--N,其污染负荷高达66.80%;乌鳢池塘的主要污染物为TN、NO3^--N、TP和NH3,其污染负荷达59.43%;对CODMn的分析与评价结果显示,池塘水体中还原性有机质含量高;由综合污染指数判定,所有池塘水体均为＂重污染＂等级,并超出警戒水平。

Pond-farming is the main form of fisheries production in the Pearl River Delta region. We monitored the water quality in intensive ponds of Ctenopharyngodon idellus,Oxyeleotris marmoratus,Micropterus salmoides and Channa argus in the Pearl River Delta region during May to December of 2012. Ten parameters including pH,dissolved oxygen（ DO）,non-ionic ammonia（ NH3）,ammonia nitrogen（ NH4^＋-N）,nitrate nitrogen（ NO3^--N）,nitrite nitrogen（ NO2^--N）,total nitrogen（ TN）,total phosphorus（ TP）,potassium permanganate index（ CODMn） and transparency were assessed by single pollution index and duty ratio. The water quality was assessed by comprehensive pollution index. The results reveal that high nutrient loadings were the prominent problems,and NH3,NO3^--N,NO2^--N,TN and TP were the main pollutants in intensive ponds. The main pollutants in C. idellus pond were NH3 and TN（ pollution load： 37. 58%）. The main pollutants in O. marmoratus pond were NH3,TN and NO3^--N（ pollution load： 59. 37%）. The main pollutants in M. salmoides pond were NH3,TN and NO3^--N and NO2^--N（ pollution load： 66. 80%）. The main pollutants in C. argus pond were TN,NO3^--N,TP and NH3（ pollution load： 59. 43%）. The research on CODMnreveal that there was a large amount of reducible organic matters in these ponds. The pond water was heavily polluted,and the degree of contamination exceeded the alert levelbased on comprehensive pollution index.