典型城市人工湿地优势植物汞分布特征

Distribution characteristics of mercury in plants in typical urban constructed wetlands

以重庆市4个典型城市人工湿地(观音塘湿地公园、彩云湖国家湿地公园、园博园湿地公园、秀湖湿地公园)为研究对象,分别于2017年3、6、9、12月调查并采集了湿地优势植物样品,分析样品总汞、甲基汞浓度,探讨城市人工湿地中植物汞的时空分布特征.结果表明,调查区域植物汞质量浓度范围为45.29—231.01μg·kg-1(平均值为33.99±8.61μg·kg-1).甲基汞质量浓度范围为45.29—232.01 ng·kg-1(平均值为145.45±48.72 ng·kg-1);其中,园博园湿地植物总汞质量浓度最低,观音塘湿地公园植物甲基汞质量浓度均较其他3个湿地公园植物高;在同一湿地中,植物总汞春秋浓度较高,夏季略有降低,冬季最低,而甲基汞浓度先逐渐升高,并在6—9月达到最大值,随后开始下降;植物根部总汞、甲基汞含量高于茎和叶.城市人工湿地植物有一定的汞富集能力,可在一定程度上减轻水体汞污染.

To explore the spatial and temporal distribution of plant mercury in different constructed wetlands in Chongqing,total mercury and methylmercury in the dominant plants in four selected wetlands(Guanyintang Wetland Park,Caiyun Lake National Wetland Park,Yuanboyuan Wetland Park,Xiuhu Wetland Park)were analyzed seasonally in 2017.The results showed that the concentration of plant mercury in the study area ranged from 11.57 to 75.44μg·kg-1,with an average of 33.99±8.61μg·kg-1,and methylmercury concentration was in the range of 45.29—231.01μg·kg-1 with an average of 145.45±48.72 ng·kg-1.The lowest total mercury concentration appeared in the Yuanboyuan wetland,and the methylmercury concentration in Guanyintang Wetland Park was higher than that in the other three wetland parks.Seasonal variation of the total mercury and methylmercury was obvious with higher plant mercury in the spring and autumn and higher methylmercury in the summer and autumn.The total mercury and methylmercury contents in the plant roots were higher than those in the stems and leaves.Urban constructed wetland plants showed certain mercury enrichment ability,which could reduce mercury pollution to some extent.