淮河流域沈丘县地表水藻类及其毒素污染状况研究

Pollutions by algae and microcystins in surface water in Shenqiu County in Huaihe River basin

目的研究淮河流域沈丘县2012—2013年不同水体藻类及藻毒素的污染状况。方法于2012年4月—2013年3月,采集沈丘县S河上、中、下游及其主要支流Y河水和有代表性的池塘水,测定水中总氮、总磷、叶绿素a(Chl-a)、透明度(SD)、化学耗氧量(CODMn)及藻细胞密度、溶解性和细胞内微囊藻毒素水平。结果各水体污染严重,水质均处于劣Ⅴ类水平。S河以总氮污染最严重,最高可达13.15 mg/L,其总磷浓度和CODMn最高分别达0.61、9.3 mg/L;Y河CODMn最高可达15.39 mg/L,而其透明度最高达2.10 m;池塘水以总磷与化学耗氧量污染最为严重,最高分别达2.01、43.32 mg/L,其透明度最低达到0.14 m,且叶绿素a波动较大,最高值可达129.10 mg/m3。各水体均处于重度富营养化状态。总藻密度以7月的池塘水最高,达到3.54×107个/L。不同水体藻类种属呈现季节性变化,春季和冬季的优势藻分别为绿藻和硅藻,夏季蓝藻比例明显较高,成为优势藻,其中,7月Y河的蓝藻占总藻的比例可达68%。溶解性藻毒素、细胞内藻毒素均以7月池塘水的值为最高,分别为3.69、6.21μg/L。各水体Chl-a指标与蓝藻密度、细胞内藻毒素均呈正相关(P<0.05),而蓝藻密度与细胞内藻毒素也呈正相关(P<0.05)。结论沈丘地区地表水藻类及其藻毒素污染严重,夏季蓝藻为优势藻。

Objective The purpose of this study is to analyze the polluted status of algae and microcystins in different water bodies of Shenqiu County in Huaihe River basin during 2012-2013. Methods Surface water samples were collected from S River, Y River and a representative pond from April 2012 to March 2013. Total nitrogen （TN）, total phosphorus （TP）, chlorophyll-a （Chl-a）,transparency （SD）,chemical oxygen demand （CODMn） and algal density were determined and analyzed. The concentrations of microcystins （MCs）,including dissolved MCs in water and cellular MCs in algal, were determined by high performance liquid chromatography with solid phase extraction. Results Different water bodies of Shenqiu County were serious, most items of water quality exceeded the national standard for surface water quality Class V. Total nitrogen in the mainstream of S River was serious,the maximum concentration was 13.15 mg/L,and the highest concentrations of TP and CODMn were up to 0.61 mg/L, 9.3 mg/L,respectively; The CODMn of Y River was up to 15.39 mg/L, and its SD value was as high as 2.10 m; Total phosphorus and CODMn were serious in the pond where the maximum concentrations were 2.01 mg/L and 43.32 mg/L,respectively,and the minimum transparency of the pond was 0.14 m,and the highest concentration of Chl-a was up to 129.10 mg/m3. The eutrophication level of different water bodies were heavy eutrophic status. The peak of total algal cell density was 3.54-107/L in pond water in July. Algae species in water bodies showed seasonal change,the Chlorophyta and Bacillariophyta were dominant in spring and winter,respectively. Cyanobacteria was dominant in summer and significantly increased. Meanwhile,Cyanobacteria in Y River was 68% in July. The maximum concentrations of dissolved and cellular MCs were observed in pond water in July,3.69 /xg/L and 6.21 /a,g/L,respectively. The correlation analysis indicated that the chlorophyll-a in different water bodies had a significantly positive correlation with the Cyanobacteria density （P〈0.01） and cellular microcystins （P〈0.05）. And the density of Cyanobacteria was also positively correlated with cellular microcystins （P〈0.05）. Conclusion Algae and microcystins of surface water in Shenqiu County were heavily polluted. Cyanobacteria in different water bodies was dominant during summer.