次氯酸钠对池塘微宇宙结构和功能的影响

Effects of sodium hypochlorite on structure and function of pond microcosms

目的研究次氯酸钠对模拟池塘水生态系统造成破坏的程度及恢复规律。方法构建6个池塘微宇宙模拟水生态系统,连续投加次氯酸钠13天,投加量分别为0、1.0、2.5、5.0、10.0和20.0mg/L,13天后再观察10天,定期测定系统中余氯、细菌总数、叶绿素a、总生产力的值。结果余氯量随次氯酸钠投加量的加大和时间的延长而不断升高;叶绿素a、总生产力和次氯酸钠投加量之间呈负相关;1.0mg/L和2.5mg/L次氯酸钠在微宇宙中促进细菌的繁殖,5.0、10.0和20.0mg/L的投加量可有效灭菌。低投加量次氯酸钠(1.0、2.5和5.0mg/L)不影响微宇宙的恢复,高投加量(10.0mg/L和20.0mg/L)对微宇宙造成严重破坏。结论在该试验条件下,根据叶绿素a、总生产力等指标的变化趋势,可认为池塘微宇宙的结构和功能均受次氯酸钠的影响而发生改变,但1.0、2.5和5.0mg/L投加量的影响是可逆的,而10.0mg/L和20.0mg/L的投加量使微宇宙结构和功能难以恢复。

Objective To study the influence of sodium hypoehlorite on destruction and restoration of simulated pond ecosystems. Methods Six pond microcosms were established to simulate aquatic ecosystems. 0, 1, 2.5, 5.0, 10,0 and 20.0mg/L of sodium hypochlorite were put in these simulated pond microcosms every 24h for 13 days and followed by observation for 10 days. The values of chlorine residual, total bacteria count, chlorophyll-a and total productivity were detected regularly. Results Chlorine residual increased continuously with the increase of doses and time course. Content of chlorophyll-a, total productivity negatively correlated with dose of sodium hypochlorite. 1.0mg/L and 2.5mg/L of sodium hypochlorite promoted the growth of bacteria, but 5.0mg/L, 10.0mg/L and 20.0mg/L of sodium hypochlorite could kill bacteria effectively. Under low doses of sodium hypoehlorite （1.0, 2.5 and 5.0mg/L）, there were no influence on microcosms＇ restoration, but the high doses （10.0mg/L and 20.0mg/L） could severely damage the microcosms. Conclusion According to the tendency of ehlorophyll-a and total productivity, structure and function of every pond microcosm could be changed by sodium hypochlorite in this test condition, the influence was reversible under the doses of 1.0, 2,5 and 5.0mg/L, but microcosms could not be restored under the doses of 10.0mg/L and 20.0mg/L.