Dipartmento di Biologia, Università di Roma Tor Vergata, Via della Ricerca Scientifica, 00133 Roma, Italy.
Dipartmento di Biologia, Università di Roma Tor Vergata, Via della Ricerca Scientifica, 00133 Roma, Italy.
Ecotoxicol Environ Saf. 2018 May 30;153:54-59. doi: 10.1016/j.ecoenv.2018.01.053. Epub 2018 Feb 3.
The efficacy of the removal of contaminants from wastewater depends on physico-chemical properties of pollutants and the efficiency of treatment plant. Sometimes, low amounts of toxic compounds can be still present in the treated sewage. In this work we considered the effects of contaminant residues in treated wastewaters and of temperatures on Lemna minor L. Treated effluent waters were collected, analyzed and used as duckweed growth medium. In order to better understand the effects of micropollutants and seasonal variation, the plants were grown under ambient conditions for seven days in summer and winter. Relative growth rate, pigments and phenolic compounds concentrations were determined, as well as the activities of catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (G-POD) and polyphenol oxidase (PPO). The pollutant concentrations varied in the two seasons, depending on the industrial and municipal activities and efficiency of treatments. Treated waters contained heavy metals, nitrogenous and phosphorus compounds, surfactants and hydrocarbons. Compared to the control, duckweed growth of treated plants decreased by 25% in summer, while in the winter due to the lower temperatures and the presence of pollutants was completely impeded. The amounts of photosynthetic pigments of treated plants were not significantly affected in the summer, while they were higher than the control in the winter when the effluent had a high nitrogen amount. High CAT activity was registered in both seasons. Treated plants had significantly lower APX activity in the summer (53%) and winter (59%) respect to the controls. The observed inhibition of the peroxidase activities in the exposed plants, confirms the controversy existing in the literature about the variability of enzymatic response in stress condition.
废水污染物的去除效果取决于污染物的物理化学性质和处理厂的效率。有时，处理后的污水中仍可能存在低浓度的有毒化合物。在这项工作中，我们考虑了处理废水中污染物残留和温度对浮萍生长的影响。收集、分析并使用处理后的废水作为浮萍的生长介质。为了更好地理解微量污染物和季节性变化的影响，在夏季和冬季的环境条件下将植物培养了七天。测定了相对生长率、色素和酚类化合物的浓度，以及过氧化氢酶（CAT）、抗坏血酸过氧化物酶（APX）、愈创木酚过氧化物酶（G-POD）和多酚氧化酶（PPO）的活性。这两个季节的污染物浓度因工业和市政活动以及处理效率而异。处理水中含有重金属、含氮和含磷化合物、表面活性剂和碳氢化合物。与对照相比，处理过的植物在夏季的生长速度下降了 25%，而在冬季，由于温度较低且存在污染物，生长完全受到抑制。与对照相比，处理过的植物在夏季的光合色素含量没有显著变化，但在冬季由于废水中氮含量较高，其含量高于对照。两个季节都检测到 CAT 活性较高。与对照相比，处理过的植物在夏季（53%）和冬季（59%）的 APX 活性显著降低。暴露于污染物下的植物过氧化物酶活性受到抑制，这证实了文献中存在的关于在胁迫条件下酶反应变异性的争议。
