高砷煤矿区大金发藓生化指标反映砷氧化应激特征

Biochemical indices of Polytrichum commune Hedw. in arsenic-rich coal mines reflect the characteristics of arsenic oxidative stress

通过对贵州省兴仁县猫石头水库上游高砷煤矿区酸性矿山废水流域及附近未污染区设置点位并采集优势藓种——大金发藓(Polytrichum commune Hedw.),测定其可溶性蛋白质含量、过氧化氢(H2O2)含量、总抗氧化水平等生化指标,探究高砷煤矿区优势藓种大金发藓在砷氧化应激环境下表现出的生物地球化学特征。结果表明:大金发藓能吸收砷并进入代谢,污染区大金发藓可溶性蛋白质含量均出现降低,在矿洞出水口处最低,仅为0.151 mg·g^(-1),未污染区含量则最高达0.404 mg·g^(-1),并与各点位砷含量呈负相关,地下部分低于地上部分;大金发藓体内活性氧(ROS)出现累积现象,砷的氧化应激在其体内产生作用,污染区大金发藓H_2O_2含量最高达5.93μmol·g^(-1),相比于未污染区苔藓(3.37μmol·g^(-1))明显升高,地下部分低于地上部分,与砷含量呈正相关;污染区大金发藓对砷氧化应激存在一定抵抗性,总抗氧化水平在极高砷含量情况下出现明显降低,A3点位的总抗氧化能力(ferric reducing/antioxidant power,FRAP值)为0.577,距矿洞距离在A3点位之后的点位砷含量较低,FRAP值也基本平稳。

We measured soluble protein concentration,hydrogen peroxide（ H2O2） concentration,total antioxidant level and other biochemical indices of samples of dominant moss Polytrichum commune Hedw.,which were collected from the acid mine wastewater basin of arsenic-rich coal district and nearby unpolluted area in the upper reaches of Maoshitou Reservoir of Xingren County,Guizhou Province. The biogeochemical characteristics of P. commune in the arsenic-rich coal district under the conditions of arsenic oxidative stress were examined. The results showed that P. commune absorbed arsenic which was involved in metabolism. The soluble protein concentration in P. commune in the polluted area was lower,with a lowest value of 0.151 mg·g-1 in the water outlet of mine hole,while the value was up to 0.404 mg·g-1 in the unpolluted area. The concentration of soluble protein had negative correlation with arsenic concentration across all sampling locations. The belowground part of P. commune had lower soluble protein concentration than aboveground part. The active oxygen（ ROS） in P. commune was accumulated,indicating that the arsenic oxidative stress on P. commune. The H2O2 concentration of P. commune in the polluted area was up to 5.93 μmol·g-1,being obviously higher than that in the unpolluted area（ 3.37μmol·g-1）. The belowground part had lower H2O2 concentration than the aboveground part. The H2O2 concentration had a positive correlation with the arsenic concentration. P. commune in the polluted area was resistant to the arsenic oxidative stress to a certain degree. The total antioxidant level was significantly decreased under extremely high concentration of arsenic. The ferric reducing/antioxidant power（ FRAP value） of site A3 was 0.577. The arsenic concentration was relatively low in the sampling locations after site A3,with the FRAP value being generally stable.