中国南部的天宝水库(被桉树人工林包围)是居民的饮用水来源。然而,水库水经历黑水(BW),其原因尚不清楚。在这项研究中,进行了现场观察和模拟实验室实验,以了解BW的原因。薄膜(DGT)器件中的扩散梯度监测了铁(Fe2)浓度的空间变化,锰(Mn2+),硫化物(S2-),和在SWI处溶解的有机碳(DOC)。平面光电(PO)表明缺氧对高正流Fe2有很大贡献,Mn2+,和S2-测量,其在SWI处共沉淀形成黑色材料(FeS和MnS)。Fe-S和Mn-S之间的共沉淀具有显着的正相关性(Fe-S:r>0.05,p<0.05,Mn-S:r>0.2,p<0.05)。从11月(强热分层)到12月(弱热分层)单宁浓度显着降低(p<0.05)表明,由于分层较弱,Fe2和单宁在12月的水库水混合过程中发生了反应。模拟实验证实,新鲜桉树叶在缺氧过程中产生大量(p<0.05)单宁,并与Fe2反应产生黑水。Fe2和DOC之间的高度正相关(r>0.8)表明Fe2和DOC结合并有助于水库水变黑。该研究有助于更好地了解桉树人工林对水质的影响,为我国南方水库流域科学种植桉树人工林,保证饮用水安全提供指导。
Tianbao reservoir in southern China (surrounded by Eucalyptus plantation) serves as a source of drinking water for the inhabitants. However, the reservoir water experiences black water (BW) of which the cause remains unclear. In this
study, field observation and simulated laboratory experiment were conducted to understand the cause of the BW. The diffusive gradient in thin-film (DGT) device monitored the spatial changes in concentration of iron (Fe2+), manganese (Mn2+),
sulfide (S2-), and dissolved organic carbon (DOC) at the SWI. The planar optode (PO) showed that hypoxia contributed immensely to the high positive fluxes Fe2+, Mn2+, and S2- measured, which co-precipitated to form black materials (FeS and MnS) at the SWI. The co-precipitation between Fe-S and Mn-S was supported by their significant positive correlation (Fe-S: r > 0.05, p < 0.05, Mn-S: r > 0.2, p < 0.05). Significant reduction (p < 0.05) in tannins concentration from November (strong thermal stratification) to December (weak thermal stratification) indicated that Fe2+ and tannins reacted during the mixing of reservoir water in December due to weak stratification. The simulated experiment confirmed that fresh Eucalyptus leaves produces a significant (p < 0.05) amount of tannins during hypoxia and reacts with Fe2+ to produce black water. A high positive correlation (r > 0.8) between Fe2+ and DOC demonstrated that Fe2+ and DOC combined and contributed to the reservoir water blackening. The
study provides a better understanding on the impact of Eucalyptus plantation on water quality and provide guidance for scientific planting of Eucalyptus plantation in reservoir basins in southern China to ensure safe drinking water.