College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China.
Key Laboratory of Ecological Impacts of Hydraulic-Projects and Restoration of Aquatic Ecosystem of Ministry of Water Resources, Institute of Hydroecology, Ministry of Water Resources and Chinese Academy of Sciences, Wuhan, 430079, China.
Environ Sci Pollut Res Int. 2018 Nov;25(31):31262-31271. doi: 10.1007/s11356-018-3087-7. Epub 2018 Sep 7.
Hydrological regimes have been significantly altered since the Three Gorges Dam (TGD) raised the water level of the reservoir to the maximum design level of 175 m in October 2010. This change might greatly influence the forms of phosphorus (P) in the sediment and the adjacent riparian soil. The purpose of this study was to reveal the lateral (sediment, water-level-fluctuation zone soil, and upland soil) and longitudinal (from the end of backwater area to the TGD) trends in P factions. Samples from 11 sites located along the main stem and ten sites located along eight tributaries were collected in June 2017. The P fractions were determined using the Standards, Measurements, and Testing (SMT) protocol. The results showed that the order of increase for average pH values was sediment (7.58 ± 0.62), WLFZ soil (7.44 ± 0.29), and adjacent upland soil (7.20 ± 0.68). The total organic carbon in the sediment was also highest with an average of 9.15 ± 2.97 mg·g. The average concentrated HCl-extractable P (total P), organic P (OP), inorganic P (IP), HCl-extractable P (HCl-P), and NaOH-extractable P (NaOH-P) were 630.02 ± 212.24, 161.89 ± 90.77, 468.13 ± 194.92, 335.65 ± 159.88, and 51.40 ± 36.20 mg·kg, respectively. The concentration of both total P and NaOH-P in the sediment of the main stem exhibited an increasing trend from the backwater area to the TGD. The average concentration of P species in the sediment was higher than those in the upland soil and the water-level-fluctuation zone (WLFZ) soil. For all the sediment and soil samples, the rank order of P species concentrations was HCl-P > OP > NaOH-P. Both IP and HCl-P were highly positively correlated with total P in the upland soil, the WLFZ soil and the sediment. However, only in the sediment, NaOH-P was positively correlated with total P and OP. All P species in the upland soil demonstrated greater spatial heterogeneity than those in the WLFZ soil and the sediment. Redundancy analysis revealed that the main variables explaining the variance in P species concentrations were Al in the upland soil and pH in the sediment.
自 2010 年三峡大坝（TGD）将水库水位提高到设计最高水平 175 米以来，水文状况发生了重大变化。这种变化可能会极大地影响沉积物和相邻滨岸土壤中磷（P）的形态。本研究的目的是揭示 P 组份的横向（沉积物、水位波动带土壤和高地土壤）和纵向（从回水末端到 TGD）趋势。2017 年 6 月，在干流的 11 个地点和 8 条支流的 10 个地点采集了样本。采用标准、测量和测试（SMT）方案测定 P 组份。结果表明，平均 pH 值增加的顺序为沉积物（7.58±0.62）、WLFZ 土壤（7.44±0.29）和相邻高地土壤（7.20±0.68）。沉积物中的总有机碳含量也最高，平均为 9.15±2.97mg·g。浓缩盐酸可提取磷（总磷）、有机磷（OP）、无机磷（IP）、盐酸可提取磷（HCl-P）和氢氧化钠可提取磷（NaOH-P）的平均浓度分别为 630.02±212.24、161.89±90.77、468.13±194.92、335.65±159.88 和 51.40±36.20mg·kg。干流沉积物中总磷和氢氧化钠磷的浓度均呈现从回水末端到 TGD 逐渐增加的趋势。沉积物中 P 组份的平均浓度高于高地土壤和水位波动带（WLFZ）土壤中的浓度。对于所有的沉积物和土壤样品，P 组份浓度的排序是 HCl-P>OP>NaOH-P。在高地土壤、WLFZ 土壤和沉积物中，IP 和 HCl-P 与总磷高度正相关。然而，只有在沉积物中，NaOH-P 与总磷和 OP 呈正相关。高地土壤中的所有 P 组份的空间异质性均大于 WLFZ 土壤和沉积物中的 P 组份。冗余分析表明，解释 P 组份浓度变化的主要变量是高地土壤中的 Al 和沉积物中的 pH。
