【作者】 韩璐；

【导师】 黄岁樑；

【作者基本信息】 南开大学 ， 环境科学， 2010， 博士

【摘要】 本论文选取海河干流柱芯沉积物、美国佛罗里达Alafia河水系表层沉积物及岸边带土壤研究河流沉积物总磷污染及沉积物磷形态分布特征,并对各形态磷与沉积物理化指标进行相关性研究；初步探讨不同土地利用方式下岸边带土壤中微生物生物量磷的分布；同时探讨环境因素(溶解氧、有机碳源、金属铝)联合作用对沉积物释放磷的影响。在此基础上,通过室外大型反应柱实验,模拟研究疏浚、置换水条件下沉积物氮、磷释放对上覆水水质的影响。主要结论如下：1.海河干流沉积物以细砂和极细砂为主,分别达到总量的30.9%～54.7%和28.8%～63.7%,粉粒和粗砂粒含量较低。海河干流沉积物中有机质、总磷含量分别为4.07%～8.43%和560-1035mg/kg,与我国太湖接近,已属国内较高水平。垂直方向上,总磷含量变化趋势是随着深度增加而降低,其最大值在表层处取得。不同深度不同粒径沉积物中,钙磷(HCl-P)为沉积物中磷的主要存在形态,其含量占总磷含量的60%～80%,说明沉积物中磷的一半以上不能被生物利用。可交换态磷(Ex-P)含量最低(2%～3%)。沉积物中各形态磷含量,除钙磷外,与沉积物中细粒径含量相关,相关系数达到0.72以上2.Alafia河流域内水系沉积物以砂粒为主。沉积物中各形态磷含量由高到低顺序为H2SO4-P>NaOH-P>CDB-P>NH4Cl-P。各形态磷含量与区域污染状况、矿物质含量、区域地质环境条件有关。Alafia河流域内岸边带土壤中有机碳、土壤微生物磷含量存在差异。生物量磷含量在86.4～479.6mg/kg之间,不同土地利用方式的生物磷含量由高到低顺序为森林用地＞农业农地＞居民用地＞矿区用地。3.环境条件对沉积物磷释放有较大影响。厌氧条件下沉积物磷释放量明显高于好氧条件下。聚铝(PAC)有显著抑制沉积物磷释放的作用。有机碳源对沉积物释放磷的影响较为复杂：未添加金属铝时,未添加有机碳源的沉积物中磷释放量高于添加碳源时的释放量。而在添加金属铝后,添加有机碳源的沉积物中磷释放量略高于未添加碳源时的释放量。4.模拟疏浚、一次性全部换水、周期性置换水后疏浚深度对沉积物释放氮、磷的影响的试验结果表明,疏浚对沉积物释放氮、磷污染物有一定影响。自来水作为上覆水时,沉积物中总氮、COD浓度随沉积物深度增加而增大。同一释放装置内,上覆水总氮、总磷和COD浓度均沿垂直方向自下而上逐渐降低。在沉积物氮、磷污染严重情况下,通过疏浚、置换水在短期内能降低上覆水氮、磷浓度,但污染沉积物有持续释放氮、磷的能力,释放的氮、磷足以维持富营养化需求。更多还原

【Abstract】 Sediment cores from Haihe River mainstream, surface sediments and riparian soil from Alafia River stream were collected. Spatial distributions of total phosphorus contents and phosphorus fractions in these sediments were determined experimentally. Correlations between phosphorus fractions and sediment characteristics, distributions of microbial biomass phosphorus with different land use patterns and the effect of multiple factors (dissolved oxygen, organic carbon, aluminum) on phosphorus release from sediments were discussed. Furthermore, outdoor column experiments were carried out to study static release of phosphorus, nitrogen and COD from sediments. The main results were as follows:1. Sediments in the Mainstream of Haihe River were mainly comprised of fine sand and very fine sand, accounting for 30.9%-54.7% and 28.8%-63.7%, respectively. Clay and coarse sand contents were quite low. Total contents of organic matter and total phosphorus in the sediments of Haihe River mainstream were in the range of 4.07%-8.43% and 560-1035mg/kg, which were similar to those in Taihu Lake. Sediment pollution in Haihe River mainstram was at higher level compared to other river sediments in China. Vertical profiles of total phosphorus contents was decreased with increasing depth, and the highest vaule was found in surface sediments. The calcium bound phosphorus (HCl-P) is the largest sediment phosphorus fraction, accounted for 60～80% of sedimentary TP. This reflected that over half amount of the phosphorus was not bioavailable in Haihe River mainstream. Exchange phosphorus (NH4Cl-P) content was quite low in the sediments. Except carbon bound phosphorus, other phosphorus fractions were correlated well with contents of fine grain sedimts (r> 0.72).2. Coarse sand was the dominated component in the Alafia River stream sediments. Generally speaking, the order of P-fractions in most sediment samples was ranked as H2SO4-P> NaOH-P> CDB-P> NH4Cl-P. P fractions were related to pollution status and physiochemic characteristics of sediments. Organic matter and microbial biomass phosphorus contents in riparian soil of Alafia River watershed was diffferent. The microbial biomass phosphorus ranged from 86.4 to 479.6mg/kg. The rank order of microbial biomass phosphorus contents with different land use patterns was Forest> Agricultural land> Residents> Mining.3. It was indicated in the study that the anaerobic condition was much more propitious to the P transformation at the water-sediment interface than the aerobic condition. It also showed that aluminum was able to retain phosphorus in sediments. Addition of OC reduced the release of phosphorus from sediments to overlying water without addition of Al under aerobic and anaerobic conditions. However, with addition of Al under both anaerobic and aerobic conditions the OC enhanced the release of phosphorus from sediments to overlying water.4. It was showed in the study that the dredging depth had an effect on the release of nitrogen and phosphorus from sediments to overlying water. The concentrations of total nitrogen, total phosphorus, and COD in the overlying water of column experiments decreased from bottom to top vertically. Dredging and replacement of overlying water with tap water could decrease the concentrations of total nitrogen, total phosphorus, while sediment could sustainded release nitrogen and phosphorus. The concentration of nitrogen and phosphorus will meet the needs of eutrophication.更多还原