升钟湖夏季水和沉积物中磷形态分布特征

为探究升钟湖水和沉积物中磷污染情况,于2019年8月(夏季),采集了升钟湖湖区15个样点的水样和沉积物样品,测定了升钟湖表层水、间隙水及沉积物的磷形态,并分析各种形态磷之间的相关性。结果表明:①升钟湖表层水总磷含量介于0.033～0.085 mg/L,各形态的磷含量由高到低依次为DTP(61.93%)、DOP(40.00%)、PP(38.07%)和DIP(21.93%);②间隙水的总磷含量介于3.49～7.57 mg/L,是水体磷的“源”,正磷酸盐仅占总磷的1.9%;③沉积物总磷含量介于299.04～1 138.69 mg/kg,Psenner法连续分级提取出表层沉积物共有5种形态的磷,各形态磷含量由高到低依次为残渣磷(Res-P:44.78%)、金属氧化物结合态磷+有机碎屑腐殖酸磷(NaOH-P:22.92%)、钙结合态磷(HCl-P:14.82%)、可还原态磷(BD-P:13.39%)和弱吸附态磷(NH₄Cl-P:4.09%),各形态磷含量均表现一定的空间分布差异,其中,总磷含量整体为西北部高于东南部;④相关性分析结果显示,沉积物中磷的释放主要通过BD-P、NaOH-P及NH₄Cl-P进行,间隙水正磷酸盐(PO^3-₄-P)与水体各形态的磷之间均无显著的相关性(P>0.05),升钟湖沉积物磷在夏季时释放潜力较低。研究成果对于管理升钟湖的政策实施及其资源的可持续利用可提供参考。     

升钟湖冬季氮和磷内源静态释放风险初探

为探究升钟湖冬季氮和磷的内源静态释放风险及释放规律,于2018年冬季在升钟湖湖区设置了15个采样点,采集了各样点的水样和沉积物样品,测定了水体常规理化指标及沉积物间隙水氮、磷含量,并进行了沉积物氮、磷室内模拟静态释放试验。结果表明：(1)升钟湖沉积物间隙水总氮(TN)含量在1.846～5.293 mg/L之间,氨氮(NH₄⁺-N)是主要形态,含量在0.437～3.603 mg/L之间,硝态氮(NO₃^--N)次之,含量在0.545～1.452 mg/L之间,各形态氮、磷具有较为明显的空间分布差异。(2)升钟湖沉积物间隙水总磷(TP)含量在0.194～0.561 mg/L之间,其中溶解性正磷酸盐(PO₄^3--P)含量在0.029～0.417 mg/L之间。(3)升钟湖在冬季存在氮和磷的内源静态释放,相对而言,磷的释放风险更大,释放规律更加明显,而氮的释放主要是通过硝态氮(NO₃^--N)的形式进行,基本不进行氨氮(NH...     

水源型水库底泥中磷形态及其分布特征研究

以长江下游某水源型水库为例,对水库表层底泥应用淡水沉积物磷形态的标准测试程序（SMT）测定了总磷（TP）、铁铝结合态磷（Fe/Al-P）、钙结合态磷（Ca-P）、无机磷（IP）和有机磷（OP）,分析了各形态磷之间的相关性。研究结果表明：水库总磷含量在652.55～889.78 mg/kg ,表层沉积物中 T P含量的增加主要来自Fe/Al-P部分,其次来自IP和OP部分。OP含量与 Ca-P和 Fe/Al-P的含量均有较好的正相关关系,而Ca-P 与 Fe/Al-P相关性较弱。5个采样点底泥中的铁铝结合态磷含量都低于钙结合态磷,且两者比值都小于0.5,应考虑环境酸化引起的磷释放风险。     

黄河内蒙古段表层沉积物磷的吸附行为

为探明黄河内蒙古段表层沉积物对磷的吸附行为,模拟研究了内蒙古段6个采样点表层沉积物磷的动力学吸附和等温吸附行为,并分别运用动力学吸附模型、等温吸附模型对试验数据进行拟合,探究沉积物理化性质与磷最大吸附量的相关性。结果表明:沉积物磷的动力学吸附过程符合Lagergren准二级吸附动力学反应;沉积物磷的等温吸附过程用Langmuir等温吸附回归方程、Friendlich等温吸附回归方程均能较好地拟合,属于单分子层吸附;6个采样点吸附/解吸平衡浓度(EPC0)依次为0.114、0.089、0.140、0.098、0.065、0.082 mg/g,沉积物磷最大吸附量依次为0.246 0、0.109 6、0.049 5、0.189 9、0.284 9、0.033 0 mg/g。研究发现,在乌拉特前旗、老牛湾采样点,沉积物对磷吸附表现为"汇";乌海、临河、包头、呼市托县沉积物表现为水体中磷的"源",有向上覆水释放磷的潜力;内蒙古段6个采样点表层沉积物磷的最大吸附量与沉积物有机质含量呈正相关关系。     

湖泊沉积物-水微界面上磷的释放过程研究

为揭示湖泊内源污染的微界面环境行为及机制,从环境微界面角度出发,研究湖泊沉积物-水微界面磷的释放过程。利用新兴的湖泊沉积物原位高分辨率间隙水采集技术(DGT和Mini-peeper)分别获取了大纵湖、蜈蚣湖和九龙口沉积环境中生物有效磷和可溶性活性磷的垂直剖面分布,并在微尺度下发现了由局部有机质强烈降解释放磷酸盐形成的异常突变点。利用DIFS模型分析了沉积物对磷的吸附解吸特性,结果发现:疏浚后的九龙口沉积物对磷酸盐的吸附解吸能力较弱,而大纵湖和蜈蚣湖表层沉积物磷酸盐则以弱结合态为主,具有良好的磷吸附特性,表明稳定的沉积物表层环境微界面系统对内源磷的释放具有很好的缓冲作用;同时发现大纵湖和蜈蚣湖表层沉积物对间隙水中的磷具有较强的补给能力,补给源主要分布在沉积物表层2~3 cm附近,对界面磷的释放起关键的调节作用。     

沉水植物苦草对上覆水各形态磷浓度的影响

沉水植物是影响湖泊磷营养状态的重要因素。在室内模拟了"水-苦草-沉积物"生态系统,在沉水植物苦草生长过程中分析上覆水中的总磷(TP)、溶解性总磷(TDP)、溶解性有机磷(DOP)、溶解性活性磷(SRP)、颗粒态总磷(PP)的变化,探讨了苦草对上覆水磷赋存形态的影响。结果表明,苦草在生长过程中减缓了沉积物磷的相对释放速率使上覆水中TP、SRP、DOP、PP均呈现不同程度的下降。上覆水TP、SRP、DOP、PP分别下降了37.5%、74.6%、42.0%、19.5%;苦草主要通过吸收上覆水和间隙水中的磷及对环境因子的影响,使得上覆水中各形态磷浓度保持在较低的水平,降低沉积物向水体释放磷的速率。     

黄河中下游表层沉积物各形态磷的研究

采用改进的Ruttenberg连续萃取法对黄河中下游表层沉积物进行磷形态分析,结果表明:黄河中下游表层沉积物中总磷以无机磷为主;弱吸附态磷和Fe结合态磷的含量不高,自生磷和碎屑磷合占总磷含量的89.41%～96.11%;难溶有机磷含量变化不大,与有机质的变化趋势相同;弱吸附态磷、Fe结合态磷、无机磷3种较易被生物利用的形态磷虽然只占总磷的9%左右,但这部分磷参与生态循环,对生态环境有重要影响.     

黄柏河流域水库底泥内源磷释放对水质影响分析

为分析宜昌市黄柏河流域饮用水水库内源磷释放对水质的影响,于2016年对流域内3座梯级水库的水体进行了逐月采样,在10月进行一次沉积物柱状样品的采集。根据样品分析数据,估算了沉积物-水界面磷释放通量,以及内源磷占磷总量的比例。结果发现:流域内玄庙观水库磷释放通量为0.492 mg/(m~2·d);天福庙水库为0.37 mg/(m~2·d),西北口水库为0.175 mg/(m~2·d);玄庙观水库年内内源磷释放最大月份占比为28.4%,天福庙水库为18.5%,西北口水库为19.5%;水库底泥内源磷释放已对水库水质产生了影响。研究结果为黄柏河流域饮用水水库的水质治理、保护提供了科学依据。     

环境因子对黄河甘宁蒙段表层沉积物中磷吸附-解吸的影响

为研究环境因子对黄河水体磷污染的影响,采集黄河上游甘宁蒙段表层沉积物进行室内试验,模拟环境因子变化对表层沉积物中磷吸附-解吸过程的影响。结果表明,沉积物对磷的吸附过程是可自发进行的吸热反应,温度升高有利于表层沉积物对磷的吸附,并促进磷的解吸过程;吸附量随振荡频率的升高而增大,且存在能显著提高表层沉积物磷吸附量的振荡频率阈值;上覆水体积一定时,随沉积物质量的增加,磷吸附量减小;去除有机质后,表层沉积物对磷的吸附量增大;有机质含量较高时可明显促进磷的吸附过程,有机物含量较低时促进磷的解吸过程;上覆水KCl浓度小于0.02 mol/L时,KCl浓度越高,表层沉积物对磷的吸附量越大;上覆水KCl浓度大于0.02 mol/L时,KCl浓度越高,表层沉积物对磷的解吸量越大。     

水体紊动作用下湖泊泥沙解吸释放磷的实验研究

为了揭示水体紊动对湖泊泥沙解吸释放磷的影响,本文选取东洞庭湖湖底表层泥沙作为研究对象,通过近似均匀紊流模拟装置模拟不同强度的紊动水体,研究紊动作用下泥沙解吸释放磷的影响因素和基本规律,结果表明:泥沙起动之前,在垂向紊动扩散作用下,表层泥沙孔隙水与上覆水之间的溶解态磷交换,是溶解态磷迅速增大的主要原因;在较强紊动作用下,泥沙普遍起动,悬浮泥沙所吸附的磷解吸至水体中,溶解态磷含量显著增大,泥沙浓度越高,溶解态磷含量增长速率越大,达到平衡的时间越短;紊动扩散作用对泥沙解吸释放磷影响显著。     

洱海沉积物磷的化学赋存形态研究

本文对洱海沉积物磷的含量、空间分布以及沉积剖面上沉积磷的化学赋存形态进行了研究。结果发现，洱海表层（5cm）沉积物中总磷的含量范围为736．40～1602．50mg／kg，平均为964．60mg／kg；北部湖区高于南部，弥苴河是湖泊的主要磷来源；洱海沉积物中各形态磷的含量高低顺序为：钙结合态磷，碎屑态磷，有机态磷，铁结合态磷，吸附态磷，磷形态的剖面变化反映了埋藏作用对沉积磷的强烈改造作用。     

不同芦苇生境下白洋淀底泥磷形态分析研究

该实验采用化学连续提取方法(EDTA方法)分析白洋淀底泥中磷形态，并且该底泥经过芦苇生态滤池的处理。结果表明总磷(TP)浓度高达1597—1860mg／kg，远远超出试验参照的当地土壤中TP的浓度。因此，底泥中的磷很有可能超过水体中的而成为主要的可溶性磷释放源。无机磷在总磷中占到53％—68％，高于有机磷(OP)含量。钙磷(Ca-P)是无机磷的中主要磷形态，占到41％～46％。OP主要以酸可溶性有机磷形态存在，占到总有机磷的65％～95％，酸可溶性有机磷酸盐的释放可能成为导致湖泊富营养化的重要过程。     

引黄济青工程渠首水质变化研究

2011年4月至2012年3月从引黄济青工程渠首取样并分析水质变化情况。结果表明，渠首黄河水含沙量和浊度年平均值分别为0．83kg/m3、754NTU；总氮（TN）含量变化范围为3．43~6．84mg／L，平均值为4．70mg／L；硝酸盐氮（N03-N）是TN的主要形式，占TN的58．5％-90．2％；氨氮（NH3-N）、亚硝酸盐氮（N02-N）、总磷（TP）含量较低；叶绿素a（Chla）变化范围为1．10-7．60mg／m2，平均值为3．96mg／m3。除泄洪、流量低等特殊情形外，不同季节间含沙量、浊度及其他水质指标没有明显差异。     

Sedimentation and internal phosphorus loads in Krishnagiri Reservoir,India

This study examines sedimentation rate and its consequences on the bathymetry, capacity and internal phosphorus loading of Krishnagiri Reservoir in Tamil Nadu, South India, utilizing an acoustic Doppler profiler and remote sensing data in an ArcGIS environment. There was a significant change in the reservoir bathymetry for the year 2012, compared with the 2007. The sedimentation rate was 0.818 MCM from 1960 to 1990 and 0.83 MCM over past 5 years. The present reservoir volume is 35.57 MCM, having been reduced to nearly half of its original capacity over a 55 year span, pointing to a seriously threatened lifespan. The sediment total phosphorus (TP) load spatially varied from 6.84 to 23 394 kg, depending on the sediment deposition zones. Sequential extraction indicated the dominance of phosphate fractions to be Al‐P> Fe‐P> Ca‐P> SRP, with an average TP value of 27.27 mg g^?1 dry weight. Aluminium‐ (35%) and iron(25%)‐bound forms are the major sediment phosphorus fractions, suggesting temperature, pH and redox or related chemical reactions may be important means of sediment P release in Krishnagiri Reservoir. The sediment phosphorus load in Krishnagiri Reservoir is estimated to be 44.50 tons, with an average TP release of 40.97 mg m^?2 (range of 10.22–70 mg m^?2). The measured pore water TP concentration and calculated sediment phosphate release exhibited a linear relation. Even with a reduced external P load, the eutrophication of Krishnagiri Reservoir cannot be reduced immediately because of its high internal load and nutrient remobilization.     

Modelling of sediment oxygen demand and organic flux for a pulsed sediment organic load.

Biodegradation of organic matter in the sediment affects both the level of dissolved oxygen (DO) in the overlaying water and material flux into the water body. In the present study, a mathematical model was developed to describe the DO dynamics and related organic transformation in the sediment after a pulsed load of rich organic, sediment. The model includes DO diffusion at the sediment-water interface and inside the sediment, diagenetic reactions of particulate organic to soluble organic, substances, biodegradation of soluble organic, and related DO consumption. The model can simulate sediment oxygen demand (SOD) in a dynamic system after a sudden organic load on the sediment and the flux of both biodegradable and non-biodegradable organic can be predicted. In addition, laboratory experiments were conducted using SOD chambers to investigate the SOD dynamics and sediment material fluxes. The sediment of the batch SOD tests was loaded with fish food at various rates for the sudden organic input. Numerical simulations for SOD and organic fluxes compared well with the experimental measurements. The results demonstrate that the model can be used to predict the effect of sediment pollutants on the water quality of surface waters.     

于桥水库沉积物内源污染特性研究

通过对天津市于桥水库沉积物中污染物的释放实验研究,找出了于桥水库底泥中磷、有机质、氮、铁、锰等污染物释放的影响因素,得出了溶解氧、pH值、水温等影响因素对底泥污染物释放的影响程度,并对各污染物的释放机理进行了探讨。磷的释放条件:pH值≥8时,好氧条件下会缓慢释放,当ρ(DO)<2 mg/L时快速释放;在中酸性条件下,当ρ(DO)<1 mg/L时发生较快速释放;低溶解氧和高pH值协同作用强烈。有机物和氮的释放主要受溶解氧浓度影响,与pH值关系不大,在ρ(DO)<2 mg/L时发生了快速释放。溶解性铁、锰的释放取决于水体pH值,在酸性条件下,ρ(DO)<1 mg/L时释放。     

Does Manganese Influence Phosphorus Cycling under Suboxic Lake Water Conditions?

The comparative roles of iron and manganese in internal phosphorus loading were examined in a managed lake. Sediments and the water column of Irondequoit Bay, an embayment along Lake Ontario's southern shore, were sampled monthly during summer thermal stratification. Total phosphorus, total iron, and total manganese concentrations in the sediment averaged 1.389 ± 0.150 g/kg dry wt, 24.415 ± 0.760 g/kg dry wt, and 1.727 ± 0.053 g/kg dry wt, respectively. Elevated total phosphorus (maximum = 0.915 mg P/L) and soluble reactive phosphorus (maximum = 0.749 mg P/L) concentrations were observed in the hypolimnion. Sequential extraction of phosphorus fractions from the top 25 cm of deepwater sediment revealed that approximately 25% of phosphorus was stored in a redox-sensitive form, most likely associated with iron and manganese oxyhydroxides. Typically, phosphorus released from sediments is associated with iron, not manganese. However, iron and manganese profiles from the water column indicated that manganese from the sediment was cycling with phosphorus into the overlying waters, while iron did not demonstrate evidence of cycling. Although reductive dissolution of iron likely occurs in the sediment, iron was retained in the sediment and kept out of the water column by the maintenance of low concentrations of dissolved oxygen in the hypolimnion.