共查询到20条相似文献，搜索用时 15 毫秒
1.
Phosphorus forms and bioavailability of lake sediments in the middle and lower reaches of Yangtze River 总被引：5，自引：2，他引：5
Forms of phosphorus in sediments from 25 lakes in the middle and lower reaches of Yangtze River were analyzed by the sequential extraction procedure. Contents and spatial distrubution of algal available phosphorus (AAP) in sediments of Lake Taihu, the third largest freshwater lake of China, were also studied. Relationships between phosphorus forms in sediment and macrophytes coverage in sample sites, as well as phosphorus forms in sediments and chlorophyal contents in lake water were discussed. Exchangeable form of phosphorus (Ex-P) in surface sediments was significantly positive correlative to total phosphorus (IP), dissolved total phosphorus (DTP) and soluble reactive phosphorus (SRP) contents in the lake water. Bioavailable phosphorus (Bio-P) contents in sediments from macrophytes dominant sites were significantly lower than that in no macrophyte sites. In Lake Taihu, Ex-P content in top 3 cm sediment was highest. However, content of ferric fraction phosphorus (Fe-P) was highest in 4 - 10 cm. Bioavalilble phosphorus (Bio-P) contents in surface sediments positively correlated to Chlorophyll a contents in water of Lake Taihu with significant difference. Therefore, contents of Bio-P and AAP could be acted as the indicators of risks of internal release of phosphorus in the shallow lakes. It was estimated that there were 268.6 ton AAP in top 1 cm sediments in Lake Taihu. Sediment suspension caused by strong wind-induced wave disturbance could carry plenty of AAP into water in large shallow lakes like Lake Taihu. 相似文献
2.
Forms of phosphorus in sediments from 25 lakes in the middle and lower reaches of Yangtze River were analyzed by the sequential extraction procedure. Contents and spatial distrubution of algal available phosphorus (AAP) in sediments of Lake Taihu, the third largest freshwater lake of China, were also studied. Relationships between phosphorus forms in sediment and macrophytes coverage in sample sites, as well as phosphorus forms in sediments and chlorophyal contents in lake water were discussed. Exchangeable form of phosphorus (Ex-P) in surface sediments was significantly positive correlative to total phosphorus (TP), dissolved total phosphorus (DTP) and soluble reactive phosphorus (SRP) contents in the lake water. Bioavailable phosphorus (Bio-P) contents in sediments from macrophytes dominant sites were significantly lower than that in no macrophyte sites. In Lake Taihu, Ex-P content in top 3 cm sediment was highest. However, content of ferric fraction phosphorus (Fe-P) was highest in 4–10 cm. Bioavalilble phosphorus (Bio-P) contents in surface sediments positively correlated to Chlorophyll a contents in water of Lake Taihu with significant difference. Therefore, contents of Bio-P and AAP could be acted as the indicators of risks of internal release of phosphorus in the shallow lakes. It was estimated that there were 268.6 ton AAP in top 1 cm sediments in Lake Taihu. Sediment suspension caused by strong wind-induced wave disturbance could carry plenty of AAP into water in large shallow lakes like Lake Taihu. 相似文献
3.
天津于桥水库沉积物磷赋存特征及其环境意义 总被引：2，自引：0，他引：2
研究天津于桥水库沉积物中磷形态的空间分布特征和垂直分布特征对了解水源型水库富营养化现状及其过程具有重要的现实意义.利用抓斗式采泥器及柱状采泥器分别采集表层沉积物样品及柱状沉积物样品,采用Psenner提出的连续提取法对沉积物磷形态进行分级测定,揭示整个水库沉积物各形态磷的空间分布特征以及不同区域垂直方向上的分布规律.结果表明:于桥水库表层沉积物总磷(TP)含量为303.7~997.8 mg/kg,各形态磷含量大小顺序依次为:钙结合态磷(Ca-P)铁结合态磷(Fe-P)残渣态磷(Res-P)铝结合态磷(Al-P)有机态磷(Org-P)可交换态磷(Ex-P).表层沉积物中Fe-P、Al-P、Ca-P与TP含量由东至西逐渐递减,主要受到黎河河水夹带的外源性磷输入的影响;Res-P含量由东至西逐渐递增,与活性磷的分布规律相反,表明水库下游比上游的水质更好.垂直分布上,南部区域底层与表层沉积物相差不大,说明从1960s以来磷的沉积量就比较大;西部区域沉积物中Fe-P和Org-P含量较高,随深度的增加有明显降低的趋势;中心区域的各形态磷和TP含量均较低,且随着深度增加逐渐降低,现阶段沉积物中的磷以滞留为主,释放潜力较小. 相似文献
4.
《国际泥沙研究》2017,(4)
Phosphorus sorption capacity was investigated in surface sediments derived from an abandoned zinclead mine area located in northeastern Algeria. The forms and the distribution of phosphorus in the raw sediment were identified using the sequential chemical extractions method. Batch experiments were done to study the adsorption kinetics and isotherms. The pH effect was evaluated by macroscopic and infrared analyses. In raw sediment, speciation results show that phosphorus is dominantly bound to oxyhydroxides. Sorption experiments demonstrate that phosphorus uptake is principally related to sediment composition. The nature of the dominant iron oxyhydroxide has a substantial role in the adsorption capacity and the mechanism interaction. The adsorption kinetics can be described by the second order and Elovich models. The isotherms data are successfully modeled by the Temkin equation.The maximum phosphorus removal is reached under acidic pH. Spectroscopic analyses reveal that the predominance of jarosite implies electrostatic interaction with sediment particles. However, in the case of schwertmannite predominance, phosphate ions are adsorbed by the ligand exchange mechanism. 相似文献
5.
Sorption behavior of nonylphenol on marine sediments: effect of temperature, medium, sediment organic carbon and surfactant 总被引：3，自引：0，他引：3
The sorption behavior of nonylphenol (NP, a toxic endocrine disruptor) on marine sediments was studied in detail through a series of kinetic and thermodynamic sorption experiments. The results showed that the sorption reaction of NP on marine sediments reached equilibrium in 1.5 h and that it accorded well with the non-linear Ho-McKay pseudo-second-order model. The sorption isotherms of NP on H2O-treated sediments could be well described by the Linear isotherm model, while the sorption isotherm on H2O2-treated sediments could be well fitted with the Freundlich isotherm model. A positive correlation was found between the distribution coefficient (Kd) and the sediment organic carbon contents. The medium salinity showed a positive relation with the Kd and a negative relation with the dissolved organic carbon (DOC). Hexadecyl trimethyl ammonium bromide (CTAB) enhanced the sorption amount of NP the most, while sodium dodecylbenzenesulfonate (SDBS) enhanced it the least. The sorption reaction of NP on marine sediments was a spontaneous, physical, exothermic and entropy-decreasing process. 相似文献
6.
Sorption behavior of Lanaset Red (LR) G on lentil straw (LS) was studied as a function of particle size, adsorbent dose, initial pH value, initial dye concentration, and contact time. Sorption kinetics data was well described by logistic model. Modified logistic equation can be used to explain effects of initial dye concentrations and contact time on the sorption of LR G with high R2 value. Freundlich model was found to be excellent in representing the equilibrium data. Thermodynamic parameters like free energy (ΔG0), enthalpy (ΔH0), and entropy (ΔS0) were calculated by the use of Langmuir constant. Thermodynamic data showed that the sorption processes were spontaneous and endothermic in nature. Desorption process suggested that strong binding and weak interactions could be formed between adsorbent surface and dye molecules. Results revealed that LS has a remarkable potential for the sorption of LR G. 相似文献
7.
太湖表层沉积物磷的吸附容量及其释放风险评估 总被引：34，自引：2，他引：34
利用沉积物磷吸附指数(PSI)和磷吸附饱和度(DIS)等指标来表征太湖表层沉积物的磷吸附容量，并探讨了太湖沉积物磷吸附容量的空间变化．研究发现：草酸铵提取的磷以及活性铁、铝氧化物含量在梅梁湾东北部至五里湖一带的沉积物中较高，而在太湖南部湖区相对较低，这主要是与附近城市污水的实际贡献有着密切关系；太湖沉积物的磷吸附指数大体上有着北高南低、西高东低的分布特征，而磷吸附饱和度分布与PSI恰有相反的特征；沉积物中磷的吸附容量可能主要受到无定形的铁和铝的氧化物控制，也受沉积物有机质含量的影响．初步确定了用磷吸附指数和磷吸附饱和度来表征的湖泊沉积物磷释放风险指数概念，并应用于对太湖沉积物磷诱发的富营养化风险的评估． 相似文献
8.
Seasonal variations and bioavailability of inorganic phosphorus in soils of Yeyahu Wetland in Beijing, China 总被引：4，自引：0，他引：4
Phosphorus (P) in soils has an important influence on the development and productivity of wetland. The objective of this study was to investigate the distribution, bioavailability and seasonal variations of inorganic phosphorus (IP) in soils of Yeyahu Wetland. The results showed that the concentration of Ca-bound P (Ca-P) remained the main occurrence in all IP fractions despite the season, at the same time the Al-bound P (Al-P) was always the lowest IP fraction despite the season. Al-P and Fe-bound P (Fe-P) concentration were all reached the highest value in May and the lowest in November, which was opposite to the occluded P (Oc-P) fraction. The notable higher Oc-P concentration in November observed in this study was probably due to the decomposition of plants and the subsequently releasing of oxides to soils. Ca-P didn't change much with season variations. Exchangeable P (Ex-P) and Oc-P were all positively correlated with soil moisture content and organic matter content, but Al-P was negatively correlated with these two soil properties. As a stable form, Ca-P was not associated with soil properties. Al-P, Fe-P and Ca-P might contribute to the storage of P in studied wetland with the principle component analysis results. The concentration rank order of the bio-available P in soils was generally as follows: Olsen-P > Algal available P (AAP) > Water soluble P (WSP) > Readily desorbed P (RDP). Olsen-P was positively correlated with Ex-P and Oc-P, and it was thought to be a more suitable indicator for bio-available P in soils. 相似文献
9.
After installation of phosphorus elimination plants at the inflows of the eutrophic Lake Tegel and Schlachtensee, phosphorus (P) loading declined by a factor of 40 and 100, respectively. This resulted in a pronounced reduction of phosphorus concentrations in the lake water, followed by a decline of chlorophyll‐a concentrations. However, for many years P release from sediments due to mineralization and desorption of sedimentary P continued. In Schlachtensee, the presence of nitrate above the sediment suppresses P release, because the Fe/P ratio is sufficient to provide enough aerobic sorption capacity. In Lake Tegel, some P release occurs even under aerobic conditions because of the low aerobic P sorption capacity of the sediments. There, nitrate could moderate the P release peaks which occur when the Fe‐P cycle at the sediment water interface is disturbed by precipitation of iron sulfide after reduction of sulfate during times of high mineralization intensity. The potentially mobile P pool in the sediments of both lakes is rather small, indicating that the P release could subside after sufficient reduction of the external P load in Lake Tegel and the disruption of the internal P cycle in Schlachtensee. 相似文献
10.
Batch sorption technique was carried out for the removal of anionic dye Congo red (CR) from aqueous solution using raw rectorite (R‐REC) and organified rectorite (CTA+‐REC) modified by cetyltrimethylammonium bromide (CTAB) as adsorbents. The effects of organification degree of CTA+‐REC as well as the process parameters including the pH of dye solution, sorption time, and initial dye concentration on adsorption capacity for CR were investigated and the sorption kinetics was also evaluated. The results showed that the sorption behaviors of R‐REC and CTA+‐REC for CR followed pseudo‐second‐order kinetic model and the sorption equilibrium data perfectly obeyed the Langmuir isotherm. The thermodynamic parameters including entropy of sorption (ΔS0), enthalpy of sorption (ΔH0), and Gibbs free energy of sorption (ΔG0) were obtained and analyzed. Fourier transform infrared study revealed that a chemisorption process occurred between CR and CTA+‐REC. REC modified by cationic surfactants showed the higher adsorption capacities for CR compared to R‐REC and in theory would be used as an efficient and promising adsorbent for the removal of anionic dyes in wastewater treatment. 相似文献
11.
水生植被恢复对城市景观水体磷浓度及沉积物磷形态的影响 总被引：2，自引：1，他引：1
以上海市两个水生植被恢复时间为5—10年的城市景观水体为研究对象,通过分析水体理化性质以及水和沉积物磷的含量和形态,研究水生植被恢复对富营养化水体修复的长期生态效应.结果表明,水生植被恢复能有效降低水体氮、磷浓度,对水体富营养化有明显的改善作用.在外源磷的污染源得到控制后,水体磷浓度会随着修复时间的增加而逐渐降低并相对稳定.沉积物磷形态以钙磷为主,随着水生植被恢复时间的增加,生物活性较强的可交换态磷、铝磷和铁磷的含量下降,而相对稳定的钙磷所占的比例增加.研究结果还表明,即使不进行底泥疏浚,长期的水生植被恢复也可以使城市河流沉积物中内源磷释放及水体磷浓度得到有效控制. 相似文献
12.
Sorption of perfluorooctane sulfonate (PFOS) on marine sediments 总被引：2，自引：0，他引：2
Sorption of anionic perfluorooctane sulfonate (PFOS) on marine sediment was investigated in detail. It was found that solution ionic composition and sediment-specific parameters played important roles in affecting the sorption of PFOS. The results indicated that sorption of PFOS in seawater to marine sediments was strong (≈ 10 times higher than that in freshwater) and nonlinear (Freundlich n(F) values of 0.77-0.96). The sorption affinity was well correlated with sediment organic carbon content, indicating the importance of hydrophobic interactions. At a PFOS aqueous concentration of 10 μg/L, PFOS distribution coefficients increased with the increasing salinity in solution, with an average rate of 0.48 ± 0.03 log units per a log unit of salinity. Further studies demonstrated that among common ions contributing to the salinity in seawater, dissolved calcium and magnesium are dominantly responsible for the sorption-enhancing effect of salinity for PFOS. This work will aid in better understanding of PFOS sorption mechanisms, and be useful for fate modeling of this class of contaminants in the marine environment. 相似文献
13.
14.
武汉东湖和南湖沉积物中磷形态分布特征与相关分析 总被引：1，自引：0，他引：1
采用七步连续提取法,探讨了东湖子湖(郭郑湖、庙湖)及南湖柱状沉积物中的水环境特征、不同赋存形态磷的垂向分布特征及所占的百分比,并分析了各形态磷之间的相关性.结果表明:通过分析采样点水环境特征,发现郭郑湖和南湖间隙水中总磷含量均高于上覆水体,并有较强的释放趋势;而庙湖间隙水中总磷含量小于上覆水,有较大的沉积趋势.通过分析不同赋存形态磷的垂向分布特征,发现可交换态磷、铝结合态磷、铁结合态磷和有机磷这几种生物活性磷含量随着深度的增加逐渐减少,并且15 cm以下含量变化不大;而闭蓄态磷、碎屑磷和自生钙磷这几种相对惰性的磷含量随着深度的增加变化趋势不明显.从不同形态磷的百分含量的变化幅度发现,南湖的变化范围最大,郭郑湖其次,庙湖的变化范围最小.各形态磷相关分析表明,郭郑湖总磷的增加主要来自于无机磷,其次来自于有机磷;庙湖总磷的增加主要来自于无机磷中的生物有效磷,有机磷对其贡献并不大;南湖无机磷和有机磷与总磷的关系都非常密切. 相似文献
15.
This work seeks to understand how the balance of abiotic and biotic kinetic processes in sediments control the residual concentration of TNT in marine systems after release from ocean-dumped source. Kinetics of TNT disappearance were followed using marine sediments at different temperatures and under both biotic and presumably abiotic conditions (through sodium azide addition). Sediments exhibiting the highest rate of TNT disappearance under biotic conditions also exhibited the highest sorption affinity for TNT under abiotic conditions. Significant temperature dependence in the abiotic processes was observed in the diffusion coefficient of TNT and not sediment sorption affinity. At higher temperature, kinetics of biotic processes outpaced abiotic processes, but at low temperature, kinetics of abiotic processes were much more significant. We concluded that the differential influence of temperature on the kinetics of abiotic and biotic processes could provide distinguishing predictions for the potential residual concentration of TNT contamination in marine-sediment systems. 相似文献
16.
选取贵州红枫湖为研究对象,在实验室条件下模拟了自然、好氧和厌氧条件下沉积物内源磷的释放过程,联合应用微电极技术和沉积物磷形态分析对沉积物—水界面开展了微尺度观测与研究.结果表明,厌氧条件下红枫湖沉积物总磷含量显著降低,且主要是NaOH提取态磷(NaOH-P)和残渣态磷(rest-P)含量降低所致,厌氧条件下沉积物孔隙水中磷酸盐浓度明显升高,而好氧条件下沉积物孔隙水磷酸盐浓度显著降低,反映厌氧条件显著促进了红枫湖沉积物磷释放.厌氧条件下沉积物内部溶解氧浓度下降、硫还原活动增强可能是导致NaOH-P释放的主要原因.O_2浓度的降低加速了沉积物还原作用并产生大量H2S,进而与二价铁离子形成硫化亚铁沉淀,最终导致NaOH-P(Fe-P)释放到孔隙水中.好氧条件向厌氧条件的转换可通过改变沉积物内部pH值分布和微生物活动促使rest-P释放:厌氧条件下,厌氧微生物不仅可以消耗硫酸根产生H_2S,导致pH值降低,还可消耗有机质,将有机磷转变为无机磷.上述研究结果表明,沉积物—水界面氧化还原环境可影响沉积物氧渗透深度、pH值分布、微生物活动、硫循环以及有机质降解过程,进而控制沉积物磷的形态转化与释放.联合应用微电极技术和沉积物磷形态分析对湖泊沉积物—水界面开展微尺度观测研究是揭示沉积物内源磷释放机制与控制因素的有效途径. 相似文献
17.
The paper analyses the concentrations of total phosphorus and its forms in sediments from the Gulf of Gdańsk on the basis of studies conducted at 25 sampling sites in 2001–05. The phosphorus speciation analysis was performed by sequential extraction. The extensive spatial variability of Ptot concentrations and speciation was found to be dependent on the physicochemical properties of the sediments, the oxygen conditions in the water and sediments, and the depth of the water column above the sediment surface. In the coastal zone, the sedimentation of riverine suspended matter and the sorption and chemisorption processes exert a considerable influence on P speciation. Over 70% of variation of total phosphorus concentration in sediments in the Gulf of Gdańsk could be explained by changes of proportion of fine fraction of sediments (grain size <0.0625 mm). Maximum Ptot concentrations were recorded in clays and silts in the deep water, stratified part of the Gulf of Gdańsk. In the coastal zone, where sandy sediments are dominant, phosphorus concentrations were much lower; this was due to the considerable dynamics of the bottom water and intensive sea floor transport. Ptot concentrations in the Gulf of Gdańsk sediments ranged from 1.75 to 957.17 μmol g−1 d.w. Of all the forms of phosphorus, the highest concentrations were found for organic phosphorus (Org-P). Of its inorganic forms, the highest concentrations were of phosphorus bound to clay minerals and aluminium oxides (NaOH-P), the lowest ones were of loosely bound phosphorus (NaCl-P). On the basis of determinations of total phosphorus concentrations in sediments of a given type and the available data on the seabed areas covered by particular sediment types in the Gulf of Gdańsk, the mass of total phosphorus in the surficial sediment layer (0–2 cm) was estimated at ca. 15.6×103 tonnes. 相似文献
18.
环太湖河流进出湖水量及污染负荷(2000-2002年) 总被引：22，自引：5，他引：22
天然水域,尤其是富营养的浅水湖泊,沉积物中磷的释放是蓝藻水华发生、形成和持续生长的重要因素．分析沉积物中磷的赋存形态转化及其潜在生态效应,有助于理解沉积物中磷的迁移转化过程及其与湖泊富营养化之间的关系．本文综述国内湖泊水域中磷的主要形态、来源和转化过程以及其生物有效性的研究进展．重点讨论了近5年来中国东部浅水湖泊沉积物磷的形态分析、转化和生物有效性评估的现状,以及沉积物中磷形态与浅水湖泊富营养化之间的潜在联系． 相似文献
19.
The potential to remove Ni(II) ions from aqueous solutions using sea beach sand, a carbonate‐quartz mineral, was thoroughly investigated. The effects of relevant parameters such as solution pH, adsorbent dose, metal ions concentration, and temperature on Ni(II) sorption onto beach sand were examined. The sorption data followed the Langmuir, Freundlich and Dubinin‐Radushkevich (D‐R) isotherms. The adsorption was endothermic in nature at ambient temperature and the computation of the parameters, ΔH, ΔS and ΔG indicated the interactions between sorbate and sorbent to be thermodynamically favorable. Equilibrium was achieved very quickly within 30 min of shaking. A pseudo‐first order Lagergren equation was used to test the adsorption kinetics. Other kinetic models, e. g., the Morris‐Weber and Reichenberg equations, were used to calculate the rate constant of intraparticle diffusion and the fate of the diffusion process, respectively. The influence of some of the common cations and anions were also a subject of this study. 相似文献
20.
First order removal rates for 15 polyaromatic hydrocarbons (PAHs) in soil, sediments and mangrove leaves were compared in relation to the parameters used in fate transport analyses (i.e., octanol–water partition coefficient, organic carbon–water partition coefficient, solubility, diffusivity in water, HOMO–LUMO gap, molecular size, molecular aspect ratio). The quantitative structure activity relationships (QSAR) and quantitative structure property relationships (QSPR) showed that the rate of disappearance of PAHs is correlated with their diffusivities in water as well as molecular volumes in different media. Strong correlations for the rate of disappearance of PAHs in sediments could not be obtained in relation to most of the parameters evaluated. The analyses showed that the QSAR and QSPR correlations developed for removal rates of PAHs in soils would not be adequate for sediments and plant tissues. 相似文献