黑藻对沉积物及土壤中不同形态磷的利用与转化

利用同一区域湖泊和河流沉积物及土壤培养黑藻,运用化学连续提取法对底质中磷的不同形态进行分离,同时分析黑藻生物量及底质中上覆水和间隙水中磷浓度的变化,并对底质中生物可利用磷进行了估算,揭示沉水植物对底质中不同形态磷的利用与转化规律。结果表明,底质中弱吸附态磷、可还原性磷（RSP）是黑藻利用的主要磷形态;土壤与沉积物相比不利于黑藻生长,营养水平高的河流沉积物有利于黑藻初期生长,但容易使其早衰;沉积物作底质上覆水和间隙水磷浓度主要受底质中RSP含量的控制;土壤作底质上覆水和间隙水磷浓度主要受弱吸附态磷控制;黑藻能促进底质中磷向可利用态转化;黑藻对土壤中生物可利用磷的利用率比沉积物低。     

Evaluation of phosphorus bioavailability in El Mex Bay and Lake Mariut sediments

Phosphorus (P) fractions and their bioavailability in the sediments from El Mex Bay and Lake Mariut in Egypt were investigated using different chemical extraction methods. Sodium bicarbonate (NaHCO3) extractable P (Olsen-P) was the largest fraction (14.42%), followed by algal available P (AAP) (3.56%), water soluble P (WSP) (0.79%), and readily desorbable P (RDP) (0.06%) for El Mex Bay. While AAP con-tributed 9.94% to total P in sediments from Lake Mariut, Olsen-P 8.53%, WSP 4.11%, and RDP 0.92%. Summation of the bioavailable P fractions didn't exceed the sediment quality guidelines, and, therefore, P doesn't represent a danger to marine organisms. Correlation coefficients showed that no apparent relations between total P (TP) and iron (Fe), aluminum (Al), and calcium (Ca) in the sediments. Fur-thermore, Fe:P ratio was less than 15 indicting that there was not enough Fe in surface sediments to bind to P at most of the sampling sites. The positive correlation between TP and organic matter (OM) for Lake Mariut and El Mex Bay sediments indicated that the organic matter content of the sediment was a useful predictor of the total phosphorus content. Data from this study constitute a baseline of phosphorus bioavailability in sediments from El Mex Bay and Lake Mariut and could be used as a reference for future studies on the changes of bioavailable and residual phosphorus fractions over time.     

Assessments of Potential Spatial‐temporal Variations in Phosphorus Distribution and Fractionation in River Bed Sediments

Sediment characteristics influence the distribution and bioavailability of phosphorus (P) in river sediments. In this study, we analyzed different P fractions in the sediments of the Bronx River, New York City, NY, using sequential extraction. The results showed that the average P pool rank order was HCl?P > NaOH?P > NaHCO₃?P > residue?P, and their relative proportions were 3.7: 2.0: 1.4: 1 in sediments collected in 2006, while HCl?P > NaOH?P > residue?P > NaHCO₃?P, with their relative proportions of 27.8:6.2:2.7:1 in the sediments obtained in 2007. The strong correlation between microbial P and organic P (OP), along with the changes in microbial P over time indicate that most of the OP in the river bed sediments is potentially bioavailable. The sediment transport, deposition, assimilation, the exchange of P between sediments and water columns, the land use changes, raw sewer discharge, gas spill, construction, fertilizer application, etc., as well as the hydro‐climatic changes could result in the spatial and temporal variations in P bioavailability in the river bed sediments. The estimations of P pools and their bioavailability in river bed sediments could help determine the spatial and temporal variations in P transport and impacts of land use on water quality, in turn, help regulate P in the river's watershed.     

南四湖消落带底泥有机磷赋存形态及分布特征

研究南四湖消落带底泥有机磷赋存形态及分布特征,有利于全面揭示湖区各形态磷迁移转化规律,对南四湖富营养化防控及南水北调东线调水水质保障具有重要的科学意义。以南四湖消落带底泥为研究对象,采用改进Hedley连续分级提取法测定底泥中各形态有机磷含量,通过紫外可见分光光谱与三维荧光光谱技术表征底泥有机分子结构特征及稳定性,反映消落带有机磷结构及稳定性差异,运用Pearson相关性分析及主成分分析解析底泥各形态磷与其他理化指标的相关性。研究结果表明,南四湖消落带底泥总磷含量均值为679.90 mg/kg,其中有机磷(OP)占比20.03%~45.69%。各赋存形态有机磷含量及相对比例大小依次为:残渣态有机磷(67.58%)＞钙结合态有机磷(16.61%)＞铁/铝结合态有机磷(7.62%)＞碳酸氢钠提取态有机磷(5.97%)＞水提取态有机磷(2.22%)。南四湖消落带底泥OP含量及形态主要受内源影响,主要来自内源性微生物代谢。南四湖消落带西岸底泥磷释放风险高于东岸和南岸消落带。相关性分析发现,消落带底泥pH与磷含量显著负相关,表明随着底泥碱性的增强可能导致底泥磷向水体中释放的风险更高;底泥有机质与OP显著正相关,表明有机质可能是OP的重要载体;主成分分析发现底泥各形态磷呈正相关性,表明消落带底泥各形态磷具有同源性。研究结果可为南四湖湖区内源磷释放控制及富营养化风险防控提供科学依据。     

Two Experimental Methods to Determine the Speciation of Cadmium in Sediment from the River Neckar

The binding forms of Cd to an anaerobic sediment of low sulfide content from Lauffen reservoir (River Neckar, Germany) were studied using two different approaches, i. e. sequential extraction (modified from published protocols) and titrimetric study of the pH-dependent Cd release. Thermodynamic equilibrium calculations were applied to calculate both the release pattern of Cd during the titrations and the speciation of Cd within the single fractions of the extraction protocol. The calculations were based on measured sediment parameters such as hydrous ferric oxide (HFO), acid volatile sulfide, carbonate content and total Cd content, and the extractants (oxalate, acid etc.) used. The results of the two independent approaches coincided well in that they both assigned more than two thirds of the total Cd content to be adsorbed to organic matter. Cd bound as CdS is of little importance. Sequential extraction after a 3-month oxidation period at pH 7 revealed a shift of Cd from being mainly bound in stronger surface complexes with organic matter to being mainly bound in weaker surface complexes with organic matter and HFO, and thus becoming more bioavailable. This study suggests that the use of sequential extraction although being frequently criticized due to its operational character can be used to determine binding forms of metal ions if they are accompanied by 1) careful supporting experiments, 2) analysis of important sediment parameters, and 3) the use of thermodynamic equlibrium models which can help to understand Cd speciation within the extraction fractions.     

Sediment geochemistry of the urban Lake Paulo Gorski

The objective of this study was to evaluate the concentration and distribution of heavy metals in the sediments of Paulo Gorski Lake, as well as the metals’ bioavailability and potential ecological risk, and to define the anthropogenic and natural heavy metal contributions to the lake. The chemical elements calcium (Ca), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), potassium (K), magnesium (Mg), manganese (Mn), sodium (Na), nickel (Ni), lead (Pb), and zinc (Zn) were quantified by flame atomic absorption spectrophotometry with two extraction methods to quantify the bioavailable and non-bioavailable fractions. The data were evaluated using multivariate statistics and sediment quality indices. All sediment collection points (S1, S2, S3, S4 and S5) are different in terms of the concentration of heavy metals, except for S4 and S5, which were statistically equal. The bioavailable fraction of the elements in the sediment follows the sequence Pb>Cu>Mn>Zn>Ni>Cr>phosphorus (P) for all points. The elements Co, Cr, Pb, and Zn showed moderate to considerable contamination at all points. Only points S3 and S5 had moderate ecological risk. Urbanization has been affecting Paulo Gorski Lake via the input of chemical elements, especially Co and Pb. The points most affected by heavy metal contamination are S3 and S5 when the sedimentological sensitivity factor is considered. The lake has high hydrodynamics, causing some of the contaminants that enter the system to leave it, leading to potential negative impacts downstream.     

Speciation of heavy metals on suspended sediment under high flow conditions in the River Aire,West Yorkshire,UK

Concentrations of heavy metals (Cd, Cu, Pb and Zn) on suspended sediments during a flood event at Thwaite Mills, River Aire, were analysed using a five step sequential extraction technique to determine their major chemical associations (exchangeable, surface oxide and carbonate, Fe and Mn oxides, organic and residual metal ions). Total metal concentrations were lowest at higher discharges, resulting from dilution by clean sediment. The major transport fractions are the Fe and Mn oxides, which carry 29% of the total metals. Knowledge of the chemical forms of heavy metals on suspended sediment is essential for estimating their biological availability and physicochemical reactivity. © 1998 John Wiley & Sons, Ltd.     

贵州红枫湖沉积物生物可利用磷分布特征及其与粒径的关系

应用化学提取法分析了红枫湖主要出入湖河口及湖心沉积物生物可利用磷(BAP)的含量,并探讨了BAP空间分布与总磷(TP)和粒度组成之间的关系.研究结果表明,各形态BAP含量顺序为:藻类可利用磷(AAP)NaHCO3可提取磷(Olsen-P)水溶性磷(WSP)易解吸磷(RDP).沉积物柱芯中BAP迅速降低,剖面变化比TP更为明显.各形态BAP与TP显著相关,除RDP与AAP外,其它形态BAP之间也显著相关.Olsen-P是评价红枫湖沉积物磷的生物有效性的最佳指标.红枫湖沉积物颗粒组成以粘土及粉砂为主,湖心沉积物比河口粒度小.表层(0-5cm)沉积物中Olsen-P和AAP的含量与细组分(粘土)的比例呈正相关,而RDP、WSP与细组分呈负相关性,表明沉积物细组分对深水湖泊富营养化的重要性.     

Bioavailability of heavy metals in soil of the Tieguanyin tea garden,southeastern China

The bioavailability of 22 heavy metals was investigated at 19 sampling sites in Tieguanyin tea garden in Anxi County,Fujian Province,southeastern China.Heavy metal concentrations were determined by inductively coupled plasma-mass spectrometry(ICP-MS)and evaluated by geo-accumulation index(I_(geo)).Dilute nitric acid extraction was used to evaluate biological activity.Cu,Pb,and Cd were highly bioavailable and most easily absorbed by tea trees.Heavy metal bioavailability in the surface soil was as the ratio of the effective state to the total amount.Cd had the highest I_(geo)values,and the respective samples and sites were classified as moderately/strongly contaminated.Cd element is considered the main factor of heavy metal pollution in the tea garden in Anxi.The other heavy metals studied were present in lower concentrations;thus,the samples were classified as uncontaminated or slightly contaminated.     

Bioavailability and Interaction of Si and P in a Coastal Saline Soil Amended with Pig Slurry

The effects of widely applied organic waste amendment on soil Si and P bioavailability and their interaction have rarely been investigated. The study examined bioavailability and interaction of Si and P in response to pig slurry (PS) amendment in a coastal saline (CS) soil. The final purposes of the study are to assess fertilizer Si and P needs and to ensure environmental quality. The results show that PS amendment can cause accumulation of bioavailable Si in surface soil (0–20 cm), and significantly improve both soil bioavailable P content and soil P lability through PS‐Si and P input, and by the input of PS‐organic matter (OM) and enhancing the complexation of OM with soil Si and P. As a result of the Si‐P competitive sorption, Si shows a more rapid increase in bioavailability than P at the preliminary stage of PS amendment. However, under the weakly alkaline conditions as a result of relatively long term PS amendment, the fixation capacity of Si by soil solid components increases causing a rapider decline of Si bioavailability than that of P.     

环太湖河流进出湖水量及污染负荷(2000-2002年)

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．     

Distribution and accumulation of heavy metals in carbonate and reducible fractions of marine sediment from offshore mid-western Taiwan

Two marine sediment cores from offshore mid-western Taiwan were subsampled and pre-treated using a sequential extraction procedure to separate carbonate and reducible fractions. Aliquots of these extracts were analyzed to determine their chemical composition to evaluate the geochemical processes responsible for heavy metal distribution and accumulation in the coastal environment. Our data demonstrate that sedimentation rates derived from excess ²¹⁰Pb associated with metal fluxes show large increases circa A.D. 1990. A well-synchronized increase in metal flux in both geochemical fractions was found and validated by Pearson’s correlation. Principal component analysis revealed the heavy metal fluxes to be highly correlated with the sediment deposition rate, with metal contamination potentially driven by a sole contributor. This study emphasizes the changes in sedimentation rate is potentially caused by activities associated with the inland economic development during this time, rather than by raising heavy metal pollution dominated the accumulation offshore mid-western Taiwan.     

Distribution of geochemical fractions of phosphorus and its ecological risk in sediment cores of a largest brackish water lake,South Asia

The current study focuses on the vertical profile of different geochemical fractions of phosphorus-loosely bound(Lo–P),aluminium bound(Al–P),iron bound(Fe–P),calcium bound(Ca–P),and organic bound phosphorus(O–P)along with ecological risk assessment of sediment cores from Chilika Lake,eastcoast of India.The percentage contribution of the different fractions to the sedimentary phosphorus in the sediment column of the whole lake are on the order:O–P(33.2%)>Ca–P(20.3%)>Fe–P(18%)>Al–P(6.7%)>Lo–P(0.35%).The Phosphorus Pollution Index(PPI)revealed the contamination of lake sediment with phosphorus.The principal component and cluster analyses highlighted the anthropogenic contribution of phosphorus.The negative loading of Ca–P with Ca points towards its origin from marine shells.The discriminate analysis showed that the variables like Ca–P,bio-available phosphorus(BAP),and pH were able to effectively discriminate the sectors in a significant manner.     

Comprehensive assessment of heavy metal contamination in sediment of the Pearl River Estuary and adjacent shelf

Total metal concentrations (Cr, Ni, Cu, Zn, and Pb), acid volatile sulfide and simultaneously extracted metals (AVS-SEM), and heavy metal fractionation were used to assess the heavy metals contamination status and ecological risk in the sediments of the Pearl River Estuary (PRE) and adjacent shelf. Elevated concentrations at estuarine sites and lower concentrations at adjacent shelf sites are observed, especially for Cu and Zn. Within the PRE, the concentration of heavy metals in the western shore was mostly higher than that in the middle shore. The metals from anthropogenic sources mainly occur in the labile fraction and may be taken up by organisms as the environmental parameters change. A combination of total metal concentrations, metal contamination index and sequential extraction analysis is necessary to get the comprehensive information on the baseline, anthropogenic discharge and bioavailability of heavy metals.     

湖泊沉积物中元素相态的连续提取分析—以岱海为例

如何利用湖泊/海洋沉积物地球化学代用指标有效地指示环境很大程度取决于元素的来源及其在沉积物中赋存形态的确定.对位于半干旱区的内蒙古岱海14个沉积物样品的连续提取实验及18个元素在水可溶态、可交换态、碳酸盐结合态、铁锰氧化物结合态、有机物结合态及残留态等六种赋存相态中含量变化进行了测试和研究,结合沉积物的矿物组成,结果表明在岱海流域内只经历了较弱的化学风化过程,除了Ca和Sr外,其他元素主要赋存于残留态中,只发生了很小程度的活化溶解.受元素亲合性和湖水物理化学状态的制约,出溶的Sr与Ca的赋存相态基本一致,而出溶的Pb、Be、Co、Cu、K、Mn、Fe等元素则与自生碳酸盐、有机质表现出一定的亲合性.元素在不同赋存相态中分布为地球化学环境代用指标的提取和解释提供了机理性的实验依据.     

An analysis of chemical loads and forms in overland flow from dairy pasture in South Australia

Two adjacent subcatchments on soils with very strong texture contrast between the A soil horizons (sandy loam texture) and B soil horizons (clay texture) in the Adelaide Hills, South Australia were instrumented to collect overland and subsurface flow from dairy pasture. Subcatchments were defined by exclusion drains in the upper reaches and stainless steel barriers at the lower boundary. Water samples were analysed for 20 different chemical fractions. Chemical loads were examined in order to determine relationships among simple empirical event and site characteristics, and between chemical fractions. All but five of the chemical fractions could be separated into one of two clear groups using a statistical technique based on the magnitude of simple correlation coefficients. The two groups consisted of either dissolved or particulate fractions. The clear separation into these groups is consistent with the majority of chemical fractions moving from pasture by one of only two processes. Simple empirical variables in a multiple regression explained a high proportion of variation in chemical loads in runoff water. These findings may have major implications in the modelling and prediction of chemical loads in runoff from agricultural catchments and the setting of environmental limits, in simplifying chemical loss predictions by adding a nutrient loss module to runoff volume predictions. Copyright © 2001 John Wiley & Sons, Ltd.     

Eignung mikrobieller Biotests für gebundene Schadstoffe Suitability of Microbial Bioassays for Bound Contaminants

Toxicity of soil spiked with water soluble and insoluble contaminants was assessed with bacteria. Three bioassays were used with common soil bacteria. Water soluble fractions from the soils were estimated in microtiterplates via dehydrogenase activity of B. cereus and growth of P. putida. A new method was developed using B. cereus to include effects of soil particles with bound contaminants. As contaminants p-nitrophenol and 2-naphthol were tested in these systems. Results indicated that the concentration of the contaminants in the soil solution is determined by soil properties. Toxicity of water soluble fractions was not only a result of the toxicant's concentration but further modified by soluble components of the soils. It is not possible to assess soil pollution from toxicity of the water soluble fraction in general, because unknown factors of the soluble soil fraction can influence toxicity greatly. The newly developed contact bioassay with B. cereus showed clearly higher toxicity of 2-naphthol estimated in soil suspension than did the comparable test system with the same bacteria using water soluble fractions only. The results stress the importance of including soil particles into bioassay procedures. It was shown that also water insoluble, bound contaminants can act as toxicants. For an estimation of toxicity under conditions more relevant for the environment, the suggested test system can provide useful information to bioavailability of bound contaminants.     

武汉东湖和南湖沉积物中磷形态分布特征与相关分析

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.     

Redox status and heavy metal risk in intertidal sediments in NW Spain as inferred from the degrees of pyritization of iron and trace elements

Mariculture is an important economic activity in shallow marine areas of the Rías Baixas (Galicia, NW Spain). The maintenance of high product quality requires surveillance of environmental quality, including the risk of metal toxicity. In this study the redox status of intertidal sediments in the Bay of San Simón, and the risk of toxicity posed by their As, Cd, Cr, Cu, Mn, Ni, Pb and Zn contents, were evaluated by determination of operationally defined reactive, silicate-bound, organic and pyrite-related fractions of these elements and of Fe. The large silicate-bound fractions of most of these metals indicate their lithogenic origin; the main exception is Pb, which in all respects exhibits singular behaviour associated with its predominantly anthropogenic origin in a ceramics factory. In sediments with larger fine-grained particle contents, which are oxic only in the top few centimetres, greater proportions of the trace elements are present as sulphides or associated with sulphide minerals: the degree of pyritization of Fe (DOP) is 46% overall, and the pyrite fraction of some elements doubtless increases at the expense of the reactive fraction, most overall degrees of trace metal pyritization (DTMPs) lying in the range 10-50%. A decline in pyrite genesis at depths below about 18 cm in these sediments is attributed to the exhaustion of organic matter susceptible to metabolization by sulphide-generating bacteria. In coarse-grained, oxic sediments the oxidation of sulphides makes pyrite-related fractions very small, and reactive and silicate-bound fractions are negatively correlated; reactive fractions associated with Fe-Mn oxyhydroxides are large, and DOP and DTMPs are low (generally much lower than in mud-rich sediments), except for Pb. Most of the elements studied are mainly present in forms that are neither bioavailable nor potentially bioavailable, and so do not constitute a significant environmental threat. However, the high DTMPs of Cu and Pb indicate significant potential bioavailability, which should be taken into account in evaluations of environmental quality and the risk to bivalve cultures.     

鄱阳湖流域赣江(南昌段)沉积物磷赋存形态特征及释放风险分析

本研究采用化学连续提取法,分析赣江南昌段表层沉积物磷赋存形态特征及其生物有效性,并通过等温吸附实验探讨了沉积物磷释放风险。结果显示:赣江南昌段表层沉积物总磷(TP)含量范围为235.21~702.24 mg/kg,均值为522.93 mg/kg,具有较高的空间异质性。所有采样点位中无机磷(IP)均以闭蓄态磷(Oc-P)为主要赋存形态,各形态无机磷含量特征表现为:Oc-P>铁结合态磷(Fe-P)> 碎屑钙磷(De-P)> 自生钙磷(ACa-P)> 可交换态磷(Ex-P)> 铝结合态磷(Al-P);有机磷(OP)以残渣态有机磷(Res-P_o)为主要赋存形态,按活性划分表现为:非活性有机磷(NOP)> 中活性有机磷(MLOP)> 活性有机磷(LOP)。生物有效磷(BAP)含量范围为61.59~218.27 mg/kg,占TP含量的比例为27.07%。BAP总量及占TP的比例均处于较低水平,沉积物内源磷释放风险较低。BAP中Fe-P平均占比为56.72%,表明沉积物磷潜在释放风险主要来源于Fe-P。TP、Fe-P和De-P之间均存在显著相关关系,表明外源输入可能是赣江沉积物磷的主要来源。采样期间赣江南昌段沉积物磷平衡浓度(EPC₀)高于上覆水溶解性活性磷(SRP)浓度,磷吸附饱和度(DPS)均低于沉积物磷大量流失的临界值25%,表明此阶段沉积物磷虽作为上覆水的“磷源”,但出现大量释磷的可能性不高。因此,沉积物内源磷释放引起赣江水体富营养化的风险不高,这意味着赣江水体应更多关注外源输入问题。本研究结果为赣江南昌段水环境的科学管理提供了数据支撑和科学依据。