湖泊沉积物中磷形态标准物质研制

水体富营养化与沉积物中磷元素的形态有密切关系。为了准确测定沉积物中不同形态的磷的含量,欧盟在2000年研制了第一个湖泊沉积物中磷形态标准物质(BCR 684),但基本用尽已不能满足需求,而且该标准物质采集于欧洲某湖泊,沉积物类型及污染情况与我国湖泊不相匹配。本文结合我国沉积物的类型和湖泊污染状况,研制了我国首批2个湖泊沉积物中磷形态标准物质(编号为 GBW 07462和GBW 07463)。候选物样品采集地点为江苏太湖和湖南洞庭湖,样品经过自然干燥、研磨、灭菌、陈化等加工处理,随机抽取15个子样采用单因素方差分析(F检验法)进行均匀性检验,检验的F实测值均小于临界值,表明样品均匀性良好。根据ISO导则35推荐方法对候选物样品在一年内进行四次稳定性检查,分析结果无方向性变化,再通过2次验证实验,样品稳定性良好。此批磷形态标准物质采用8家实验室联合定值,定值参数包括五种磷形态:总磷、无机磷、有机磷、磷灰石态磷、非磷灰石态磷;磷形态提取方法采用欧盟SMT法,测定方法采用钼锑钪光度法和电感耦合等离子体发射光谱法(实验过程中用欧盟BCR 684作为质量监控);按照《一级标准物质研制规范》(JJG 1006—1994)和ISO导则35的要求给出了五种磷形态的标准值和不确定度。此批磷形态标准物质样品代表了我国典型富营养化湖泊的沉积物类型,采样点的区域代表性强,定值项目选择合理、量值准确,可应用于环境、地质、农业、地球化学等研究领域沉积物的磷形态样品质量监控。     

磷在硅酸盐矿物与熔体之间分配系数的研究进展

硅酸盐矿物与熔体之间的磷分配系数对研究岩浆演化和结晶分异程度具有重要意义,也是了解地幔磷储库和建立地球各圈层间磷运移模式的基础。本文分析和总结了前人采用天然样品和合成实验样品研究不同硅酸盐矿物和熔体间的磷分配系数的成果,分析了不同物理化学参数对分配系数的影响,包括熔体组成(如Mg O、Al2O3含量)、矿物结构(分配系数与[Si O4]4-聚合度呈负相关关系)、温度、压力和氧逸度等,指出当前研究中有关更高压力条件(15 GPa)及有流体存在时分配系数的研究是不足的。     

电感耦合等离子体发射光谱法测定高油脂和非油脂类植物中钾和磷样品前处理方法研究

测定植物样品中的钾和磷,通常采用高压密闭微波消解-电感耦合等离子体发射光谱法(ICP-OES),但复杂的基质会增加消解难度,如花生、核桃等含有高油脂类大分子聚合物的样品难以快速消解彻底,易使测定结果偏低。为了提高植物中钾和磷的检测效率,本文采用硫酸-过氧化氢消解法和高压密闭微波消解处理样品,将待测元素磷转化成磷酸盐,钾成为游离的钾离子,形成单相单价态消解溶液,通过对比实验确定了应用ICP-OES快速、准确测定不同类型样品中钾和磷含量的前处理方法。经实际样品分析验证表明：(1)对于高油脂类样品,硫酸-过氧化氢消解法通过强酸破坏植物外层结构,使有机物快速炭化,随后滴加过氧化氢快速消解(约2.5h),能直接消解样品,且消解更安全和彻底;而高压密闭微波消解法耗时较长(约4.5h);与大多学者研究结果对比,硫酸-过氧化氢消解法准确度优于高压密闭微波消解法,建议优先采用。(2)对于非油脂类样品,2种处理方式均适宜,钾和磷测定结果无显著性差异,并且与目前大多学者的研究结果较为一致,其中高压密闭微波消解法试剂消耗少、空白值低、操作简便,建议优先采用。(3)硫酸-过氧化氢消解法测定钾和磷的方法检出限分别...     

X射线荧光光谱法同时测定钛精矿中主次量组分

采用铁矿标准样品和高纯二氧化钛混合配制钛精矿的校准样品,X射线荧光光谱法同时测定钛精矿中氧化镁、三氧化二铝、二氧化硅、磷、硫、氧化钙、二氧化钛、五氧化二钒、锰、铁等主次量成分,并对熔剂选择、熔融条件、钒Kα峰位确定及基体效应校正等进行了探讨。测定结果与标准样品标称值吻合,相对标准偏差(RSD,n=7)除低含量的磷、硫外均在5%以下,能满足钛精矿的检测需要。     

太湖五里湖表层沉积物中不同形态磷的分布特征

利用连续提取法(SEDEX)详细调查了太湖五里湖表层沉积物中不同形态磷的组成和分布特征。结果显示：其中磷的含量较高，受人为污染输入的影响较大，并且已经有了一定的释放。总磷的变化范围为2．05～4．05mg/g。平均约为2．80mg/g。总磷主要由无机磷组成(70％～90％)，大多数无机磷为CDB溶液提取的铁结合态磷(75％～85％)。CDB溶液的n(Fe)／n(P)都较小(2．0～5．3)。说明CDB溶液提取的铁主要是以无定形态存在的，并且铁与磷酸盐之间的吸附可能已经达到了平衡状态。除底部个别样品以外。多数样品n(Gorg)／n(Norg)较小(8．8～10．6)，所有样品的n(Gorg)／n(Porg)都较大(135～320)，表明沉积物在早期成岩作用过程中，湖泊内源自生有机质降解时有机磷优先释放。无机磷，特别是铁结合态磷，在氧化还原条件变化的情况下。能够通过沉积物一水体界面被再次释放到水体中去，这可能对湖泊的水体质量和营养状况有一定的影响。     

内标校正-电感耦合等离子体发射光谱法测定磷矿石中的磷

采用电感耦合等离子体发射光谱法(ICP-OES)可以同时测定磷矿石中的主、次量元素,但在实际测量过程中,仪器的漂移以及基体效应引起的分析误差不容忽视。本文以碲为内标,对高含量磷的测定进行校正,可以有效降低由仪器漂移以及基体效应引起的分析误差,12次平行测定磷的相对标准偏差(RSD)为0.5%,与未经校正的RSD值(4.1%)相比,显著提高了分析精度,极大地降低了仪器波动对测定结果的影响,因此获得了更低的方法检出限(0.0044%)。实验还对比了王水溶样与盐酸-硝酸-氢氟酸-高氯酸(四酸)溶样两种样品前处理方法对磷矿石分析的影响,结果表明:以王水对磷矿石标准物质进行快速溶解,磷、钙、铁、镁、锰等元素的测定结果与标准值间的相对误差范围为-6.7%~1.6%,满足日常测定要求;而钾、钠、铝是否能够完全溶出与样品的矿物组成及氟含量存在联系,若需要分析钾、钠、铝等元素,如果样品中的硅酸盐矿物组成不多,氟含量较高时可以考虑采用王水溶解;四酸可以完全溶解样品,适合于磷、钙、铁、镁、铝、钾、钠、锰、锶等元素的同时测定。     

云南安宁磷矿区水系沉积物磷赋存形态及分布特征

磷污染是水污染的重要组成部分,因其可造成水体富营养化、水质下降,从而引起人们的广泛关注。研究沉积物中不同磷赋存形态及其分布特征有助于了解沉积物中磷的行为特征及迁移能力,从而为水体富营养化防治提供支撑。磷矿的开采、冶炼对矿区内水资源环境可能产生严重影响,本文以安宁磷矿区内河流、水库为研究区域,分析了不同水系沉积物磷元素赋存形态及分布特征,并对其生态风险进行评估。采用X射线荧光光谱法测定研究区水系沉积物总磷(TP)含量,并基于顺序提取及Hupfer改进的磷形态分析方法,将研究区各水系沉积物中磷分为弱吸附态磷(NH₄Cl-P)、可还原态磷(BD-P)、金属氧化物结合态磷(NaOH-P)、钙结合态磷(Ca-P)、残渣态磷(Res-P)等5种形态,采用单因子污染指数法对其进行生态风险评估。结果表明：研究区水系沉积物样品中TP含量范围为567.6～48115.5mg/kg,NH4Cl-P含量范围为0.07～115.2mg/kg,BD-P含量范围为8.84～802.5mg/kg,NaOH-P含量范围为21.3～3129.5mg/kg, Ca-P含量范围为12～45098mg/k...     

磷矿磷肥及土壤中活性磷的准确测定

研究了CaHPO_4、Ca(H_2PO_4)_2、MgHPO_4、(NH_4)_2HPO_4、K_2HPO_4、KH_2PO_4、磷灰石、鸟粪石、磷铝石及红磷铁矿在乙酸-乙酸钠体系中的溶解行为,建立了测定活性磷的条件。样品中的活性磷用乙酸-乙酸钠混合溶液溶解,用光度法或滴定法进行测定。二十多种共存矿物在一定范围内不干扰测定。此新方法应用于磷矿、磷肥和土壤中活性磷的测定,获得满意的效果。     

广西岛坪磷氯铅矿的谱学特征

磷氯铅矿(Pyromorphite)在我国比较罕见,2001年在广西岛坪发现的磷氯铅矿结晶较好,运用XRD、XRFI、R和UV/Vis等分析方法对黄色和绿色样品进行了研究。结果表明,二者XRD谱只是峰强有所不同。在它们的红外吸收谱带中,除了标准的PO43-吸收峰外,在670~800 cm-1之间和430 cm-1左右出现的两组肩峰为SiO44-振动峰。黄色样品的振动频率偏高、半峰宽偏窄、透射率与绿色样品相比较高。通过XRF分析发现黄色晶体比绿色晶体含有更多的Fe3 ,而Fe3 常使矿物呈现黄色,同时证实了黄色磷氯铅矿的红外吸收峰频率偏高是因为它的铅含量低于绿色矿。UV/Vis进一步说明在可见光区的吸收不同是使二者颜色差异的主要原因,Fe离子含量较大使磷氯铅矿呈现黄色。     

覆盖沉淀容量法测定磷矿石中的磷

本文研究了表面活性剂存在下,不经沉淀分离的EDTA络合滴定法间接测定磷。采用SLS和CCl_4联合覆盖BiPO_4沉淀,滴定终点敏锐、稳定。方法简便、快速,适用于磷矿石中磷的测定。对含P_2O_5 18.13％的样品分析(n=9)RSD为0.58％。     

再悬浮条件下沉积物内源磷迁移-转化机制研究进展

对沉积物再悬浮的驱动力及其耦合效应、再悬浮-内源磷迁移转化机制及主要影响因素进行了阐述,探讨了该领域未来可能的研究方向。相关研究发现,沉积物再悬浮的各种驱动力既可以单独作用也可相互耦合,其耦合效应具有显著的时空变异性;再悬浮使还原态沉积物暴露于有氧环境,沉积物中铁、锰的氧化以及沉积物颗粒的吸附促进了内源水溶态无机磷(SRP)的去除,而进入水体的内源有机磷则通过生物矿化和光化学分解转化为SRP;沉积物物化特征、水动力、水生生物以及水体理化性质等因素控制着再悬浮过程中内源磷的迁移和转化。指出再悬浮条件下沉积物内源磷迁移转化的多过程耦合效应、沉积物中磷形态的转化及其生物有效性、内源有机磷矿化与光化学分解机制及其调控因素将是本领域需要进一步研究的重点。     

Sediment phosphorus fractions and profile distribution at different vegetation growth zones in a macrophyte dominated shallow Wuliangsuhai Lake,China

Sediment phosphorus (P) fractions and profile distribution at submerged macrophyte growth zone, emergent macrophyte growth zone and open-water zone were studied in Wuliangsuhai Lake, China, as well as the correlations among water content, grain size, and organic matter and P fractions. Among the three surveyed zones, the highest concentrations of most P forms occurred in the surface sediment and the lowest between a depth of 12 and 22 cm, except HCl-P and NaOH-P. Sediment phosphorus was mainly associated to inorganic forms (>50%) in three surveyed areas, and the highest value of inorganic phosphorus (IP) in the surface sediment was obtained from submerged macrophyte growth zone. Submerged and emergent macrophytes increased the IP content by 107 and 44 μg/g, respectively, in the surface sediment compared with open-water zone. Vertical profiles of IP in the three surveyed zones showed that the concentrations decreased from surface to 12 cm depth and then increased. There was a similar trend in the sediment profiles of organic phosphorus (OP) and total phosphorus (TP), but the highest concentration of OP and TP in surface sediment was obtained from the emergent macrophyte growth zone. Compared with open-water zone, the emergent macrophyte increased TP content in surface sediment by 1.73 times to 1,320 μg/g, while submerged macrophyte enhanced TP content in the surface sediment by 1.13 times to 865 μg/g. It was observed that in macrophyte growth zones, a strong linear correlation existed between organic matter and OP (r > 0.98), and the maximum concentrations of OP were present in the areas with maximum concentrations of organic matter. Results show that, although rooted macrophyte could uptake directly P from sediments, it is responsible for increasing the internal P loading especially OP by reducing current velocities, attenuating wave energy and generating organic residue in Wuliangsuhai Lake.     

A sediment chronology of the eutrophication of Chesapeake Bay

Chesapeake Bay sediments were examined for biogeochemical evidence of eutrophication trends using two mesohaline sediment cores. Measurements of ²¹⁰Pb geochronology and sediment profiles of organic carbon, nitrogen, organic phosphorus, inorganic phosphorus, and biogenis silica (BSi) were used used to develop temporal concentration trends. Recent sediments have 2–3 times as much organic carbon and nitrogen as sediments from 80 to 100 yr ago, but the increases result from both changes in organic matter deposition and time-dependent changes in organic matter decomposition rates. Despite increases in phosphorus loading, no major changes in phosphorus concentration were noted throughout most of the century; anthropogenic phosphorus deposition, though not evident in sulfidic mid-bay sediments, must occur in more oxidizing sediment environments in both the northern and southern bays. Temporal trends in BSi concentrations are much less evident and the lack of substantial increases in this century suggest that BSi inputs may be capped by late spring-summer Si limitation.     

Phosphorus in suspended matter and sediments of a hypertrophic lake. A case study: Lake Dianchi,China

From June 2004 to December 2004, Lake Dianchi, which had large scale of cyanobacterial blooms was investigated in order to study P-fractionation in the suspended matter and the sediment. The investigation improves our understanding of phosphorus in Lake Dianchi and the relationship between phosphorus and cyanobacterial blooms. It contributes to the available literature on the behavior of P in hypertrophic lakes. The distribution of P-fractions in Lake Dianchi was not uniform from northwest to south, but was closely related to the trophic status of the whole lake. The concentrations of total phosphorus, labile P (NH₄Cl-P), Organic P (NaOH-NRP) and loss on ignition in suspended matter were positively correlated with the strength of cyanobacterial blooms. Total phosphorus in suspended matter was relatively stable for almost half an year and closely related to Chl. a concentration. The main content of organic phosphorus is in the cyanobacterial blooms. The concentrations of phosphorus bound to metal oxides and carbonates (NaOH-SRP and HCl-P) in sediment were similar to NaOH-SRP and HCl-P in the corresponding suspended matter. The latter two forms of P in suspended matter were not affected by cyanobacterial blooms, indicating that the inorganic phosphorus is derived from the sediment after resuspension from the sediment due to wind and wave action. The contribution of the different P-fractions to TP in sediment and in suspended matter indicates that NH₄Cl-P in the suspended matter is an important buffer for maintaining dissolved phosphorus in water.     

The effect of dried and cracked sediment on the availability of phosphorus in a coastal lagoon

Caimanero Lagoon (Sinaloa, México) is subjected to alternate periods of low water and flooding. In the first case, more than 70% of the lagoon is dry, cracked and colonized by halophytes to a variable proportion. During the dry season, mineralization of organic matter and reavailability of phosphorus takes place to a great extent. So far, the effect of dried and cracked sediment on the reincorporation of phosphorus to the coastal lagoon ecosystem has not been evaluated. This work is the result of experiments which emulate natural conditions present during the dry season and the beginning of the flood season under the influence of tidal flux. The availability of phosphorus (orthophosphates and soluble phosphates) was significantly increased in the dry and cracked material; this phosphorus is derived from the mineralization of organic matter present in the sediment. The amount of soluble organic matter also increased during the dry season. The sedimentary drying and cracking process contributes significantly to estuarine productivity.     

Application of allochthonous organic carbon and phosphorus forms in the interpretation of past environmental conditions

Organic matter in sediments, for instance, carbon, nitrogen and phosphorus, can be used to reconstruct the paleoecological and pollution history of lakes and their catchment basins. In this paper, the contents of allochthonous organic carbon (allochthonous OC) and autochthonous organic carbon (autochthonous OC) in sediment cores taken from Wuliangsuhai Lake and Daihai Lake in northern China are quantified by using a binary model, and phosphorus forms in the sediment cores from the two lakes are extracted by sequential extraction techniques. The results indicate that the palaeoenvironment and paleoclimate of Daihai Lake and its catchment basin in the recent 250 years can be well reconstructed based on the content of allochthonous OC. The climate was relatively humid and warm in the period of 1865–2005, while relatively dry and cold in the period of 1765–1865. The sedimentary information of allochthonous OC in the 22–42-cm portion of the sediment cores in Daihai Lake corresponds to the final cold fluctuation of the Little Ice Age that occurred since the Middle Holocene. The difference of phosphorus forms in the sediment cores between the two lakes indicates that phosphorus input to the lakes and the correlation between phosphorus forms and distribution and the changes of environment are influenced by the eutrophication mechanisms and environmental conditions of the two lakes.     

Spatial variations and distributions of phosphorus and nitrogen in bottom sediments from a typical north-temperate lake,China

Concentrations and vertical distributions of total nitrogen (TN), total phosphorus (TP) and their different forms in sediments obtained from nine locations of Lake Dalinouer in September 2008 were analyzed. The results demonstrated that TP in surface sediments ranged from 0.493 to 0.904 g/kg, and inorganic phosphorus was the main fraction of total phosphorus, ranging from 335 to 738 mg/kg. Simultaneously, the autogenetic calcium phosphorus (ACa-P) was the main fraction of inorganic phosphorus, ranging from 145.4 to 543.2 mg/kg. Vertical distribution of different phosphorus forms in different sediment cores was distinguishing, and most of them tended to increase toward the surface sediment, indicated that the phosphorus concentration was related to the humanity with a certain extent. The relationships between TP and occluded phosphorus and ACa-P were significant. Nitrogen in the sediment was composed mainly of organic nitrogen, accounting for grater than 80 % of TN. NO₃ ^?-N was the dominate fraction of inorganic nitrogen in the surface sediment, ranging between 51 and 346 mg/kg (151.1 ± 104.4 mg/kg), and accounting for between 2.2 and 17.7 % of total sediment nitrogen (6.2 ± 5.6 %). The ratio of organic carbon and TN in sediment was in range of 6.0–25.8 and presented a tendency of lake centre >lake sides, indicating that nitrogen accumulated in the sediments from lake sides came mainly from terrestrial source and nitrogen was mainly autogenetic in lake centre. Ratio of N:P in all sampling sites was below 14, indicated that N was the limiting nutrient for algal growth in this lake.     

中国北方某湖泊底泥污染分析及重金属潜在生态风险评价

以中国北方某湖泊(以下称A湖)为例,开展了底泥中氮磷污染及重金属生态风险评价研究,探讨多种评价方法的相关性,并分析底泥中氮磷元素向上覆水迁移造成水体富营养化的风险.选取A湖中心区域的10个底泥监测点位数据,对其总氮、总磷及重金属(Pb、Cr、As、Cd、Ni)含量进行分析,并采用有机污染指数法评价总氮污染,单因子指数法...     

太湖东部湖湾水生植物生长区底泥氮磷污染特征

为了解太湖东部湖湾(贡湖湾、光福湾、渔洋湾)表层底泥中氮、磷的污染特征及其与水生植物生长的关系,采集了各湖湾滨岸带水生植物生长区的表层底泥,探讨了水生植物的生长与分布对表层底泥中总氮(TN)、总磷(TP)及总有机碳(TOC)等含量的影响,并对表层底泥进行营养评价.结果表明,水生植物生长密集区底泥中TN、TP、TOC的含量均显著低于水生植物零星生长区,说明水生植物的生长对太湖东部湖湾表层底泥中营养盐与有机碳含量具有较为明显的影响;相关性分析显示,表层底泥中TOC与TN含量呈显著相关性(R2=0.832 8),而与TP的相关性则较弱(R2=0.166 5),反映了TOC在湖泊底泥中的沉积可能成为湖泊氮的重要来源,而对磷的影响较小.利用有机指数与有机氮指数两种方法分别对东部各湖湾底泥进行污染评价,贡湖湾、光福湾、渔洋湾底泥有机指数平均值分别为0.142 7、0.228 6与0.208 6,均属较清洁与尚清洁水平,而各湖湾有机氮指数平均值均为Ⅲ与Ⅳ级,说明底泥已遭受了一定程度的氮污染.因此,对水生植物零星生长区表层底泥中氮含量的控制与削减有利于湖泊富营养化的预防与治理.     

Phosphorus Mobilization at the Sediment–Water Interface in Softwater Shield Lakes: the Role of Organic Carbon and Metal Oxyhydroxides

The adsorption of phosphorus on natural diagenetic iron (Feox) and manganese (Mnox) oxyhydroxides was studied in deep and littoral zone sediments of mesotrophic Lac Saint-Charles (46°56 N, 71°23 W), using a Teflon sheet technique for collecting diagenetically produced metal oxyhydroxides. Collected metal oxide amounts were greater at the deep-water station, relative to littoral zone stations reflecting sediment and local diagenetic differences. Two-layer surface complexation modeling on iron oxyhydroxide was consistent with the measured total P/Fe molar ratios except for the upper mixed Mn–Fe oxide layer from the littoral stations, where measured phosphorus exceeded the modeled phosphorus by more than fivefold. Soluble reactive phosphorus (SRP) exchange between oxyhydroxide samples and natural lake water in the laboratory revealed a labile phosphorus pool. Phosphorus determined on the Teflon sheets from the littoral zone stations appears to be related to a distinct non-humic organic carbon pool that readily exchanges SRP, while little exchange was observed from material collected from the deep-water station. We suggest that the enhanced SRP release from littoral zone sediments is due to an organic carbon and/or metal oxide-impoverished sediment matrix, limiting microbial oxide reduction and allowing phosphorus to be rapidly recycled at the sediment–water interface, instead of being slowly incorporated into humic material. The SRP fluxes revealed in our study, which originate from the solid phase at the sediment–water interface, would be difficult to resolve using interstitial pore-water samplers and might be a quantitatively important source of inorganic phosphorus in Shield lakes.