Particulate n-alkanes and fatty acids in the Changjiang river system

Particulate samples were collected from the Changjiang river system during a flood period, in May 1997, and POC, stable isotope and lipids associated with particles were examined. Results showed the decrease （0.84% ～ 1.88%） of organic carbon content from the upper reaches to the estuary.δ^13 values of particulate organic carbon was in the range of -24.9×10^-3 to -26.6×10^-3, which were close to the isotopic signature of continental C3 vegetation. Total particulate n-alkanes concentrations varied from 1.4 to 10.1μg/dm^3,or from 23.7 to 107μg/g of total suspended matter. Fatty acids were present in all the samples, from 1.4 to 5.4μg/dm^3, with saturated and unsaturated straight-chain and branched compounds in the carbon number range from C12 to C30. Both δ^13 and the ratio of carbon content to nitrogen content indicate the predominance of terrestrial inputs （soil organic matter） among the particles. The biomarker approach has been used to identify the relative portion of terrigenous and autochthonous fraction in the particulate samples. The distribution of fatty acids suggests a striking phytoplanktonic and microbial signal in most particle samples. The terrestrial alkanes are used to estimate the contribution of terrestrial inputs along the mainstream.

Spatial Source Contributions Identification of Acid Rain over the Yangtze River Delta Using a Variety of Methods

The source-receptor relation of wet deposition has been a continuous issue in studies of regional environmental pollution over the past two decades.In the absence of direct observational evidence,the problem is difficult to solve—a topic of broad international debate since the turn of the present century.In the present study,a variety of methods focused on the sources of the wet deposition of acidic substances,like sulfate and nitrate,were used to investigate the precipitation chemistry over the Yangtze River Delta(YRD)during 2007.Back-trajectory analysis associated with the observation data and a source tracing method coupled with the Nested Air Quality Prediction Modeling System(NAQPMS)are proved to be effective methods for investigating the sources of wet deposition over the YRD.Comparison among the back-trajectory,footprint,and NAQPMS results shows good consistency,both qualitatively and quantitatively.The most important contributor to acidic substances in the YRD,as well as heavy acid rain over the region,is the anthropogenic pollution from East China,which accounts for more than 70%.

Impact of Water-Sediment Regulation on Variations of Amino Acids in the Middle-Lower Yellow River, China

In order to examine the impacts of water-sediment regulation on regional carbon cycling,we collected water,particulate and sediment samples from the middle-lower Yellow River in late June and early July,2015 and analyzed their specific amino acids(AA),DOC,POC,and bacteria abundance.Summarized by 14 specific AA,the total hydrolysable AA(THAA),particulate AA(PAA),and sediment AA(SAA)varied in ranges of 2.29-9.05μmol L^-1,5.22-22.96μmol L^-1,and 81.7-137.19μg g^-1 dry weight.After the regulation,dissolved free AA(DFAA)decreased by 29%while DCAA increased by 72%.These variations suggested that DFAA were further degraded,while DCAA molecules were further activated.Meanwhile,PAA increased almost 4 times as many as those before regulation,and SAA increased as well.After regulation,the amounts of bioactive amino acids(Asp,Glu and Gly)increased in THAA but decreased in PAA,with little changes in SAA.The ratios of Asp/Gly in different phases increased after regulation,indicating the AA contributions were promoted by calcareous organisms rather than by siliceous organisms.Multiple correlation analysis showed that PAA was primary representatives of AA and organic carbon,followed by DCAA and POC.Moreover,bacterial reproduction played a key role in shaping the AA compositions and properties,followed by the redox condition and acid-base balance.The results of this study provided a clear evidence for the effects of water-sediment regulation on regional biogeochemistry of organic carbon in the middle-lower Yellow River.

Assessment of Acid Deposition Effects on Water Quality of the Upper Rio Grande River Section in Texas

Airborne pollutants such as SO42- and NO3- that cause acid rain may pollute water resources via acid deposition. However, such effects on the water quality of the upper Rio Grande River section in Texas have not been systematically studied. The objective of this study is to collect and analyze field data, and perform hydrological and water chemistry analyses to assess acid deposition effects on the river water quality. The analysis of the precipitation data indicates that the concentrations of ions decrease as the quantity of precipitation increases. The precipitation with higher concentrations of SO42- and NO3- has a lower pH while that with higher concentrations of Ca2+ and Na+ has a relatively higher pH value. The analysis of river data demonstrates that the pH value, Dissolved Oxygen (DO), and Total Dissolved Solid (TDS) generally decrease when the flow rate increases immediately following precipitation events. The drop in pH following a precipitation event is due to the low pH in the precipitation. The DO and TDS decrease after the precipitation due to the increased flow rate. The slightly higher pH and lower DO values in the eastern section of the river (where the basin is limestone-dominated) as compared to the western section is due to the limestone erosion caused by the acid deposition. The annual stone loss by the acid deposition is about 72,000 m3. The fluctuation between the pH value and the temperature suggests the effect of CaCO3 solubility on the pH value. The water chemistry analysis using Geochemist’s Work Bench (GWB) has been performed to estimate the effect on the oscillation of CaCO3 dissolution-precipitation process. The equilibrium pH decreases with decreasing temperature, but increases as the CaCO3 concentration decreases. The effect of limestone on observed daily pH fluctuations appears to be supported by the simulation.

Variation of reactivity of particulate and sedimentary organic matter along the Zhujiang River Estuary

To investigate organic matter source and reactivity in the Zhujiang River (Pearl River) Estuary and its adjacent areas, particulate organic carbon (POC), particulate hydrolysable amino acids (PHAA), and Chl a during two cruises in July 1999 and July 2000 were measured. The highest POC and PHAA concentration was observed in the waters with maximum Chl a. The spectra distribution, relative content (dry weight in milligram per gram), PHAA-C% POC and other indicators such as the ratios of amino acids vs. amino sugars (AA/AS) and glucosamine vs. galactosamine (Glum/Gal) suggested that particulate amino acids in the water column and sediments in the Zhujiang River Estuary were mainly derived from biogenic processes rather than transported from terrestrial erosion. In inner estuary where high turbidity was often observable, organic matter was mainly contributed by re-suspension of bottom sediments with revealed zooplankton, microbial reworked characteristics, which suggest that these organic matters were relatively 'old'. In the estuarine brackish region, organic matter in water column is mainly contributed by relatively fresh, easily degradable phytoplankton derived organic matter. During physical - biological processes within the eastuary, organic matter derived from phytoplankton was subjected to alteration by zooplankton grazing and bacterial reworking.

STUDY ON THE ISOTHERMS OF THE INTERACTION BETWEEN SUSPENDED PARTICLES AND Cu (Ⅱ) IN THE HUANGHE RIVER

The isotherms of the interaction between the suspended particles and Cu 2+ ,and the effects of lysine and asparaginic acid on the isotherms in the Huanghe (Yellow) River were studied by applying the theory and method of interfacial stepwise ion/coordination particle exchange. We obtained a new stepped river isotherm, formed by two curves joined together with a “plateau” in the middle. The adsorption equilibrium constants K 1 and K 2 were calculated by using the isothermal equation of surface stepwise ion exchange. Amino acid in small amount promotes exchange adsorption of the suspended particles with Cu 2+ . The degree of promotive action relates to the isoelectric point of amino acid. The promotive effect of lysine is bigger than that of asparaginic acid.

Erythrocyte invasions and receptor heterogeneity in field isolates of Nanay river basin Iquitos

Objective:To determine whether the requirements for sialic acid varies and whether several types of silaic acid independent receptors utilized for invasion mechanisms of fresh filed isolates collected around Nanay river basin,Iquitos.Methods:The field isolates were cultured as described previously by Jensen and Trager and MR4 protocol with little modifications.The erythrocytes preparation and subsequent enzyme treatment was done as described previously by Sharma.with little modification.Invasion assay was performed as described previously by Sharma et al with little modification.Results:The Nanay river basin isolates showed five types of invasion mechanisms or types of receptors-ligand interactions.Here we observed that an equal numbers of neuraminidase sensitive and resistant invasion receptor-ligand interaction profiles as the most common receptor-ligand invasion profiles.Neuraminidase resistance trypsin sensitive chymotrypsin sensitive(NM_RT_SCT_S) invasion of receptor-ligand interaction profile was found in seven isolates,Five field isolates and one reference strain showed neuraminidase sensitive, trypsin sensitive and chymotrypsin resistant(NM_RT_SCT_R) invasion of receptor-ligand interactions, six isolates including one reference strains dd2 showed neuraminidase sensitive,trypsin and chymotrypsin resistance(NM_ST_RCT_R) indicating its dependence on sialic acids and independence of trypsin and chymotrypsin sensitive proteins.Four isolates showed neuraminidase sensitive, trypsin sensitive and chymotrypsin sensitive(NM_ST_SCT_S) invasion of receptor-ligand interactions, seven isolates were neuraminidase resistant,trypsin sensitive and chymotrypsin resistance (NM_RT_SCT_R) invasion of receptor-ligand interactions,indicating its dependence on trypsin sensitive proteins.Conclusions:The Nanay river basin isolates showed five types of invasion mechanisms or types of receptors-ligand interactions.A full understanding of theses invasion mechanisms may allow the development of novel prophylactic and therapeutic strategies that block erythrocyte receptor-ligand invasion mechanisms.

Assessment of the Groundwater Quality in Parts of Imo River Basin, Southeastern Nigeria: The Case of Imo Shale and Ameki Formations

Hydro-geochemical survey is undertaken in parts of Imo River Basin, Southeastern Nigeria, particularly in the geologic formations of Imo Shale and Ameki, to assess the quality of groundwater. Eleven samples of groundwater are obtained from various boreholes in the study area and subjected to physico-chemical analysis using standard laboratory techniques. The study is aimed at the assessment of the groundwater quality indicators namely: pH, electrical conductivity (N), phosphate (PO4), sulphate (SO4), nitrate(NO3-) and total dissolved solids (TDS). The result shows that the water from boreholes in Umuahia has low pH, and is therefore acidic. The pH values range between 4.40 and 5.60, which is below the acceptable range of 6.5-8.5. The acidity probably results from carbonic acid derived from the solution of CO2 from both the atmosphere and the decomposition of plant materials in the soil zone. The acidity of the groundwater gives slight sour taste to drinking water, due to the mobilization of trace metals from the aquifer material into the groundwater system, because of the corrosive effect of acidic water. Since borehole supply is rarely treated, these trace metals end up in domestic supplies resulting in health implications and complaints. Acidic waters are typically low in buffering calcium minerals, but are high in dissolved carbon dioxide gas, which can cause the low pH or acidity. Calcite neutralizer tanks with natural crushed and screened pure calcium carbonate easily neutralize acidic water from 6.0 to 6.9. Below 6.0 a blend of calcite and Corosex is recommended. Common systems used to treat low pH: Calcite Neutralizer, calcite & Corosex Blend Neutralizer, pflow Neutralizer, Soda Ash Feed Pump Injection System.

钱塘江华鳈肌肉营养成分分析

鉴于华鳈(Sarcocheilichthys sinensis)地理分布广泛,不同水域的种群可能存在营养成分差异,为进一步评估钱塘江华鳈(S.sinensis from the Qiantang River)肌肉的营养价值,本研究根据国家相关标准,对钱塘江华鳈肌肉的常规营养成分、氨基酸和脂肪酸组成进行了测定和分析。研究结果显示,钱塘江华鳈肌肉中粗蛋白含量为18.14%±0.49%,粗脂肪含量为2.25%±0.10%,粗灰分含量为1.24%±0.02%,水分含量为78.47%±0.13%;肌肉中含有15种常见氨基酸,氨基酸总量(TAA)为17.83%±0.45%,其中8种必需氨基酸(EAA)总量为7.35%±0.31%,鲜味氨基酸总量(DAA)为6.91%±0.10%;肌肉中富含18种脂肪酸,包括11种饱和脂肪酸(SFA,含量为32.34%±0.31%)、2种单不饱和脂肪酸(MUFA,含量为40.46%±0.53%)和5种多不饱和脂肪酸(PUFA,含量为27.19%±0.71%);肌肉中含有铁(Fe)、锌(Zn)、锰(Mn)和锡(Sn)等微量元素。总之,钱塘江华鳈肉质鲜美,且肌肉中氨基酸、脂肪酸及微量元素的组成丰富、合理,是一种有着丰富营养价值和开发价值的小型经济鱼类。

莨纱绸生产用河泥关键成分的定量方法

为了快速有效评价莨纱绸生产用河泥的品质,本文开发了一种基于比色法的莨纱绸生产用河泥关键有机成分(腐殖酸和富里酸)的定量检测方法。研究了反应试剂福林酚与碳酸钠溶液的用量、反应温度和反应时间等对显色反应结果的影响,并进行了方法学检验。研究结果表明,测试10.0 mg河泥样品,最佳反应条件为:1.0 mL、1 mol/L福林酚,0.6 mL、150 mg/mL碳酸钠溶液,3.4 mL去离子水,40℃、40 kHz超声处理条件下反应60 min,检测波长760 nm。在标准物质量浓度为0.12~0.30 mg/mL时线性相关性良好,线性相关系数为0.99834。该方法的稳定性和重复性较好,RSD值分别为0.68%、1.43%;平均加标回收率为102.96%,RSD值为3.41%。利用此方法测得佛山顺德和西樵地区河泥(莨纱绸生产用泥)及杭州下沙河泥(非莨纱绸生产用泥)中关键有机成分的总含量分别为9.64%、5.61%和1.88%,与分离称重法所得的结果相近。

长三角全氟辛烷磺酸及前体物的迁移归趋模拟

全氟辛烷磺酸(PFOS)作为一种新污染物备受关注。文章利用CoZMo-POP 2逸度模型分析了1988-2022年长三角区域PFOS和其前体物(PreFOS)(N-乙基全氟辛基磺酰胺(N-EtFOSA)、N-甲基全氟辛基磺酰胺(N-MeFOSA)、N-乙基全氟辛基磺酰胺乙醇(N-EtFOSE)和N-甲基全氟辛基磺酰胺乙醇(N-MeFOSE))的环境行为。结果显示:1988-2022年研究区域PFOS、N-EtFOSA、N-MeFOSA、N-EtFOSE和N-MeFOSE的累计排放量分别约为26、2.5、0.16、7.8和5.9t。PFOS在土壤、淡水和沉积物中的模拟浓度与实测浓度残差在1个对数单位内,验证了模型的可靠性。敏感性分析表明:温度和分配系数是影响污染物浓度的关键参数。当环境系统达到平衡时,近海水体是PFOS主要的汇,占PFOS环境总量的79%;从淡水到河口到近海水体的迁移是PFOS在环境中的主要迁移过程,占PFOS总迁移量的53%;流向外部是PFOS最主要的输出途径。土壤是N-EtFOSA、N-MeFOSA、N-EtFOSE和N-MeFOSE最主要的储存库,各目标污染物分别约占其环境总量的99%、98%、91%和97%;降解反应是N-EtFOSA、N-MeFOSA、N-EtFOSE和N-MeFOSE的主要输出途径。该文探讨并明确了长江三角洲PFOS和PreFOS的迁移归趋,可为长三角的生态风险评价和污染控制提供一定的科学依据。

CE-C^(4)D用于黄河水中6种苯氧羧酸和2种苯甲酸类除草剂的分离检测

利用自建的毛细管电泳-电容耦合非接触电导检测系统,通过对缓冲溶液、添加剂、分离电压、有效长度等条件的优化,实现了6种苯氧羧酸类和2种苯甲酸类除草剂的同时分离检测,并应用于黄河水中8种除草剂残留的检测.结果表明,在含有α-环糊精的三乙胺体系中,可实现8种除草剂在6 min内同时分离检测;在7.8~300μmol/L范围内浓度与峰面积呈良好的线性相关,检出限为2.00~3.93μmol/L;迁移时间和峰面积的日内、日间重现性的相对标准偏差为0.40%~5.78%;黄河水样的加标回收率为80.11%~114.41%.与传统检测分析方法相比,该方法的设备便于携带、操作简单,有望成为环境中多种农药残留同时检测的新型技术.

云南金沙江干热河谷土壤微生物群落结构特征及影响因素

金沙江干热河谷区是长江上游重要的生态屏障和典型生态脆弱区,对金沙江干热河谷土壤微生物群落结构变异特征及其驱动因素的了解仍不清楚。沿着金沙江选择5个地点的典型干热河谷植被,采用磷脂脂肪酸法研究了土壤微生物生物量和群落结构的空间变异,并探讨了气候、植被因子和土壤性质等对土壤微生物群落结构的影响。结果表明:不同研究点土壤总微生物生物量介于4.30—13.20 nmol/g,以细菌为主,其中革兰氏阳性菌(G+)占26.22%—33.65%,革兰氏阴性菌(G-)占18.35%—23.67%;真菌占9.02%—15.13%。不同研究点土壤微生物生物量、真菌/细菌和G+/G-差异显著,并且非度量多维尺度分析形成不同聚类,表明土壤微生物群落结构在研究点间发生了变化。方差分解结果揭示了土壤微生物群落结构的变异主要受土壤因子的驱动,其次是植被和气候因素。草本生物量、土壤硝态氮、全碳、pH和含水量对土壤微生物群落结构具有显著影响。气候因素中年均降雨量对微生物生物量呈负影响效应。揭示了不同研究点通过土壤性质驱动了土壤微生物群落结构的变异,并发现了草本生物量在其中的重要作用,对干热河谷区植被恢复具有重要的意义。

珠江口及海南岛东南海域海水中氨基酸的分布及其对有机物降解指示的研究

于2021年8月对珠江口及海南岛东南海域海水中的总溶解态氨基酸(THAA)、溶解有机碳(DOC)、有机氮(TN)和叶绿素a(Chl a)的浓度及分布进行了系统的调查研究。结果表明,调查站位海水中THAA的浓度范围为0.68~4.22μmol/L,平均浓度为(1.69±0.98)μmol/L,呈现近岸高、远岸低的分布趋势;垂直分布上,氨基酸浓度均呈现出随深度增加逐渐减小的特征。THAA浓度分布与天冬氨酸(Asp)/β-丙氨酸(β-Ala)和谷氨酸(Glu)/γ-氨基丁酸(γ-Aba)的比值具有显著正相关性,表明细菌活动对THAA的分布以及降解有重要影响。细菌源有机碳对DOC的贡献率约(13.04%±4.50%),呈现出近岸低于远岸、表层高于底层的特征。氨基酸中碳对有机碳的贡献率(THAA-C%)的分布趋势为近岸低于远海,说明近岸站位有机物降解程度更大。降解指数(DI)和活性指数(RI)也和THAA-C%呈现了相似的分布趋势,在调查海域的东部和珠江口近岸海域出现了高值区。垂直方向上,珠江口附近的S8-S14断面底层相对于表层降解因子的值更低,表明底层海水中的有机物降解程度更高,而海南岛东南海域表层降解因子低于底层,底层海水中有机物更新鲜。

全氟辛酸物种敏感性分布平均模型及生态风险评估

收集并筛选了30个水生物种及其相关的53个单一毒性数据,基于不同的毒性终点数据,构建了全氟辛酸(PFOA)的优化物种敏感性分布(SSD)模型.为了降低模型选择的不确定性,采用了模型平均法,并将其应用于生态风险评价.根据致死、生长抑制、繁殖毒性及生化毒性数据,推导得出的预测无效应浓度(PNEC)值分别为2.09,0.02,0.006和0.024mg/L.值得注意的是,在PFOA暴露下,水生物种的繁殖终点表现出最高的敏感性,因此,选取基于繁殖毒性终点的PNEC值作为PFOA的水生生物标准(ALC).此外,还收集了长江流域地表水中的PFOA暴露浓度数据,并运用危害商值法(HQ)对长江流域地表水的生态风险进行了评估.研究结果显示,在所考察的12个长江流域站点地表水中,所有地表水样品的HQ值均在0.0004~0.04之间,表明长江流域中PFOA的生态风险处于低水平状态.本文的研究结果将为中国水生生物保护和降低PFOA生态风险提供重要参考.

珠三角大气降水化学特征及其来源解析

揭示大气降水化学特征及其来源贡献,对于大气环境质量改善与水生态安全提升具有重要意义。以典型酸雨区——珠三角为研究区,分析了2000—2021年29个监测站点降水的pH值、电导率以及主要离子浓度特征,并采用相关分析、PMF模型等统计方法解析了降水离子之间的相关性及其来源贡献。结果表明,2000—2021年降水pH值和电导率分别介于(4.66±0.18)~(5.91±0.45)和(1.63±0.59)~(5.49±1.62)mS/m,相对酸度为(0.05±0.062)~(0.19±0.13),pH值呈先降后升年际变化,电导率和相对酸度则相反。降水总离子浓度为(166.63±46.56)~(631.48±212.83)μeq/L,呈先升后降变化趋势。各离子加权当量浓度排序为SO_(4)^(2-)>Ca^(2+)>NH_(4)^(+)>NO_(3)^(-)>Cl->Na^(+)>K^(+)>Mg^(2+)>F^(-),其中SO_(4)^(2-)、NO^(-)_(3)、Ca^(2+)和NH_(4)^(+)是主要离子组分,占总浓度的72.98%。SO_(4)^(2-)浓度占总离子浓度比值由2000年的32.71%降至2021年的14.33%、而NO_(3)^(-)由9.03%升至13.74%。2000—2021年SO_(4)^(2-)与NO_(3)^(-)浓度比值降低了65.95%,2008年后SO_(4)^(2-)/NO_(3)^(-)值为0.5~3,降水由前期硫酸型向后期硫酸—硝酸混合型转变,表明城市化和农业集约化背景下珠三角NOx排放增加改变了降水污染结构,并进一步增加了区域大气污染的复杂性。各离子之间呈显著正相关关系,其中NO_(3)^(-)和SO_(4)^(2-)的正相关性(r=0.69~0.74)最强,通常NOx和SO2联和排放并以重叠途径进入降水。降水离子来源分为6种,燃煤对SO_(4)^(2-)和F-的贡献率(>60%)最高,二次无机盐贡献了82.30%的NO_(3)^(-),农业源、海盐源、生物质燃烧源和扬尘源分别对NH_(4)^(+)、Na^(+)、K^(+)和Ca^(2+)的贡献率高于70%,二次无机盐对SO_(4)^(2-)、Cl^(-)和NH_(4)^(+)的贡献率也高于25%。随着城市化推动机动车保有量的升高,二次无机盐源对降水离子的影响更具广泛性,亟需控制氮氧化物的排放以有效防控二次污染源。

螺蛳肉汤包的DNA提取方法效果比较及优化研究

为有效提取预包装柳州螺蛳粉中螺蛳肉汤包的DNA,以DNA浓度、纯度、有效性为指标,比较了SDS法、CTAB法、深加工食品DNA提取试剂盒(沉淀法)、食品DNA提取试剂盒(过柱法)4种方法提取DNA的效果,并选取提取效果较好的方法进行优化改良。结果表明,4种方法中CTAB法的提取效果较好,对该方法的样品前处理、提取过程进行优化后,提取得到的DNA浓度达到110.800 ng·μL^(-1),纯度指标A_(260)/A_(280)为1.803、A_(260)/A_(230)为1.670,适用于进一步的分子生物学检测,为进一步的源性成分鉴定奠定了基础。