A study on the chemical forms of radionuclides in seawater—II chloride and sulfate complexes of60Co

The apparent stability constants for chloride and sulfate ions with Co (II) at ionic strength of 0.67 were determined by the cation exchange method. The value of the stability constant ₁ for chloride ion with Co (II) ion was 0.79±0.055. The stability constants ₁, ₂ and ₃ for sulfate ion with Co (II) ion were 12.0±0.27, 91.5±11.4 and l,110±250, respectively. The chemical species of Co (II) in seawater was estimated at the pH of 8.0 to be present as Co²⁺ (63%), CoCl⁺ (27%) and CoSO₄ ⁰ (8.6%) using the known value of dissociation constant of Co (II), and under the assumption that only major inorganic anions are responsible for the chemical equilibrium of Co (II).     

Study on the chemical forms of radionuclides in seawater—I

The stability constants for sulfate, chloride and hydroxide ions with cerium (III) in the solution at ionic strength of 0.67 have been determined by cation exchange method, the values of ₁ and ₂ for sulfate complexes of cerium being 40±13 and 453±140, respectively and those for chloride complexes being 1.28±0.23 and 0.56±0.076, respectively. The values of ₁, ₂ and ₃ for hydroxide complexes of cerium were (4.5±0.9)×10⁷, (3.3±0.7)×10¹⁴ and (1.8±0.7)×10²³, respectively.Using the above constants the ratios of individual chemical species of¹⁴⁴Ce were calculated in a solution at ionic strength of 0.67 containing sulfate and chloride ions approximately the same as in seawater of 35 %. The result of calculation indicates that the dominant species of¹⁴⁴Ce in this solution is Ce(OH)₃ ⁰ at pH 8.     

两种甲藻对人工海水中胶体磷的利用初探

采用批次培养方法,研究了东海原甲藻(Prorocentrum donghaiense)和链状亚历山大藻(Alexandrium catenlla)对胶体磷的生物可利用性,并初步探讨了甲藻利用胶体磷的机制问题.结果表明东海原甲藻和链状亚历山大藻均能利用胶体磷生长繁殖.东海原甲藻在接种11d后细胞密度在无机磷和胶体磷培养基中分别为10.53×107和3.43×107个/dm3.链状亚历山大藻在接种11d后细胞密度在无机磷和胶体磷培养基中分别为39.0×105和28.3×105个/dm3.通过对比细胞密度,胶体磷对东海原甲藻生长的促进作用要低于无机磷的作用;胶体磷对链状亚历山大藻生长的促进作用与无机磷的作用相当.东海原甲藻和链状亚历山大藻在胶体磷源下碱性磷酸酶活性迅速升高,前期均显著高于各自无机磷组的碱性磷酸酶活性,碱性磷酸酶活力最高值分别为0.29和0.30μmol/(dm3·h).初步结果表明,两种甲藻均能通过碱性磷酸酶的降解来利用胶体磷.     

Dissolved uranyl complexed species in artificial seawater

The distribution of dissolved uranyl species was calculated on the basis of the stability constants published elsewhere and compared with the results obtained from the experiments performed in artificial seawater. According to the distributions calculated and electrochemical and spectrophoto-metrical measurements performed in model electrolytes and artificial seawater (pH=8.2) in the presence of sufficient hydrogen peroxide, uranium most probably predominates in the form of a mixed uranyl-dicarbonato-hydrogenperoxo complex. The results obtained could be applied to the natural marine photic zone.The mixed complex has to be taken into account as an additional form of dissolved uranium species influencing their cycle in natural water systems. Recent discovery of the presence of hydrogen peroxide in the surface waters of seas has challenged a long-held notion of the prevalence of uranyl-carbonato complexes in seawater.     

A comparison of diatom colonization on natural and artificial substrata in seawater

Experiments to investigate diatom colonization on various substrata in seawater are described. No differences were found due to different methods of preparation of the substrata. Differences in the numbers of diatoms colonizing the different substrata emphasize the care needed in selecting a substratum on which to study the settlement of organisms, especially if the experiments are to be used for subsequent prediction.     

Forty years of anthropogenic radionuclides in surface seawater. Italian and Japanese data

The concentrations of man made radionuclides in surface seawater since early ′60s are here reported as measured in Italy and Japan. Most of the data refers to⁹⁰Sr and¹³⁷Cs, but occasionally the concentrations of⁸⁹Sr and¹³⁴Cs in some Italian samples are also given. The main sources of man made radionuclides were the global fallout produced by the nuclear weapon tests and the Chernobyl accident. The respective contributions to the contamination of surface seawater around both countries are discussed.     

人工海水中碳酸根—碳酸氢根离子对的研究

本工作测定了有效离子强度I_=0.5277mol/L和25℃下碳酸在若干人工海水介质中的表现离解常数,计算了碳酸根和碳酸氢根与钾、钠、镁、钙的缔合常数,讨论了包括氯离子缔合和未考虑氯离子缔合的海水化学模型,还通过试验证实了钾与碳酸根、碳酸氢根的缔合是不可忽视的,其缔合常数与钠的缔合常数相近,从而扩展了Pytkowic和Hawley(1974)的碳酸根-碳酸氢根离子对的海水化学模型。     

正方体人工鱼礁流场效应试验研究

采用无干扰的粒子图像测速技术(PIV),针对中空型正方体人工鱼礁,选取3个不同的来流速度6.7 cm/s、11.0 cm/s和18.0 cm/s,研究了该模型单体(90°和45°)和组合(平行和垂直)工况时的流场效应。结果显示,单体90°迎流时上升流的规模和强度大于45°迎流,但产生的缓流区和背涡流的规模远小于45°工况。横向组合中单个鱼礁模型产生的流场效应较强于单体工况。纵向组合中,第一个迎流鱼礁在不同间距时内部流速分布和单体时较为相似,间距为1.0L时流速大小与单体最为接近。第二个迎流鱼礁内部基本上未出现回流区域,水平流速较单体时明显减小,但随着间距的增加流速值不断增大。     

The process of self-purification of the Baltic Sea waters from artificial radionuclides

An analysis of the variations in the concentrations of ¹³⁷Cs and ⁹⁰Sr radionuclides in the Baltic Sea surface waters after the accident at the Chernobyl nuclear power plant was performed. An instability of the ¹³⁷Cs concentration values during the short-term observations was found, when these values were differed 2-to 3-fold. The concentrations of ⁹⁰Sr appeared to be more stable; meanwhile, their deviations sometimes exceeded the ranges of the experimental errors. By the variations in the monthly average values of the radionuclide concentrations in the surface waters of the Baltic Sea in 1989–1995, no trend of the water self-purification was observed. The theoretical results obtained confirmed the potential of the formation and propagation of patches with increased concentrations of ¹³⁷Cs in the southeastern part of the Baltic Sea. The most reliable factor that controlled the process of self-purification of the Baltic Sea water appeared to be the mean annual value of the concentration of radionuclides. Pronounced divergences were obtained between the measured and calculated mean annual concentrations of ¹³⁷Cs and ⁹⁰Sr radionuclides in the surface waters of the Baltic Sea in 1989–2001. These divergences are explained by the potential influence of the waters from the Gulf of Bothnia and by other additional supplies of radionuclides to the marine environment, which were not included into the mathematical models.     

厦门湾富营养化程度趋势变化研究

本文根据2003～2006年厦门湾水质调查资料,研究了水体中化学耗氧量(COD)、溶解态无机氮(DIN)和磷酸盐(PO43--P)的含量分布及该海域富营养化程度的变化趋势.结果表明,近4a来,厦门湾COD平均含量呈现下降趋势;而水体的DIN和PO43--P平均含量呈增加趋势.厦门湾水体中平均N/P大于16,主要表现为磷限制特征,而马銮湾海区则表现为"丰磷"状态.厦门湾水体富营养化指数由1.1增加至5.4,增加趋势明显.     

A potentiometric study of ferric ion complexes in synthetic media and seawater

An investigation of ferric ion complexing has been conducted in synthetic media and seawater at 25°C. Formation constants were potentiometrically determined for the species FeCl²⁺, FeCl₂⁺, FeOH²⁺, and Fe(OH)₂⁺ at an ionic strength of 0.68 m. Formation constants for the ferric chloride complexes were determined as _Clβ₁ = 2.76 and _Clβ₂ = 0.44. In a study of the reaction Fe³⁺ + nH₂O ? Fe(OH)_n^(3?n)+ + nH⁺ in NaClO₄, NaNO₃ and NaCl the formation constants ${}^1\text{β}{}_1\text{and}{}^1\text{β}{}_2$ were shown to be relatively independent of medium when the effects of nitrate and chloride complexing were taken into account. The average values obtained for these constants are ${}^1\text{β}{}_1\text{= 1.93 · 10}{}^{\mathrm{?3}}\text{and}{}^1\text{β}{}_2\text{= 8.6 · 10}{}^{\mathrm{?8}}$. Reasonable agreement with these values was obtained when these constants were determined in seawater by accounting for the effects of chloride, fluoride and sulfate complexing.     

海水中文石溶解、沉淀速率及动力学研究

利用free-drift开放反应系统,在恒压力(1×105Pa)、恒温度(25.0℃±0.2℃)环境下,研究人工海水中近溶解、沉淀平衡状态时二氧化碳分压(pCO2)的变化对文石溶解、沉淀速率及其动力学方程的影响。每组实验中通入混合气体的pCO2分别为2300×10-6和320×10-6两种,并保持通入气体的pCO2恒定,通过实验得到了这两种pCO2环境下,文石的溶解和沉淀速率及动力学方程。研究结果表明:(1)文石在近溶解、沉淀平衡附近,溶解速率相对于Ac(碳酸盐碱度值)或?(饱和度)的变化速率要大于沉淀速率相对于Ac或?的变化速率;(2)Ac相同时,pCO2越高,溶解速率越高,沉淀速率越低;?相同时,亦是如此;(3)溶解实验中,在?0.8的区间内,反应液和混合气体之间pCO2平衡,反应级数n介于9～10之间;沉淀实验中,文石的反应级数介于2.0～3.2之间。     

Study of the seawater transparency field in the Crimea-Caucasus shelf area

This paper discussesin situ observational data on the directed light attenuation index in the near-surface layer, collected in September 1987. The absolute light attenuation index has been evaluated for a near-shore strip of water 10–15 miles in width. When multidisciplinary research is conducted in the open sea, this part of the sea surface remains unstudied, as the observational grid for it is made larger than the spatial-temporal parameters of the biophysical processes producing optical inhomogeneities.Translated by Vladimir A. Puchkin.     

A comparative study of three methods for the determination of iodate in seawater

A comparative study of three methods for the determination of iodate-iodine in seawater is described. In one method the iodate is determined polarographically while in the others the iodate is determined colorimetrically as iodonium ions. In one of the colorimetric methods each sample is pre-treated with excess iodine-water in an attempt to eliminate suspected interference from naturally occurring reducing agents. The tests were conducted on a selection of open-ocean and near-shore waters with iodate concentrations ranging from 0 to 60 μg 1^?1-I. The tests indicated that the polarographic method and the colorimetric method without iodine-water give the more reliable measurement of iodate concentration. Also, the method with iodine water was found to be in error especially at low iodate concentrations. Reducing agents, if present, were found not to interfere significantly.     

A study on seawater apparent heavy metalcomplexation capacity in the Haikou Bay

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海水中臭氧总残留氧化物三种检测方法的比较研究

对臭氧总残留氧化物(TRO)常用3种检测方法(碘化钾-N,N-二乙基-1,4-苯二胺(KI-DPD)分光光度法、硼酸碘化钾(H3BO3-KI)比色法、靛蓝二磺酸钠(IDS)分光光度法)进行了比较研究。结果表明:在0~0.5 mg/L的TRO浓度范围内,KI-DPD分光光度法和H3BO3-KI比色法线性关系良好,检出限分别为0.040 mg/L和0.034 mg/L,并且这两种测定方法的准确性和重复性较佳,相对标准偏差(RSD)均小于5.0%,低于传统碘量法;而IDS分光光度法只有在高浓度臭氧海水样品(0.6~1.2 mg/L)检测时,RSD才小于5.0%,且测定浓度明显低于另外两种方法。故对于海水养殖水体中的TRO检测,KI-DPD分光光度法和H3BO3-KI比色法均准确有效,并且H3BO3-KI比色法在检测操作上更为简便快捷。     

A tentative determination of methylmercury in seawater

A bioassay experiment using caged mussels has suggested a total concentration of methylmercury in the seawater of a polluted estuary of 0.06 ng dm^?3. The technique may provide a useful tool for the assessment of relative concentrations of methylmercury in seawater at different locations.     

Interactions between dissolved petroleum hydrocarbons and pure and humic acid-coated mineral surfaces in artificial seawater

The adsorption of total petroleum hydrocarbons (TPHs) on suspended particles in the marine environment is an important process affecting the fate of oils spilled in the ocean. Adsorption kinetics and adsorption isotherms of the water-soluble fraction of Fuel Oil No. 6 were performed on pure and humic acid-modified montmorillonite, alumina and kaolinite. The rates of adsorption on all sorbents are very fast and a pseudo-equilibrium is reached within 0.5 h. Linear adsorption isotherms were obtained for TPH and individual aromatic hydrocarbons on all sorbents. Higher sorption coefficients (Kd) were obtained for the humic acid-coated clays compared to the pure clays. However, a great contribution of mineral surface to overall adsorption was found on humic acid-modified particles in this study. A linear relationship between the log K and log Kow was also found for individual compounds on both pure alumina (log Km) and humic acid-coated alumina (log Koc).     

A field study of the development of wind-waves

This paper presents the results of observation on the development of wind-waves which were generated in a lake water about 420 cm deep with a fetch 12 km long. Measurements of surface elevation were carried out at the end of an observational pier where the water depth was 80 cm. The wave momentum flux, i.e., the growth rate of the wave momentum, was estimated from both significant waves and power spectral densities for the wave records. The values obtained by the two ways accorded fairly well and they were 57 % as large as the wind stress measured simultaneously. The exponential growth rate of spectral densities for a frequency component was in good accord with that observed bySnyder andCox (1966) and by others. If these growth rates are applied to all the components of the spectrum, the wave momentum flux must exceed the wind stress. This cannot explain the experimental results nor can be physically accepted. The difference of spectral densities between the two successive runs showed that the increase of spectral densities was. limited in several bands of frequency. The phenomena are discussed in relation with the overshoot-undershoot effects studied byBarnett andSutherland (1968).Observational results suggest that the spectral growth of a certain component is closely related to the spectral densities of other components. Energy exchange among componented waves has not been considered in the theories for generation and development of wind-waves established by Phillips, Miles and others.New generation mechanism suggested byLonguet-Higgins (1969) was found to be able to describe the observed growth rates of the form(f)={(1/2)(t–t_1/2)}²: the spectral density(f) was proportional to the square of durationt. However, the mechanism can not explain the overshoot-undershoot effects peculiar to the equilibrium spectrum of windwaves.Three frequencies characterizing the discrete distributions of frequency bands where spectral densities increased were examined and three waves corresponding to these frequencies were found to be satisfying the resonance conditions for the wave-wave interactions among three sinusoidal wave trains as studied byPhillips (1960),Longuet-Higgins (1962) andBenny (1962). The interactions are suggested to predict well both the spectral growth proportional to squares of duration and the ceaseless oscillations of spectral densities in an equilibrium spectrum.