Yb：Ca5（PO4）3F激光晶体的生长缺陷

采用提拉法生长了质量优异的Yb：Ca5（PO4）2F（Yb：FAP）晶体。运用化学腐蚀，光学显微镜、扫描电子显微镜以及能量散射光谱仪观察了该晶体中的生长条纹和包裹物等宏观缺陷，以及晶体的位错腐蚀形貌、位错密度及其分布情况，同时观察了晶体中亚晶界的形态。由晶体中位错的径向变化以及生长条纹可知：晶体在生长过程中为微凸界面生长。高温下CaF2的挥发造成了在晶体生长后期熔体中组分偏离化学计量比，出现组分过冷，形成包裹物。且位错密度显著增加。Yb：FAP晶体的各向异性使得晶体在（10 10）面的位错蚀坑形状、大小以

温梯法蓝宝石（Al2O3）晶体的脱碳去色退火研究

温度梯度法（TGT）生长的Al2O3晶体因石墨发热体在高温时的挥发和原料中过渡性金属离子的存在，晶体在不同部位呈现不同颜色，一般上部为浅红色，尾部为浅黄绿色，将TGT法生长的Al2O3晶体（Ф110×80mm^3）依次经过高温氧化气氛、高温还原气氛脱碳、去色退火实验，即“两步法”退火实验，晶体变成无色、透明，经测试，Al2O3晶体的完整性、光学透过率和光学均匀性均有显著提高。

高质量LiGaO2晶体的提拉法生长及表征

采用提拉法成功地生长了高质量的LiGaO2单晶体,生长过程中没有观察到挥发现象。通过四晶X射线衍射、化学腐蚀、光学显微、透过光谱以及原子力显微镜对晶体的质量进行了表征。结果表明：晶体中无包裹物及气泡,具有很高的质量,（001）面晶片的摇摆曲线半高宽仅为16.2arcsec,正交的（001）、（100）及（010）三个晶面具有不同的腐蚀形貌,其位错密度均低于10^4/cm^2;LiGaO2晶体的吸收边约为220nm;化学机械抛光后的晶片表面非常光滑,其均方根粗糙度仅为0.1nm（5×5μm^2）。

ScAlMgO_4晶体的生长缺陷

采用提拉法生长出φ30 mm×55 mm的ScAlMgO4晶体。在晶体生长过程中有轻微的挥发,粉末X射线衍射分析表明:挥发物质为MgO单相。运用扫描电镜、光学显微镜以及高分辨X射线衍射仪对晶体中的包裹物、开裂、生长条纹和小角晶界缺陷进行了研究。结果表明:温度梯度和热应力是形成晶体中缺陷的主要原因。通过合理设计温场,控制固-液界面的形状及冷却过程的降温速率,可以提高晶体的完整性。

Emissões atmosféricas oriundas da biorremediação de solo do Complexo Petroquímico do Estado do Rio de Janeiro (COMPERJ) experimentalmente contaminado por diesel Defesa

As pesquisas relacionadas às questões ambientais têm aumentado nos últimos anos à medida que os fenômenos climáticos têm mostrado alterações cada vez mais intensas, assim como eventos de contaminação têm ocorrido. Para reduzir a concentração de contaminantes em solos, podem ser empregados processos de biorremediação, que têm por objetivo reduzir a carga poluente através do uso de micro-organismos em condições específicas. Notadamente, a possibilidade, durante o tratamento, da emissão de gases de efeito estufa (GEE) ou compostos orgânicos voláteis (COV) possui poucos dados na literatura. Este trabalho avaliou o uso da biorremediação sob condições anaeróbicas e aeróbicas, para solo contaminado com diesel, em condições do solo de atenuação natural, processos abióticos e bioestímulo. Os estudos anaeróbios mostraram que as emissões de GEE (CH4, CO2 e N2O) alcançaram valores de 2,0 μg kg-1; 4,0x102 μg kg-1 e 0,3 μg kg-1, respectivamente e as emissões de COV foram observadas em toda a série (de hexano a decano). O estudo estatístico descritivo mostrou mudança na hierarquização dos produtos remanescentes no solo evidenciando atividade microbiana neste estudo. Para a eliminação da possibilidade de processos metanogênicos serem responsabilizados pelas emissões de CH4 observados no estudo anaeróbio, foi realizado o mesmo experimento, porém em condições de aeração forçada. Foi observado aumento das emissões de GEE e COV em 2,0 μg kg-1 h-1 para CH4, 5,0x102 μg kg-1 h-1 para CO2 e 0,4 μg kg-1 h-1 para N2O. O estudo estatístico descritivo também mostrou mudança na hierarquização dos produtos. As propriedades metanogênicas foram excluídas pelo estudo aeróbio, corroborando o fato de que ocorre emissão de GEE durante as etapas de biorremediação

Species transformation of trace elements and their distribution prediction in dyestuff residue incineration

The release of heavy metals from the combustion of hazardous wastes is an environmental issue of increasing concern. The species transformation characteristics of toxic heavy metals and their distribution are considered to be a complex problem of mechanism. The behavior of hazardous dyestuff residue is investigated in a tubular furnace under the general condition of hazardous waste pyrolysis and gasfication. Data interpretation has been aided by parallel theoretical study based on a thermodynamic equilibrium model based on the principle of Gibbs free energy minimization. The results show that Ni, Zn, Mn, and Cr are more enriched in dyestuff residue incineration than other heavy metals (Hg, As, and Se) subjected to volatilization. The thermodynamic model calculation is used for explaining the experiment data at 800 degrees C and analyzing species transformation of heavy metals. These results of species transformation are used to predict the distribution and emission characteristics of trace elements. Although most trace element predictions are validated by the measurements, cautions are in order due to the complexity of incineration systems.

下辽宁省河平原稻田生态系统的NH_3挥发和N淋溶

在地处下辽河平原的中国科学院沈阳生态实验站潮棕壤上布置施N量分别为180、240和300kg·hm~(-2)，施P量分别为70、100和130kg·hm~(-2)的稻田田间试验。应用通气密闭室法和陶土渗滤管法，测定了稻田生态系统三个不同施肥期施用氮肥后的NH3挥发损失和N淋溶，结果表明：1．水稻生长季节施用氮肥后有明显NH3挥发，总挥发量为11.64kgN·hm~(-2)-34.01kgN·hm~(-2)，占施N量的4.66％-11.66％，主要发生在施用分孽肥后，每次NH3挥发高峰出现在施氮肥后的2-4d内。2．水分渗漏对NH3挥发损失有重要影响。田面积水条件下，NH3挥发损失量及其占施N量的比率都较大，不同施N处理间差异显著（P＜0.05），NH3挥发量随施N量增加而增加；田面不积水条件下，NH3挥发损失挥发量相对较小。3．氮肥用量、田面水NH4斗一浓度和田面水pH是影响NH3挥发重要因素；180kgN·hm~(-2)条件下，积水时不同P处理间NH3挥发差异不显著。4．水稻生长季节各次施用氮肥后，60cm和gocm深处渗漏液中NH4+-N含量都小于2mg·L~(-1)，各施氮肥处理与对照间差异不显著。但NO3-淋溶比较显著，多集中在3mgN·ul-15mgN·L~(-1)之间。NO3-的淋溶随施N量增加而增加。水分渗漏状况影响N03一在不同土层深度的累积，渗水越快NO3-淋溶深度越大。渗水快或者施N量高时NO3，淋溶浓度高于国际饮用水卫生标准10mgN·L~(-1)，已有污染浅层地下水的可能。5．施用基肥后灌水，NH_4~+、NO_3~-立即出现淋溶高峰，而两次追施氮肥的淋溶高峰出现在施肥后10d或更久；并且基肥时期的淋溶浓度也比较高。

The toxicology of climate change: environmental contaminants in a warming world.

Climate change induced by anthropogenic warming of the earth's atmosphere is a daunting problem. This review examines one of the consequences of climate change that has only recently attracted attention: namely, the effects of climate change on the environmental distribution and toxicity of chemical pollutants. A review was undertaken of the scientific literature (original research articles, reviews, government and intergovernmental reports) focusing on the interactions of toxicants with the environmental parameters, temperature, precipitation, and salinity, as altered by climate change. Three broad classes of chemical toxicants of global significance were the focus: air pollutants, persistent organic pollutants (POPs), including some organochlorine pesticides, and other classes of pesticides. Generally, increases in temperature will enhance the toxicity of contaminants and increase concentrations of tropospheric ozone regionally, but will also likely increase rates of chemical degradation. While further research is needed, climate change coupled with air pollutant exposures may have potentially serious adverse consequences for human health in urban and polluted regions. Climate change producing alterations in: food webs, lipid dynamics, ice and snow melt, and organic carbon cycling could result in increased POP levels in water, soil, and biota. There is also compelling evidence that increasing temperatures could be deleterious to pollutant-exposed wildlife. For example, elevated water temperatures may alter the biotransformation of contaminants to more bioactive metabolites and impair homeostasis. The complex interactions between climate change and pollutants may be particularly problematic for species living at the edge of their physiological tolerance range where acclimation capacity may be limited. In addition to temperature increases, regional precipitation patterns are projected to be altered with climate change. Regions subject to decreases in precipitation may experience enhanced volatilization of POPs and pesticides to the atmosphere. Reduced precipitation will also increase air pollution in urbanized regions resulting in negative health effects, which may be exacerbated by temperature increases. Regions subject to increased precipitation will have lower levels of air pollution, but will likely experience enhanced surface deposition of airborne POPs and increased run-off of pesticides. Moreover, increases in the intensity and frequency of storm events linked to climate change could lead to more severe episodes of chemical contamination of water bodies and surrounding watersheds. Changes in salinity may affect aquatic organisms as an independent stressor as well as by altering the bioavailability and in some instances increasing the toxicity of chemicals. A paramount issue will be to identify species and populations especially vulnerable to climate-pollutant interactions, in the context of the many other physical, chemical, and biological stressors that will be altered with climate change. Moreover, it will be important to predict tipping points that might trigger or accelerate synergistic interactions between climate change and contaminant exposures.

Aquatic Distribution And Heterotrophic Degradation Of Polycyclic Aromatic-Hydrocarbons (PAH) In The Tamar Estuary

Variations in the concentrations and microheterotrophic degradation rates of selected Polycyclic Aromatic Hydrocarbons (PAH) in the water column of the Tamar Estuary were investigated in relation to the major environmental variables. Concentrations of individual PAH varied typically between i and 50 ng l−1 Based on their observed environmental behaviour the PAH appeared divisible into two groupings: (1) low molecular weight PAH incorporating naphthalene, phenanthrene and anthracence and (a) the larger molecular weight homologues (fluoranthene, pyrene, chrysene, benz(a)anthracene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)-pyrene). Group 1 PAH showed a complex distribution throughout the estuary with no significant correlations with either salinity or suspended particulates. Based on their relatively low particle affinity and high water solubilities and vapour pressures, volatilization is proposed as an important process in determining their fate. Microheterotrophic turnover times of naphthalene varied between x and 30 days, and were independent of suspended solids with maximum degradation rates located in the central and urban regions of the Estuary. When compared with the flushing times for the Tamar (3–5 days), it is probable that heterotrophic activity is important in the removal of naphthalene (and possibly the other Group 1 PAH) from the estuarine environment. In contrast Group 2 PAH concentrations exhibited highly significant correlations with suspended particulates. Highest concentrations occurred at the turbidity maximum, with a secondary concentration maximum localized to the industrialized portion of the estuary and associated with anthropogenic inputs. Laboratory degradation studies of benzo(a)pyrene in water samples taken from the estuary showed turnover times for the compound of between 2000 and 9000 days. Degradation rates correlated positively with suspended solids. The high particulate affinity and microbial refractivity of Group 2 PAH indicate sediment burial as the principal tate of these PAH in the Tamar Estuary. Estuarine sediments contained typically 50–1500 ng g−1 dry weight of individual PAH which were comparable to the levels of Group 2 PAH associated with the suspended particulates. Highest concentrations occurred at the riverine end of the estuary resulting from unresolved inputs in the catchment. Subsequent dilution by less polluted marine sediments together with slow degradation results in a seaward trend of decreasing concentrations. However, there is a secondary maximum of PAH superimposed on this trend which is associated with urban Plymouth.

Field fluxes and speciation of arsines emanating from soils

The biogeochemical cycle of arsenic (As) has been extensively studied over the past decades because As is an environmentally ubiquitous, nonthreshold carcinogen, which is often elevated in drinking water and food. It has been known for over a century that micro-organisms can volatilize inorganic As salts to arsines (arsine AsH(3), mono-, di-, and trimethylarsines, MeAsH(2), Me(2)AsH, and TMAs, respectively), but this part of the As cycle, with the exception of geothermal environs, has been almost entirely neglected because of a lack of suited field measurement approaches. Here, a validated, robust, and low-level field-deployable method employing arsine chemotrapping was used to quantify and qualify arsines emanating from soil surfaces in the field. Up to 240 mg/ha/y arsines was released from low-level polluted paddy soils (11.3 ± 0.9 mg/kg As), primarily as TMAs, whereas arsine flux below method detection limit was measured from a highly contaminated mine spoil (1359 ± 212 mg/kg As), indicating that soil chemistry is vital in understanding this phenomenon. In microcosm studies, we could show that under reducing conditions, induced by organic matter (OM) amendment, a range of soils varied in their properties, from natural upland peats to highly impacted mine-spoils, could all volatilize arsines. Volatilization rates from 0.5 to 70 µg/kg/y were measured, and AsH(3), MeAsH(2), Me(2)AsH, and TMAs were all identified. Addition of methylated oxidated pentavalent As, namely monomethylarsonic acid (MMAA) and dimethylarsinic acid (DMAA), to soil resulted in elevated yearly rates of volatilization with up to 3.5% of the total As volatilized, suggesting that the initial conversion of inorganic As to MMAA limits the rate of arsine and methylarsines production by soils. The nature of OM amendment altered volatilization quantitatively and qualitatively, and total arsines release from soil showed correlation between the quantity of As and the concentration of dissolved organic carbon (DOC) in the soil porewater. The global flux of arsines emanating from soils was estimated and placed in the context of As atmospheric inputs, with arsines contributing from 0.9 to 2.6% of the global budget.

Quantitative and qualitative trapping of volatile methylated selenium species entrained through nitric acid

Quantification and speciation of volatile selenium (Se) fluxes in remote areas has not been feasible previously, due to the absence of a simple and easily transportable trapping technique that preserves speciation. This paper presents a chemo-trapping method with nitric acid (HNO3) for volatile Se species, which preserves speciation of trapped compounds. The recovery and speciation of dimethylselenide (DMSe) and dimethyl diselenide (DMDSe) entrained through both concentrated nitric acid and hydrogen peroxide (H2O2) were compared by HPLC-ICP-MS and HPLC-HG-AFS analyses. It was demonstrated that trap reproducibility was better for nitric acid and a recovery of 65.2 +/- 1.9% for DMSe and 81.3 +/- 3.9% for DMDSe was found in nitric acid traps. HPLC-ES-MS identified dimethyl selenoxide (DMSeO) as the trapped product of DMSe. Methylseleninic acid (MSA) was identified to be the single product of DMDSe trapping. These oxidized derivatives have a high stability and low volatility, which makes nitric acid a highly attractive trapping liquid for volatile Se species and enables reconstruction of the speciation of those species. The presented trapping method is simple, quantifiable, reproducible, and robust and can potentially be applied to qualitatively and quantitatively study Se volatilization in a wide range of natural environments.

Quantitative and qualitative trapping of arsines deployed to assess loss of volatile arsenic from paddy soil

Arsenic volatilization in the environment is thought to be an important pathway for transfer from terrestrial pools to the atmosphere. However, this phenomenon is not well characterized due to inherent sampling issues in trapping, quantifying and qualifying these arsine gases; including arsine (AsH(3)), monomethyl arsine (MeAsH(2)), dimethyl arsine (Me(2)AsH) and trimethyl arsine (TMAs). To quantify and qualify arsines in air we developed a novel technique based on silver nitrate impregnated silica gel filled tubes. The method was characterized by measuring the recovery of trapped arsines after elution of this chemo-trap with hot boiling diluted nitric acid. Results from three separate experiments, measured by ICP-MS, showed that the method is reproducible and quantitative. Arsine species recovery ranged from 80.1 to 95.6%, with limit of detection as low as 3.8 ng per chemo-trap tube. Moreover, HPLC-ICP-MS analysis of hot boiling water eluted traps showed that the corresponding oxy ions of the arsines were formed with the As-C bonds of the molecule intact, hence, allowing qualification of trapped arsine species. A microcosm study examining volatile arsenic evolution from field contaminated Bangladeshi paddy soils (24.2 mg/kg arsenic) was used to show the application of silver nitrate chemo-trapping approach. Traps were placed on the inlet and the outlet of microcosms containing the soils that were either (cattle derived) manured or not, or flooded or not, in a factorial design. The headspace was purged with air at a flow rate of 12 mL/min. Results showed that as much as 320 ng of arsenic (0.014% of total soil content) could be emitted in a 3 week period for manured and flooded soils and that TMAs was the dominant species evolved, with lesser quantities of Me(2)AsH. No volatile arsenic evolution was observed for nonmanured treatments, and arsine release from the nonflooded, manured treatment was much less than the flooded treatment.

Degradation of 4-fluorobiphenyl in soil investigated by 19F NMR spectroscopy and 14C radiolabelling analysis

The incubation of the model pollutant [U-14C]'-4-fluorobiphenyl (4FBP) in soil, in the presence and absence of biphenyl (a co-substrate), was carried out in order to study the qualitative disposition and fate of the compound using 14C-HPLC and 19F NMR spectroscopy. Components accounted for using the radiolabel were volatilization, CO2 evolution, organic solvent extractable and bound residue. Quantitative analysis of these data gave a complete mass balance. After sample preparation. 14C-HPLC was used to establish the number of 4FBP related components present in the organic solvent extract. 19F NMR was also used to quantify the organic extracts and to identify the components of the extract. Both approaches showed that the composition of the solvent extractable fractions comprised only parent compound with no metabolites present. As the 14C radiolabel was found to be incorporated into the soil organic matter this indicates that metabolites were being generated, but were highly transitory as incorporation into the SOM was rapid. The inclusion of the co-substrate biphenyl was to increase the overall rate of degradation of 4FBP in soil. The kinetics of disappearance of parent from the soil using the data obtained were investigated from both techniques. This is the first report describing the degradation of a fluorinated biphenyl in soil.

The effects of global climate change on the cycling and processes of persistent organic pollutants (POPs) in the North Sea

The fate and cycling of two selected legacy persistent organic pollutants (POPs), PCB 153 and gamma-HCH, in the North Sea in the 21st century have been modelled with combined hydrodynamic and fate and transport ocean models
(HAMSOM and FANTOM, respectively). To investigate the impact of climate variability on POPs in the North Sea in the 21st century, future scenario model runs for three 10-year periods to the year 2100 using plausible levels of both in
situ concentrations and atmospheric, river and open boundary inputs are performed. This slice mode under a moderate scenario (A1B) is sufficient to provide a basis for further analysis. For the HAMSOM and atmospheric forcing, results of the IPCC A1B (SRES) 21st century scenario are utilized, where surface forcing is provided by the REMO downscaling of the ECHAM5 global atmospheric model, and open boundary conditions are provided by the MPIOM global ocean model.
Dry gas deposition and volatilization of gamma-HCH increase in the future relative to the present by up to 20% (in the spring and summer months for deposition and in summer for volatilization). In the water column, total mass of
gamma-HCH and PCB 153 remain fairly steady in all three runs. In sediment,
gamma-HCH increases in the future runs, relative to the present, while PCB 153 in sediment decreases exponentially in all three runs, but even faster in the future, due to the increased number of storms, increased duration of gale wind conditions and increased water and air temperatures, all of which are the result of climate change. Annual net sinks exceed sources at the ends of all periods.
Overall, the model results indicate that the climate change scenarios considered here generally have a negligible influence on the simulated fate and transport of the two POPs in the North Sea, although the increased number and magnitude of storms in the 21st century will result in POP resuspension and ensuing revolatilization events. Trends in emissions from primary and secondary sources will remain the key driver of levels of these contaminants over time.

Air-Sea Exchange of Legacy POPs in the North Sea Based on Results of Fate and Transport, and Shelf-Sea Hydrodynamic Ocean Models

The air-sea exchange of two legacy persistent organic pollutants (POPs), γ-HCH and PCB 153, in the North Sea, is presented and discussed using results of regional fate and transport and shelf-sea hydrodynamic ocean models for the period 1996–2005. Air-sea exchange occurs through gas exchange (deposition and volatilization), wet deposition and dry deposition. Atmospheric concentrations are interpolated into the model domain from results of the EMEP MSC-East multi-compartmental model (Gusev et al, 2009). The North Sea is net depositional for γ-HCH, and is dominated by gas deposition with notable seasonal variability and a downward trend over the 10 year period. Volatilization rates of γ-HCH are generally a factor of 2–3 less than gas deposition in winter, spring and summer but greater in autumn when the North Sea is net volatilizational. A downward trend in fugacity ratios is found, since gas deposition is decreasing faster than volatilization. The North Sea is net volatilizational for PCB 153, with highest rates of volatilization to deposition found in the areas surrounding polluted British and continental river sources. Large quantities of PCB 153 entering through rivers lead to very high local rates of volatilization.