Chemical species distribution and transformation in polyaluminum chemical solutions

The hydrolysis polymerization precipitation process of Al(III) was studied with pH titration method, and the prepared polyaluminum solutions were characterized by various experimental methods: acid depolymerization, timed complex-colorimetric procedure, ultrafiltration, X-ray diffraction and infrared absorption spectrum. The results showed that the chemical species transformation and distribution of Al(III) in the hydrolysis-polymerization process depended on B=(OH/Al) ratio, pH and other factors. By their structures, the chemical species can be divided into three categories of monomeric (Ala), polymeric (Alb), sol or gel precipitates (Alc) and the polymeric species may be further divided into three groups such as linear low polymer (Alb1), linear high polymer (Alb2) and high polymer with cyclic structure (Alb3). The nominal molecular weight of polymeric species obtained by ultrafiltration was about 1000-50000 and most of them failed into a range around 10000. A scheme for the chemical speciation model     

重庆地区酸化水体中几种元素形态特征初探

研究了碳、氮、硒和铝在酸化水体中的形态特征。被研究的典型酸化水体中４种元素的最主要的形态分别为ＤＯＣ、Ｓｅ（ＩＶ）和。分析了这些元素的形态与水体中３９种测定参数之间的相关性；探讨了几种主要形态与浮游植物、浮游动物和底栖动物的关系。     

京密运河与北京排污河浮游藻类的群落演替与水质污染的关系

对京密运河及北京排污河进行了不同季节的藻类生态调查,根据藻类群落结构特征,对河流质量进行评价,并将河流水质划分为五级.相关性分析结果表明,藻类数量和生物量与水质相关性显著.根据藻类组成、分布特征及河流水质选出了作为评价京密运河和北京排污河污染程度的几种指示藻类.     

牛蛙入侵新案例与管理对策分析

牛蛙是ISSG／SSC公布的100种最危险的入侵种之一，也是进入我国最早、分布最广和危害最大的外来两栖动物．1980年以后，由于野外放养和人工驯养地区的迅速扩大，野化种群的数量增加很快，对土著蛙类和农田生态系统的稳定形成了严重威胁．本文依据近年来发现的3个新案例，初步分析了牛蛙在我国的分布状况和牛蛙成功入侵我国的主要原因，以及牛蛙在生物链中的位置和危害，并提出了3条相应的管理对策．图1表2参18     

Threatened Peripheral Populations in Context: Geographical Variation in Population Frequency and Size and Sexual Reproduction in a Clonal Woody Shrub

Abstract:  Geographically peripheral populations of widespread species are often the focus of conservation because they are locally rare within political jurisdictions. Yet the ecology and genetics of these populations are rarely evaluated in a broader geographic context. Most expectations concerning the ecology and evolution of peripheral populations derive from the abundant-center model, which predicts that peripheral populations should be less frequent, smaller, less dense, and have a lower reproductive rate than central populations. We tested these predictions and in doing so evaluated the conservation value of peripheral populations for the clonal shrub Vaccinium stamineum L. (Ericaceae, deerberry), which is listed as threatened in Canada. Based on 51 populations sampled from the center to the northern range limits over 2 years, population frequency and size declined toward the range limit, but ramet density increased. Sexual reproductive output varied widely among populations and between years, with many populations producing very few seeds, but did not decline toward range margins. In fact seed mass increased steadily toward range limit, and this was associated with faster germination and seedling growth, which may be adaptive in seasonal northern environments. Our results did not support the prediction that clonal reproduction is more prevalent in peripheral populations or that it contributed antagonistically to the wide variation in seed production. Peripheral populations of V. stamineum are as productive as central populations and may be locally adapted to northern environments. This emphasizes the importance of a broad geographical perspective for evaluating the ecology, evolution, and conservation of peripheral populations.     

Evaluation of preservation methods for nutrient species collected by automatic samplers

Automatic samplers are a common method of data collection for numerous monitoring projects in the South Florida region and elsewhere. Although total phosphorus (TP) is the primary parameter of interest within this region, nitrogen species such as ammonia nitrogen (NH₄-N), nitrate+nitrite nitrogen (NO_x-N), and total kjeldahl nitrogen (TKN) are also collected and analyzed. Federal and state quality assurance guidelines require nutrient samples to be preserved by acidification with H₂SO₄ to a pH < 2 and stored immediately at 4 °C. However, the remoteness of manysampling locations in South Florida makes it difficult to supplyelectricity for the refrigeration of samples collected by autosamplers. In addition, the use of propane-powered refrigerated autosamplers is a costly and ineffective solution in the South Florida climate. Consequently, while samples collected at these remote locations are routinely pre-preservedwith acid, they are not cooled to 4 °C for a period fromone to seven days. This study evaluated if a statistically significant difference ( = 0.05) existed between concentrations of nitrogen species from a common source samplethat was either: processed immediately; refrigerated to 4 °C for seven days; or not refrigerated for seven days.In all cases, the collected sample was pre-preserved by adding 1 mL of 50% H₂SO₄ to each 1 L discrete sample container before each 7 day testing period. Differences in concentrations of the calculated parameter total nitrogen (TN)were also investigated.Analyses using the Wilcoxon Signed-Rank Test showed no significant differences among the three treatment groups for NO_x-N, TKN, TN and TP. Significant differences were observedwhen the NH₄-N samples that were processed immediately werepaired with NH₄-N samples that were left unrefrigerated or refrigerated for seven days. Information from this study can be used by researchers and managers in evaluating the usefulness of nutrient water quality data that is collected when sample refrigeration is not available.     

Environmental Contaminants in Blood, Hair, and Tissues of Ocelots from the Lower Rio Grande Valley, Texas, 1986–1997

The ocelot (Felis pardalis) isan endangered neotropical cat distributed within asmall range in the Lower Rio Grande Valley (LRGV), inTexas, U.S.A. Studies of the impacts of environmentalcontaminants in wild cats are few. Approximately onefourth of the estimated population (about 100) ofocelots in the LRGV was sampled to evaluate theimpacts of chlorinated pesticides, polychlorinatedbiphenyls, and trace elements on the population. Hairwas collected from 32 ocelots trapped between 1986–1992,and blood was collected from 20 ocelots trappedbetween 1993–1997. A few blood samples were obtainedfrom individuals recaptured two or three times. Tissue samples from 4 road-killed ocelots were alsoanalyzed. DDE, PCBs, and Hg were some of the mostcommon contaminants detected in hair and blood. MeanHg levels in hair ranged from 0.5 to 1.25 g g^-1 dw,Se from 1.5 to 3.48 g g^-1 dw, and Pb from 0.56 to26.8 g g^-1 dw. Mean DDE concentrations in plasma ranged from 0.005 g g^-1 ww to 0.153 g g^-1 ww, and PCBs ranged from 0.006 g g^-1 ww to 0.092 g g^-1 ww. Mean Hg levels in red blood cells rangedfrom 0.056 g g^-1 dw to 0.25 g g^-1 dw. Concentrations of DDE, PCBs, or Hg, did not increasesignificantly with age, although the highestconcentrations of DDE and Hg were found in olderanimals. Overall, concentrations of DDE, PCBs, and Hgwere low and at levels that currently do not pose anythreat to health or survival of the ocelot. This isfurther supported by good reproduction of the ocelotin the LRGV, where adult females averaged about 1.5kittens/litter. Thus, it seems that the current majorthreat to recovery of the ocelot in the LRGV may behabitat loss, although potential impacts of newgeneration pesticides, such as organophosphorus andcarbamate insecticides need further study.     

Ecohydrological impact–assessment modeling: an example for terrestrial ecosystems in Noord-Holland, the Netherlands

In the Netherlands the increasing demand for ecohydrological models on a regional (provincial) scale has resulted in the development of an empirical statistical impact–assessment model for semi-natural terrestrial herbaceous ecosystems. This model, called ITORS, describes the relationship between plant species and site factors such as soil, groundwater and management. The model, developed for the region of Noord-Holland, is applied to support provincial policy on soil and water management. The empirical statistical approach required the collection of a large set of field data, describing the biotic and environmental variation of a variety of semi-natural terrestrial ecosystems in Noord-Holland. These data were used to calculate species response models with help of logistic regression, resulting in significant models for 130 out of 144 species. Significant species response models were incorporated in the computer program ITORS. With help of ITORS the effect of various management scenarios can be easily evaluated, which is demonstrated by an example. This revised version was published online in July 2006 with corrections to the Cover Date.     

濮阳市VOCs污染特征及其臭氧生成潜势分析

以京津冀及周边"2+26"城市之一濮阳为例,对环境空气VOCs的污染特征及其臭氧生成潜势进行分析。研究表明:濮阳市的臭氧生成对VOCs浓度比较敏感,VOCs各组分的平均浓度表现为含氧有机物烷烃芳香烃烯烃炔烃,乙烯和丙酮是浓度水平最高的2种物质,对VOCs浓度贡献分别为11. 3%和10. 5%; VOCs各组分的臭氧生成潜势量表现为含氧有机物芳香烃烯烃烷烃炔烃。OFP排名前三位的是乙醛、乙烯和甲苯,其对臭氧生成的贡献量超过了总量的三分之一;制定关键物质选取原则,筛选出濮阳市VOCs的关键种类; VOCs及其关键种类与气温和风向存在一定的相关关系;濮阳市VOCs关键种类的污染主要来源于化石燃料燃烧、石油化工生产和溶剂涂料挥发等工业生产和机动车尾气排放等。     

A comparison of fixed-site and non-fixed-site approaches for species protection

The efficacy of simultaneously advancing two distinct conceptual designs (referred to here as fixed-site and non-fixed-site) for species conservation and protection is addressed. In the literature, numerous models can be found that typically stem from a particular design, but rarely are comparisons made between approaches. This paper presents a more integrated optimization framework that models landowner behavior and species viabilities at a landscape scale. Regional demand for resource extraction is used as the economic driver, a variant of simulated annealing is used to solve the model under different species protection approaches, and a detailed species population simulator is utilized to measure biological responses. When directly comparing the outcomes of different species protection strategies from a case study in Oregon (USA), it was found that neither approach was universally superior in terms of financial value or degree of protection for two late seral forest dependent species.