用改进的凯氏法测定生物样品和水样中总氮方法的探讨

对凯氏法测定生物环境样品中总氮的测定方法进行了研究和改进，以简易装置代替凯氏消解装置，省略了蒸馏步骤。避免了称量时易造成的样品损失及蒸馏过程的氨氮损失。经过实际样品的测定，并与原测定方法进行了对比实验，证明改进后的测定方法具有准确度高，精密度好，实验装置及步骤简便易行的特点。缩短了实验周期，提高了氮的回收率。同时，用改进后的方法对水样进行了测定，也取得了良好效果。     

微波消解法在生物样品分析中的应用

本文利用国产的ＷＭＸ－１型微波炉对牡蛎、牛肝、大米粉和西红柿叶等生物标准样品的微波消解条件进行了研究，并用火焰原子吸收光度法对其中的Ｃｕ、Ｚｎ、Ｆｅ、Ｍｎ等元素进行了分析。     

微波消解法测定有机磷农药废水中的总磷

应用微波消解技术进行了农药废水测定总磷的研究，考察微波消解方法的消解时间、功率对消解的影响，并将该方法与GB11893—1989《钼酸铵分光光度法》中规定的消解方法进行比较．实验证明，微波消解法操作简便，测定结果准确可靠．     

应用微波消解快速测定水样中总磷

应用微波密封消解系统对水样中的总磷进行消解，探讨了消解功率、消解时间等不同实验条件对样品微波消解的影响，与传统的总磷测定的常规消解方法相比较，本方法具有简便、快速、准确、可靠等特点，实验取得令人满意的结果。     

微波消解-原子吸收光度法测定土壤中铜锌铅镉镍铬

用微波消解－原子吸收光度法测定土壤中铜，锌，铅，镉，镍和铬。通过硝酸－氢氟酸－过氧化氢体系消解液对土壤样品消解，选择出微波最佳消解条件。对硝酸－盐酸－过氧化氢体系消解液和硝酸－氢氟酸－过氧化氢体系消解液进行消解对比试验，发现前者不能将土壤样品完全消解，后者能将样品消解完全，但需将消解液中剩余的酸赶尽，否则测定结果将明显偏低。微波消解土壤与传统电热消解相比，操作简便快速，可提高工作效率。     

微波消解技术在沉积物样品重金属元素分析中的应用

通过利用微波消解—原子吸收法测定标准河流沉积物样品中重金属元素Cu、Ni、Zn、Mn的含量，优化了微波消解的工作条件，并与电热板消解法进行了比对试验。结果表明，微波消解法与传统方法相比无显著性差异，且高效快速、试剂消耗量少、节约能源。     

石墨炉原子吸收光谱法测定农产品中痕量铍

采用石墨炉原子吸收光谱法测定农产品中痕量铍，比较了微波消解和电热板消解两种前处理方法，选择了基体改良剂。方法在0μg／L—4.00μg／L范围内线性良好，微波消解法和电热板消解法的检出限分别为0.002mg／kg和0.0002mg／kg，标样平行测定的RSD为2.4％—4.1％，农产品加标回收率为80.0％—95.0％。     

微波消解预处理测定水和废水中总磷

提出一种用微波消解技术作为测定水和废水中总磷的预处理方法，这种消解方法只需10min即可，比用常规的高温高压消解法节省三分之一时间。用这身份种消解法对标样、地表水、海水、生活污水和工业废水样品进行了对比测定，所得结果经统计检验，两方法之间无显著性差异。对微波消解法的精密度和准确度进行了验证。     

不同消解方法对黄河水样总磷测定的影响

用三种不同的消解方法，消解黄河水样后，用氯化亚锡还原光度法测定总磷，结果发现三种消解方法的精密度较好。但三种消解方法测定值的平均值存在着明显差异。差异是由方法本身的误差造成的。     

在同一消解液中同时测定总磷和总氮

探讨了在同一消解液中同时测定总磷、总氮的分析方法。实验结果表明，选用合适的氢氧化钠和过硫酸钾的加入量，可在同一消解液中同时测定总磷和总氮，并能克服消解液保存时间短的缺点。应用本文所拟最佳条件对标样和水样进行分析，结果准确，方法实用。     

Using dual classifications in the development of avian wetland indices of biological integrity for wetlands in West Virginia, USA

Considerable resources are being used to develop and implement bioassessment methods for wetlands to ensure that “biological integrity” is maintained under the United States Clean Water Act. Previous research has demonstrated that avian composition is susceptible to human impairments at multiple spatial scales. Using a site-specific disturbance gradient, we built avian wetland indices of biological integrity (AW-IBI) specific to two wetland classification schemes, one based on vegetative structure and the other based on the wetland’s position in the landscape and sources of water. The resulting class-specific AW-IBI was comprised of one to four metrics that varied in their sensitivity to the disturbance gradient. Some of these metrics were specific to only one of the classification schemes, whereas others could discriminate varying levels of disturbance regardless of classification scheme. Overall, all of the derived biological indices specific to the vegetative structure-based classes of wetlands had a significant relation with the disturbance gradient; however, the biological index derived for floodplain wetlands exhibited a more consistent response to a local disturbance gradient. We suspect that the consistency of this response is due to the inherent nature of the connectivity of available habitat in floodplain wetlands.     

Using two classification schemes to develop vegetation indices of biological integrity for wetlands in West Virginia, USA

Bioassessment methods for wetlands, and other bodies of water, have been developed worldwide to measure and quantify changes in “biological integrity.” These assessments are based on a classification system, meant to ensure appropriate comparisons between wetland types. Using a local site-specific disturbance gradient, we built vegetation indices of biological integrity (Veg-IBIs) based on two commonly used wetland classification systems in the USA: One based on vegetative structure and the other based on a wetland’s position in a landscape and sources of water. The resulting class-specific Veg-IBIs were comprised of 1–5 metrics that varied in their sensitivity to the disturbance gradient (R ²?=?0.14???0.65). Moreover, the sensitivity to the disturbance gradient increased as metrics from each of the two classification schemes were combined (added). Using this information to monitor natural and created wetlands will help natural resource managers track changes in biological integrity of wetlands in response to anthropogenic disturbance and allows the use of vegetative communities to set ecological performance standards for mitigation banks.     

底质样品微波消解总磷测定研究

使用硫酸_高氯酸在微波消解系统消解 ,以钼锑抗比色法测定底质中的总磷 ,通过实验确定最佳消解及分析条件。结果表明 ,该方法快速简便并有较高准确度、精密度和较低的检测限 ,值得推广和应用。     

地表水总氮总磷联合消解测定方法的研究

针对目前我国文献中总氮(TN)和总磷(TP)联合消解测定的试验条件差异较大的问题,通过与标准方法对比。建立了一种地表水总氮和总磷联合消解测定的方法。当水样量为25ml时,过硫酸钾和氢氧化钠的加入质量分别为0.5g和0．12g,可同时满足2个项目的消解要求。该方法操作简单快速,可应用于地表水的检测。     

Correspondence of biological condition models of California streams at statewide and regional scales

We used boosted regression trees (BRT) to model stream biological condition as measured by benthic macroinvertebrate taxonomic completeness, the ratio of observed to expected (O/E) taxa. Models were developed with and without exclusion of rare taxa at a site. BRT models are robust, requiring few assumptions compared with traditional modeling techniques such as multiple linear regression. The BRT models were constructed to provide baseline support to stressor delineation by identifying natural physiographic and human land use gradients affecting stream biological condition statewide and for eight ecological regions within the state, as part of the development of numerical biological objectives for California’s wadeable streams. Regions were defined on the basis of ecological, hydrologic, and jurisdictional factors and roughly corresponded with ecoregions. Physiographic and land use variables were derived from geographic information system coverages. The model for the entire state (n?=?1,386) identified a composite measure of anthropogenic disturbance (the sum of urban, agricultural, and unmanaged roadside vegetation land cover) within the local watershed as the most important variable, explaining 56 % of the variance in O/E values. Models for individual regions explained between 51 and 84 % of the variance in O/E values. Measures of human disturbance were important in the three coastal regions. In the South Coast and Coastal Chaparral, local watershed measures of urbanization were the most important variables related to biological condition, while in the North Coast the composite measure of human disturbance at the watershed scale was most important. In the two mountain regions, natural gradients were most important, including slope, precipitation, and temperature. The remaining three regions had relatively small sample sizes (n?≤?75 sites) and had models that gave mixed results. Understanding the spatial scale at which land use and land cover affect taxonomic completeness is imperative for sound management. Our results suggest that invertebrate taxonomic completeness is affected by human disturbance at the statewide and regional levels, with some differences among regions in the importance of natural gradients and types of human disturbance. The construction and application of models similar to the ones presented here could be useful in the planning and prioritization of actions for protection and conservation of biodiversity in California streams.     

Determination of cadmium and lead in human biological samples by spectrometric techniques: a review

The analysis of human biological samples, such as blood, urine, nails, and hair, is generally used for the verification of human exposure to toxic metals. In this review, various spectrometric methods for the determination of cadmium and lead in biological samples are discussed and compared. Several spectrometric techniques are presented and discussed with respect to various characteristics such as sensitivity, selectivity, and cost. Special attention is drawn to the procedures for digestion prior to the determination of cadmium and lead in hair, nails, blood, and urine.     

测定废水重金属样品的高压蒸汽消解方法

本文采用正交实验方法，用自己研制的“自控式高压蒸汽消解器”，详细研究了测定废水重金属，样品的最佳消解条件，并用于实际废水样的消解和重金属的测定，准确度和精密度均优于传统的敞口消解法，并具有试剂用量少、时间短、不受污染、操作简单，批处理样品量大等优点，可作为测定废水中重金属，样品的常规消解方法。     

Assessing the soil quality of alpine grasslands in the Qinghai-Tibetan Plateau using a modified soil quality index

Soil degradation has caused various problems on the planet. Human disturbance and land use changes always negatively affect soil quality. In this study, we used a modified soil quality index (SQI) to assess soil quality under differing degrees of human disturbance and land use. The alpine grasslands were studied at different levels of degradation [i.e., severely degraded grassland, heavily degraded grassland, moderately degraded grassland, and non-degraded grassland (NDG)] in a case study conducted in Qinghai-Tibetan Plateau (QTP) to test the feasibility of using the SQI. Fifteen chemical, physical, and biological soil parameters were measured in each type of grassland. Significant variations in SQI were found across the different types of grasslands according to severity of human disturbance and changes in land use. Urease, the ratio of microbial biomass nitrogen to total nitrogen, proteinase, and soil organic carbon were found to be the most important indicators for assessing soil quality. NDG had a higher SQI than the other three types of grasslands. It was concluded that SQI is effective for assessing the soil quality of alpine grasslands in the QTP. The intensity of human disturbance had a negative effect on soil quality in the QTP.