Population-level variation in plant secondary chemistry,and the population biology of herbivores

Summary Modern population ecology is becoming increasingly spatially-explicit. For insect hervibores, spatial variation in plant quality is a critical component of distribution and abundance. We argue that populationlevel measurements of phytochemical variation among individual plants has not kept pace with recent developments in population ecology. With examples from our own work, we demonstrate the importance of spatial variation in plant chemistry for insect herbivores, and suggest that phytochemistry should play a central role in the development of any spatially-based ecological theory.     

ⅠA族和ⅡA族金属的消烟助燃效应及其理论

ⅠＡ三金属和ⅡＡ碱土金属元素是有灰型消烟助燃剂的功能元素，就各族内而言，这些ｓ区金属元素的消烟助燃效应与它们的热电离电离热成反比，此特征与烃火焰条件下碳烟生成的正离子机制有关，就两族间而言，ⅡＡ族金属的消烟助燃效应通常大于ⅠＡ族金属，该特征与ｓ区金属元素的火焰电离特性有关，在实质上，ｓ区金属元素的消烟助燃效应与它们在火焰条件下发生电离的活化能有关，基于碳烟生成的双途径模型，含ⅠＡ，ⅡＡ族金属消烟助     

环境样品前处理技术及其进展（一）

本文讨论了环境分析化学中样品制备及前处理技术的现状及其进展。有关环境样品的特点、前处理的目的及其作用、选择前处理技术的依据等也做了阐述。重点评述了近年来在环境分析化学领域中发展最快、用得比较普遍的几种新方法，即超临界流体萃取、固定萃取、微波溶出和液膜萃取等。（一）介绍样品前处理的原则和有关的基础，以及超临界流体萃取法；（二）其它方法及今后的发展动向（将刊登在《环境化学》１９９４年第二期）。     

我国环境化学研究的进展

本文综合介绍了二十年来我国环境化学研究的发展概况。在环境分析化学方面包括了环境分析监测方法、标准参考物质、环境分析方法、形态分析、采样技术与分析测试仪器化等方面。环境污染化学包括了有关大气、水体和土壤环境中化学问题的研究，着重对大气污染物表征、迁移和转化、化学模式和重金属、有机物的水环境化学、水环境中金属烷基化以及土壤中农药等环境化学研究。有关污染生态效应中的化学集中介绍了硒与地方病环境因素关系有     

Evaluation of water quality of the Qaraaoun Reservoir,Lebanon: suitability for multipurpose usage

The increased demand on water resources in Lebanon as a resultof: progressive urbanization, socio-economic growth, agriculturalactivities and development of industries is, according to the national authorities, a major critical factor by the year 2010.Political difficulties in earlier years imply a dearth of pertinent data. The objective of this study was to evaluate water quality of the Qaraaoun Reservoir of the Litani River andassess its feasibility for multi-purpose usage as one of the solutions to the aggravated water problems in Lebanon. Sampleswere collected from 18 sampling sites at several dates duringthe dry season. Parameters analysed were, pH, electrical conductivity, TDS, turbidity, alkalinity, Ca, Mg, TH, Cl^-, SO₄ ^2-, NH₃, NO₃ ^-,PO₄ ^3-, Fe, Al, Na, Zn, Cr, Cu and As. The reported data were in compliancewith WHO guidelines, USEPA regulation and EEC directives. Statistical analysis of the data defined three distinct environmental zones and water quality in the central, main zone satisfied most criteria. It is concluded that the reservoir water is fit for multipurpose uses, namely, drinking, domestic,recreational activities, irrigation, fisheries, livestock and industrial, and should be properly managed accordingly.     

Making performance-based chemistry work: how we created comparable data among laboratories as part of a Southern California marine regional assessment

Quality assurance procedures to ensure consistency among chemistry laboratories typically involves the use of standard methods and state certification programs that require laboratories to demonstrate their ability to attain generic performance criteria. To assess whether these procedures are effective for ensuring comparability when processing local samples with potentially complex matrices, seven experienced, state-certified laboratories participated in an intercalibration exercise. Each laboratory was permitted to use their typical methodology for quantifying PAH, PCB and DDT on shared samples collected from Santa Monica Bay and the Palos Verdes Shelf, two sites with a complex mix of constituents. In the initial intercalibration exercise, results from these laboratories differed by as much as an order of magnitude for all three chemical groups. Much, but not all, of the difference was attributable to differences in detection capability. A series of studies was conducted to identify the reasons for the observed differences, which varied among laboratories and included methodological differences, instrument sensitivity differences, and differing interpretations of chromatograms. Following these investigations and resulting modifications to laboratory procedures, the exercise was repeated. The average coefficient of variation among laboratories across all chemical parameters was reduced to less than 30%. Our results suggest that performance-based chemistry can produce comparable results, but the certification processes presently in place that focus on general laboratory procedures and simple matrices are insufficient to achieve comparability.     

Inter- and Intra-Annual Chemical Variability During the ice-Free Season in Lakes with Different Flushing Rates and Acid Deposition Histories

Quantifying chemical variability in different lake types is important for the assessment of both chemical and biological responses to environmental change. For monitoring programs that emphasize a large number of lakes at the expense of frequent samples, high variability may influence how representative single samples are of the average conditions of individual lakes. Intensive temporal data from long-term research sites provide a unique opportunity to assess chemical variability in lakes with different characteristics. We compared the intra- and inter-annual variability of four acidification related variables (Gran alkalinity, pH, sulphate concentration, and total base cation concentration) in four lakes with different flushing rates and acid deposition histories. Variability was highest in lakes with high flushing rates and was not influenced by historic acid deposition in our study lakes. This has implications for the amount of effort required in monitoring programs. Lakes with high flushing rates will require more frequent sampling intervals than lakes with low flushing rates. Consideration of specific lake types should be included in the design of monitoring programs.     

我国大气污染化学研究进展

本文综述了我国大气污染化学研究的概况。阐明了大气颗粒物（气溶胶）的表征研究，包括颗粒物的物理化学特性和环境化学行为；大气污染物的迁移、转化和归宿的规律，包括化学过程和大气化学模式的研究等。介绍了某些大气污染物的特殊分析测试方法和采样技术，对今后发展大气化学的展望和战略作了讨论。     

废物利用发展油田助剂

油田开发需要大量的化学助剂,由于昂贵的价格影响了成本。为减少耗资,吉林油田利用化工产品的下脚料和煤矸石等研制并合成了油田的化学助剂,例如增产剂、ＣＥＡ解堵剂、吗啉驱油剂、ＰＳ增油剂,以及堵水剂ＨＰＡＮ等。将其应用于生产,保护了生态环境,减少了环境污染,节省了大量资金。为油田废物再利用打开了极其广阔的应用市场。     

Blood chemistry of human fetuses in the second and third trimesters

Six biochemical parameters and four enzyme activities were determined from the serum of 76 healthy and 56 pathological human fetuses between the 20th and 38th week of pregnancy. In the normal fetuses studied within that period, creatinine, immunoglobulin M, lactate dehydrogenase, and gamma-glutamyltransferase increased; haemoglobin F and glucose progressively decreased; and alkaline phosphatase was at a peak around the 26th week; cholesterol and triglycerides were always low. The same parameters were also measured in some of the pathological fetuses and compared with their normal counterparts.