Reproduction and teratogenesis: current methods and suggested improvements.

The risks to human reproduction, particularly in regard to possible induction of birth defects, from present levels of environmental chemicals are thought to be low but in need of closer scrutiny than is now the case. Methods currently used to estimate the hazards to reproduction of new chemicals and drugs are reviewed and some shortcomings and potential sources of error are noted. Specific suggestions are made for improving existing methodology. In addition to the widely used treatment span encompassing all or most of the period of organogenesis, it is proposed that some exposure periods of shorter duration be added to avert possibly adaptative changes in maternal homeostatic systems. Greater diversity of test animals, beyond the rodent-rabbit species largely used today, is urged with the objective of better matching metabolic pathways in a test animal to those of man. The demonstration of an embryotoxicity effect-level must be regarded as essential in all tests, and once found this level should be used as the basis of extrapolating downward to find an acceptable tolerance level of dosage. More attention should be focused on postnatal functional evaluation after prenatal and perinatal exposure of test animals to environmental chemicals, especially those that might interfere with the maturation of the central nervous system, endocrine glands, and immunological mechanisms. The use of nonhuman primates should be reserved for the testing of drugs essential for use during human pregnancy or early pregnancy, because of the scarcity of such animals and the high costs of doing meaningful tests with them.     

Overview and status of in vitro transformation.

The development of standardized assay procedures has permitted the exploitation of cell culture systems as bioassay tools for the detection of chemical carcinogens. These systems fall generally into 3 classes: diploid cell strains, Syrian hamster embryo cells; cell lines, mouse BALB/c-3T3 and mouse C3H-10T1/2; and cells+virus, Fischer rat cells infected with Rauscher leukemia virus and Syrian hamster embryo cells infected with adenovirus. The results accumulated to date show a good correlation between transformation response in cell culture and carcinogenicity of chemicals in whole animal studies. The major advantages of these systems are their relative brevity (10 days-6 weeks) and resultant low costs, their agreement with whole animal bioassays, and their direct biological relevance to the carcinogenic process. The present major disadvantages are the uncertain nature of the metabolic capabilities of the target cells and the lack of a metabolic activation system that is reliable and adaptable for routine bioassays. The development of epithelial cell systems such as breast, liver, lung, and skin may solve the problem of carcinogen metabolism as well as provide target cells that are representative of major organ sites for cancer in man. The rational use of cell culture bioassays for neoplastic transformation is a valuable component of the toxicological armamentarium to assess risk to humans from exposure to chemicals.     

Eine Methode zur quantitativen Bestimmung von Pentachlorphenol in Umweltproben

A method for the quantitative determination of pentachlorophenol in environmental samples An analytical method is presented for the rapid extraction, purification and quantitative detection by gaschromatography of pentachlorophenol in environmental samples (plant, animal and soil samples). The detection sensivity of this method gets up to 5 ppb or 10 pg absolute.     

Problems and prospects in the utilization of animal traction in semi-arid west Africa: evidence from Niger

The use of animal draft power for soil tillage has long been a major theme of agricultural development programmes in semi-arid West Africa. The rationale for animal traction utilization ranges from increasing agricultural productivity and income to relieving the drudgery in farm work. Yet, its adoption remains low and localized. Previous research has identified the conditions which favour the adoption of animal traction, but evidence on the potential benefits realizable from its use is mixed. The issue of how to improve the adoption and profitable utilization of animal traction in semi-arid West Africa remains an important topic given that mechanization of agriculture is inevitable. This paper uses data collected from villages in two different agroclimatic zones of Niger to demonstrate the regional variability of potential gains from animal traction. Production functions were estimated to determine the impact of animal traction use on area cultivated, labour input and aggregate yield. Multi-year partial budget streams were also estimated to evaluate the profitability of animal traction at each location. The results show that the use of animal traction did not have any significant impact on area cultivated, but increased the yields of sorghum (Sorghum bicolor (L.) Moench) and maize (Zea mays L.) by 12–15%. It increased labour input by 15 man-hha⁻¹ (man hours per hectare) in the dry agroclimatic zone, but reduced it by 50 man-h ha⁻¹ in the wet zone. Rates of return on animal traction investment ranged from −4 to 18% in the dry zone and from 14 to 58% in the wet zone. These results suggest that the impact of animal traction on agricultural production varies by region and depends on a broad set of agroecological and economic conditions. The absence of these conditions in marginal areas strictly limits potential utilization and profitability. On efficiency grounds, it is recommended that animal traction should be promoted only in areas where the climate, soil and economic conditions permit its intensive and profitable utilization.     

Analytical behavior data for chemicals determined using AOAC multiresidue methodology for pesticide residues in foods

Analytical methods capable of detecting more than one pesticide residue simultaneously (multiresidue methods) become more effective with an increase in the number of chemicals whose behavior through the various steps of the method has been documented. Since 1970, the method behavior data related to the AOAC official method for residues of 25 chlorinated and phosphated pesticides and polychlorinated biphenyls have been extended to include information on twice as many chemicals as was previously available. The value of having a large bank of method behavior data is outlined and the experimental protocol by which the data were collected is described. A complete listing is included of the available data on the analytical behavior of over 300 pesticidal and/or industrial chemicals.     

Analysis of soil fungal communities by amplicon pyrosequencing: current approaches to data analysis and the introduction of the pipeline SEED

Fungi are important in soils as both decomposers and plant symbionts, and an understanding of the composition of their complex communities is thus indispensable to answer a variety of ecological questions. 454 Pyrosequencing is currently the method of choice for the in-depth analysis of fungal communities. However, the interpretation of its results is complicated by differences in data analysis approaches that make inter-study comparisons difficult. The pyrosequencing studies published so far have also used variable molecular targets in fungal rDNA. Although the ITS region and, in particular, ITS1 appear to be the most frequent sequencing targets, the use of various primers with different coverages of fungal groups remains a serious problem. Sequence length limits also vary widely across studies, and in many studies, length differences may negatively affect sequence similarity clustering or identification. Unfortunately, many studies neglect the need to correct for method-dependent errors, such as pyrosequencing noise or chimeric sequences. Even when performed, error rates in sequences may be high, and consensus sequences created by sequence clustering therefore better represent operational taxonomic units. We recommend a data analysis workflow that includes sequence denoising, chimera removal, sequence trimming before clustering and random resampling before calculating diversity parameters. The newly developed free pipeline (SEED) introduced here can be used to perform all the required analytical steps. The improvement and unification of data analysis procedures should make future studies both more reliable and comparable and allow meta-studies to be performed to provide more general views on fungal diversity, biogeography or ecology.     

Strategies for risk assessment of existing chemicals in soil

In the risk assessment of industrial chemicals, an assessment of the risk to soil should be performed whenever relevant inputs occur via the following pathways: application of sewage sludge, wet or dry deposition, application as a pesticide constituent (e.g. solvent or metabolite), irrigation. An evaluation of the results for 34 chemicals from the first EU priority list showed that only 35% of the risk assessments for the terrestrial compartment were performed on the basis of at least 2 valid tests with soil organisms. In the vast majority of cases, the equilibrium partitioning method was used to extrapolate from aquatic to soil toxicity. However, no indications exist for a correlation between aquatic and terrestrial toxicity. Moreover, the exposure routes for soil organisms (uptake via pore water, air included in soil pores, ingestion of soil particles) are much more complex than those for aquatic organisms. As a new approach, it is therefore suggested that, in cases of relevant exposure (e.g. estimated or measured concentrations of >10 μg/kg), an assessment should generally be performed on the basis of valid terrestrial tests rather than on an extrapolation from the aquatic toxicity. It is recommended that prolonged exposure tests should be used already for an initial assessment of substances that have a strong tendency to adsorb on soil particles and thus a long residence time in soil. A decision scheme for the risk assessment of industrial chemicals in soil is presented, trigger values, testing strategies as well as assessment factors for derivation of a Predicted No Effect Concentration (PNEC_soil) are discussed. An example of a terrestrial risk assessment for substances from the first EU priority list is given in order to illustrate current practice.     

The use of Si MAS-NMR and Monte Carlo methods in the study of Al/Si ordering in silicates

The use of ²⁹Si Magic Angle Spinning NMR to provide information about the local structure and order about the SiO₄ tetrahedra in framework silicates is reviewed. A number of problems, including difficulties of peak assignment and the necessity to measure accurate intensities of the weakest peaks in the NMR spectra, are discussed. 29 Si MAS-NMR can be used to determine the number of Al---O---Al linkages in the structure, but the sensitivity of the final answer to experimental errors can lead to absurd results. A new method, involving an inverse Monte Carlo algorithm, to analyse ²⁹Si MAS-NMR data for silicates with long-range Al/Si disorder is described, and illustrated with examples of Cs-leucite, analcime, and annealing measurements for cordierite.     

基于GIS的空间统计分析在奶牛地氟病监测中的应用

目前在动物流行病监测中监测点数量较少,监测数据有限。而利用有限的动物疾病监测数据,分析动物疾病的整体空间分布情况,则需要建立符合动物疾病发展规律的监测预测方法。该文运用空间分析软件ArcGIS9和GEODA软件对A区奶牛地氟病空间分布特征进行了分析,然后建立A区地氟病分布预测图,再与实际分布图进行了叠加分析比较,发现其预测效果较好。这种利用空间统计学研究方法建立的GIS预测模型,可为监测和预测其它与空间相关的疾病提供借鉴。     

Tolerance setting process in the U.S. Environmental Protection Agency

The U.S. Environmental Protection Agency (EPA) is responsible for setting tolerances for pesticide residues in food, under the authority of the Federal Food, Drug, and Cosmetic Act. The residue chemistry data required to set tolerances include metabolism in plants and animals, analytical methods, magnitude of the residue, and concentration in processed foods. A key aspect of tolerance-setting procedures is the identity of the residue in the matrix of concern; without knowledge of the chemical moieties that occur as residues, it is impossible to develop suitable methods or generate meaningful residue data. For new chemicals, EPA carries out a single-laboratory validation of the analytical method needed to generate residue data and to enforce tolerances. Tolerance enforcement methods need to be rapid and inexpensive and to use commercially available equipment and reagents. Methods are more complex for many newer pesticides, which are polar compounds that leave low levels of residue. EPA now requires that the registrants of older pesticides, for which methods are not acceptable by today's standards, must develop better methods.     

Imputation Approaches for Animal Movement Modeling

The analysis of telemetry data is common in animal ecological studies. While the collection of telemetry data for individual animals has improved dramatically, the methods to properly account for inherent uncertainties (e.g., measurement error, dependence, barriers to movement) have lagged behind. Still, many new statistical approaches have been developed to infer unknown quantities affecting animal movement or predict movement based on telemetry data. Hierarchical statistical models are useful to account for some of the aforementioned uncertainties, as well as provide population-level inference, but they often come with an increased computational burden. For certain types of statistical models, it is straightforward to provide inference if the latent true animal trajectory is known, but challenging otherwise. In these cases, approaches related to multiple imputation have been employed to account for the uncertainty associated with our knowledge of the latent trajectory. Despite the increasing use of imputation approaches for modeling animal movement, the general sensitivity and accuracy of these methods have not been explored in detail. We provide an introduction to animal movement modeling and describe how imputation approaches may be helpful for certain types of models. We also assess the performance of imputation approaches in two simulation studies. Our simulation studies suggests that inference for model parameters directly related to the location of an individual may be more accurate than inference for parameters associated with higher-order processes such as velocity or acceleration. Finally, we apply these methods to analyze a telemetry data set involving northern fur seals (Callorhinus ursinus) in the Bering Sea. Supplementary materials accompanying this paper appear online.     

Safety evaluation concepts.

The approach to safety evaluation is strongly influenced by the standard of safety to which one aspires. Practical considerations demand that realistic limits be set to the attainable assurances of freedom from anticipated hazard under actual conditions of use of a product. The fact is that, in the interests of consumer health, more can be expected from a flexible, intelligent, and experienced approach to safety evaluation than from efforts at conformity with a set of rigidly standardized requirements that are theoretically all-encompassing. Establishment of safety demands a wide background of information about the properties and likely uses of the product; above all, knowledge of the chemical composition of the product and its impurities, degradation products, and metabolites is essential. Lack of such information is a frequent source of errors in safety evaluation. Based on a secure foundation of this sort, a program of investigations may be designed, aimed at establishing the basic biological properties of the material. Determination of the metabolic dynamics of the principal chemical agent or agents makes possible the emergence of a clear picture of the behavior of the compound(s) in the body and paves the way for more specialized studies of long term toxicity, carcinogenicity, effects on reproduction and teratogenesis, and investigations of multitest mutagenic potential. Emphasis is laid on the problems of interpretation of results in terms of hazard to man and on the crucial contribution that experience of human exposure can make toward assuring safety-in-use. Decisions on acceptable risk are the joint responsibility of many individuals but an essential element in reaching such decisions is contributed by the depth of understanding and broad experiences of the toxicologist.     

基于数据仓库和数据挖掘技术的温室决策支持系统(简报)

农业领域的专家知识多是描述性和经验性的知识,难以进行精确的数学描述,这给农业决策支持系统的构建带来了一定的困难。为解决这种传统的决策支持系统的不足,介绍了基于数据仓库技术和数据挖掘技术构建的温室决策支持系统。该系统通过建立数据仓库来存储各种来自异质的信息源的数据,利用联机分析处理实现多维数据分析,然后通过数据挖掘技术从数据仓库中获得新的农业知识,以丰富决策支持系统的知识库。在系统的实现过程中,采用了SQL Server分析服务,实现数据挖掘与数据仓库以及应用程序的紧密耦合,从而大大提高了数据挖掘效率。将数据仓库、联机分析处理、数据挖掘三者结合起来形成了一种新的温室决策支持系统。     

Man's exploitation of the gorilla

For hundreds of years the gorilla has been exploited and utilised by man in one form or another, its uses as a natural commodity ranging from raw protein to circus performer. Indigenous man in Africa has long hunted this near-relative, sometimes in reprisal for the destruction of his crops but more often simply for food, while so-called civilised man has hunted and slaughtered it in the name of sport and science. More recently, animal dealers have made fortunes by supplying living infant gorillas to zoos, laboratories and wealthy private owners, but the final trauma may well be one that the gorilla will not survive—the total destruction of its natural habitat in the never-ending quest for raw materials to supply the insatiable industrial nations—and only international intervention will save it.     

Fluorescence spectroscopy: a rapid tool for analyzing dairy products

This paper gives a critical evaluation of the use of fluorescence spectroscopy for measuring chemical and physical changes in dairy products caused by processing and storage. Fluorescence spectroscopy is able to determine various properties of foods without use of chemicals and time-consuming sample preparation. This is shown by examples where the measurement of a given chemical parameter has been appropriately described and validated, as well as situations showing potential applications, but where further research and validation is required. The interpretation of fluorescence spectroscopic data is complex due to absorbance by other molecular groups, changes caused by variation in the sample matrix, etc. It is illustrated how advanced data analytical techniques are required to obtain optimal interpretation of the data. Even though the review focuses on examples from the dairy industry, the principles are broader and can be applied to other fields of food and agricultural research.     

Potential of gas chromatography-orthogonal acceleration time-of-flight mass spectrometry (GC-oaTOFMS) in flavor research

Gas chromatography-orthogonal acceleration time-of-flight mass spectrometry (GC-oaTOFMS) is an emerging technique offering a straightforward access to a resolving power up to 7000. This paper deals with the use of GC-oaTOFMS to identify the flavor components of a complex seafood flavor extract and to quantify furanones formed in model Maillard reactions. A seafood extract was selected as a representative example for complex food flavors and was previously analyzed using GC-quadrupole MS, leaving several molecules unidentified. GC-oaTOFMS analysis was focused on these unknowns to evaluate its potential in flavor research, particularly for determining exact masses. N-Methyldithiodimethylamine, 6-methyl-5-hepten-2-one, and tetrahydro-2,4-dimethyl-4H-pyrrolo[2,1-d]-1,3,5-dithiazine were successfully identified on the basis of the precise mass determination of their molecular ions and their major fragments. A second set of experiments was performed to test the capabilities of the GC-oaTOFMS for quantification. Calibration curves were found to be linear over a dynamic range of 10(3) for the quantification of furanones. The quantitative data obtained using GC-oaTOFMS confirmed earlier results that the formation of 4-hydroxy-2,5-dimethyl-3(2H)-furanone was favored in the xylose/glycine model reaction and 2(or 5)-ethyl-4-hydroxy-5(or 2)-methyl-3(2H)-furanone in the xylose/alanine model reaction. It was concluded that GC-oaTOFMS may become a powerful analytical tool for the flavor chemist for both identification and quantification purposes, the latter in particular when combined with stable isotope dilution assay.     

Phosphorus loss from agricultural catchments: pathways and implications for management

Abstract. The contribution non-point P sources make to the total P loading on water bodies in agricultural catchments has not been fully appreciated. Using data derived from plot scale experimental studies, and modelling approaches developed to simulate system behaviour under differing management scenarios, a fuller understanding of the processes controlling P export and transformations along non-point transport pathways can be achieved. One modelling approach which has been successfully applied to large UK catchments (50-350km² in area) is applied here to a small, 1.5 km² experimental catchment. The importance of scaling is discussed in the context of how such approaches can extrapolate the results from plot-scale experimental studies to full catchment scale. However, the scope of such models is limited, since they do not at present directly simulate the processes controlling P transport and transformation dynamics. As such, they can only simulate total P export on an annual basis, and are not capable of prediction over shorter time scales. The need for development of process-based models to help answer these questions, and for more comprehensive UK experimental studies is highlighted as a pre-requisite for the development of suitable and sustainable management strategies to reduce non-point P loading on water bodies in agricultural catchments.     

Terrestrial Ecotoxicity of Eight Chemicals in a Systematic Approach (7 pp)

Background and Objective   Terrestrial ecotoxicity data are required for many research purposes. The data are derived either from the literature or elaborated by own investigations. As the terrestrial toxicity tests are usually time-consuming and labour intensive, the experiments are performed with a limited number of test organisms and soils. In the context of a project sponsored by CEFIC-LRI (European Chemical Industry Council – Long-Range Research Initiative), EC50-values were systematically elaborated for eight chemicals with a wide range of logKow-values (CdCl2, Trinitrotoluene, 3,4-dichloroaniline, 2,4-dichlorophenol, Tributyltinchloride, Pentachlorophenol, Benzo(a)pyrene, p,p-dichloro-2,2-diphenyl-1,1,1-trichloroethane). The substances were selected covering a broad range of physico-chemical and ecotoxicological properties. As toxicity endpoints, microbial activities, plant germination and growth as well as reproduction of earthworms and collembola were determined. As such systematic investigations are rarely performed and for some substances no data existed, the data pool is made available to the scientific community.Methods   All toxicity tests were conducted on three different soil types (sandy soil, silty soil, loamy soil), according to ISO and OECD guidelines Results, Discussion, Conclusion and Outlook   The different toxicities of the chemicals, the influence of soil properties on bioavailability as well as different sensitivities of test organisms and test parameters are reflected by the EC50-values. The results showed that the EC50-values calculated on the basis of nominal concentrations can significantly vary from EC50-values derived from analytical concentrations for some substances. To avoid false conclusions, this has to be considered especially when concentrations determined in the field are compared with toxicity data obtained from the literature or calculated on the basis of nominal concentrations. Moreover, the results indicate that terrestrial ecotoxicological tests should be accompanied by chemical analyses, to be sure to derive sound EC50-values. As the tests were performed according to international guidelines, the comprehensive data pool relevant for the terrestrial ecotoxicity of eight chemicals is considered to be of great value for further research and discussions dealing with the habitat function of soils.     

The science and application of ecological monitoring

We provide a broad overview of the underlying philosophy of ecological monitoring. We argue that the major characteristics of effective monitoring programs typically include: (1) Good questions. (2) A conceptual model of an ecosystem or population. (3) Strong partnerships between scientists, policy-makers and managers. (4) Frequent use of data collected.We classify monitoring programs into three categories - (1) Passive monitoring, which is devoid of specified questions or underlying study design and has limited rationale other than curiosity. (2) Mandated monitoring where environmental data are gathered as a stipulated requirement of government legislation or a political directive. The focus is usually to identify trends. (3) Question-driven monitoring, which is guided by a conceptual model and by a rigorous design that will typically result in a priori predictions that can be tested.There are advantages and disadvantages of mandated monitoring programs, which are typically large-scaled, and generally smaller-scaled, question-driven monitoring programs. For example, while question-driven monitoring programs can provide insights into the ecological processes giving rise to emergent environmental patterns, spatial generalization from them is difficult because results may not extrapolate well to other regions, states or to a national level. Conversely, while mandated monitoring can be useful for producing coarse level summaries of temporal changes in a target population or resource condition they may not identify the mechanism influencing a change in an ecosystem or an entity. A key remaining challenge is to develop much improved mandated monitoring programs through more widespread adoption of the features of successful question-driven monitoring programs in efforts to enhance biodiversity conservation and environmental management.