Photochemical behavior of chlorsulfuronR in water and in adsorbed phase

The photochemistry of the herbicide chlorsulfuron^R (2-chloro-N-[[4-methoxy-6-methyl-1.3.5-triazinyl-2-amino]carbonyl]benzene sulfonamide) was investigated in methanol, distilled water, natural creek-water, on silica gel and on montmorillonit surfaces. The rate of degradation was determined in outdoor and indoor experiments simulating tropospheric conditions (λ>290 nm). Two major photoproducts were identified in all cases.     

The U.S. Environmental Protection Agency’s SITE Emerging Technology Program

Under the SITE Emerging Technology Program, the U.S. Environmental Protection Agency is seeking to foster the further development of technologies that have been successfully tested at bench-scale and are now ready for pilot-scale testing, prior to field- or full-scale demonstration. The goal is to ensure that a steady stream of permanent, cost-effective, technologies will be ready for demonstration in the field, thereby increasing the number of viable alternatives available for use in Superfund removal and remedial actions. Under this program, EPA can offer technology developers financial assistance of up to $150,000 per year, for up to two years. The program is in its second year with seven projects underway and eight more ready to start, pending completion of award actions. The Third Emerging Technology Program Solicitation is open to the receipt of new proposals from July 8,1989 through September 7,1989. The purpose of this article is to provide the reader with: (1) an introduction to the Emerging Technology Program; (2) an understanding of how the Program operates; (3) a summary of those technologies currently being tested and evaluated under the Program; and (4) information on how to apply to the Program.     

Betriebliche Umweltinformationssysteme (BUIS) Anforderungen und struktureller Aufbau

Appropriate organization structures, environmental controlling systems, and corporate environmental information systems (CEIS) are generally considered to be the essential instruments of a modern environmental management. Frequently, acceptance problems have been observed with respect to the installation of a CEIS due to the facts that there are no legal demands to implement such a system and, on the other hand, that theoretically based definitions of standards and structural principles of an CEIS are not yet available. As a consequence, different isolated solutions with rather low efficiency were hurriedly implemented by various companies. Regarding more precise request profiles for CEI systems, the present paper deals with the structural environment and the priority targets of an enterprise and with the organizational integration of environmental tasks. The operationalization into typical function fields yields tools to derive rough enterprise models, to analyze information streams and to select enviromentally relevant information as well as the routes which they tend to go. Based on these fundamental instruments, a CEIS architecture (structure and organization) can be developed whose realization is eventually supported by a ten-step plan. Existing EDP solutions are deliberately excluded in order to verify the general validity of the system architecture and to encourage creative potentials. The CEIS concept presented here, however, requires a transformation into operative practices, i.e. adjustment, completion, and combination of the elements concerning the detailed conditions of the enterprise under study.     

Systemic risks of genetically modified crops: the need for new approaches to risk assessment

Background

European chemicals legislation (registration, evaluation, authorisation and restriction of chemical substances (REACH)) requires a broad assessment of chemicals with respect to, inter alia, their health-relevant properties. Due to the extreme number of substances to be assessed and the limited current toxicological knowledge on their respective properties, REACH implicitly requires a paradigm change: away from knowledge generated mainly from costly animal experiments towards the use of mechanistic findings. Moreover, effect mechanisms at the biochemical or cellular level are essential when conclusions shall be drawn about "new" endpoints and mixtures of xenobiotics. This study (funded by the German Federal Environment Agency) describes examples of biochemical processes in the mammalian organism and how xenobiotics interfere with them. Interference with physiological processes expected to lead to adverse health effects is characterised as "toxicity pathway". The study describes toxicological endpoints not usually covered in routine animal testing and the respective toxicity pathways.

Results and conclusions

Screening for chemicals which exert effects via common toxicity pathways and subsequently conducting targeted short-term tests may generate new information about the toxicity of chemicals without performing extensive substance-by-substance animal experiments. Information on common toxicity pathways may also provide input for the assessment of mixture effects. The U.S. Environmental Protection Agency is working intensely on this concept. It involves the use of enormous amounts of data on relevant biochemical and cellular processes, which are generated by "high-throughput screening" methods, and then are combined with substance-specific kinetic data, experimental apical test outcomes and modelling. Current limitations in the regulatory use of this integrated approach on risk assessment will be outlined.     

Hydrological Variability and Uncertainty of Lower Missouri River Basin Under Changing Climate

The lower Missouri River Basin has experienced increasing streamflow and flooding events, with higher risk of extreme hydrologic impacts under changing climate. The newly available North American Regional Climate Change Assessment Program (NARCCAP) climate projections were used as atmospheric forcing for Soil and Water Assessment Tool (SWAT) model which runs with varying potential evapotranspiration (PET) methods to assess the hydrological change and uncertainty of 2040‐2069 over 1968‐1997. The NARCCAP temperature and precipitation predictions were refined using a bias correction method. The results show that, following the seasonal variability of precipitation, various water fluxes would increase in most seasons except the summer. Expected precipitation tends to increase in intensity with little change in frequency, triggering faster surface water concentration to form floods. The greatest streamflow increase would occur from November to February, increasing by around 10% on average. An increase of 3% occurs in the other months except for July and August in which river discharge decreases by around 2%. The climate predictions contribute more uncertainty annually, but PET algorithms gain more influence in winter or when other weather factors such as wind play a relatively more important role on evapotranspiration flux. This study predicts an even wetter environment compared to the historically very wet period, with the possibility of more flooding.     

Interactive effects of rabbit grazing and environmental factors on plant species-richness on dunes of Norderney

On the German island Norderney rabbit grazing effects on vegetation, soil and microclimate were investigated with exclosures in different dune vegetation. Differences in species composition between grazed and ungrazed plots increased with grazing activity. A decline in growth height resulted in higher light availability and temperature on the grazed sites. One of the most visible effects was the decline in flowering plants. Most grazing effects varied between habitat types. Grey dunes were distinctly affected by rabbit grazing. In relation to the habitat type, life forms were differently affected: in closed vegetation, rabbit activities further open patches, resulting in more therophytes. In contrast, in open vegetation rabbit activities were too strong and following sand dynamics too high for many therophytes. In general, grazing diversified habitats, slightly supported the total species-richness, and enhanced the heterogeneity of species composition. Highest species-richness in total and of herbs was reached at intermediate levels of grazing pressure. The study is in line that highest species-diversity will be found at intermediate levels of disturbance and environmental stress and that grazing effects vary with the habitat type.     

Ecotoxicological effects of Trichloroethene upon plankton

A case study in an experimental pond was performed to evaluate the ecotoxic effects of Trichloroethene (TRI) upon the population density and productivity of phyto‐ and zooplankton. TRI was continuously released into two pond enclosures over 11 weeks (mean concentrations 1.5 and 7.5 mg/l). The chronic chemical treatment showed distinctive toxic influences upon the biota. Following the high TRI concentration, the phytoplankton density slightly increased; the productivity per single cells, however, was significantly reduced compared to the controls and the low TRI concentration. Cryptophyceae were the most sensitive algae taxa. The density and reproductivity of Daphniae and Phyllopodae decreased by the high TRI concentration. Most of the Rotatoriae were not negatively influenced. With increasing TRI concentrations two different bacteria forms showed a mass development. Small amounts of Trichloroacetic acid were detected in both enclosures as a conversion product of TRI (～3 μg/l after 80 days treatment).     

?kotoxikologie soll endlich wissenschaftliches Fach werden

Ohne Zusammenfassung