Mineralization and Transfer Processes of <Superscript>14</Superscript>C-labeled Pesticides in Outdoor Lysimeters

A recently designed two-chamber-lysimeter-test-system allows the detailed investigation of degradation, transport and transfer processes of ¹⁴C-labeled substances in soil–plant–atmosphere-systems under outdoor conditions. With this test system it is feasible to distinguish between ¹⁴C-emissions from soil surfaces and ¹⁴C-emissions from plant surfaces in soil monoliths under real environmental conditions. Special soil humidity sensors allow the measurement of soil water content near to the soil surface, in 1 and 5 cm depth. The behavior of organic chemicals can be followed for a whole vegetation period and a mass balance for the applied chemical can be established. Some selected results of the herbicides isoproturon and glyphosate – using the two-chamber-lysimeter-test-system – are presented to demonstrate its applicability for the identification and quantification of the processes that govern pesticide behavior in soil–plant-systems. Mineralization of ¹⁴C-isoproturon was very different in four different soils; the mineralization capacity of the soils ranged from 2 to 60%. Leaching of isoproturon in general was very low, but depending on the soil type and environmental conditions isoproturon and its metabolites could be leached via preferential flow, especially shortly after application. For the herbicide ¹⁴C-glyphosate no accumulation of residues in the soil and no leaching of the residues to deeper soil layers could be observed after three applications. Glyphosate was rapidly degraded to AMPA in the soil. Glyphosate and AMPA were accumulated in soy bean nodules.     

Mercury and other element exposure to tree swallows (Tachycineta bicolor) nesting on Lostwood National Wildlife Refuge, North Dakota

Elevated mercury concentrations in water were reported in the prairie wetlands at Lostwood National Wildlife Refuge, ND. In order to determine whether wildlife associated with these wetlands was exposed to and then accumulated higher mercury concentrations than wildlife living near more permanent wetlands (e.g. lakes), tree swallow (Tachycineta bicolor) eggs and nestlings were collected from nests near seasonal wetlands, semi-permanent wetlands, and lakes. Mercury concentrations in eggs collected near seasonal wetlands were higher than those collected near semi-permanent wetlands or lakes. In contrast, mercury concentrations in nestling livers did not differ among wetland types. Mercury and other element concentrations in tree swallow eggs and nestlings collected from all wetlands were low. As suspected from these low concentrations, mercury concentrations in sample eggs were not a significant factor explaining the hatching success of the remaining eggs in each clutch.     

Prüfanforderungen des Umweltbundesamtes zur Bewertung der Auswirkungen von Pflanzenschutzmitteln auf terrestrische Pflanzen

The fundamental data requirements for the authorization of plant protection products and the inclusion of active ingredients in Annex I of Council Directive 91/414/EEC are described in the Annexes II and III of this Directive. Definite instructions with regard to preconditions and for implementation and methodology (guidelines) concerning investigations with terrestrial plants are deficient. In the following, the scientific data requirements are explained for assessing the effects of plant protection products on terrestrial plants.     

Eintragspfade von PCDD/PCDF-Belastungen über landwirtschaftliche Rohstoffe und Futtermittel in die menschliche Nahrungskette

Ohne Zusammenfassung     

Source-term development for a contaminant plume for use by multimedia risk assessment models

Multimedia modelers from the US Environmental Protection Agency (EPA) and US Department of Energy (DOE) are collaborating to conduct a comprehensive and quantitative benchmarking analysis of four intermedia models: MEPAS, MMSOILS, PRESTO, and RESRAD. These models represent typical analytically based tools that are used in human-risk and endangerment assessments at installations containing radioactive and hazardous contaminants. The objective is to demonstrate an approach for developing an adequate source term by simplifying an existing, real-world, ⁹⁰Sr plume at DOE's Hanford installation in Richland, WA, for use in a multimedia benchmarking exercise between MEPAS, MMSOILS, PRESTO, and RESRAD. Source characteristics and a release mechanism are developed and described; also described is a typical process and procedure that an analyst would follow in developing a source term for using this class of analytical tool in a preliminary assessment.     

Methyl tert-butyl ether (MTBE) in urban and rural precipitation in Germany

The use of the oxygenate methyl tert-butyl ether (MTBE) in gasoline has led to detectable concentrations in urban and rural air up to 160 ppbV. Results from MTBE measurement in precipitation have not been reported so far. In the present study, 120 samples of precipitation collected at 17 sampling locations all over Germany have been analyzed for their MTBE content. Analysis is performed by a combination of headspace-solid-phase microextraction (HS-SPME) and gas chromatography/mass spectrometry (GC-MS). A 75 μm poly(dimethylsiloxane)/Carboxene fiber and a cryostat is used for SPME. The detection limit is 10 ng/l. In precipitation samples, MTBE was detected in wintertimes only with a maximum concentration of 85 ng/l. Measurement at Frankfurt/M City from 6 September 2000 to 12 March 2001 provided for 49% of the data concentrations in the range of 30–85 ng/l (n=17). Sampling in winter 2000/2001 at several German cities and rural locations showed that MTBE is more often detectable in urban (86%, n=78) than in rural (18%, n=42) precipitation. By comparing the results with corresponding temperatures and amounts of precipitation it can be concluded that the detection of MTBE in urban precipitation is observed at ambient temperatures lower than about 10–15°C. Moreover, the first precipitation after a dry period accumulates more MTBE than precipitation during or at the end of a wet period (wash-out effect). Highest concentrations occurred in snow samples. Corresponding mean air equilibrium concentrations of 0.04 ppbV (urban samples) and 0.01 ppbV (rural samples) are calculated. This is about one magnitude lower than year round and summertime measurements in the US and in Switzerland. Urban runoff (n=12) and corresponding precipitation sampling indicate that urban runoff might be composed of about 20% MTBE that is already transported by air and precipitation, whereas about 80% may be attributed to direct uptake of vehicle emissions and leakage near the road during precipitation.     

Public understanding and its effect on recycling performance in Hampshire and Milton Keynes

Improving the recycling rate might be the primary aim of ‘recycling targets’, but good diversion from disposal can be achieved in different ways. Public participation is obviously critical to success; however it is not just how many people participate, but how well they do so, that is important. Analysis of public attitude research gave insight into how effectively recyclers were participating, and examined levels of public understanding. These were correlated with design parameters and publicity and education strategies to try to identify aspects of successful schemes that led to high quality of participation.     

QUANTIFICATION OF ACTINIDE MIGRATION PATHWAYS AT ROCKY FLATS,COLORADO1

ABSTRACT: Migration of plutonium, americium, and uranium (actinides) in the environment at the Rocky Flats Environmental Technology Site (RFETS) is the subject of ongoing studies to develop effective strategies for cleanup and regulatory closure of the Department of Energy facility. The Actinide Migration Evaluation pathway analysis quantified actinide transport processes to validate a qualitative conceptual model of environmental actinide transport. Major actinide transport mechanisms evaluated include surface water, ground water, airborne, and biological pathways. Relative quantities of actinide movement via different pathways were compared in terms of actinide loads delivered off the RFETS, using a combination of monitoring data, predictive transport models and results from historic RFETS studies. Results indicate air and surface water constitute the dominant transport mechanisms for plutonium and americium. In ground water, shallow alluvial flow is a limited pathway for plutonium and americium because of the low aqueous solubility of these actinides and their tendency to sorb to soil. However, localized flow in shallow alluvium is a more significant pathway for uranium movement, because of the relatively higher solubility of uranium (VI) species, though isotopic ratios indicate much of the uranium is from natural sources. Biological transport of actinides by mammals, birds, fish, and arthropods is small compared to the other pathways.     

Ecology and characterization of yeasts from aquatic regions of South Florida

Mycological investigations, entailing over 400 samples from 120 separate collection stations, of the composite aquatic regions of southern Florida and adjacent areas have been developed. A collection of over 1000 yeasts, representing more than 50 taxa, has been characterized and studied. Highest yeast densities were found in freshwaters with the recovery of yeasts per sample decreasing from 100% to approximately 70% with lowered organic content, increasing salinity and remoteness from land. Average cell population densities, variety of species, and particularly the number of sexual yeasts, decreased in saline samples. The isolation media used were evaluated and have been discussed in terms of yeast densities obtained. Stritly oxidative species of Candida, Cryptococcus, and Rhodotorula and the sexual yeast, Debaryomyces hansenii, were the most widespread in all the habitas studied and the predominant forms in water of relatively low organic content. Selective survival of certain yeasts in the various aquatic environments was suggested. Definite distributional patterns were exhibited by various taxa and the possible existence of indicator species wa suggested. The systematics of the fungi have been reviewed at length and the significance of strain differences considered and discussed as related to the unique characteristics of the various ecological habitats.