Dioxin-/Furan-“Verbrennungsprofile” in Abgasen aus Hochtemperaturprozessen

Zusammenfassung  Verschiedene Mechanismen in der Abkühlungsphase von Hochtemperaturprozessen führen zur Neubildung von polychlorierten Dibenzo(p) dioxinen (PCDD) und polychlorierten Dibenzofuranen (PCDF) und, unabh?ngig von den jeweiligen Absolutkonzentrationen, zu vergleichbaren PCDD/F-Profilen, also prozentualen Anteilen einzelner Kongenere bzw. Homologengruppen an der Summe der betrachtten 17 Kongenere nach 17. BImSchV bzw. Homologengruppen Tetra-bis Octa CDD/F. Die Charakteristik dieser “Verbrennungs-profile” kann zur Plausibilit?tsprüfung von Messergebnissen sowie zur weitergehenden Deutung und zum Verst?ndnis der ablaufenden Reaktionsmechanismen beitragen. Online-First: 9. M?rz 2000     

Sedimentary record of environmental pollution in the Western Baltic Sea

The chronological development of environmental pollution in the Western Baltic Sea for the past hundred years was investigated in dated sediment cores. An artificial radionuclide (¹³⁷Cs), nutrients, heavy metals, chlorinated hydrocarbons (PCB, DDT, Lindane) and plasticizers (phthalate esters) show characteristic distribution patterns within the various cores. They can be related to the production and use of specific chemicals and goods, to emissions associated with the increased combustion of coal parallel to industrialization and —in the case of ¹³⁷Cs — to emissions associated with atomic weapons tests in the high atmosphere. Characteristic trends in the general development of pollution may be superimposed by specific emissions from local sources.     

Bewertungskriterien des Umweltbundesamtes: Auswirkungen von Pflanzenschutzmitteln auf terrestrische Arthropoden

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 the Directive. Definite guidelines concerning investigations with arthropods are partially deficient. The uniform principles for the registration of plant protection products in the Member States described in Annex VI of the directive were primarily developed to assess the effects on the beneficial capacity of arthropods in agriculture. However, the risk for arthopods as an essential part of the environment need to be assessed, too. Hence, the German Federal Environmental Agency has developed a tiered approach to assess the effects of plant protection products on arthopods based on the data requirements of Annex II and III of the Directive 91/414/EEC. The risk is assessed using the effect-concentration evaluated in ecotoxicological tests and the environmental concentration predicted by validated exposure models. To protect non-target species in terrestrial ecosystems assessment factors need to be considered.     

Oak Conservation and Restoration on Private Forestlands: Negotiating a Social-Ecological Landscape

In the midwestern United States, oak (Quercus spp.) forests are considered critical habitat for conserving biodiversity and are a declining resource. Ecological conditions, such as deer herbivory and competition from more mesic broad-leaved deciduous species, have been linked to poor oak regeneration. In the Midwest, where up to 90% of forestland is privately owned, a greater understanding of social dimensions of oak regeneration success is especially critical to designing effective restoration strategies. We sought to determine factors that serve as direct and indirect constraints to oak restoration and identify policy mechanisms that could improve the likelihood for restoration success. We conducted in-depth qualitative interviews with 32 natural resource professionals working in the Midwest Driftless Area. We found that most professionals anticipate that oak will remain only a component of the future forest. Furthermore, they identified the general unwillingness of landowners to adopt oak restoration practices as a primary driving force of regional forest change. The professionals pointed to interdependent ecological and social factors, occurring at various scales (e.g., economic cost of management, deer herbivory, and exurban residential development) as influencing landowner oak restoration decisions. Professionals emphasized the importance of government cost-share programs and long-term personal relationships to securing landowner acceptance of oak restoration practices. However, given finite societal resources, ecologically- and socially-targeted approaches were viewed as potential ways to optimize regional success.     

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.     

Dioxin-/Furan-‘Verbrennungsprofile’ in Abgasen aus Hochtemperaturprozessen

Different mechanisms operating downstream from high temperature processes lead to the formation of polychlorinated dibenzo(p) dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). Independent of the level of concentration, these mechanisms lead to comparable PCDD/F patterns, as has been observed from the proportion of single congeners to the total of 17 2,3,7,8-Cl-substituted congeners or to the individual homologous groups related to the sum of the homologous tetra to octa CDD/F groups. A comparison of these so-called “combustion profiles” with the congeners Heats of Formation (HoF), as calculated via semiempirical molecular orbital methods, may provide an idea of the course of thermodynamical forced reaction.     

Tributylzinn auf dem Weg zu den ‘Top of the POPs’?

Two groups of pollutants established during the past years, the impact of which on the eco-system gave cause for concern and legislative reaction: Persistent Organic Pollutants (POPs) and Endocrine Disrupters. At present, only the 12 POPs (‘Dirty Dozen’) are subject to serious international bans as long as they do not belong as well to potential endocrine disrupters, such as the PCDDs/PCDFs (Polychlorinated Dibenzo(p)dioxins and furans). But there are endocrine disrupters which fulfil, the POP-criteria stated in the Stockholm Convention. The organotin compounds are part of them, especially the tributyltin (TBT), since the toxicity increases with increasing alkylation. The present investigations may contribute to the discussion on the POP-potential of TBT on the basis of the results from GfA-internal and literature findings.     

Nitrogen fertilizer replacement value of cattle slurry in grassland as affected by method and timing of application

Slurry application with methods such as trailing shoe (TS) results in reduced emissions of ammonia (NH3) compared with broadcast application using splashplate (SP). Timing the application during cool and wet weather conditions also contributes to low NH3 emissions. From this perspective, we investigated whether reduced NH3 emissions due to improved slurry application method and timing results in an increase in the nitrogen (N) fertilizer replacement value (NFRV). The effects of application timing (June vs. April) and application method (TS vs. SP) on the apparent N recovery (ANR) and NFRV from cattle slurry applied to grassland were examined on three sites over 3 yr in randomized block experiments. The NFRV was calculated using two methods: (i) NFRV(N) based on the ANR of slurry N relative to mineral N fertilizer; and (ii) NFRV(DM) based on DM yield. The TS method increased the ANR, NFRV(N), and NFRV(DM) compared with SP in the 40- to 50-d period following slurry application by 0.09, 0.10, and 0.10 kg kg(-1), respectively. These values were reduced to 0.07, 0.06, and 0.05 kg kg(-1), respectively, when residual harvests during the rest of the year were included. The highest NFRV(DM) for the first harvest period was with application in April using STS (0.30 kg kg(-1)), while application in June with SP had the Slowest (0.12 kg kg(-1)). The highest NFRV(DM) for the cumulative harvest period was with application in April using TS (0.38 kg kg(-1)), while application in June with SP had the lowest (0.17 kg kg(-1)). Improved management of application method, by using TS instead of SP, and timing, by applying slurry in April rather than June, offer potential to increase the NFRV(DM) of cattle slurry applied to grassland.