Future research directions and data requirements for developing ambient ozone guidelines or standards for agroecosystems

The ambient air quality in Central Europe appears to have the potential to adversely affect the productivity of the agroecosystems in that geographic area. Therefore, there is a need to develop, validate, and apply air pollutant exposure-plant response models to explain the relationships between the stochastic chemical climate and ecosystem responses. Such models will have to include numerical terms for the effective air pollutant exposure regime to account for the fluxes of matter, energy and information within the ecosystem and its components. The structure and function of the ecosystem which are influenced by the air pollutant flux can be described by a combination of empirical and mechanistic models. A discussion of such an approach is presented in this paper.     

Immunoassay monitoring of polychlorinated biphenyls (PCBs) in the Great Lakes

Although polychlorinated biphenyls (PCBs) are no longer manufactured, they are still entering the environment. In some compartments of the environment, PCB concentrations are a serious concern. This is especially true in compartments which accumulate PCBs, and in food items consumed by humans and wildlife. Also, there are situations in which management decisions require rapid, sensitive, accurate measurements, which can be made in real time under field conditions. Methods to use an enzyme-linked immunosorbent assay (ELISA) for PCBs were developed and applied to sediments and fish muscle homogenates collected from the Great Lakes. The extraction methods developed can be applied in the field with non-hazardous solvents, in the absence of sophisticated laboratory equipment. The method detection limit for PCBs in dimethyl sulfoxide (DMSO) extracts of sediment was 0.9 mg/kg. For PCBs in isopropanol extracts of fish tissue, the method detection limit was 0.6 mg/kg. The resolution of the ELISA was 0.83 mg/kg at 1.1 mg/kg and 1.6 mg/kg at 1.7 mg/kg, for sediment and fish tissue, respectively.     

Status of PCDD/F-emission control in Germany on the basis of the current legislation and strategies for further action

The protection of environment from polychlorinated dibenzodioxin and -furan (PCDD/F) impacts, caused by a heterogeneous spectrum of thermal stationary sources and several others in chemical industry, bases on a comprehensive legislation in Germany. The results of this emission reduction strategy are presented by emission inventories for stationary, mainly industrial sources comparing in this paper data for emissions between 1994 and 2001. These results show that the implementation of best available techniques (BAT) at industrial sources for PCDD/F-reduction has been nearly fully exhausted at nearly all relevant sources and extensive overall emission reductions were achieved by the end of the 1990s. Further reductions for PCDD/F are needed for specific sources in metallurgical industries, especially sinter plants, and for domestic furnaces only. For coplanar PCBs (co-PCBs) almost no emission data are available from German sources; a few data from measurements of co-PCB have been published from two waste incineration plants. These measurements show that the emission limit value of 0.1 ng TEQ/m3 is not exceeded by co-PCBs in the waste gas in addition to the background PCDD/F concentration. As a consequence from the new appraisals for toxicity equivalences (TEQ) and tolerable daily intakes (TDI) of the World Health Organisation the Federal Environmental Agency in Germany discusses a level of 1 pg WHO TEQ/(kg(bw) d) as an acceptable limit value for adult's burden, taking into account, that this value is too much for children in the pre- and post-natal age and further action for PCDD/F- and co-PCB reduction is needed for the last sensitive group. As a summary can be reported that PCDD/F and co-PCB intakes into the nutrition chain could not have their origin from stationary industrial sources mainly. More attention should be given to more diffuse source such as residential combustion and others, which are more directly connected to the nutrition chain, like green food drying. Important effects could be expected by restrictions of PCDD/F impacts by regulations for control of feed, feed components and compounds feed for pigs and cattle.     

Bodennahes Ozon: Trends in Bayern

Long-term ground-based measurements of ozone in Bavaria (Germany) are evaluated in respect of their trend during the last 20 years. First a method is described to characterize the measuring-sites in relation to the levels of precursors: The derived division in three classes proved its worth interpreting the results. Following, the trend of ozone-concentration are calculated by linear regression analysis and are tested in respect of their significance. Generally the Bavarian results fit in the trends of a long-term increase of ozone-concentrations observed at several central European stations. In detail, there are differences between stations situated at elevated sites or at other sites without traffic (class I) and stations situated at sites with significant influence of nearby traffic (classes II and III). At stations of class I an increase of ozone until the mid 80’s is recorded. Afterwards this trend seems to be stopped. But at the stations of classes II and III an increase of ozone is occuring only since the mid 80’s. The observed trends are correlated with the trends of NO_x-emissions.