Biotoxizitätstests mit PAK

There is great need for toxicity tests with higher plants for the investigation and monitoring of chemicals in the environment — especially for tests which are quick, easy, and inexpensive. Such tests should add to and improve current guidelines, e.g., OECD- and BBA-Guidelines. This article describes the nodulation of leguminous plants withRhizobium bacteria used in a bioassay with polycyclic aromatic hydrocarbons (PAH). Plants growing on a solid medium were exposed simultaneously to bacteria and PAH. This axenic culture system allows to observe the impact of PAH on plant growth and the interaction between plant and bacteria (nodulation). Dose-response-experiments indicated that nodulation measured as number of nodules per plant, was more sensitive to the inhibition by PAH than other plant growth parameters.     

Economists' opinions on environmental policy instruments: Analysis of a survey

Incentive instruments (effluent charges) are theoretically expected to be preferred to direct regulations (individual emission ceilings) by university-employed, theoretically inclined politically right-wing, professional economists living in a market-oriented country, ceteris paribus. Public sector employed, politically left-wing, professional economists living in a country with a long tradition of government involvement prefer the regulatory approach, ceteris paribus. These theoretical hypotheses tend to be supported by a bivariate probit analysis based on a survey of more than 1400 economists in five countries.     

Grundwassergefährdung durch Holzschutzmittel

Goal and Background

As a consequence of the implementation of EU Directive 98/8/EC into national law in June 2002, all biocidal products will be subjected to an authorization procedure. Condition for issue of an authorization is that the product or its residues do not exert unacceptable effects on human and animal health or on surface water and groundwater. Hence, among other issues, impact of wood preservatives on groundwater is to be assessed. Focus is particularly on impregnating plants with open-air storage sites for treated wood.

Methods

Based on already in-use versions of the leaching model PELMO, an advanced version (MC-PELMO 3.0) was developed with a specific focus on estimating groundwater contamination under storage sites at wood preserving facilities in Germany. The model processes twenty-two different leaching scenarios that were derived from twelve characteristic soil profiles representing pedological regions in Germany along with recorded meteorological data from nine weather stations. These data are related to geographic distribution of industrial wood preserving activity. The model calculates statistic probabilities of concentrations of wood preservatives in seepage water beneath timber storage sites of regions to be selected by the user.

Results and Discussion

The reports provided by MC-PELMO 3.0 include mean average concentrations, 55 to 99 percentiles, and single maximum concentrations for each of the scenarios. the results can be related to the total area of Germany, its forest area or to the density of preversation activity in various regions. Beside concentrations of the parent compounds, those of degradation products may be calculated for the seepage water.

Conclusion

The described model is a particularly useful tool for comparative assertion of various wood preservative products under aspects of the exposure of groundwater resources. Comparative assertion is a new element within EU-chemicals policy, for the first time materialized in the biocidal products directive 98/8/EC. Furthermore, the results of model calculations identify vulnerable regions in Germany for which appropriate risk management measures have to be taken in order to protect groundwater from contamination.     

Growth and development of Calanus spp. (Copepoda) during spring phytoplankton succession in the North Sea

Experiments were carried out to determine growth and development rates of the herbivorous copepod Calanus finmarchicus (Gunnerus) under natural conditions during the phytoplankton spring bloom in the northern North Sea. From 28 April to 25 May 1983 copepodite stages I, IV and V were incubated for a 3-d period on board a ship in vessels with naturally occurring phytoplankton or cultured algae as food. Highest rates of growth and development were achieved while the diatom Chaetoceros sp. was the dominant phytoplankton organism. These rates decreased considerably when this chain-forming diatom was succeeded after one week by the small-celled diatom Thalassiosira conferta. Again one week later, during the bloom of the succeeding colonial microflagellate Corymbellus aureus, copepodite stage IV still managed to maintain moderate rates of growth and development, but these rates dropped to almost zero in CV, suggesting the start of a resting stage. Nevertheless, brood collected from this generation and from Calanus helgolandicus (Claus) was raised in the laboratory to the adult stage at high speed. Since temperature and the total phytoplankton concentration in the sea remained almost constant it seems that the retardation and arrestment of growth and development were an immediate response to a qualitative change of the food composition related to the successive blooms of different algal species.     

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