National audience

peer reviewed | The critical load concept is now widely used as a tool for developing emission control policies in Europe. As a signatory country of the Convention of Long-Range Transboundary Air Pollution, critical loads for acidity, nutrient nitrogen, nitrogen and sulphur have been calculated for the Flemish and Walloon regions in Belgium. This paper describes the methodology used for estimating critical loads for forest soils in the Walloon region according to the Steady-State Mass Balance equations. As an example the methodology was applied to the catchment `Waroneu', situated in a sensitive area of the Haute Ardenne. Main input parameters to the equations were derived from precipitation and runoff data of the catchment study. Improved estimates of nitrogen uptake (Nu) and base cation uptake (BCu) were obtained by intensive sampling of Picea abies and Quercus robur trees. Nutrient contents (Ca, Mg, K, N) and nutrient to nitrogen ratios of Picea abies reflected the poor soil quality at a site with high N deposition. Quercus robur nutrient contents increased from stem to higher order branches with a high proportion of nutrients located in the bark. However the simulation of stem only harvesting had a minor effect on critical loads. Measured wood densities were lower than reported literature values with a main effect on Nu and BCu estimates. The use of recommended default values and/or data derived from the experimental site resulted in a wide range of critical loads, some of which were largely overestimated. Results demonstrated the importance of site specific data for critical load calculations.

International audience | Estimates of standing biomass and fluxes of biomass in a mixed-deciduous woodland were derived, and used with results for concentrations of seven polycyclic aromatic hydrocarbons (PAHs) in different compartments of the woodland system to quantitatively assess some of the key fluxes and burdens of PAHs in this complex system. We quantified PAH burdens in air, in leaves of three deciduous tree species, in leaf litter and in soil, and uptake of PAHs by the tree leaves; PAH fluxes in litterfall, and deposition to the litter layer on the woodland floor during winter were calculated from these data. Air burdens exhibited marked seasonal variations for all compounds, with lowest values in summer when combustion-related emissions were low. Leaves did not accumulate large burdens of PAHs while on the trees and consequently, litterfall-associated fluxes of PAHs were small, representing only a fraction of the burdens in the litter layer to which they were deposited. Higher PAH burdens in air in winter, combined with the organic-matter-rich nature of the litter layer, are thought to be responsible for fluxes of PAHs to the litter layer in winter being 20–170 times the peak litterfall fluxes. The soil compartment was calculated to contain 25 years' worth of deposition of benzo[ghi]perylene, the most recalcitrant PAH in this study. Storage quotients for fluoranthene, pyrene, benzo[k]fluoranthene and benzo[a]pyrene burdens in soil represented 7–10 years' worth of deposition, while fluorene and phenanthrene storage in soil approached unity with inputs (1 and 3 years' worth of deposition, respectively). The relative importance of storage and loss processes was therefore closely related to the physico-chemical properties of the PAH, and is discussed in relation to the cycling of carbon in the woodland.

Withdrawal of water from surface water network should be concerned with preservation of the environment, meaning that the low flow regime in streams should be preserved within the range of natural regime. In order to formulate criteria for minimal allowed flows in streams, it was necessary to perform statistical analysis of low flows in rivers in Serbia (Yugoslavia). The criteria for water withdrawal are proposed on the basis of characteristic ratios between minimum and mean flows. Different criteria are proposed for cold and warm seasons.

Paper points the present water quality of the Moraca river (Montenegro, Yugoslavia), from rivermouth of Zeta to Skadarsko jezero lake. Hydrological analysis, level of water pollution are also presented, together with proposed water quality protection measures regarding the Yugoslav federal regulations for surface waters.

The investigations of the macrozoobenthos of the Crvena Reka river (Serbia, Yugoslavia), left tributary to the Nisava river, were performed during July in 1999. Samples were collected from 15 localities, from the spring of the Crvena Reka river (originating from Toponicka and Vetska rivers) to the lower course, the aim being to investigate the diversity of macrozoobenthos of these running waters which had not been investigated. The community of macroinvertebrates of the Crvena Reka river and the streams, which make it, consists of 54 determined taxa (at species and genus level) from 16 animal groups. Larvae of Ephemeroptera and Trichoptera have the greatest diversity, each having ten determined taxa. The middle course of the Topnicka river (locality T4) is characterized by the greatest diversity (25 taxa), while the springs (due to constant ecological parameters) have poor diversity with two and one determined taxa in locality V1 and V2, respectively. The water quality of the investigated river and streams, which make it, on the basis of the results of saprobiological analysis, is of beta-mezosaprobic quality, i.e. second class of quality in most localities.

This paper points out the role and significance of civil engineering in dealing with the problems related to the water environment. Examples presented consider hydraulic structures and their impact on the aeration level in the watercourse. Aeration and reaeration have the most important effect on the oxygen water quality parameters and therefore on the entire living world in the particular ecosystem.

This paper is an abstract of the operative program for water protection in the Republic of Serbia (Yugoslavia) for the next five-year period of time (2001-2005). There is a short review on the present water protection status, particularly status of wastewater treatment plants. It includes layouts of water protection solutions in different fields, by priorities, as well as assessment of necessary capital investments for their implementation.

The paper deals with the results of the phytoplankton investigations carried out in the 7 localities along the Yugoslav section of the Tisza river in the period of 13 Februar - 3 March 2000, after accidental pollution with the cyanide and heavy metals. Although certain decrease in the density of the phytoplankton and variation in the qualitative and quantitative composition were recorded, there are no significant differences in comparison with the data before accident. The short-term and possible long-term consequences were recognized, having in mind ability of algae to accumulate pollutants into their cells, and that algae are the first link on food chains. Since the content of pollutants increases with every next member in the chain, it is easy to assume cumulative effect of the all previous members.

Aerobic bioremediation of oil contaminated soil was investigated on laboratory-scale for purpose of pilot-plant installation. Mineral oil was analysed using IR spectroscopy. Sediment was qualitative analysed on GC/MS. Research also included microbiological analysis.