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.

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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.

In the scope of the Program of surface water quality examinations in the Republic of Srpska (Bosnia and Herzegovina), hydrometric measurements and water quality examinations had been realized, where zooplankton and microzooperiphyton researches have been performed. Sampling were performed in the period from 6th to 20th May 2000, at 13 water courses with taken in total 21 samples. In qualitative structure of examined fauna, Rotatoria, Cladocera and Copepoda groups were treated, with ascertained in total 109 taxa from 41 genus. In qualitative structure periphyton taxa are predominant. On the basis of bioindicatory species structure it is noticed that dominant species are oligasaprobic and oligobetamesosaprobic character.

The work gives the regime of surface water flows with hydrographic net and the regime of waters at hydrologic stations for the period of 1988-1998. Consequently in this paper will be designed a resonant indicator which is derived out of the composite index group of WQI for the flow field in the period under research. Depending on the index points won at the examined profiles, estimation of waterflows quality will be adapted to the goals of indicator users, in this case to the public. Indicators of the type very poor, poor, good, very good and excellent. Hereto it is important to mention that hereby validity of original composite indicator will have to be sacrificed.

As a result of this study the overload by pollutants and low quality of canal water in the zone downstream of Vrbas and Srbobran towns (Serbia, Yugoslavia) has been recorded. Regarding to started work on demudification of canal bottom in the industrial zone of Vrbas town, in the course of 2000 the additional investigations of mud profile downstrean of wastewater discharge into the canal have been done. In the investigated mud samples the extremely high number of organotrophic bacteria was found (up to 1.7 x 10**10 cfu/ml), but also high number of conditionally pathogenic bacteria (opportunistic bacteria) was recorded. Also, the high number of fecal (thermo-tolerant) coliform bacteria (Escherichia coli and Klebsiella - Enterobacter - Citrobacter group of bacteria), as well as the presence of colifags was found. Such findings indicate possible bad consequences to the health of humans contacting this mud, as well as to the ground water quality, indirectly, via drainage water.

The paper deals with evaluation of surface water quality in Vojvodina (Serbia, Yugoslavia) by integral methods. The aim was to emphasize streams and localities where water quality is insatisfied condition longer period of time. The profiles, chosen according to continuity of quality problems which are not results of short excesses, rightfully could be named as a "black points".

Aim of this study was to assess quality of the Danube sediment from the water source "Ratno Ostrvo", which is in the vinicity of the Oil Refinery "Novi Sad" (Serbia, Yugoslavia), after bombardment of the refinery in 1999. In the period March-October 2000, sediment samples were analysed for their oil and oil-derivates contents, i.e. mineral oils contents, by quantitative IR-spectrophotometry, and by qualitative and quantitative GC/MS analyses for their polycyclic aromatic hydrocarbons (PAH) contents. Oil pollution was detected in sediment samples.

The last decade of 20th century in Serbia (Yugoslavia) was marked with economy recession, war surroundings, and finally bombing in the period March-June 1999. Global increment of environmental pollution was one of the catastrophic consequences. War actions caused destroying of big oil refineries and reservoirs, chemical complexes and industrial objects. Afterwards, toxic and carcinogenic substances reached out to atmosphere, soil and hydrographic system. Also, ammunition with depleted uranium was used. Heavy metals are very dangerous, so that, in this paper are presented results of investigation of heavy metals contents in surface soil layers. Heavy metals are movable, by erosion processes, with possibility of reaching hydrographic network and water supply systems. Investigation was carried out at a few localities: Fruska Gora, Ivanovo, Goc and Crni Vrh. Total contents of heavy metals (Zn, Cu, Pb, Cd, Mn) was determined by AAS (atomic spectrophotometry), by usage "Varian-Spectra AA-10" apparatus.