Combined effects of organic or inorganic pollutants on soil microbial activities were investigated in field plots grown with four types of covering plants. It was derived from this study that combined effects were dependent not only on the type and dose of pollutants, addition of soda lime, plant type and season variation, but also on test parameters. When jointly added, higher doses of Cd, Cu, Pb, Zn and As caused significant inhibition. Addition of soda lime could even enhance inhibition. Joint effects of phenanthrene, MET (active ingredient: paclobutrazol) and 1,2,4-trichlorobenzene were not significant, and may be covered by other biotic or abiotic factors. Compared with other two parameters (respiration and microbial biomass), dehydrogenase activity appeared to be more sensitive for evaluating the toxicity of anthropogenic pollutants in soil. Soil samples collected in summer often had higher microbial activities than those in fall. The microbial activity in soil decreased with covering vegetation in the order alfalfa > pine > poplar and maize, albeit some exceptions were observed.

The Catalonian river sediments were found to be rich in keratinolytic fungi. The keratinolytic fungal populations showed clear seasonal changes in the river sediments. The main factors ‘regulating’ these populations in such habitat were temperature, dissolved oxygen concentration, pH, ammonium, nitrates, total fungal number, BOD₅, water poisons (cyanides, detergents, phenols), salinity and, presumably, strong insolation associated with low water levels. The last was probably of special importance in the deterioration of the fungal populations in the spring/summer season. A toxic effect on keratinolytic fungi in sediments was observed.Chrysosporium keratinophilum was found to be most resistant to industrial contaminants and salinity. Therefore, this species could be used as an indicator of water pollution.

Total mercury (Hg) and methylmercury (MeHg) concentrations were determined in sediments and in the polychaete wormNereis diversicolor at 13 stations of a brackish water intertidal mudflat of the Scheldt estuary. Hg and MeHg concentrations in sediments ranged from 144 to 1192 ng g⁻¹ dw and from 0.8 to 6 ng g⁻¹ dw, respectively. Both Hg and MeHg concentrations increased with an increase of organic matter (OM) content and fine grain fraction. In contrast, Hg accumulation byN. diversicolor was significantly (p<0.05) higher at stations with sandy sediments (mean value: 125 ng g⁻¹ dw) than at stations with muddy sediments (mean value, 80 ng g⁻¹), probably because Hg availability for bioaccumulation at muddy stations was reduced by high OM content of the muddy sediments. MeHg accounted for an average of 0.7% of the total Hg in sediments and 18% of the total Hg inN. diversicolor. Seasonal variations significantly affected Hg concentrations in sediments and MeHg inN. diversicolor. Total Hg concentrations in sediments were significantly (p<0.05) higher in autumn and winter than in spring and summer whereas MeHg concentrations were lowest in winter compared to the other seasons. On the other hand, total Hg concentrations in the worms were lowest in spring whereas MeHg concentrations were significantly (p<0.01) higher in spring and summer than in autumn and winter.

In summer 1994, stream water, moss and humus samples were collected for sulphur isotopic analysis from eight catchments located in the western Kola Peninsula region, where several industrial centres emit high loads of SO₂ and other elements to the atmosphere. Three potential sources of sulphur and their isotopic signatures were identified: (1) marine (δ ³⁴S+20 to +21‰ CDT), (2) anthropogenic emissions (<+10‰), and (3) geogenic (variableδ ³⁴S, mostly <+10‰). Averaged per catchment, the sulphur isotopic composition varies between +6.0 and +16.3‰ for stream water sulphate, +6.0 and +8.4‰ for moss sulphur, and +5.2 and +12.2‰ for humus sulphur. Theδ ³⁴S composition of stream water from the more remote catchments is quite variable, reflecting several natural (geogenic) sources, but it becomes restricted to the range +8 to +10‰ near the pollution sources. A plot ofδ ³⁴S vs. 1:SO₄ in stream water suggests that sulphate originating from the smelters has aδ ³⁴S value ≈+9.5‰, and is a dominant source. Sulphur isotope values for moss and humus are consistent with the deduced composition for the emitted sulphur, though for humus a component of geogenic sulphur incorporated via vegetation uptake may play a role. Further isotopic characterisation of atmospheric emissions, together with environmental samples, is needed to better understand sulphur sources and sinks in the area.

Daily total ozone observations made during 1985–1993 by both the Total Ozone Mapping Spectrometer (TOMS) flown on the Satellite Nimbus-7 and the Dobson Spectrophotometer have been used in order to investigate the fluctuations of the daily broad-band and spectral solar ultraviolet radiation reaching the ground. This investigation has been performed by employing a recently developed parametric algorithm for the estimation of the spectral and broad-band solar ultraviolet radiation which takes the total ozone variations into consideration. Total ozone reductions during the summertime from 1985 to 1993 over Athens, Greece (37.6° N, 23.4° E), cause an increase in the ultraviolet irradiance which reaches the ground of 0.54 %, 0.98 %, 2.60 % and 0.79 % per decade for the months of July at 300 nm, 312 nm, 320 nm and UVB (280-320 nm), respectively.