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In Slovakia more than a half of the landfill‘s waste consist of the biodegradable waste (BDW). Therefore the BDW composting can decrease significantly the production of the landfill gas as well as the financial and space requirements for landfills. However, the composts production have to be solved comprehensively, including their rational usage. In Slovakia the use of composts is ineffective if the location of their production is farther than 50 km, because of the high tranportation costs. The objective of the experiments was to determine the ratio of vermicompost in the soil growing medium in order not to decrease the yield quantity and quality of radish - the most commonly grown vegetable in the gardens in Slovakia. Five shares of vermicompost were tested in the soil substrate (0%, 10%, 20%, 25% and 50%). The results show that 50% share of vermicompost in the soil substrate, i.e. the ratio of vermicompost to soil 1:1, was not the optimal solution of the vermicompost usage. However, even this quantity of vermicompost did not have a negative impact on the weight of the aboveground and underground phytomass in comparison with the treatment without vermicompost. 50% share of vermicompost in the growing medium had the negative impact on the qualitative parameters of radish. It decreased the content of vitamin C and increased the content of nitrates in radish roots and leaves. Along with the higher share of vermicompost in the growing medium, the content of vitamin C was decreased in radish roots and leaves, and the content of nitrates in radish roots was increased. The roots of the biggest diameter, and consequently the highest yield of radish roots and leaves was formed in the treatment where the soil substrate consisted of four portions of soil and one p ortion of vermicompost (20% proportion of vermicompost).

Many of the world’s findings indicate the positive effect of earthworms on soil parameters, and consequently, on the formation of phytomass of cultivated plants. In our experiment we studied: A) the influence of soil itself, soil mixed with vermicompost in a ratio of 9:1; B) the influence of earthworms number (genus Eisenia foetida, 10 and 20 individuals per pot) supplied to soil mixed with vermicompost in the ratio of 9:1 on the dynamics of changes in the weight of radish roots, the total chlorophyll content in leaves and the selected qualitative parameters of the roots. The results obtained showed that one tenth proportion of vermicompost from the total weight of soil substrate caused the statistically significant increase in the total chlorophyll content in leaves, the increase in yield of radish roots, the reduction of the vitamin C content and the increase of nitrate content in the roots. The impact of earthworms on the chlorophyll content in leaves and on the root weight was negative. The addition of 10 individuals of earthworms into 20 kg of substrate (soil + vermicompost) resulted in the increased content of vitamin C and the decreased content of nitrates in the radish roots. Twenty earthworms added to vermicompost, compared to vermicompost alone, did not affect the vitamin C content and reduced the nitrate content.

In this study, the effects of arsenic, cadmium, copper and chromium treatments were examined on a nematode community structure and proportion of functional groups in the microcosm for 30 days. The toxic effects on the nematode community did not correspond with metals mobility (EDTA extraction) in soil as it was expected. The most toxic element with a significant degradation of community structure was chromium (low mobile), which negatively affected almost all observed ecological parameters (abundance, diversity and ecological indices). On the other hand, cadmium and arsenic influence was negligible even in the plots treated with the highest concentrations and the communities resembled to the control samples. Copper showed a stimulative effect on the community under low concentration (40 mg.kg-1), while under higher concentrations the stimulation was replaced by stress responses. The widely used ecological indices, such as the Maturity Index 2-5, Structure Index, and Shannon-Weaver Index and c-p groups showed the best bioindication potential among nematode parameters.

The effect of industrial pollution from chromium ferroalloys production on soil free-living nematode assemblages, c-p groups and generic composition was investigated along 7-km transect. From trace elements (Cr, Cu, Ni and Pb), only chromium exceeded the thresholds for uncontaminated soils (10 mg.kg-1) near the pollution source. In contrast mobilizable fraction of Cr has increased with the distance from the pollution source and was found to be positively correlated with Cox, soil pH, and moisture. Generic richness (nematode diversity) was also higher at remote sites. The low contamination has no significant impact on the nematode communities as illustrated by the c-p groups composition and balanced community structure. Widely applied ecological indices SI and EI also proved maturing ecosystem without any significant stress responses

A long-term and intensive magnesium (Mg) ore processing in Slovenské Magnezitové Závody a.s. in Jelšava has resulted in a high Mg content and alkaline pH of the soil environment, noticeable mainly in the close vicinity of the smelter. Nematode communities strongly reacted to the contamination mostly by a decrease in abundance of the sensitive groups. Nematodes from c-p 1 group and bacterivores, tolerant to pollution played a significant role in establishing the dominance at all sites. With increasing distance from the pollution source, the nematode communities were more structured and complex, with an increase in proportion of sensitive c-p 4 and 5 nematodes, composed mainly of carnivores and omnivores. Various ecological indices (e.g. MI2-5, SI, H') indicated similar improvement of farther soil ecosystems.

Heavy metal concentrations were determined in 43 perches (Perca fluviatilis) and in two of its most common parasites, the acanthocephalan Acanthocephalus lucii and the cestode Proteocephalus percae, collected in the period 2009-2010 from Ružín, a seriously polluted water reservoir in Slovakia. Samples of muscle, liver, kidney, brain, male and female reproductive organs and adipose tissue of fish and both parasites were analyzed for As, Cd, Cr, Cu, Hg, Mn, Ni, Pb and Zn, by ICP-MS. Mean concentrations of individual heavy metals in all fish samples decreased in the order zinc > copper > manganese > mercury > arsenic > chromium > cadmium > nickel > lead. Zinc was found to be the dominant element and its antagonistic interaction with copper was confirmed. The kidney was a key target organ receiving the highest mean concentrations of all analyzed metals, but some metals showed specific affinity for particular tissues. In terms of human health, concentration of Hg in fish muscle, which exceeded more than two-times its maximum level admitted in foodstuffs in European countries, is of great importance and should be taken into account. Bioaccumulation factors (C([parasite])/C([fish tissue])) calculated for all elements indicated much higher detection skills of A. lucii and P. percae parasites than fish organs and hence, present results allow proposing both parasite models as useful tools to monitor aquatic environmental quality. Acanthocephalans, however, seem to be superior for heavy metal monitoring, also demonstrated under experimental conditions. Present results also indicate the decreasing heavy metal burden of the reservoir and its gradual recovery in the course of time.

Soil nematode communities (taxa composition, trophic structure, ecological indices) in the area of metallurgical factory (Oravské ferozliatinárske závody) in Široká, Northern Slovakia were investigated in 2009. The factory belongs to main sources of emissions originated by ferroalloy production in this region. Four sites (meadows) were selected in a downwind direction from the factory: site A was located 0.85 km far from the factory, and the other sites were maintained in approximately 2-km intervals from each other. Chemical analysis of soil samples showed low concentrations of heavy metals (As, Cd, Cr, Cu, Ni, Pb and Zn), with all values being under Slovak limit concentrations of heavy metals in soils. Only the Cd content in the soil sample from site A slightly exceeded the allowable threshold, but it was decreasing with the distance from the factory, similarly as remaining metals except Cr, with slightly increasing trend of concentration. Within 64 identified nematode genera, the Helicotylenchus, Paratylenchus, Pratylenchus, Acrobeloides, Cephalobus and Rhabditis were most common and eudominant. This was clearly reflected on the trophic structure of nematode communities, where plant feeding nematodes and bacteriovorous prevailed. Significant negative correlation (P < 0.05) was observed between the abundance of bacteriovores and the concentration of Cu in the soil. On the other hand, fungivores showed significant correlation with Ni and Cr (P < 0.05) as well as predators with Cd, Pb and Zn contents in the soil (P < 0.01). The highly significant correlation (P < 0.05; P < 0.01) was found between As, Cd, Ni, Pb and Zn and Maturity Index 2-5. A negative relationship was detected between Maturity Index and the concentration of Cr in the soil (P < 0.01). On the other hand, Cu was in positive correlation with MI values. The MI, reflecting the degree of disturbances and changes in the structure and function of the soil ecosystem, was found to be the most sensitive indicator among all used indices.