| Summary: | Initially the sediment load of water-work Ruín I. reservoir was evaluated according to the law on wastes 606/92 st and according to the decision of Ministry of Agriculture No. 531/1994-540 about maxima permissable values of hazardous materials in soils. On the score of utilisation possibilities of these sediment load in the agriculture they were appreciated to reference values of groups A and to the indicator value B and C. The new Methodical Instruction of Ministry of Environment Slovak Republic from 27. 8. 1998 No. 549/98-2 (MI) for the evaluation of risks from the contaminated sediment load of streams and reservoirs focuses to the unification of procedures by taking samples, analysis and by the evaluation of risks. On the basis of this we have revaluated our procedures by taking samples now. Considering the new MI sampling of new sediment load layer on the older sediment load from last 5 years was performed. Approximately on the same places as previous period and small layer of 10 cm sediment load was taken from the bottom under water level from the depth of minimal 1 m. The samples were analysed using the method AAS for the chosen elements.In the main branches of Hornád and Hnilec we can find elements Cu, Zn, Co and Ni in the sediment load in negative values. Dangerous were contents of Hg in the past, mostly from vertical profiles where Hg markedly indicated periods when and by which way passed mining. At present the contents of Hg in the sediment load are is acceptable. Only in the sector of Margecany it is higher against norms, as was detected also in the past. Unfit values of Mn content are in the main branch of Hornad namely at the entrance and at the dam wall. (Tab.1). According to this finding we assume that these elements are bonded, mainly on dust (0, 063-0,004 mm) and clay (< 0,004 mm), i.e. pelite fraction or bed-load sediments.The sector from EP21 (identification of registration profiles, Fig. 1) to the end - EP44 swell contains 1 000 000 m3 sediment load by the calculations. The sediment load from this branch could be used for agricultural purposes after the exploitingIn the branch of Hnilec from the confluence with Hornad sediment the load occurs in the amount of 460 000 m3. The first sector in the length of 150 m from the confluence with Hornad is possible to be exploied with the sediment load of the main stream and another sector as far as the end of swell selective. We suppose the simple exploiting and sediment load could be used as well as for biotical purposes.In Bela and Opatka Branch we have 180 000 m3 simply exploitable sediment loads. 120 000 m3 occurs in the Bela branch. The contents of heavy metals (Tab.1) shows that the sediment load from the Bela branch could be used directly for the biotical purposes. The biotical use is accepted as a direct application of sediment load in agricultural areas.The non-biotical use could present a wider scale, in dependency on the content of heavy metals.The issue of bonded metals reactivation is open. We have observed this at the entrance branch of Hornad, where the increase of Hg content was observed in the metallic form by the storage and quartering of sediment load from the vertical profile. The other metals haven´t accounted increased values, therefore their reactivation is not expected.The last measurements (Holubová et. al. 1996) show that from 1969( when the original volume was 59 mil. m3 ), for 27 years of reservoir choking the volume of reservoir reduced by 7 mil m3 what represent about 260 000 m3 annually. With intensity of choking we could determine the vitality of the reservoir by 80% choking to 140 years. Therefore, the consistent monitoring of the quantitative and qualitative index of the reservoir sediment load for commodities of accelerated realisation of their exploiting to the use or liquidation is considered as a hightly actual.
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