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ANTHROPOL . PROT Résumé de rapport

Project ID: ICA2-CT-2002-10009
Financé au titre de: FP5-INCO 2
Pays: Bosnia and Herzegovina

Investigation of water quality and water supply capacities in Bihac area

Main springs in the Bihac area (Klokot, Privilica, Ostrovica and Toplica) satisfy current regulations for public water-supply drinking waters in Bosnia and Herzegovina. NH4, NO2 and HPO4 showed only occasionally concentration above maximal permitted concentration. Physico-chemical analyses of all tapped springs in the Bihac region made by the Public Health Institute - Bihac in 2003 and 2004, and the results satisfy the present regulations. Presence of microorganisms in each spring as indicator of faecal pollution does not point at the anthropogenic influence on water.

One could not define clear difference on bacteriological correctness of waters before and after the war, because the state of protection was very similar in both periods and not any improvement of quality of all spring waters after the war was shown.

Measurements of spring and river waters showed that the major pollutants in water were ammonia, nitrites and phosphates. Increased ammonia concentrations in Una River downstream from Bihac are indicators of pollution of faecal waste waters, soil erosion and of filtered waters from waste dumps, etc. Waste waters are being left without being processed before, and the final collector of all these waste waters is Una River. The presence of ammonia concentrations in the spring water indicates the possible water pollution from Croatian side (fields Krbavsko Polje and Korenicko Polje).

In all tested water samples, there was only a small amount of nitrate concentrations detected. Sulphates occurred in natural water in high concentrations. In springs they range from 3.9 to 6.6mg/l, and in the water of Una River basin from 20.0 to 29.4mg/L. The concentration of phosphates was detected in all researched waters samples taken in September 2004 except in Una River in Ripac. In all researched waters maximal detergent content is 0.003mg/L which cannot present the hazard to the ecosystem stability in Una River basin. In some water samples, there was no detergent content found. Wastewaters of the urban sewage of town Bihac outflow to Una River in Vrkašic, downstream of the town without any treatment.

The same situation is with all other industrial wastewaters in the Bihac area. No reliable data on locations and characteristics of illegal waste deposits exist in Bihac. Hygienic-sanitary state of resident houses is in general not satisfactory, faecal material pollute the soil, ground and surficial waters. Unknown consequences of contamination yet exist from toxic matters, which were stored in abandoned military facilities. The most important are the ex-airport and tunnels of Željava (close to Bihac) and Udbina (in field Krbavsko Polje, Croatia).

Valid protection of water-supply springs and Una River is not possible without finding the solution of waste water purification of town Bihac, settlements, and industry prevent illegal waste deposits, sanitation of terrain, regular exploitation of quarries and prevention measures in agriculture.

The understanding of groundwater behavior like residence times, their flow paths and mixing between different aquifers is essential for the protection of karst water in both countries. Also for the protection of karst water in both countries, knowledge on dynamics of groundwater flow, groundwater residence times, recharge rates and mixing between different aquifers is essential.

The concentrations of natural and anthropogenic trace substances can provide insights into these questions. In this study concentrations of stable isotopes (d18O and d2H), chlorofluorocarbons (CFC-11, CFC-12, CFC-113), sulphur hexafluoride (SF6), tritium (3H), helium (He) and neon (Ne) as well as the isotope ratio of helium (3He/4He) were measured in spring, lake and surface water.

The complexity of the karst system requires an approach using several such tracers, since one alone leaves too much ambiguity in interpretation. A multi-tracer approach was applied for the determination of mean residence times in ten springs. For groundwater dating in many cases a two-component model is used, describing the mixture between two water contributions of different age. For example this can be the combination of an exponential model for the “young” and a piston flow model for the “old” component.

As expected from hydrological point of view, the springs show very different mean residence times. The “young” water component in the springs shows MRTs between 0.1 and 0.8 years, whereas the “old” component is between 2 and 130 years (s. pages 12-15 in final report of P2). The information about the residence time of water in an aquifer is very important regarding the eventual pollution and storage capacities of the aquifers.

Informations connexes

Reported by

University of Bihac
Biotechnical faculty
77000 Bihac
Bosnia and Herzegovina