2. ENVIRONMENTAL ChEMISTRy & TEChNOLOGy 2.1. Lectures

Chem. Listy, 102, s265–s1311 (2008) Environmental Chemistry & Technology
P16 ThE NATuRAL AND ANThROPOLOGICAL
CONTAMINATION SOuRCES OF ThE
HALČIANSKY WATER RESERVOIR
SLAVOMíRA KAŠIAROVá a and MELánIA
FESZTEROVá b
a Trenčín University of A. Dubček, Department of public
management, Študentská 2, 911 50 Trenčín, Slovakia
b Constantine the Philosopher University, Faculty of Natural
Sciences, Department of Chemistry, Tr. A. Hlinku 1, 949 74
Nitra, Slovakia
kasiarovas@azet.sk
Introduction
Many technical sights, as an integral part of a landscape
structure, are at the same time its dominant features as they
are directly related to its history. In the Banská Štiavnica
region they are mostly related to mining traditions. Importance
of water reservoirs, also called “tajchy”, in the region
stems their recreational utilisation. The cleanliness of water
is therefore a key issue 1 .
This study has focused on the identification of possible
natural and anthropogenic sources 2 of pollution in the model
territory of the Halčiansky water reservoir and consequently
on its contamination. Water reservoirs built to provide the
water energy for driving mining machinery are a part of a
mining history. As such they are a typical landscape-ecological
component of the Banská Štiavnica landscape. Because of
their significance they are listed on The State List of Cultural
Monuments as sights of technical development and on The
World Catalogue of Water Reservoirs.
Experiment and Methods
In the model territory of the Halčiansky Water Reservoir,
conditions of potential movement of water and related contaminants
were analysed in relation to natural and anthropogenic
sources of contaminants with the use of GIS (Geomedia
Professional) tools. The aim of the analysis was to determine
the vector of the transport and representative sampling points.
Based on the system analysis of the above conditions, the
selection of sampling points was proposed with the sampling
points for the transport system set as transparent. Samples of
water taken at the representative points (period 2006–2007)
were analysed in situ by spectrophotometer (Hach DR 2000,
Horiba) and related to an assumed model of contamination.
The results of physical-chemical analysis were further compared
with the expected transit and interpretation of the contamination
in the territory.
Results and Discussion
The following characteristics have been derived from
the results and water quality monitoring:
(i) Water reaction, conductivity, turbidity, temperature,
salinity, nitrates (1.3–2.2 mg dm –3 ) and amount of chlorides
(1.6–9.3 mg dm –3 ) and sulphates (18–33 mg dm –3 ) complied
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with the norm no. 490/2002 Z. z. during all seasons, and no
measured value exceeded the norm.
(ii) An increase of ammonia, nitrites, phosphates concentrations
and of chemical consumption of oxygen exceeding
the limit value set by the norm no. 491/2002 Z. z. was
recorded during all four seasons.
Free ammonia – concentration values of nH3 were in a
range of 0.07–1.07 mg dm –3 them exceeding the limits
of the norm ( < 0.3 mg dm –3 ). In the vicinity of the sampling
points 2 and 3 there were grazing grounds foraged
by cattle and sheep and an agricultural land fertilized by
ammoniac, sulphate ammonia or liquid manure, increasing
concentration of ammonium salts in water. Cattle
excrements and fertilizers are entering water reservoir
by the run-off flowing down the surrounding slopes.
The directions of run-off conditions also confirm this.
Another source of pollution at the sampling points 5 and
6 was stabled cattle and cesspools from the residential or
recreational areas.
The most distinctive representation of pollution in the
form of nitrites 0.004–0.226 mg dm –3 was detected in
spring when the concentration of those contaminants
exceeded the value set up by the norm almost eleven
times. Mutual comparison of sampling points indicated
the highest concentration of nitrites at the sampling
sites 3, 4, 5 and 6. nitrites are products of biochemical
oxidation of ammonia and to lesser extent products of
the reduction of nitrates. Their sources are household
sewage and wastewater.
There were also excessive concentrations of phosphates
0.6–2.1 mg dm –3 , which exceeded limits set up by the
norm five times, with maximum concentrations registered
in autumn at the sampling site 2. Main sources of
phosphates are household sewage and wastewater together
with dead bodies of plants and animals.
Chemical consumption of oxygen 10–2,800 mg dm –3
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had the highest value in winter, at the sampling site 1
(the dam), exceeding the limit value set up by the norm
eighty times. Organic water pollution can be both of
natural (leaches from the organically rich soil, forest,
peat bog, etc.) and artificial origin (pesticides, fertilisers).
The above results have shown that the selection of sampling
points based on the system analyses and GIS outcomes
confirmed assumptions of physical-chemical analysis of
water in natural and residential zones. The exceptions were
nitrates and chlorides concentrations, in case of which the higher
values were expected especially in the agricultural areas
or residential zones.
Conclusions
Results of potential conditions of contaminants in the
territory of the vector movement of water and gravitation
confronted with results of physical-chemical analyses show
the relevance of the model. This will enable an effective