Original scientific paper
COMPARATIVE FAUNAL AND MICROBIOLOGICAL RESEARCH OF THE WELL WATERS OF VIRJE FROM 1986 TO 1989
Dražen PODRAVEC
; Novigradska 5, 48326 Virje, Croatia
Abstract
The interest in studying ground waters arose in the 17th century, with intensive study beginning in the 20th century. In the 1950s, a more systematic approach was taken to investigating the subterranean fauna of northwestern Croatia. Considering that the ground waters of Virje and the surrounding areas have not previously been investigated, 20 wells were selected for the research of physico-chemical, bacterial and faunal properties of their waters. These are areas in which the ground waters are under the influence of the Drava and Bilogora Rivers. The research was conducted during 1987. The physico-chemical factors were determined using standard methods (APHA). Bacterial methods included determining the total number of saprophytic bacteria, determining the coli-titre and coli-index of total coliform bacteria and bacteria of faecal origin, and thermophilic bacteria. Faunal samples were taken by filtering 100 L of well water. Changes were observed to the ecological properties of the well water, with changes to the faunal and bacterial composition of the samples. The settlement has a high influence of this biotype, as seen in the constant increase in the number of bacteria of faecal origin. Strong bacterial activity was particularly seen in the shallow wells, which are more exposed to surface pollution. A penetration of thermophilic bacteria from manure piles underground was confirmed. The changes in the physico-chemical factors caused changes in the bacterial and faunal composition of the well waters, such that the troglobionts (Niphargus) were also found in the deepest and the cleanest wells. Troglophiles and trogloxenes comprised the fauna of the shallow wells with fewer species, but with a large number of individuals (Cyclops). All the research indicates the mutual association and dependence of the bacterial and faunal system on the physico-chemical properties of well water, i.e. of pollution. The quality of well water for drinking is dependent on this, and the tested wells do not meet the prescribed criteria. It is therefore essential to begin construction of a water supply and sewage system in this area.
Keywords
ground water; flora; fauna; physicochemical properties of water; bacterial activity; drinking water
Hrčak ID:
131411
URI
Publication date:
22.12.2014.
Visits: 2.313 *