Josip Juraj Strossmayer University of Osijek. Department of biology.
Abstract
Kakvoća vode Odvodnog kanala Karašica u Baranji bila je pod jakim antropogenim utjecajem (poljoprivreda, komunalne otpadne vode), a unos zagađivala u vodotok ovisio je i o sezonskim promjenama klimatskih parametara. Utvrđene značajne promjene u specifičnoj vodljivosti prije i nakon ispusta pokazatelj su ulaska otpadnih voda. Visoke koncentracije enterokoka i vrste E. coli ukazuju na svježe fekalno onečišćenje otpadnim vodama, dok je prisutnost specifičnih onečišćujućih tvari (organoklorovi pesticidi, heksaklorcikloheksani te DDT i metaboliti) i metala kao zagađivala u kanalu najviše posljedica ispiranja s poljoprivrednih površina, posebno u jesen. Odabrani parametri u Lemna-testu (prirast i svježa masa biljaka, fotosintetski pigmenti, ukupni topljivi proteini i malondialdehid) dobri su pokazatelji utjecaja zagađivala prisutnih u istraživanoj vodi na L. minor. Niske razine hranjivih tvari u vodi, posebno dušika i visoke razine zagađivala uvjetovali su stres u L. minor indukcijom lipidne peroksidacije u gotovo svim uzorcima vode Odvodnog kanala. U tim je uvjetima došlo do povećanja omjera Chla/b i smanjenja omjera Chl(a+b)/Car, smanjene koncentracije ukupnih proteina i svježe mase biljaka L. minor. Uporabom Lemna-testa na različitim razinama složenosti (morfološke promjene, pigmenti, proteini i lipidna peroksidacija) postignuta je preciznija procjena učinka realnih uzoraka vode iz okoliša.Water quality in the Karašica drainage channel in Baranja is under a strong influence of anthropogenic sources (agriculture and municipal wastewaters), and the input of polluted waters into this watercourse also depends on seasonal changes in climate parameters. Significant changes in specific conductivity before and after the discharge site were indications of wastewater inflow. High concentrations of enterococci and E. coli were good indicators of recent faecal contamination with wastewaters, while the presence of specific pollutants (organochlorine pesticides, hexachlorocyclohexanes, and DDT and its metabolites), as well as metals, evidently derived from agricultural run-off, especially in the autumn. Selected parameters in the Lemna-test (growth rate and yield, photosynthetic pigments, total soluble proteins and malondialdehyde) proved to be useful indicators of the influence of present pollutants in the investigated waters on L. minor. Low levels of nutrients in the water, especially nitrogen and high levels of specific contaminants, have caused growth inhibition of L. minor associated with enhanced lipid peroxidation, as well as decreased Chla/b and Chl(a+b)/Car and reduced protein concentrations in almost all water samples of the drainage channel. A more accurate assessment of water quality was achieved by using Lemna test with relevant structural or functional endpoints (morphological changes, pigments, proteins and lipid peroxidation) and by considering time-varying exposure of different sources of pollution
