Geochemical characteristics of the Sava river sediment upstream and downstream of the wastewater treatment plant of the city of Zagreb

Analizirani su prikupljeni uzorci vode i sedimenta rijeke Save sa 4 lokacije, od mosta Jankomir do Rugvice, ukupne dužine 36,37 km. Cilj rada je bio odrediti postoje li značajnije razlike u sedimentu uzvodno i nizvodno od ispusta uređaja za pročišćavanje otpadnih voda grada Zagreba, ali i sastavu vode na istim lokacijama na kojima se uzorkovao sediment. Za potrebe istraživanja mjeren je pH, električni konduktivitet, utvrđene su mineralne faze, granulometrijski sastav, udio karbonatne komponente, udio organske tvari i udio kemijskih elemenata od interesa. Rezultati analiza su pokazali da tri od četiri proučavane lokacije imaju slične vrijednosti mjerenih paramerata, a da lokacija u neposrednoj blizini ispusta pročišćenih otpadnih voda pokazuje nešto drugačije vrijednosti. Na temelju dobivenih rezultata utvrđeno je da koncentracije kemijskih elemenata u vodi ne prelaze dopuštene granice prema Pravilniku o graničnim vrijednostima emisija otpadnih voda te da koncentracije elemenata u sedimentu prema Prijedlogu graničnih vrijednosti teških metala u sedimentu također ne prelaze dopuštene granice, osim elemenata Pb i Cu. Rezultati ukazuju da je kvaliteta ispuštene vode u granicama pravilnika s uočenim povećanjima pojedinih mjerenih parametara u neposrednoj blizini ispusta u Savu.The collected samples of water and sediment of the Sava river from 4 locations, from the Jankomir Bridge to Rugvica, with a total length of 36.37 km, were analyzed. The aim of the study was to determine if there were significant differences in sediment upstream and downstream from the discharge of the Zagreb sewage treatment plant, as well as the composition of water at the same locations where the sediment was sampled. Ph, electrical conductivity, mineral phases, granulometric composition, carbonate component content, organic matter content, and chemical element content of interest were determined for the purpose of the study. The results of the analyzes showed that three of the four sites studied have similar values of measured parameters, and that the location in the immediate vicinity of the discharge of the treated wastewater showed slightly different values. Based on the obtained results, it was determined that the concentrations of chemical elements in water do not exceed the permitted limits according to the Regulation on limit values for waste water emissions and that the concentrations of elements in sediment according to the Proposal for limit values of heavy metals in sediment also do not exceed the permitted limits, except for elements Pb and Cu. The results indicate that the quality of the discharged water is within the ordinance with observed increases in individual measured parameters in the immediate vicinity of the discharge into the Sava