During spring of 2005, referent monitoring of the chemical quality of surface waters and sediments in some protected areas in Vojvodina (Serbia) was conducted as a supplement to the Regular monitoring program. The aim of the study was to establish the chemical quality of surface waters and sediments regarding nutrient content. It is shown that the water quality satisfies the criteria of the 1st/2nd class according to our legislation, with the exception of the Ludos location, which showed a contamination with nitrogen matter in water and sediments. With regard to the contamination of water with phosphorus, almost all locations may be considered as potentially problematic.

Within the pollutant analysis in sediments the total organic carbon (TOC) content is determined, as well as nutrients such as nitrogen and phosphorus. In addition to this form carbon may be present as elemental or inorganic ones, as the crucial issue for sample preparation. Total phosphorus content was determined after sample digestion with sulphuric and perchloric acid. Organic nitrogen values were determined according the Kjeldahl method. Concentrations of TC, TOC, TIC, total P, organic N and total N in river Tisza sediment samples from sites Martonos, Novi Becej and Titel during 2004 and 2005 were presented.

Investigation of the nutrients and chlorophyll a concentrations, as indicators of trophic level, in the period from September 2003 to August 2004 in three sampling locations in the inner part of Boka Kotorska Bay varied widely. Nitrate concentration ranged from 0.0 to 2.42 mg/l at the surface and from 0.02 to 3.88 mg/l at the bottom, nitrate concentration from 0.02 to 0.21 mg/l at the surface and from 0.01 to 0.6 mg/l at the bottom, phosphate concentration from 0.03 to 0.18 mg/l at the surface and from 0.01 to 0.22 mg/l at the bottom, silicate concentration from 0.0 to 1.42 mg/l at the surface and 0.45 mg/l at the bottom respectively. Value of phytoplankton biomass, as represented by chlorophyll a, ranged from 1.02 to 8.68 mg/cubic meter and from 0.49 to 5.23 mg/cubic meter at the bottom. According to the UNEP criteria during the investigated period it can be concluded that the area in question is mesotrophic with the exception of December when it is eutrophic.