The river Crnojevica is a subject of lasting manny years physicochemical and microbiological investigations, which show worring pollutants presence into the water current. This work represent preliminary investigations of Crnojevica river water algal flora (phytoplankton and phytoperiphyton), carrying out over summer period of 2004. Aim of the investigation was to point, based on algal analysis, as reliable indicators of water quality and ecological status of an aquatorius, the need to protect the river from permanent communal and industrial waste water pollution. The hyperproduction of phytoplankton in the investigation period was stated, but it varys along the current, in accordance with efluent inflow. On the base of saprobiological analysis of phytoplankton, determinated water quality was in class 2, till the worse was noted at T2 measure place, on the inflow place of Rijeka Crnojevica settlements sewage.

Eutrophication is one of the main problems of water deterioration in accumulation lakes. Phosphorus is considered as the key factor for eutrophication of lacustrine water. Its concentration in lakes originates from external input and the emission from the sediment. It was necessary to determine the substrates of phosphorus by sequential extraction in order to determine the dynamics and bioavailability of phosphorus. On the basis of results obtained the proposals for the preparation of land were made in order to minimise the input of phosphorus.

Some physiological groups of bacteria can be good indicators of the oil pollution of the environment. Oil contamination represents a special problem because of their persistence and possibility of reaching drinking water supply sources. The destruction of the Novi Sad Oil Refinery in the hinterland of water supply source Ratno Ostrvo has endangered drinking water supply of the city of Novi Sad. As an acceptable protection measure appeared the solution with the hydraulic barrier located along the east side of the Refinery, bordering with the water supply source. Physiological groups of bacteria relevant to oil contamination (hydrocarbon-oxidizing and lipolytic bacteria) were detected in the waters of the barrier wells. The appearance and population of this microflora in the water of these wells were more pronounced compared with the waters of a control piezometer in the hinterland of the water supply source.

In this paper modern instrumental techniques for monitoring, control and determination of water and waste water quality parameters are presented. The efficient and reliable control of quality of water can be achieved by integrating the central, referee laboratory, the laboratory on-field for quick and adequate responses, and in-field laboratory, as well as the measurements enabled with the use of chemical sensors that are installed on the places with the highest contamination. Beside equipped laboratories every monitoring system has to be connected with the latest informational systems which beside data base provide adequate response when the water is exposed to higher contamination.

Low concentrations of synthetic- or bio-polymers in irrigation water can nearly eliminate sediment, N, ortho- and total-P, DOM, pesticides, micro-organisms, and weed seed from runoff. These environmentally safe polymers are employed in various sensitive uses including food processing, animal feeds, and potable water purification. The most common synthetic polymer is anionic, high purity polyacrylamide (PAM), which typically provides 70 - 90% contaminant elimination. Excellent results are achieved adding only 10ppm PAM to irrigation water, applying 1 - 2kgha+1 per irrigation, costing $4 - $12kg+1. Biopolymers are less effective. Using twice or higher concentrations, existing biopolymers are ≈60% effective as PAM, at 2 - 3 times the cost. A half million ha of US irrigated land use PAM for erosion control and runoff protection. The practice is spreading rapidly in the US and worldwide. Interest in development of biopolymer surrogates for PAM is high. If the supply of cheap natural gas (raw material for PAM synthesis) diminishes, industries may seek alternative polymers. Also "green" perceptions and preferences favor biopolymers for certain applications.