The fact is that in the world today water and land represents limited life resources which are more and more degrade and disturbed, mostly by anthropogenic influence. Especially water (seas, rivers, lakes) is exposed to various types of pollution. The fact is that in the world today water and land represented limited life resources which are more. That why in present time we conduct numerous scientific researches to examine, advance and protect our environment, especially water as a limited and delicate natural resource. In this work results from April to September 2011 are presented, which comprised analyses of samples from 8 stations in Boka Kotorska Bay. The main aim was to estimate trophic level, of determining the concentration of the physico-chemical parameters, chlorophyll a and TRIX index in Boka Kotorska Bay.

Complex hydrodynamics and thermal regimes of temperate lakes have a major impact on temporal and spatial distributions of water quality indices. Transport processes in lakes are driven primarily by external forces such as wind and solar radiation but also depend on the inflow and outflow regimes. This paper presents a simplified ID model developed to calculate seasonal variations in vertical distributions of temperature and dissolved oxygen in Lake Zavoj in southern Serbia. Model results that were based on monthly averaged meteorological data are in good agreement with measured vertical profiles of temperature and dissolved oxygen. The simplified model is an efficient tool for long-term prediction of water quality indices in deep, medium and long residence time lakes.

On the base of monitoring of water quality for aquaculture, performed since 2010, it is noticed that two positions are showing increased level of trophicity and bacteriological contamination. Changes in sanitary quality of farms are especially intensive during the summer months, so the results of basic physical, chamical and biological parameters, measured during periods June-September 2010 and 2011 are presented and compared.

The aim of this work is to present the trophic state of water at the pelagic zone of lake Prespa, reviewing the result of defined parameters of physico-chemical and algological aspect. Investigations are done according to standard limnological methods and the samples for analysis were collected from one vertical profile (0, 5, 10 and 15 m) monthly during 2008 year. Water categorization, on the basis of gathered data from analyses of the sampling localities was done according to the OECD-regulations, positive law regulations of the Republic of Macedonia and Nürnberg classification system. Data from this investigating period point out that this area of the lake Prespa is by great influence of the anthropogenic factor and intensive eutrophication.