Relatively dense network of irrigation channels in Vojvodina is exposed to various point and non-point pollutants impacts. Therefore, deposited channel sediments-sludges can be contaminated with high concentration of dangerous and harmful substances such as polycyclic aromatic hydrocarbons (PAH). These sediments could have long lasting harmful effects on environmental status, quality and usability of channel water, and especially on surrounding agricultural soil, where dredged sediments are deposited or scattered. In this paper above mentioned conclusions are illustrated by quality analysis of specific irrigation channels sediments in terms of PAH contents in them.

The paper presents the results of orthophosphate concentration trends in waterflows in Serbia, using the method of non-parametric Mann-Kendal test. Data used for these purposes were provided by Republic Hydrometeorological Service of Serbia (RHMZ), sampled on average once a month for the period 1998-2007. Measuring places are shown on the waterflow map by adequate symbol for the various kind of trend and colour of symbol for the intensity of orthophosphate concentration. Statistical analysis of trends is discussed within the comparative review of methods of linear regression and Mann-Kendall test.

Water quality analysis of Zelengora natural lakes, were included researches of Kotlanicko, Orlovacko and Lake Donje Bare. Apart from comprehensive analyses which demand determinations of physical-chemical characteristics, special emphasis is given to the analysis of the makrozoobenthos. As a part of all water ecosystems, benthic invertebrate serve as a reliable indicator of the quality and changes of the environment, due to a series of advantages in relation to other aquatic communities. Most of the aquatic environments of good quality of water and benthic state, enable various of benthic invertebrates communities with moderate formation of species within the overall number of the present individual species. This kind of communities react to possible changes in the community composition (abundance and macroinvertebrata composition).

During the period of 2004-2005 ichthyological research on natural waters of Bardaca wetland (Bosnia and Herzegovina) was carried out and the occurrence of 24 fish species was recorded. On the basis of the occurrence and abundance of fish species indicators as limnosaprobic parameter, water quality of the analyzed watercourses (rivers Matura and Brzaja) was found to be beta mesosaprobic (the 2nd class of bonity) with saprobic index 2.02 for Marura River and 2.03 for Brzaja River. The obtained results indicate that water quality of this part Bardaca wetland was on satisfactory level for multiple purposes (as a source of water for Bardaca fishpond and in order to sustain ichthyofauna diversity and production.

In the paper we presented the effort to collect the recent data clarifying eutrophication as one of the commonest problems of freshwater. The paper includes experience of researchers related to causes of onset and effects of eutrophicational processes on trophic level increase in reservoirs.

Environment is subject of changes in the presence of aquatic pollutants which increase synthesis of biotransformation enzymes and elicitate oxidative stress in aquatic organisms. Monitoring changes of quality of aquatic ecosystems could be based on watching certain biomarkers, like biochemical, molecular and physiological responses of aquatic organisms after exposure to organic toxicants.

Introduction of allochthonous species may have noticeable affects on populations communities of native species, ecosystem, but also could result in socio-economic consequences. Therefore, creating and applying risk assessment protocols of aquatic invasive species is a main step in supression of biological invasions. SBC index is used for estimation of biological contamination.

In this article we treat the problemof nonpoint source pollution as a problem of moral hazard in group. To solve this kind of problemwe consider a group performance based tax coupled to tradable permits market. The tax is activated if the group fails to meet the ambient standard. So the role of the tax is to provide an incitation to ensure that the agents provide the abatement level necessary to achieve the standard. The role of the tradable permits market is to distribute effectively this abatement level through the price of the permits which rises with the exchange of the permits.

Arsenic is inorganic spread out in nature. Toxicity of arsenic is different, depending on its form. However, current international and Serbian legislation in drinking water regulate maximum allowed concentration of 0.010 mg/l (of total arsenic), regardless of its form. Concentration of total arsenic in water of springs of mountain Avala (Serbia) is higher than 0.010 mg/l. This paper present determination of inorganic arsenic in drinking water of spring Sakinac (Avala), also determination which form is more represented, relation of As(III) and As(V) and implementation of legislation. We used stripping voltametry method and gain value of total arsenic-62.87 microgram/l, in which 3.97 microgram/l is As(III) and residue of 58.90 microgram/l is As(V). It is obvious that value of 62.87 microgram/l is higher than MAL, but the most abundant arsenic form is less toxic, so the question is whether the water from spring Sakinac can or cannot be used.

This study investigates removal efficiency of arsenic species from water on natural and modified sorbent materials. Selective removal of As(III) and As(V) from water was carried out with pure natural materials: bentonite, sepiolite, limonite, pyrolusite and zeolite. Materials most commonly used in water treatment, quartz sand and granular active carbon, were modified by iron coating in order to increase its sorption capacity. For the purpose of comparison, commercial material, granular ferry hydroxide (Everzit As), was investigated under the same conditions. The investigations were performed in batch experiments following the standard experimental methodology. Of all the tested natural materials zeolite exhibited significant sorption capacity: 100 microgram As(III, V)/g. Iron coating increased materials sorption capacity for at least 80%. Iron coated sand and iron coated activated carbon exhibited 340 and 430 microgram As(V)/g respectively.