evaluation of environmental impact and risk in prut river using five indicators (cbo5, cco-cr, so42-, no2-, no3-)

prut river is very important for sustaining the biodiversity and economical activities in its area for romania, ukraine and republic of moldova. anthropogenic activities are present everywhere especially near a big water flow because they need a close water resource. the major problems remain the impact and a possible risk produced as a negative result in these activities (agriculture close to river, wastewater from the cities, animal farms, industry and others). in case of prut river, there were constructed matrices for evaluation of environmental impact and risk using five different indicators (cbo5, cco-cr, so42-, no2- and no3-) during different months (september, october, november and december 2013). the sampling sites were fixed between costesti-stanca and giurgiulesti that covered a large area of study. the impacts and risks were analyzed according to each indicator and as total ones. the resulted values were integrated in different classes for impact - ei (b-environmental impact which does not cross the maximum admitted value c-environmental impact that creates slight disturbance of the organisms d-environmental impact that creates high disturbance of the organisms) and risk – er (a-insignificant risks b-minor risks = monitoring it is not required c-medium risks = monitoring is very required). the conclusions suggested that the impact is different according to each analyzed indicator and to sampling period. the highest peak was recorded between the sampling stations leuseni and leova.