Eureka! Institutional Repository

The quality of the surface water is defined by physical and chemical parameters that appeared to have physical seasonal changes. The following bachelor’s thesis intends to study the fluctuation of the physical and chemical properties at samples from the Axios’ river water. The monitoring of the parameters that define these properties took place during three months, from March to May 2019. Specifically, the measured parameters were: Dissolved Oxygen (DO), Biological Oxygen Demand (BOD), Chlorophyll a, Dissolved Organic Carbon (DOC), the Extinction Coefficient at UV (254 nm), temperature, turbidity, electrical conductivity, alkalinity, pH, Total Suspended Solids (TSS) and Total Dissolved Solids (TDS). The results were analyzed with the application of methods of simple linear regression, with the use of the statistic program Microsoft excel 2016. BOD5 values ranged between 0.32 to 2.42 mg O2/L, Dissolved Oxygen from 8.05 to 11.59 mg O2/L, and Chlorophyll a values ranged from 2.57 to 13.54 mg/m3. The range of the amount of Dissolved Organic Carbon was 0.81 to 2.77 mg C/L. Furthermore, the measurements of the Total Suspended Solids appeared to be from 0.01 to 0.05 g/L and Total dissolved solids from 0.31 to 6.19 g/L. The measurements of pH had not shown great variation. The results showed increased photosynthetic activity at normal temperatures for the season and good water quality of the river Axios according to the limits of the legislation, as defined by the low and the European Union directives.