Analysis of the main indicators of pollution in the Dotnuvele and Smilga stream
2016
Miseviciene, S., Aleksandras Stulginskis Univ., Akademija, Kauno reg. (Lithuania)
Due to intensive agricultural activities being developed in Middle Lithuania, the water quality of rivers in this region significantly decreases. Rivers, flowing through the town territory, should provide aesthetic delight to the residents, however, because of pollution, especially at the end of summer; they are usually covered in duckweed and algae layer. The paper presents the change of the main water pollution indicators (BOD7, Ntotal, NH4 -N, NO3 -N, Ptotal, PO4 -P and O2) in Dotnuvele and Smilga streams during 2013 – 2015. The aim of research is to determine the change of the main surface water pollution factors in Dotnuvele and Smilga streams, depending on the meteorological conditions. Data analysis showed that dissolved oxygen, nitrate and total nitrogen concentrations are affected by air temperature: the lower of the air temperature, and the more of these elements were found in the water of the streams, (r = -0.61), (r = -0.83) and (r = -0.64) respectively. An increasing precipitation was also increasing the amount of O2 and NO3 -N in stream’s water, (r = 0.44), (r = 0.49) respectively. Meteorological conditions did not have a significant impact on concentrations of other chemical elements, however, correlation analysis showed that concentrations of BOD7 in streams’ water were increasing as precipitation level was falling (r = 0.41), and PO4 -P – when air temperature was increasing (r = 0.46). It was determined that in every spring the stream’s water quality according to the concentrations of Ntotal and N-NO3 was in a bad or average ecological condition. This was caused by the farming fields from which these streams are collecting drainage water during the spring melt.
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