The article discusses the influence and main causes of nutrient compounds in surface waters. The article is aimed at investigating changes in nutrients – nitrogen and its compounds in the river Šventoji. The samples of analysis were collected in the town of Anykščiai in order to assess the influence of the stream of the Anykšta and waste water treatment. The largest concentrations of nutrients were identified from waste water treatment; however, it had not exceeded the MAC, except for February 2012. The conducted analysis has shown that the river Šventoji belongs to the class of a high ecological status, because physic – chemical quality elements such as nitrate – nitrogen (0,60 mg/l) and ammonium – nitrogen (0,03 mg/l) have not exceeded the range <1,30 mg/l and 0,10 mg/l.

Article in Lihuanian