Monitoring of some dissolved heavy metals in surface waters of north-west Croatia from year 2016 to 2018

Heavy metals have anegative impact on environment and wildlife. In waters, heavy metals appear intwo forms, as dissolved and bioavailable; and as solid and non-soluble. We monitoredthe concentration of dissolved copper, nickel, manganese and iron in watersamples at five river locations of north-west Croatia from 2016 to 2018.Concentrations of dissolved nickel measured at Melačka river, near Vularija inMeđimurje county and HE Čakovec dam, near Štefanec in Međimurje county werebelow 5 µg/l and could be considered as not polluted. Concentrations ofdissolved copper measured at Plitvica river, near Zbela in Varaždinska countyand Horvatska, near Veliko Trgovišće in Krapinsko-Zagorska county were mostlybelow 5 µg/l and could be considered as not polluted. At Kosteljina river nearJalšje at the Krapinsko-Zagorska county concentrations of dissolved copper weremostly below 5 µg/l; concentrations of dissolved manganese and iron were higherespecially during second part of the year, with some fluctuations. For thisreason, Kosteljina river could be considered as medium polluted.