Quality of running water from Dniester river hydrographic basin (in limits of the Republic of Moldova)

Abstract

The paper presents the results of studies focused on the quality parameters of Dniester river and its tributaries. Selfpurification capacity of the running waters in the studied area has average values of 0.30 - 0.35. Water of the Raut river (main tributary of Dniester river) has a self-purification capacity of 0.25 upstream of Orhei city and only of 0.16 downstream of Orhei city, which confirms the massive impact of wastewater discharged into the river. The investigated surface waters, taking into account the consentrations of organic substances (CCO-Cr and CBO5) are classified as being of class I (very good) - III (moderately polluted) quality. Water of the Raut river is classified as class II (good) - IV (polluted). Taking into account the Fe and Zn content, the rivers are classified as being of Class I (very good) - II (good) of quality. Content of Cu, Cd and Pb in water ranks it in class II (good) - III (moderately polluted) of quality, except water of the Raut river were their content classified water as class II (good) - >V of quality (very polluted/degraded). Content of heavy metals in underwater sediments are at admissible limits. Only the content of Pb in sediments of the Raut river both upstream and downstream of the Orhei town exceeds 2 times its limit in underwater sediment.

Keywords

• Self-purification capacity
• organic substances concentration (CCO-Cr and CBO5)
• heavy metals