Assessment of heavy metals pollution in sediments from reservoirs of the Olt River as tool for environmental risk management

Abstract

Heavy metals are among the most persistent pollutants in the ecosystem due to their resistance at decomposition in natural condition. They have low solubility in water and tend to be adsorbed and accumulated on bottom sediments. Anthropogenic actions conduct to the discharge of heavy metals from various sources (industrial, urban, and/or agriculture) to rivers water that are ultimately immobilized in marine sediments under current action. In this work, an investigation of pollution and ecological risk in the Olt River waters is performed based on assessing the accumulation of heavy metals in sediments. Therefore, sediment samples were collected from 22 locations on the Olt River, in its middle and lower basin, and investigated by inductively coupled plasma mass spectrometry which allows us to measure very low elements concentration levels. Two main aspects were foreseen in this study: (i) determining the content and spatial distribution of heavy metals in the Olt River surface sediments, and (ii) assessing the pollution level based on various parameters, namely the contamination factor, the geo-accumulation, pollution load and Nemerow pollution indexes, the potential ecological risk, and risk assessment code. This methodology proves to be an appropriate tool to apply in decision-making on environmental risk management.