Chemical characteristics with attention on toxic metals content in sediments of the urban tropical ecosystem Río Almendares, Havana, Cuba: Pollution risk assessment

Abstract

Anthropogenic disturbances have dramatically impacted surface water quality worldwide. There is no restriction placed on waste disposal in developing countries, so micropollutants, including metals, are of major concern to soil and water. A tropical river ecosystem was selected as a model for this study: Almendares River (Havana, Cuba). We investigated the occurrence of 15 toxic metals in surface sediment for ecological risk analysis. Results indicated that sediments of a silty loam type had higher concentrations of four metals (Cr concentration range: 3.59–7.35 mg kg−1, Cu: 6.23–14.82 mg kg−1, Zn: 22.64–27.40 mg kg−1, and Pb:3.85–6.72 mg kg−1), than Cuban norms. Further, the contamination indices including Enrichment Factor (EF), Geo-accumulation, Contamination Factor, Contamination Degree, Ecological Risk Factor and Potential Ecological Risk were calculated. 10 elements presented significant enrichment at the sampling stations of the 15 metals examined; Zn, Cd, Pb, Cu, and Ag had the highest EF values. Anthropogenic activities and polymetallic contamination could be the main source of these five heavy metals. The correlation analysis revealed that domestic, agricultural, and industrial sources were the main sources of contamination, along with an unregulated landfill. In terms of the extent of metal contamination in the urban site (Zone II) of Almendares River, this study constitutes the most comprehensive and extensive. The study contributes to the knowledge of the region and is crucial for the sustainable management of the Almendares River. There must be efforts made to control metal pollution in this river and ensure that metal levels are monitored.