Concentraciones de metales trazas en aguas superficiales de cinco ríos ecuatorianos y su comparación con estándares internacionales de calidad del agua

• DOI: https://doi.org/10.22533/at.ed.273122514073

• Palavras-chave: Aguas superficiales, ríos, metales trazas, Ecuador.

• Keywords: Surface water, rivers, toxic metals, Ecuador

• Abstract: The contamination of natural water sources represents a global risk to human health and aquatic ecosystems. The objective of this study was to analyze the total metal content (Al, Cd, Co, Cu, Fe, Mn, Ni, Pb, Zn) in 15 surface water samples collected in May 2024 from the Teaone, Chone, Cajones, Chico, and Portoviejo rivers (Ecuador). Metals were quantified using inductively coupled plasma optical emission spectrometry (ICP-OES). The results showed that the analyzed rivers did not comply with the trace-metal quality requirements established by Ecuadorian environmental regulations. The mean concentrations of Al (164–240 µg/L), Cd (2–6 µg/L), Cu (67–74 µg/L), Pb (15.8–19.1 µg/L), and Mn (4–240 µg/L) exceeded the Ecuadorian guideline values in most of the river samples analyzed (n = 15). According to the TULSMA standards on admissible water-quality criteria for the preservation of aquatic and wildlife in freshwater systems, the Ecuadorian maximum permissible limits (MPLs) for Al, Cd, Cu, Pb, and Mn are 100, 1, 5, 1, and 100 µg/L, respectively. Therefore, the concentrations of Al, Cd, Cu, and Pb exceeded their MPLs in 100 % of the rivers analyzed in this study, with the exception of Mn, which exceeded the limit in only one river (20 %). The concentrations of Cd and Pb exceeded these limits in all rivers and were also above the World Health Organization (WHO) guideline values (3 µg/L for Cd and 10 µg/L for Pb). In contrast, Co, Ni, and Zn were found below the detection limit. The elevated Cd and Pb levels suggest a possible anthropogenic influence, underscoring the need to investigate potential pollution sources and to initiate protective measures for the most vulnerable areas.