RT journal article T1 Geochemical baseline establishment, contamination level and ecological risk assessment of metals and As in the Limoncocha lagoon sediments, Ecuadorian Amazon region A1 Coral Carrillo, Katty A1 Rodríguez Romero, Araceli A1 Tovar-Sánchez, Antonio A1 Ruiz‑Gutiérrez, Gema A1 Viguri Fuente, Javier R. A2 Química Analítica K1 Limoncocha lagoon K1 Ramsar site K1 Sediment K1 Geochemical baseline K1 Potentially toxic elements K1 Individual and integral indices AB Purpose The Limoncocha lagoon, inside a Ramsar site in the Ecuadorian Amazon, increasingly hosts ecotourism and energy development activities. This work estimates the local sediments' baseline of As, Ba, Cd, Co, Cr, Cu, Mo, Ni, Pb, V and Zn using four methods. This makes it possible to apply single and integrated pollution indices to estimate the contamination level and the ecological risk of the sediments.Methods Seven sites were analysed for metal(oid)s by ICP-MS. The local baseline was estimated using the relative cumulative frequency method, the iterative 2 sigma- and 4 sigma-outlier-techniques and the normalisation method to a "conservative" element. Combinations of single Cf and Ef and integrated indices (NPI, mNPI, mCd, MEQ, RI, mPELq, mERMq and TRI) were applied.Results The relative cumulative frequency method had the best performance for the geochemical baselines. Cf and Ef indices classify sediments from a "low contamination" remote site to the "moderate contamination" and "minor enrichment" of the remaining sites due to As, Cd and Zn concentrations. The overall analysis of the integrated indices results in Ni, Zn and Cu being identified as priority pollutants because they have occasionally been associated with adverse biological effects in the centre of the lagoon and in the most anthropised areas. These are classified as moderately polluted with a medium-low priority risk level.Conclusions This work provides sediment baseline and contamination indicators for pollutants, which could be incorporated into the sediment quality assessment and monitoring programme of the Limoncocha lagoon. Ni, Cd and Cr due to the high baseline values in comparison with SQGs, and Cu and Zn due to their potential risk, should be of special attention. PB SPRINGER SN 1439-0108 YR 2022 FD 2022-01 LK http://hdl.handle.net/10498/27269 UL http://hdl.handle.net/10498/27269 LA eng DS Repositorio Institucional de la Universidad de Cádiz RD 13-nov-2026