Geochemical baseline establishment, contamination level and ecological risk assessment of metals and As in the Limoncocha lagoon sediments, Ecuadorian Amazon region

Abstract Purpose The Limoncocha lagoon, inside a Ramsar site in the Ecuadorian Amazon, increasingly hosts ecotourism and energy development activities. This work estimates local sediments’ baseline of As, Ba, Cd, Co, Cr, Cu, Mo, Ni, Pb, V Zn using four methods. makes it possible to apply single integrated pollution indices estimate contamination level ecological risk sediments. Methods Seven sites were analysed for metal(oid)s by ICP-MS. was estimated relative cumulative frequency method, iterative 2σ- 4σ-outlier-techniques normalisation method “conservative” element. Combinations Cf Ef (NPI, mNPI, mCd, MEQ, RI, mPELq, mERMq TRI) applied. Results had best performance geochemical baselines. classify sediments from “low contamination” remote “moderate “minor enrichment” remaining due Cd concentrations. overall analysis results Cu being identified as priority pollutants because they have occasionally been associated with adverse biological effects centre lagoon most anthropised areas. These are classified moderately polluted medium–low level. Conclusions provides sediment indicators pollutants, which could be incorporated into quality assessment monitoring programme lagoon. Cr high values comparison SQGs, their potential risk, should special attention. Graphical abstract