A method to assess the evolution and recovery of heavy metal pollution in estuarine sediments: Past history, present situation and future perspectives

A methodology to assess the historical evolution and recovery of heavy metal pollution in estuarine sediments was developed and is presented here. This approach quantifies the distribution of heavy metals in sediment cores, and investigates the influence of anthropogenic activities and/or core locations on the heavy metal pollution, by proposing and using sediment quality indices and polynomial regressions.& para;& para;The method has been applied to the Suances Estuary confirming its suitability as a comprehensive and practical management tool. In this estuary, the evolution of heavy metal pollution (since 1997-1998 to 2015)pointed out the deeper the sediments, the more polluted, indicating a recovery at the upper layers due to the closure and ending of washing discharges from mining, and the reduction of metal loads from industrial waste waters. In terms of global pollution, the intertidal and subtidal sediments will require 43.1 +/- 2.8 and 8.6 +/- 0.6 years to be unpolluted, respectively.