MODEL DATA VERSUS REAL DATA: HAVE THEY MATCHED IN REVISITED MERCURY CONTAMINATED COASTAL LAGOON (RIA DE AVEIRO, PORTUGAL)?

摘要

Back in 1994, several studies on mercury accumulation in the Laranjo Basin allowed the use of a mathematical model (EcoS) to estimate mercury concentration and mercury distribution on the surface sediments along the Esteiro de Estarreja channel and to predict mercury dispersion in following decades. The aim of this study is a long-term evaluation of the mathematical model, comparing model data predicted to 2007 (obtained back in 1995 as "the future scenario") and field data obtained in 2007. Results show that field data from 2007 are in agreement with the model scenarios for 2005-2010 when considering the Hg accumulation in downstream areas of the Estarreja channel. As predicted by the model, field data suggests a dilution/lixiviation process in the contaminated sediments surface in conjugation with a deposition/ressuspension downstream movement of contaminated particles towards the lagoon. However, ECoS predictions still underestimates mercury accumulation for the first 2000 m. Long-term evaluation of Ria de Aveiro enhances modelling as a useful toll predicting "future scenarios" concerning mercury contamination and recovery time.