Thisworkdemonstrates the huge complexity of the biological systems
as not always the most abundant elements are the most bioavailable or
even the most toxic. Moreover, organic pollutants have not been taken
into account in this work, whereas several studies have pointed out the
importance of the presence of persistent organic pollutants in the Ebro
basin that could contribute to the environmental risk (Lacorte et al.,
2006; Terrado et al., 2010). In spite of this, another study performed
in Spanish basins (including Ebro river) that took into account 339 pollutants,
concluded that metals were the main contributors to the