Barnacle species as biomonitors of metal contamination in the northwest coast of Portugal: Ecological quality classification approach

This work discusses the simultaneous use of barnacles C. montagui and P. pollicipes as biomonitors of metal (Cd, Cr, Cu, Fe, Mn, and Zn) contamination in the northwest (NW) coast of Portugal during the four seasons of 2011. The metal concentrations in soft tissues of both barnacles species, metal bioaccumulation factors (BAFs), and ecological quality classifications of coastal waters are presented. The most and the least metal-contaminated locations were, respectively, location 5 (“Cabo do Mundo”) and location 10 (“Moledo”). The most and the least metal-contaminated seasons of 2011 were, respectively, autumn and winter. Temporal comparisons with previous works of 2009–2011 showed that C. montagui bioaccumulated Cd, Cr, and Fe at higher rates and P. pollicipes accumulated more Zn besides Cd and Fe. In addition, global mean BAFs showed that the best season to collect both barnacle species for metal contamination assessment/monitoring purposes in future works would be spring and that P. pollicipes would be the best barnacle species to monitor metals. In terms of ecological quality classification, all NW coast of Portugal should be classified as “Class III – Remarkably Polluted” due the high concentrations of Zn found in barnacles species during the four seasons of 2011. This work suggested that both barnacle species are suitable species to be included in the Portuguese Environmental Specimen Banks under European Marine Strategy Framework Directive 2008/56/EC.