Combined use of Nassarius reticulatus imposex and statolith age determination for tracking temporal evolution of TBT pollution in the NW Portuguese continental shelf

摘要: Spatial and temporal trends of tributyltin (TBT) pollution on the northern continental shelf Portugal (5–34 m depth) were assessed using Nassarius reticulatus as a bioindicator. Imposex levels determined in 2006 2010, integrated with age readings from statoliths for better chronological analysis data. Females affected imposex detected 84% sites surveyed 2006, higher than Ecological Quality Objective (EcoQO) set by OSPAR Commission N. (VDSI < 0.3) approximately half those sites. In was only 20% and, when detected, VDSI lower EcoQO, except one location. The comparison between current results previously reported 2004 2005 same offshore area evidences clear decline 2010 that confirms efficacy Regulation (EC) No. 782/2003 IMO AFS-Convention (entered into force 2003 2008, respectively). Moreover, whelks used monitoring is estimated 3–5 years, indicating actual TBT water contamination may fact be extrapolated levels. We conclude legislation indeed very effective reducing NW Portuguese shelf, not terms magnitude but also fast field repercussion.