title: Combined use of Nassarius reticulatus imposex and statolith age determination for tracking temporal evolution of TBT pollution in the NW Portuguese continental shelf.
abstract: Spatial and temporal trends of tributyltin (TBT) pollution on the northern continental shelf of Portugal (5-34 m depth) were assessed using Nassarius reticulatus as a bioindicator. Imposex levels were determined in 2006 and 2010, and integrated with age readings from statoliths for a better chronological analysis of the data. Females affected with imposex were detected in 84% of the sites surveyed in 2006, with levels higher than the Ecological Quality Objective (EcoQO) set by the OSPAR Commission for N. reticulatus (VDSI < 0.3) in approximately half of those sites. In 2010, imposex was only detected in 20% of the surveyed sites and, when detected, the VDSI were lower than the EcoQO, except for one location. The comparison between the current results and the levels previously reported for 2004 and 2005 in the same offshore area evidences a clear decline of imposex in 2010 that confirms the efficacy of Regulation (EC) No. 782/2003 and the IMO AFS-Convention (entered into force in 2003 and 2008, respectively). Moreover, the age of the whelks used in the monitoring is estimated in 3-5 years, indicating that actual TBT water contamination in 2010 may in fact be lower than that extrapolated from the imposex levels. We conclude that the legislation was indeed very effective in reducing TBT pollution in the NW Portuguese continental shelf, not only in terms of the magnitude but also in terms of fast field repercussion.
authors: Department of Biology & CESAM, University of Aveiro, 3810-193 Aveiro, Portugal. cmiguez@ua.pt
authors: Carlos M
authors: CM
authors: Barroso
authors: Milene
authors: M
authors: Rato
authors: Alfredo
authors: A
authors: Veríssimo
authors: Ana
authors: A
authors: Sousa
authors: José António
authors: JA
authors: Santos
authors: Sónia
authors: S
authors: Coelho
authors: Miguel B
authors: MB
authors: Gaspar
authors: Francisco
authors: F
authors: Maia
authors: Susana
authors: S
authors: Galante-Oliveira
mesh_terms: D000367:Age Factors; D000818:Animals; D001267:Atlantic Ocean; D012734:Disorders of Sex Development / Q000139:chemically induced*; D004784:Environmental Monitoring / Q000379:methods*; D005260:Female; D049851:Gastropoda / Q000187:drug effects*; D016018:Least-Squares Analysis; D008297:Male; D011174:Portugal; D013997:Time Factors; D014220:Trialkyltin Compounds / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000633:toxicity*; D014877:Water Pollution, Chemical / Q000032:analysis* / Q000331:legislation & jurisprudence
chemical_list: D014220:Trialkyltin Compounds; D014874:Water Pollutants, Chemical; C011559:tributyltin