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Williamson, C.E., Stemberger, R.S., Morris, D.P., Frost, T.M., Paulsen, S.G., 1996. Ultraviolet radiation in North American lakes: attenuation estimates from DOC measurements and implications for plankton communities. Limnology and Oceanography 41, 1024–1034. 0025-326X/$ - see front matter Crown Copyright Ó 2006 Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.marpolbul.2006.11.011 Mercury contamination in invertebrate biota in a temperate coastal lagoon (Ria de Aveiro, Portugal) J.P. Coelho b, * , E. Policarpo a , M.A. Pardal c , G.E. Millward a , M.E. Pereira b , A.C. Duarte a a School of Earth, Ocean and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth, PL4 8AA, UK b CESAM – Chemistry Department, University of Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal c IMAR – Institute of Marine Research, Zoology Department, University of Coimbra, 3004-517 Coimbra, Portugal Mercury is an element that has both natural and anthro- pogenic sources (OSPAR, 2004). Given the significant inputs of mercury to the environment, this metal is consid- ered a ‘‘blacklisted’’ pollutant in terms of environmental damage and a threat to human health. Its high mobility, persistence in the environment, and lipophilicity, justify the importance of the environmental study of mercury, as it is a toxic element to all living organisms (Boening, 2000). The Ria de Aveiro (Fig. 1), situated on the northern coast of Portugal and with a total area ranging from 83 (high tide) to 66 km 2 (low tide) (Dias et al., 2001) has, for the past five decades, received continuous discharges of a mercury-rich effluent from a chlor-alkali factory. This situation led to widespread contamination of sediments, water and biota of the area, and created a well defined anthropogenic mercury gradient in the system. Research on the fate and behavior of mercury in the nearby area of the discharge has so far focused mainly on identifying the major impacted areas, quantifying the level of contam- ination and assessing the response of mercury to physico- chemical changes in sediment and water (Pereira et al., 1998a,b). Determinations of mercury concentrations in marine biota are limited to plankton (Monterroso et al., 2003), estuarine macroalgae (Coelho et al., 2005) and sea bass (Abreu et al., 2000), hence further work is required on other species, especially edible varieties with economic interest. The main aim of this work was to assess the mercury accumulation through various trophic levels in locations subject to different contamination levels, and relate it to sediment, water and suspended particulate matter (SPM) mercury concentrations. Moreover, to verify whether mer- cury accumulation represents any potential risk for public health, economically important macroinvertebrate species placed at different levels of the food web were selected: (a) Nereis diversicolor, (a subsurface deposit feeder) used as fish bait; (b) Scrobicularia plana (a surface deposit feeder) and (c) Carcinus maenas (an omnivore or top predator). Three locations were selected for sampling, as shown in Fig. 1. The Laranjo Basin corresponds to a highly contam- inated area located close to the mercury discharge source, whereas the two other sites, Coroa and Mira, are located at two opposite extremes of the lagoon, respectively the furthest and closest to the estuary mouth. All samples were collected on a consecutive three-day sampling campaign in the summer of 2003, at equivalent * Corresponding author. Tel.: +351 234370737; fax: +351 234370084. E-mail address: jcoelho@dq.ua.pt (J.P. Coelho). Baseline / Marine Pollution Bulletin 54 (2007) 464–488 475