MP8 Metals in the Environment: Dietary concerns in Aquatic Systems
Monday, 14 November 2005: 8:00 AM - 5:30 PM in Exhibit Hall

(GRI-1117-850015) Metal bioaccumulation in Mediterranean mussels: Application of DYMBAM and other models to Mytilus galloprovincialis.

Griscom, S^{1, 2}, Thebault, H², Desnues, A², Shine, J¹, Senn, D¹, Andral, B³, Gonzalez, J-L³, Kantin, R³, Sauzade, D³, ¹ Harvard School of Public Health, Boston, MA, USA² Institute de Radioprotection et Sureté Nucléaire, La Seyne-sur-mer, France, France³ IFREMER, La Seyne-sur-mer, France, France

ABSTRACT- Marine mussels, Mytilus sp., have been used worldwide for many years as biomonitors of coastal contaminants, such as trace metals. While monitoring programs are useful for tracking trends and narrowing our focus onto contaminants of concern, little infomation is produced that reveals the mechanisms controlling metal accumulation or the route of uptake. Recent laboratory studies have illuminated many of the mechanisms and physico-chemical parameters that influence metal bioaccumulation in mussels but the relative importance of these controling factors are unknown in nature. This study assesses a dynamic multi-pathway bioaccumulation model (DYMBAM) and evaluates the relative importance of several parameters during a one-year field experiment. The DYMBAM model is based on the assumption that metal bioaccumulation is the result of a balance among three mechanisms: uptake-rate from food, uptake-rate from dissolved forms, and loss-rate out of the organism. In October, 2004, caged mussels were placed in 4 sites across a contamination gradient. Each month, mussel and water samples are collected and total metal concentrations are measured in mussel soft tissue, suspended particulates, filtered water, and in passive equilibrium samplers ("Gellyfish"). Bioavailable particulate metals (> 5.0 m) are charaterized by filtration followed by extraction in 5% HCl for 1 h. Additional data include: total suspended solids, DOC, Chl-a, phytoplankton ID, temperature and salinity. Condition index (dry-tissue/dry-shells) of mussels is used to account for changes in metal concentrations due to seasonal effects (ie.; spawning or food availability). Utilizing laboratory-derived uptake- and loss-rate parameters combined with metal concentrations in various fractions of food and water, and in Gellyfish, model-calculated metal concentrations in mussels will be compared with metal concentrations mussels in the field. In addition, the DYMBAM model will be tested with historical mussel monitoring data to create data of greater ecological relevance (past mussel data may be useful to approximate past metal concentrations in the dissolved and particulate phases).

Key words: mussel, metals, modelling, bioavailability