Field transplantation of the freshwater bivalve Corbicula fluminea along a polymetallic contamination gradient (river Lot, France): I. Geochemical characteristics of the sampling sites and cadmium and zinc bioaccumulation kinetics

Abstract

Specimens of the Asiatic clam Corbicula fluminea were transplanted from a clean lacustrine site to four stations along a polymetallic gradient in the river Lot (France), downstream from an old Zn ore treatment facility. The bivalves were held in benthic cages for a 5-month exposure period, April to September 1996; mollusk growth and metal bioaccumulation kinetics (Cd, Zn) were followed by subsampling the cages at t ϭ 0, 21, 49, 85, 120, and 150 d. Rates of Cd bioaccumulation in the whole soft bodies and in individual organs were greater at the upstream stations located close to the pollution source, but there was no direct proportionality between Cd in the bivalves and in the unfiltered or filtered river water samples. Unlike the case for Cd, rates of Zn bioaccumulation did not reflect the contamination gradient. Marked growth differences were measured among the four stations, reflecting both nutritional differences and changes in the degree of metal contamination; these growth differences produced markedly different trends when metal bioaccumulation was expressed in terms of burdens rather than concentrations.

Phototrophic Biofilm Activity and Dynamics of Diurnal Cd Cycling in a Freshwater Stream

“…Such a mechanistic understanding of dynamic metal partitioning is critical to our knowledge of how potentially bioavailable chemical metal species behave in natural systems (see also Tercier-Waeber et al (doi: 10.1021/es900247y), this issue). We focused our work on Cd because of its toxicity, and because previous studies have reported eco-physiological effects of Cd contamination in Riou Mort, including reduced biofilm thickness and increased morphologic abnormality of diatom cells , and greatly elevated Cd body burdens in bivalves and fish , .…”

Comparison of periphytic biofilm and filter-feeding bivalve metal bioaccumulation (Cd and Zn) to monitor hydrosystem restoration after industrial remediation: a year of biomonitoring

“…28 Corbicula fluminea lives buried in the superficial sediment layers but remains in direct contact with the water column on which it depends for its respiratory and nutritional filtration activity. 29 Storage and concentration of contaminants such as heavy metals in Corbicula fluminea tissues 30,31 are the results of ingestion of the dissolved form (direct contamination), or adsorption onto potentially nutritive particles (trophic contamination). 32 This close relation with the water column makes Corbicula fluminea a good bioindicator for water pollution biomonitoring.…”

“…Metal in the dissolved phase is considered the most bioavailable with respect to the biological barriers that are in direct contact with the surrounding medium, especially gills. 30,46 For this reason, BCFs measured for dissolved metals are higher than particulate metal BCFs. Corbicula fluminea shows a BCF inversely proportional to the environmental contamination, as was described for molluscs by Mc Geer.…”

Importance and Difficulties of Research on Metal Speciation in the Aquatic Ecosystem: an Ecologist's Viewpoint

“…[33][34][35] In addition, useful information may be obtained by adopting "active biomonitoring", which consists in transferring bioaccumulators from a clean environment to a polluted one to be monitored. 36,37 This type of technique, as well as producing useful information on the contamination level of the environment, may be used to estimate the uptake-rate of various pollutants in the bioaccumulators by analysing periodically sampled individuals. At the end of the monitoring, if the contaminated environment contains an adequate number of unused bioaccumulators, they can be returned to the clean environment and used to calculate the loss-rate of the pollutants taken in during their permanence in the polluted environment.…”