Bioavailability of Cr(III) and Cr(VI) to Marine Mussels from Solute and Particulate Pathways

Abstract

Mussels have been extensively used as biological monitors of coastal contamination. This study measured the assimilation efficiencies (AEs) of Cr(III) and Cr(VI) in the mussel Mytilus edulis from ingested food, uptake from the dissolved phase, and the physiological efflux rates following uptake. A bioenergetic-based kinetic model was then employed to determine the relative contributions of different Cr species and their accumulation pathways to the overall concentration of Cr in mussels. The concentration factors of Cr(III) in four diverse marine phytoplankters ranged between 10 4 and 10 5 , whereas for Cr(VI) they were 2 to 5 × 10 2 . Rapid reduction of Cr(VI) to Cr(III) was observed in coastal sediments. AEs of Cr(III) in mussels from ingested sediments were consistently <1%, whereas the AEs of Cr(VI) from ingested phytoplankton were 1-10%. The uptake rate of Cr(VI) from the dissolved phase was 3 times higher than Cr(III). The efflux rate constant was 0.011 d -1 for mussels following 7 d dissolved uptake of Cr(VI) and 0.010 d -1 following 8 d ingestion of Cr(III)-labeled diatoms. The model predicted concentrations of Cr in mussels in South San Francisco Bay that are directly comparable to measured Cr concentrations. The model predicts that 13-38% of Cr in mussels is from dissolved Cr(VI), whereas the remaining Cr is from ingested Cr(III); dissolved Cr(III) and ingested Cr(VI) contribute little to Cr accumulation in mussels. The AE of Cr and its concentration in seston critically influence Cr concentrations in mussels.

Mercury in fishes from Augusta Bay (southern Italy): Risk assessment and health implication

“…The Hg accumulation in marine fish primarily depends on some important biokinetic parameters: assimilation from the ingested prey, uptake constants from the aqueous phase, de-toxification rate (Wang, 2012;Wang et al, 1997Wang et al, , 1998Wang and Fisher, 1999;Dang and Wang, 2011) and environmental features (e.g., Hg concentration and speciation in seawater, dietary sources, etc.) (Wang and Wong, 2003 Several studies have demonstrated that Hg concentrations in the muscles of marine organisms proportionally increase with size and age (Lange et al, 1994;Burger et al, 2001;Green and Knutzen, 2003;Simonin et al, 2008).…”

Bioaccumulation kinetics and exposure pathways of inorganic mercury and methylmercury in a marine fish, the sweetlips Plectorhinchus gibbosus

“…Experimental studies on the routes of methylmercury exposure in fishes are indeed rather controversial (Honda et al 1978, Phillips & Buhler 1978, Fujiki 1980, Hall et al 1997. Kinetic modeling now offers a powerful approach for delineating the exposure of different metal species and pathways (Wang et al 1997, 1998, Wang & Fisher 1999. Within the framework of the kinetic model, however, some important parameters need to be quantified, including the assimilation efficiency from the ingested prey, the uptake-rate constant from the aqueous phase, and the elimination-rate constant, as well as some physiological and geochemical parameters such as the feeding rate of the animals and the concentrations of metals in the water and in the dietary sources.…”

Kinetics of oxidation of Cr(III)-organic complexes by H2O2

“…Cr(VI) has obtained much attention because of its toxicity and mobility (Oshida et al, 1981;Holdway, 1988;Nieboer and Jusys, 1988;Wang et al, 1997;Sivakumar and Subbhuraam, 2005). Numerous reductants can reduce Cr(VI) to Cr(III).…”