Kinetic determinations of trace element bioaccumulation in the mussel Mytilus edulis

Abstract

ABSTRACT. Laboratory experiments employing radiotracer methodology were conducted to determine the assimilation efficiencies from ingested natural seston, the influx rates from the dissolved phase and the efflux rates of 6 trace elements (Ag, Am, Cd, Co. Se and Zn) in the mussel Mytilus edulis. A kinetic model was then employed to predict trace element concentration in mussel tissues in 2 locations for which mussel and environmental data are well described: South San Francisco Bay (California, USA) and Long Island Sound [New York, USA). Assimilation efficiencies from natural seston ranged from 5 to 18": for Ag, 0.6 to 1% for Am, 8 to 20% for Cd, 12 to 16% for CO, 28 to 34% for Se, and 32 to 41 ' :, for Zn. Differences in chlorophyll a concentration in ingested natural seston did not have significant impact on the assimilation of Am, CO, Se and Zn. The influx rate of elements from the dissolved phase increased with the dissolved concentration, conforming to Freundlich adsorption isotherms. The calculated dissolved uptake rate constant was greatest for Ag, followed by Zn > Am -; Cd > CO > Se. The estimated absorption efficiency from the d~ssolved phase was 1.53 % for Ag, 0.34 % for Am, 0.31 X for Cd, 0.11 % for CO, 0.03"' for Se and 0.89% for Zn. Salinity had an inverse effect on the influx rate from the dissolved phase and dissolved organic carbon concentration had no significant effect on trace element uptake. The calculated efflux rate constants for all elements ranged from 1.0 to 3.0% d-' The route of trace element uptake (food vs dissolved) and the duration of exposure to dissolved trace elements (12 h vs 6 d) did not significantly influence trace element efflux rates. A model which used the experimentally determined influx and efflux rates for each of the trace elements, following exposure from ingested food and from water, predicted concentrations of Ag. Cd, Se and Zn in mussels that were directly comparable to actual tissue concentrations independently measured in the 2 reference sites in national monitoring programs. Sensitivity analysis indicated that the total suspended solids load, which can affect mussel feeding activity, assimilation, and trace element concentration in the dissolved and particulate phases, can significantly influence metal bioaccumulation for particlereactive elements such as Ag and Am. For all metals, concentrations in mussels are proportionately related to total metal load in the water column and their assimilation efficiency from ingested particles. Further, the model predicted that over 96% of Se in mussels is obtained from ingested food, under conditions typical of coastal waters. For Ag, Am, Cd, CO and Zn, the relative contribution from the dissolved phase decreases significantly with increasing trace element parhtion coefficients for suspended particles and the assimilation efficiency in mussels of ingested trace elements, values range between 33 and 67% for Ag, 5 and 1 7 % for Am, 47 and 82% for Cd, 4 and 30% for CO, and 17 and 51 ?h for Zn.

Calcium influence on phosphorus regulation in Daphnia magna: implications for phosphorus cycling

“…With the biokinetic model (Wang et al 1996, Guan & Wang 2006, the steadystate concentration (C ss ) of an element in organisms (µg g -1 dry wt) is calculated by the following equation:…”

“…Therefore, in the present study we used Ca concentrations ranging from 0.5 to 200 mg l -1 . By using the radiotracer 33 P and a well-established biokinetic model (Wang et al 1996, Guan & Wang 2006, it was possible to quantify the effects of aqueous Ca levels on the influx and efflux of P, and on the relative importance of the 3 efflux routes of P. The importance of aqueous inorganic P as a source of P for daphnids was also assessed using the biokinetic modeling approach. …”

Effects of sediment composition on cadmium bioaccumulation in the clam Meretrix meretrix Linnaeus

“…Specifically, Ag associated with the diatom may bind with metal-rich granules (Ag 2 S) in the cell lining of the digestive tract, and the dissolved Ag may be stored in the kidneys in insoluble forms. Therefore, different Ag distributions probably resulted in different k e rates in M. edulis [27]. These studies indicate that Cd accumulated by the bivalves from similar substrates possibly distributed in the same physiological compartments.…”

Relationship of the Clearance Rate and Nonylphenol Uptake Rate of Three Bivalve Species with Different Size Classes and Temperatures

“…기존 연 구에서는 흡수율이 실험용액내 물질의 농도와 비례관계에 있다고 여겨 이미패류를 오염물질의 생물이용도를 측정하기 위한 생물지 시자로 이용하였다. 그리고 흡수율은 용존 오염물질의 생물이용도 를 구하는데 이용되었고, 각각 다른 용존 오염물질의 농도를 이용 하여 구할 수 있었다 (Wang et al,, 1996;Lee et al, 1998). 흡수율 은 환경적인 요인(수온 등)과 생물학적인 요인(개체 크기, 여수율 등)에 의해 영향을 받을 수 있다 (Wang, 2001;Lee and Lee, 2005).…”