Bioaccumulation of trace metals in the Antarctic amphipod Orchomene plebs: evaluation of toxicokinetic models

Bioaccumulation of Cd, Co, Cu, Ni, Pb and Zn in Antarctic gammaridean amphipod collectives, Orchomene plebs (Hurley, 1965), was investigated during a cruise of RV "Polarstern" to the Wedell Sea. With the sole exception of Cd the organisms accumulated metals during exposure and depurated them in uncontaminated seawater. Four independent toxicokinetic experiments and one field study were modelled simultaneously to calculate the following size-dependent bioconcentration factors for organisms with body length 10 mm (BCF(10 mm)): 130 (Co), 4030 (Cu), 190 (Ni), 2900 (Pb), and 5210 (Zn). On the time scale of our experiments the data suggest an increased metal uptake by previously exposed test organisms. The collectives investigated may be regarded as potentially suitable biomonitors for Co, Cu, Ni, Pb and Zn but not for Cd. An approach to evaluate the sensitivity of Orchomene plebs as a biomonitor of waterborne metals in the field indicates minimal increments of the ambient exposure concentrations of 0.01 microg Co l(-1), 0.2 microg Cu l(-1), 0.4 microg Ni l(-1), 0.6 microg Pb l(-1) and 0.3 microg Zn l(-1).     

Cadmium,lead, copper,and zinc in Elminius modestus Darwin (Crustacea,Cirripedia) from Waitemata and Manukau Harbours,Auckland, New Zealand

Abstract

Concentrations of cadmium (Cd), lead (Pb), copper (Cu), and zinc (Zn) were measured in adult barnacles (Elminius modestus Darwin) from Waitemata and Manukau Harbours in the Auckland area, New Zealand. As in studies on sediments reported in the literature, it was possible to identify areas of likely anthropogenic influence, e.g., around the Auckland Harbour Bridge for Pb, Cu, and Zn. Groups of individuals with highest concentrations for these metals showed 19.8–23.8 mg Pb kg^?1, 198–266 mg Cu kg^?1, and 4460–6530 mg Zn kg^?1 (95% confidence limits, dry weight basis). Cd concentrations found for all barnacles from the Auckland area ranged from 0.8 to 3.1 mg kg^?1. Two samples from Omaha Beach, 60 km north of Auckland, were used as a reference. Accordingly, groups of individuals with lowest concentrations for Pb, Cu, and Zn could be allocated to this site using the Student‐Newman‐Keuls Multiple Range Test (0.5–1.3 mg Pb kg^?1, 8–10 mg Cu kg^?1, and 144–214 mg Zn kg^?1 ; 95% confidence limits). Only Cd concentrations were highest at Omaha Beach (8.6–12.1 mg Cd kg^?1 ). This result may have arisen from “naturally” increased bio‐availabilities of certain metals in mangrove systems which are reported in the literature. Generally, metal concentrations in barnacles from the Auckland Harbour area and from Omaha Beach were within the wider range for E. modestus as well as other barnacle species reported in the international literature.     

Trace metal concentrations in Antarctic sea spiders (Pycnogonida, Pantopoda)

Trace metals were analysed in sea spiders collected on two Polarstern cruises in the Weddell Sea. We found a substantial interspecific heterogeneity of Cd, Cu, Ni, and Zn, indicating varying accumulation strategies and metabolic demands for essential elements. Means and 95%-confidence intervals for all 44 samples analysed are 26+/-7 mg Cd kg(-1), 38+/-22 mg Cu kg(-1), 62+/-13 mg Ni kg(-1) and 990+/-130 mg Zn kg(-1) DW. Only for Pb do we find values less than 1.0 mg kg(-1) for most collectives analysed, in good agreement with other Antarctic arthropods such as crustaceans. Our study provides further evidence for the frequently reported "Cd anomaly" in many polar arthropods. While Cu concentrations in pantopods are within the reported range for Antarctic amphipods and decapods, Ni concentrations are exceptionally high and might be part of predation defence mechanisms. These possibilities should be investigated in more detail in future studies.     

Bioaccumulation of trace metals in the amphipod Chaetogammarus marinus (Leach, 1815) from the Avon and Tamar estuaries (UK): comparison of two-compartment and hyperbolic toxicokinetic models

Bioaccumulation of Cd, Cr, Cu, Co, Pb, Ni and Zn was investigated in the eulittoral gammaridean amphipod Chaetogammarus marinus (Leach, 1815) from the Avon and Tamar estuaries (UK). The main goals were to provide information on accumulation strategies of the organisms tested and to verify toxicokinetic models as a predictive tool. The organisms accumulated metals upon exposure and it was possible to estimate significant model parameters of two-compartment and hyperbolic models, with the exception of Zn. Both types of models yielded significant model estimates in two independent toxicokinetic studies using gammarids from the Avon and Tamar estuaries, respectively. Kinetic BCFs at theoretical equilibrium were 58-102 for Cd, 95-215 for Cr, 400-963 for Cu, 38-59 for Co, 150-750 for Pb and 33-63 for Ni, and were in most cases distinctly lower than the range reported in the literature for other amphipods. To demonstrate the potential of toxicokinetic models as a predictive tool, attempts were made, further to verify time-dependent model data (Tamar) with independent experimental data (Avon). In this case only for Cd were both in good agreement, whilst for all other elements the models overestimated the measured values. The second approach was to verify time-dependent model data (Tamar) with measured values from an independent concentration-dependent uptake study (Tamar) or, alternatively, to estimate the model parameters simultaneously for both studies. A good agreement between observed and predicted values was obtained for all elements for the simultaneous two-compartment models. Only for Cd was a simultaneous estimation of the hyperbolic model more promising. A tentative estimation showed the following sequence of sensitivity of C. marinus to an increase of soluble metal exposure: 0.6 microg Cd l(-1), 1.7 microg Cr l(-1), 16 microg Cu l(-1), 3.5 microg Co l(-1), 0.8 microg Pb l(-1) and 7 microg Ni l(-1). Available information can be used to quantify a measure of agreement or disagreement between bioaccumulation in different amphipods. This can be regarded as an important step in the calibration of biomonitors which is necessary to assess the potential for bioaccumulation on a large geographical scale.