ISSN:
0268-2605
Keywords:
mercury
;
methylmercury
;
tin
;
tributyltin
;
bioconcentration
;
distribution
;
kinetics
;
starfish
;
Leptasterias polaris
;
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Starfish, Leptasterias polaris, were exposed between 30 min and 48 h to seawater containing 0.25 nmol dm-3 of radiolabelled methylmercury (Me203HgCI), tributyltin [(C4H9)3113SnCI], and inorganic 203HgCI2 and 113SnCI4, with the objectives of comparing the uptake and distribution kinetics of these metal species in organs and tissues of treated organisms. Some starfish exposed to metals for 48 h were allowed to depurate for 24 h in clean seawater. Whole-body autoradiography was used to locate radiotracers very precisely within starfish tissues. The total amount of methylmercury (MeHg) accumulated in the whole animal after 48 h reached 0.53 nmol compared with 0.09 nmol for inorganic mercury, while tributyltin (TBT) reached 0.72 nmol compared with 0.017 nmol for inorganic tin. No significant reduction of body burdens occurred during the depuration period. The first-order rate constant characterizing the uptake of metals by whole animals, k1, ranged from 0.102 h-1 for MeHg to 3.6 × 10-3h-1 for inorganic mercury(II) and to 8.4 × 10-4 h-1 for inorganic tin(IV). The first-order rate constant characterizing the translocation of metals from seawater-exposed tissues toward internal organs, k3, was available for inorganic Hg and Sn and had values similar to k1. Concentration ratios between external tissues and internal organs after a 48 h exposure were 11.5 and 25.4 for MeHg and TBT, respectively, and 2.1 and 6.1 for inorganic mercury and tin. Furthermore, autoradiograms showed that MeHg and TBT were accumulated only on the external surface of the body wall and podia. This finding indicates a much slower translocation process for organometallic species than inorganic species, a process which seems to be related to the binding mode of MeHg and TBT to the organic matrix of external tissues of starfish.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/aoc.590090406
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