The accumulation from water of⁶⁵Zn,⁵⁴Mn,⁵⁸Co and⁵⁹Fe by the mussel,Mytilus edulis

Abstract

Plate 1, Text-figs. 1-5)The accumulation from sea water of 6B Zn, M Mn, 59 Fe and 68 Co by the mussel, Mytilus edulis, has been studied in relation to the stable element levels of these isotopes both in the sea water and in individual tissues. For all four radionuclides the greatest accumulation occurred in the stomach and digestive gland samples and further localization of ^Zn and 69 Fe was demonstrated by autoradiography. As the animals were starved during the accumulation period the loss of stable elements by individual tissues was also followed. Again the most notable effect occurred in the digestive gland tissues with the exception of a large loss of iron by the foot. Autoradiography showed that after two weeks accumulation 69 Fe occurs in large clusters in the foot, notable in the byssus gland area. These clusters disappear after a further two week period and may thus be secreted into new byssus threads.The accumulation of nyclides was examined using a single exponential model and values obtained for flux rates, biological half times and asymptotic values were compared with the stable element concentration factors. An analysis of parameters of exchange of nuclides in individual tissues with the water was further examined using the Kendall coefficient of concordance which demonstrated that the highest exchange occurs in the order of stomach and digestive gland > gill > foot > mantle > gonad > adductor. The application of the Friedman test of two-way analysis of variance indicated that this order obtains for all four nuclides studied, despite the fact that in the aquaria used zinc and cobalt were largely soluble; that manganese was partly in the particulate form with the radionuclide used; and that iron was largely particulate in both stable and active forms. There is an indication that as well as accumulating nuclides via particulate matter in suspension the mucus itself is capable of sequestering them, even though they are in the soluble form, and may even preferentially accumulate soluble forms. The actual role of water in the accumulation of the nuclides studied appears to be relatively minor compared with that of food accumulation as estimated by difference from the calculated stable element values.

A double-tracer technique to determine the relative importance of water and food as sources of polonium-210 to marine prawns and fish

“…Modelling polonium accumulation in organisms. In general, the kinetics of radionuclide and trace element turnover in marine organisms can be fit to exponential mod.els (Pentreath 1973, Carvalho & Fowler 1985, Swift & Pentreath 1988. In modelling the bioaccumulation of radionuclides, it is necessary to take into consideration the rates for uptake (both from water and food) and the elimination processes (excretion, radioactive decay).…”

Problems in the assessment of heavy-metal levels in estuaries and the formation of a pollution index

“…In most species, different metals are differentially concentrated; variations are dependent upon the size of the organism (Boyden, 1977) or the species. The method of feeding is also important (Pentreath, 1973;Schulz-Baldes, 1974;Phillips, 1976). Thus metal levels in Thais lapillus (a carnivore feeding on Balanus balanoides), Littorina littorea (a herbivore feeding on Pucus), and Mytilus edulis (a filter feeder, feeding on phytoplankton and particulate matter) will all differ from each other, and from the algae, in which the bulk of the metal loading is absorbed directly from solution (see Phillips, 1979).…”

Feces of intertidal benthic invertebrates: influence of particle selection in feeding ace element concentration

“…When animals were placed in seawater with 0.3 mg l-' copper, an increase in mucus production was observed. Metals may be taken up by ion exchange onto mucus secreted by body surfaces, particularly the mantle and gills (Pringle et al 1968, Pentreath 1973 and may be exported to the gut or expelled with the pseudofeces. A concentration of trace metals in mucus substances expelled with the pseudofeces may contribute to the relatively higher concentrations found in pseudofeces (Table 2), particularly the mucilaginous material produced by Mya arenaria.…”