The effect of chelating agents on the uptake and accumulation of cadmium byMytilus edulis

✍ Scribed by S. G. George; T. L. Coombs

• Publisher: Springer-Verlag
• Year: 1977
• Tongue: English
• Weight: 657 KB
• Volume: 39
• Category: Article
• ISSN: 0025-3162
• DOI: 10.1007/bf00391000

✦ Synopsis

The uptake, storage and e x c r e t i o n of cadmium by the common mussel Mytilus edulis(L.) has been studied at sub-lethal c o n c e n t r a t i o n s using the r a d i o a c t i v e isotope 115mCd as a marker. After an initial lag period, the uptake at low c o n c e n t r a t i o n s in sea w a t e r is linear w i t h time and directly p r o p o r t i o n a l to the sea water concentration, w i t h a m a x i m u m c o n c e n t r a t i o n factor of 165 at 0.7 ug Cd/ml sea water. A d e c r e a s e occurs at h i g h e r c o n c e n t r a t i o n s indicating saturation of the available b i n d i n g capacity. Prior c o m p l e x a t i o n of the cadmium with either EDTA, humic and alginic acids or pectin doubles both the rate of a c c u m u l a t i o n and the final tissue concentrations (order: k i d n e y > > v i s c e r a > g i l l s > > m a n t l e > m u s c l e ) and eliminates the lag period, s u g g e s t i n g that ionic c a d m i u m m u s t first be complexed before uptake can occur. A m e c h a n i s m for this effect, which may involve thionein, is described. The rate of e x c r e t i o n of c a d m i u m is 18 times slower than that of uptake, with the major route via the kidney but not via the byssal threads as with p a r t i c u l a t e iron. The need to d e t o x i f y and store c a d m i u m by an i m m o b i l i z a t i o n m e c h a n i s m is a c o n s e q u e n c e of this slower rate of elimination.