Interactions between copper and cadmium during single and combined exposure in juvenile tilapia Oreochromis mossambicus: Influence of feeding condition on whole body metal accumulation and the effect of the metals on tissue water and ion content

Abstract

Aquatic Toxicology 30 (1994) 117-135 ; Interactions between copper and cadmium during single and combined exposure in juvenile tilapia O r e o c h r o m i s m o s s a m b i c u s :Influence of feeding condition on whole body metal accumulation and the effect of the metals on tissue water and ion content AbstractJuvenile tilapia (Oreochromis mossamhicus) were exposed for 96 h to ranges of sublethal concentrations of Cu or Cd, under both fed and non-fed conditions. Exposure to one metal (Cu or Cd) not only resulted in an increased whole body content of the metal exposed to, but also influenced the concentration of the other metal present in the fish. Furthermore, the total amount of Cu and Cd accumulated during exposure to heavy metals was influenced by the nutritional state of the fish. Besides exposure to either Cu or Cd, fish were also exposed to mixtures of Cu and Cd. Results indicated that accumulation during Cu/Cd co-exposure cannot be predicted by simple addition of the effects of single metal exposures. Obviously, complex interaction mechanisms are involved, as was concluded e.g. from the significantly decreased whole body Cd-content of Cu/Cd-co-exposed fish compared to the Cd-content of Cd-exposed fish. This phenomenon was observed in both fed and non-fed fish. Because ionic homeostasis is known to be affected by heavy metals, in this study also whole body water, calcium and sodium content in Cu and/or Cd-exposed fish were determined. The results indicate that also with respect to these parameters the two metals interact. The effects on water and ion appear to be dissociated. The data reveal previously unrecognized effects of interaction of the metals on whole body metal content, water and ion regulation.

Interactions between copper and cadmium modify metal organ distribution in mature tilapia, Oreochromis mossambicus

“…Exposure of the fish to Cu and Cd, both singly and combined, did not affect the water content of any of the organs studied, which contrasts with previous results on juvenile tilapia exposed to identical metal regimes (Pelgrom et al, 1994a). This may relate to an increased sensitivity of younger life-stages to osmoregulatory disturbances, i.e.…”

“…Previously, we demonstrated Cu-Cd interactions on whole body metal accumulation during waterborne metal exposure of juvenile tilapia (Pelgrom et al, 1994a). Data in the present study show that interactions observed are organ specific and therefore data for most organs are not representative for the whole organism.…”

“…During the first 6 h the flow rate was 4.5 1 h -1, followed by a flow rate of 1.5 1 h -~. In this way, the metal concentrations in the aquaria were gradually raised, reaching a plateau after 18 h. The measured concentrations deviated maximally 5% from the nominal concentrations (Pelgrom et al, 1994a). Two experiments were performed, with LOW and HIGH Cu and Cd concentrations.…”

“…Cu and Cd concentrations in both stock solutions and aquaria were monitored every hour during the first 6 h, and at least once a day during the rest of the exposure period. Water samples were acidified with nitric acid in a final (Pelgrom et al, 1994a). From the (wet)…”

“…In a previous paper (Pelgrom et al, 1994a), interactions between Cu and Cd on whole body metal accumulation in juvenile tilapia during waterborne metal exposure were demonstrated. The present study examines Cu-Cd interactions in mature tilapia, paying particular attention to organs with diverse biological functions, because it is anticipated that differences in metal accumulation between organs will be related to their functions.…”