Kinetics of cadmium accumulation and elimination in carp Cyprinus carpio tissues.

Carp (Cyprinus carpio) were tested for cadmium accumulation and elimination during and after a simulated pollution exposure. Fish were distributed in two 1000-l indoor concrete aquaria supplied with a continuous flow (8 l min(-1)) of well water. The cadmium concentration was maintained at 53 microg l(-1) in one aquarium and 443 microg l(-1) in the other aquarium for 127 days. The exposure phase was followed by a 43-day depuration period. The cadmium accumulation in liver, kidney and muscle was measured by means of ICP-MS. The data showed that cadmium exposure produces significant cadmium uptake in tissues. Cadmium concentrations increased sharply in kidney and liver, whereas the pollutant level in muscle was only significant after 106 days. After 127 days of Cd exposure (53 microg l(-1)), the cadmium concentration in kidney was 4-fold higher than in liver and 50-fold higher than in muscle for a toxic level of 53 microg l(-1). At a Cd of 443 microg l(-1), kidney cadmium content was 2-fold higher than in liver and 100-fold higher than in muscle. In kidney and liver, the toxic concentration increased as the concentration of pollutant in water increased. During the 43 depuration days, the loss of accumulated cadmium was rapid and immediate in muscle. Conversely, no loss of cadmium was observed in kidney and liver.

Cadmium bioaccumulation in carp (Cyprinus carpio) tissues during long-term high exposure: analysis by inductively coupled plasma-mass spectrometry.

This work was an attempt to investigate cadmium bioaccumulation in the carp (Cyprinus carpio) during simulated pollution. The fish, weighing 100 g, were kept for 140 days in a 1000-liter indoor concrete tank supplied with a continuous flow (8 liters min-1) of unchlorinated, aerated, and filtered well water, the cadmium concentration of which was maintained at 450 microg liter-1. Such a high cadmium concentration was chosen to achieve metal saturation of the fish organs. Carp were fed during exposure. Cadmium accumulation in liver, kidney, and muscle was measured by inductively coupled plasma-mass spectrometry (ICP-MS), which is one of the most sensitive analytical techniques. The reported data indicate that cadmium exposure results in significant cadmium uptake, but the pattern of this uptake varies with the organ. For kidney and liver, cadmium concentration increased rapidly to the saturation level, probably because of the limited ability to store the cadmium as exposure persisted. A positive correlation between the increase in metallothioneins in tissues and the increase in metal tolerance in fish has been suggested. The cadmium concentration increase in muscle was significant only after 3 months, and, then, increased as an exponential function of the exposure time. When the storage capacity limits of the liver and kidney are reached, cadmium accumulation in muscle is stimulated. In this experiment, the high contamination levels reached suggest that such muscle would be unsuitable for human consumption. After 140 days of exposure, the cadmium concentrations in muscle, liver, and kidney were respectively 9 +/- 1, 91 +/- 7, and 250 +/- 16 mg kg-1 dry wt.