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Toxicity of cadmium on larvae of Palaemon adspersus Rathke, 1837 from the Black Sea
Authors: Levent Bat , Sabri Bilgin, Ayşah Öztekin
Number of views: 515
Objective: To evaluate the suitability of Palaemon adspersus (P. adspersus) as a bio-indicator
for 4 and 10 days of cadmium toxicity bioassays.
Methods: Four and ten days experiments were designed. CdCl2·2½H2O was dissolved in
distilled water and a stock solution was made. At 4-day bioassay, the larvae of Baltic prawns
were exposed to nominal concentrations of 0, 0.02, 0.05, 0.1, 0.5, 1.0 and 5.0 mg/L of Cd
for 4 days. The 4-day LC50 was calculated by the probit analysis. At 10-day bioassay, the
concentrations of 0.05, 0.1, 0.5, 1.0, 5.0, 10.0 and 20.0 mg/L were introduced into each of the
jars in triplicate treatments and 0 mg/L as control. Each tank containing 20 larvae was exposed
to test solutions.
Results: Results from probit analysis showed that the 96-h LC50 value was 0.14 mg/L for Cd.
The 10 days bioassays were conducted with nominal concentrations of 0, 0.05, 0.1, 0.5, 1.0,
5.0, 10.0 and 20.0 mg/L Cd. Mortality increased in parallel with the increase in concentrations
of Cd on Zoea – I stage of P. adspersus and time of exposure. The toxicity rate of the organism
is concentration-dependent. All organisms except the control group died at the end of 10 days.
Less than 25% of the animals survived at the 5 days of the exposure to concentrations of
0.5 mg/kg Cd or more. Only 20% of the organisms survived at the 7 days of the exposure to
concentrations of 0.1 mg/kg Cd or less in seawater with clean sediment.
Conclusions: The results showed that Cd was highly toxic to P. adspersus. When the larvae
were exposed to concentrations of Cd, they become slightly excited and swam erratically,
probably due to stress. However, behavioural and swimming patterns in control groups were
normal, and there was not any mortality during the course of the experiment.