[Experimental poisoning of carp fingerlings (Cyprinus carpio L.) with the herbicidal preparation, lasagrin...

The acute intoxication of K1 carp (Cyprinus carpio L.) with the herbicide preparation lassagrin (alachlor) was studied under experimental conditions in a laboratory. Used were a total of 360 young carps of 10 g each, measuring 9-10 cm. The experiments were carried out in 30-1 glass aquariums that were preliminary filled with water that was adequately heated and deprived of chlorine at pH = 6.9, T0C = 18-20 degrees C, O2 = 10.4 mg/1; hardness = 1.5 German degrees. The preparation was directly placed in the aquariums in eleven concentrations. The following characteristic symptoms of intoxication were established: higher irritability of the nervous system with superactivity, lack of coordination and orientation, depression in later hours, loss of sight, disturbed pigmentation. No morphologic changes were found at necropsy. Determined was the concentration at which 50% of the test material died at the 96th hour of exposure: LC50/TLm/=4.67 mg, the interval of dependability at 95% probability being 4.04-5.30. Both toxicometry data and intoxication symptoms with the use of lassagrin (alachlor, lasso) made it reasonable to believe that the preparation could be referred to poisons having resorptive action so far as carps are concerned.