RESUMEN

In the summer of 1995, 30 tonnes of eel (Anguilla anguilla) died in Lake Balaton, Hungary. An investigation was carried out to find the causes of this ecocatastrophe. During this investigation, certain biochemical parameters, i.e. the blood sugar level, the acetylcholinesterase (AChE, EC 3.1.1.7), lactate dehydrogenase (LDH, EC 1.1.2.3), glutamic-oxaloacetic transaminase (GOT, EC 2.6.1.1), and glutamic-pyruvic transaminase (GPT, EC 2.6.1.2) activities in the blood serum of the collected surviving and dying eels were examined. Deltamethrin, the active ingredient of the insecticide K-OTHRIN 1 ULV, used against mosquitoes was detected in different animal species, i.e. eel, bream (Abramis brama), pike perch (Stizostedion lucioperca), and the common gull (Larus canus) and in sediment samples from the lake. Additionally, laboratory experiments were carried out to study the effects of deltamethrin on eels. During the investigation in the field it appeared that the AChE activity was significantly lower in the blood serum of the dying eels as compared to that in living animals (P<0.05, Student's t-test). The blood glucose content exhibited a difference, too: it was 2.5 times higher in the dying eels than in the surviving ones. A huge increase in the LDH level was measured in the dying eels. The GOT activities of the serum were twice as high in the dying eels as in the living fish, while the GPT was not significantly changed. Deltamethrin was detected in different tissue samples of the dying eels: 2.70-18.1 microg/kg in the liver, 9.0-31.1 microg/kg in the gill and 3.0 microg/kg wet tissue in the muscle. Deltamethrin residues were found in tissue samples from other animals, in the following concentrations: 0.44 microg/kg in bream, 2.14 microg/kg in pike perch and 1.06 microg/kg wet tissue in dead gulls. The sediment samples collected from the sites of the devastation contained deltamethrin in a concentration of 5.50-30.00 microg/kg wet sediment at the time of the eel deaths, and in a concentration 7.00-8.75 microg/kg wet sediment a month later. Laboratory experiments with the insecticide K-OTHRIN 1 ULV revealed that 1.00 microg/l of its active ingredient, deltamethrin, caused the death of 50% of the eels after an exposure time of 96 h. During this experiments similar trends could be observed in changes of enzyme activities of the treated eels to those that were detected in filed study during the eel devastation in Lake Balaton. At the end of a one-week treatment with the insecticide at the concentration of 0.5 microg/l of its active ingredient the gills of the treated eels contained deltamethrin at 12.6-44.8 microg/kg wet tissue concentration, while at the 24th hour after the treatment (11.2-42.7 microg/kg wet tissue) deltamethrin concentration in the liver of treated eels could be detected. All the above-mentioned changes and the detected deltamethrin residue in the eels appear to demonstrate the contribution of deltamethrin to the severe eel devastation. This information on the ecological risk of pyrethroid insecticides might be useful in their further application.

Asunto(s)

RESUMEN

1. The cholinesterases play an important role in the innervation of organs. The ratio of solubilized to membrane-bound cholinesterase and the quantitative distributions of acetylcholinesterase and butyrylcholinesterase were measured in different segments of the gut of carp (Cyprinus carpio) connected with different types of nerve-muscle synapses in different parts of the alimentary tract. 2. The inhibition of acetylcholinesterase (EC 3.1.1.7.) by the herbicide paraquat and the insecticide metidathion was measured in different parts of the gut of carp. 3. Metidathion and paraquat significantly decreased the activity of acetylcholinesterase in different segments of the alimentary tract of common carp, in a concentration-dependent manner.

Asunto(s)

RESUMEN

1. The effect of a herbicide (paraquat) and an insecticide (methidation) on the periodic activity of mussel in relation to serotonin and dopamine levels and their release and uptake in nervous system was investigated. 2. LC50 values of methidation in 24-, 48-, and 96-hr treatments, respectively, were 50% lower than those of paraquat. 3. Serotonin and dopamine levels decreased in all three ganglia by 20% on average upon 24- and 48-hr in vivo treatments with paraquat. In the 96-hr treatment, however, both monoamines showed a 20-40% increase. With methidation treatment, the level of monoamines tested did not change significantly. 4. After paraquat treatment, both the average lengths of resting periods and their total duration significantly increased. Parallel to this, the average length of active periods and their total duration dramatically decreased. Methidation increased the average length and total duration of resting periods during the first 2 days at the expense of active periods. On the fourth day, however, the effect reversed: average length and total duration of active periods increased of the expense of parameters characteristic of the resting state.

Asunto(s)

RESUMEN

In the past few years, two massive eel (Anguilla anguilla L.) devastations occurred in Lake Balaton, Hungary. In 1991, 300 tons of eel perished in the western basin of the lake, while in the summer of 1995 30 tons of eel died in the eastern part of the lake. Investigations carried out to find the causes of these ecocatastrophes included measurements of certain biochemical parameters: the blood sugar level, and the acetylcholinesterase (AChE, EC 3.1.1.7), lactate dehydrogenase (LDH, EC 1.1.2.3), glutamic-oxaloacetic transaminase (GOT, EC 2.6.1.1) and glutamic-pyruvic transaminase (GPT, EC 2.6.1.2) activities in the blood serum of the collected eels. In both 1991 and 1995, deltamethrin (DM), the active ingredient of the insecticide K-OTHRIN 1 ULV used against mosquitoes, was detected in the eels; in 1995 it was demonstrated in several other animal species, i.e., bream (Abramis brama L.), pike perch (Stizostedion lucioperca L.), and the common gull (Larus canus), and in sediment samples from the lake. Additionally, laboratory experiments were carried out to study the effects of DM on eels. In 1991, eels were collected from the western (the site of the devastation) and eastern basins of the lake. The eels from the eastern basin were used as controls. At that time, the AChE activity in the blood serum of the eels from the western basin was significantly inhibited compared to that in animals from the eastern basin (P < 0.05, Student t test). Eels from the western part of the lake had GOT and GPT levels 20 and 100%, respectively, higher than those of eels from the eastern part of the lake. The blood glucose level was much higher in the eels from the affected area of the lake as compared to those from the eastern part. The brain and liver of the eels contained DM residues at 20 micrograms/kg wet tissue (Gönczy, 1992). Gönczy suspected that one of the causes of the massive eel loss in 1991 was the presence of DM in the fish. In 1995, when the eel devastation occurred in the eastern basin, moribund and surviving eels were collected from this part of the lake. The AChE activity was significantly inhibited in the blood serum of the dying eels as compared to that in surviving animals (P < 0.05, Student t test). The blood glucose content exhibited a difference too: it was 2.5 times higher in the dying eels than in the surviving ones. A huge increase in the LDH level was measured in the dying eels, indicating damage to different muscle tissues to an extent never observed previously. The GOT activities of the serum were twice as high in the dying eels as in the living fish. The GPT was not significantly changed in the serum of dying eels as compared to the surviving animals. DM was detected in different tissue samples of the dying eels: 2.7-18.5 micrograms/kg in the liver, 9.0-31.1 micrograms/kg in the gill, and 3.0 micrograms/kg wet tissue in the muscle. DM residues were found in tissue samples from other animals, in the following concentrations: 0.4 micrograms/kg in bream, 2.1 micrograms/kg in pike perch, 1.1 micrograms/kg wet tissue in dead gulls. The sediment samples collected from different places and at different times contained DM in a concentration of 5.5-30.0 micrograms/kg wet sediment at the time of the eel deaths, while the sediment samples collected from the same places a month later still contained DM at 7.0-8.8 micrograms/kg wet sediment. Laboratory experiments with the insecticide K-OTHRIN 1 ULV revealed that 1.0 microgram/liter of its active ingredient, DM, caused the death of 50% of the eels after an incubation time of 96 hr. In the liver of the dead eels, DM was detected at 2.9-20.0 micrograms/kg wet tissue. All the above-mentioned changes and the DM residue detected in the eels appear to demonstrate the contribution of DM in the severe eel devastation. This finding on the ecological risk of such types of insecticides might be useful in their further application.

Asunto(s)

RESUMEN

Thein vivo effects of deltamethrin (DM) on the blood sugar level, the acetylcholinesterase (AChE, EC 3.1.1.7) activities of the blood serum and various organs (heart, liver and intestine), the lactate dehydrogenase (LDH, EC 1.1.2.3), glutamic-oxaloacetic transaminase (GOT, EC 2.6.1.1), and glutamic-pyruvic transaminase (GPT, EC 2.6.1.2) activities of the blood serum, the adenosine triphosphatases (EC 3.6.1.3; Na(+)/K(+)-ATPase and Mg(2+)-ATPase) activities of the erythrocyte plasma membrane and the catalase (EC 1.11.1.6) activity of the liver were examined throughout 96 h in adult carp (Cyprinus carpio L.) Two sublethal concentrations, 1.0 and 1.5 µg/l of deltamethrin, were used. All fish survived the experiment except one, in an aquarium containing 1.5 ppb of DM, which died after 72 h.The AChE specific activity was significantly inhibited in the heart and intestine after 96 h at both concentrations compared to that in the control animals (P<0.05, Student'st-test), while there was no detectable difference between the two treatment. At the same time there was no detectable change in the liver. In the serum, the AChE activity almost remained unchanged; the only significant decrease could be measured after 96 h at 1.5 µg/l deltamethrin concentration. The blood glucose content exhibited interesting changes: after 24 h fish exposed at 1 µg/l DM seemed to be stressed, although this increase was not significant. When these fish became used to the new conditions (in practice this meant the presence of DM), the glucose level decreased, especially after 72 h. At the same time the control animals kept in similar circumstances showed a small insignificant decrease. Meanwhile fish in aquaria containing 1.5 µg/l DM reacted to the treatment with an increased blood glucose level after 48 h, and this did not change until the end of the treatment. The Na(+)/K(+)-ATPase activity decreased in a dose-dependant manner, while Mg(2+)-ATPase was less affected. A small increase in LDH level was observed, indicating damage of different muscle tissues. However, this phenomenon appeared only with the small dosage after 24 h (P<0.05). It has to be mentioned that the individual values varied to a large extent among of the eight fish.The GOT activities of the serum increased during the treatment. However, significant changes were only expressed after 72 and 96 h at 1 µg/l DM concentrations (P<0.01 andP<0.05), and after a similar long treatment at the high dosage (P<0.05, 72 and 96 h). The GPT did not change significantly in aquaria containing 1 µg/l DM. The only larger increase was measured after 96 h at 1.5 µg/l DM concentration (P<0.05). The catalase activity in the liver of treated carp remained practically at the same level compared to that in control fish.All these changes (concerning the primary effects of this compound) demonstrate the effect of DM on different fish enzymes, at low concentrations under laboratory conditions, which might be useful in practice for biomonitoring using fish.