CS273191B2 - Method of water's biological quality treatment - Google Patents

Abstract

The invention concerns a method of treating the biological quality of water, particularly freely occurring water, for example in ponds. Freely occurring water is treated at least once a year with 3-cyclohexyl-5,6-trimethyluracil or tert- 3-butyl-5-chloro-6-methyluracil in a quantity of 20 to 500 micrograms/l, preferably in the form of a preparation containing these substances.

Description

The invention relates to a method of treating the biological quality of water depending on the purpose of use, in particular water in ponds. According to the method of the invention, the species and amount of living organisms in the waters may be altered - algae, zooplankton, higher order aquatic plants, fish - primarily in the case of fish and fishery ponds where the water is eutrophized.

Eutrophic watercourses are characterized by too many blue algae. Of these blue algae, for example, Microcystis species prevent the multiplication of useful algae species serving as food for zooplankton. This is also the reason for a smaller amount of zooplankton serving as fish food. An important task is therefore to suppress unfavorable processes taking place in the water, for example excessive algae infestation.

laboratory experiments leading to the destruction of algae that have been over-multiplied due to eutrophy and the destruction of algae as such have no practical significance. There are two reasons. On the one hand, about 40,000 algae species are known, for Hungary only about 3,000 species have been described so far. Testing all these species under laboratory conditions would be too costly. In addition, the properties of algae isolated from living waters also change when they form a pure culture in the laboratory. Finally, the surface water algae show such complicated interactions with other algae present and with other members of the living aquatic organisms - zooplankton, aquatic plants, fish - that they are completely unusable for deliberately modifying the biological quality of water in laboratory teets.

There is a known killing effect of 4,5-diaminouracyl sulfate described in U.S. Patent 3,753,362. According to the disclosure, an agar plate is inoculated with various types of algae, covered with 4,5-diaminoraoyl sulfate impregnated filter paper and then incubated at 25-27 ° C. The degree of inhibition is characterized by the average relative to the control.

From this single numerical value, a conclusion was drawn about the destructive effect on all algae.

In Japanese Patent Application Publication No. 50-100237, the effect of 3-second is assessed by visual observation. butyl-5-bromo-6-methyl-aeraoyl, known as the herbicide, for algae Euglena sp. and Spirogira sp.

Japanese Laid-Open Publication No. 53-73122 is concerned with action

3-cyclohexyl-5,6-trimethyluraoyl, also known as a herbicide, always on a pair of blue, green and Plagellata. The experiments were carried out under axenic conditions. As described, 100% killing of algae with an active substance of 1000-2000 µg / l was achieved, using 2- (ethylamine) -4-isopropylamino-6-methylthio-S-triazine as a control. As evidence of progress, it has been reported that 1 500 to 3 000 µg / l of the latter compound must be used to achieve the same effect.

In addition to the aforementioned patents, a number of others are known which are generally characterized by the fact that experiments under axenic conditions to which some species of algae have been subjected have drawn conclusions about the algae suppressing effect, although they can only be considered as first knockout tests. It should further be argued that the effect on other aquatic organisms has not been investigated.

From the literature and patent literature, of the photosynthesis inhibiting compounds, the triazine and carbamide derivatives are primarily toxic to the laboratory algae strains. However, no conclusive conclusions can be drawn for the phytoplankton - algae - lake flora, which, in addition to the above, has other reasons:

(a) There is a significant difference in sensitivity between laboratory test algae and the natural algae flora. Algae flora consists of species with different sensitivity. When a more sensitive species is suppressed, more resistant species of algae will multiply. Thus, with an unchanged number of individuals, the algae composition is altered, which may be both advantageous and disadvantageous depending on the purpose of the water use. Eloranta and HalttunenCS 273191 B2

Keyrilainen (Eloranta V., Halttunen-Keyrilainen 1, 1983; The Comparison of the Selenaatrum Bottle Test and the Natural Phytoplankton Aesay in Algal Toxicity Teets - Manuscripts, pp. 1 to 16) therefore pointed out that laboratory data using the so-called single species test means only the lowest degree of toxicological research.

(b) The food chain in water consists - very simply - of at least three main members: algae, zooplankton and fish. Since these organisms together form a pyramidal nutritional system, it is necessary to determine how these three species interact in order to use certain compounds in water. While this can be approximately determined by testing these three groups individually, but for the variability of interaction across the community, it is also necessary to examine this community as an oelek.

It is an object of the present invention to provide a method by which harmful algae can be destroyed or suppressed in free-flowing water bodies in such a way that useful algae and higher aquatic animals are maintained and that fish and zooplankton are not endangered.

The object has been achieved and the disadvantages of the known methods have been eliminated by the method of treating the biological quality of the water of the invention, which consists in treating the water at least once a year with 3-cyclohexyl-5,6-trimethyluraoyl or tero. 3-butyl-5-chloro-6-methyluraoyl in an amount of 20 to 500 µg / l, preferably in the form of a known preparation containing these substances.

Effects of lenaoil on Miorooystis harmful algae cultures and on beneficial algae cultures are shown in Figure 1. Terbaoil effects are depicted in Figure 2. In Figure 1, curve 1 shows the number of useful algae individuals in 1 liter of water against lenaoil in mg / 1; individuals of harmful algae Miorooystis in 1 liter of water per Lenaoil amount in mg / l. In Figure 2, Curve 3 shows the dependence of the number of individuals of beneficial algae in 1 liter of water on the amount of Terbaoil in mg / l, Curve 4 shows the dependence of the number of individuals of harmful algae Miorooystis in 1 liter of water on the amount of Terbaoil in mg / l.

Some experiments have confirmed that the addition of 3-cyclohexyl-5,6-trimethyluraoyl (Lenacil) or tero. 3-Butyl-5-chloro-6-methyluracyl (Terbaoil) at a concentration of 10 to 500 µg / L destroys a large proportion of algae harmful to the nutritional pyramid, while anticipating the death of algae useful for the nutritional pyramid at 10 µg / l at rest, then the number of these algae starts to increase rapidly and reaches a constant value at about 100 .mu.g / l of active ingredient, as can be seen from FIGS. 1 and 2. to be advantageous for the natural nutritional pyramid. The natural ecosystem of waters will be restored without damaging zooplankton or fish.

The process according to the invention is illustrated in more detail in mild climatic conditions, but is also suitable for warmer or colder climatic conditions. Adaptation to certain climatic conditions does not require any inventive action, as it is a routine matter for the skilled person.

According to the invention, trophicity and toxicity were investigated from biological water quality factors according to the following methods:

- visual observation (colors, shape, seooi - transparency, ratio of organized aquatic plants and fish)

- microscopic determination of algae count

- determination of chlorophyll

- determination of the active substance in water and fish by gas chromatography.

According to the Pesticides Manual (R.Worthing, SB Walker, Pesticide Manual, The British Crop Protection Counoil), Lenaoil toxicity, determined by LC _5Q (96 hours) for carp of 10 mg / l, Terbacil toxicity for perch from Centrarchidae, determined by LCjq (48 hours) is 86 mg / l, for crabs of the genus Uca it is (48 hours) greater than

000 mg / l.

According to the invention, therefore, in mild climates, Lenaoil or Terbacil is preferably added to the water in order to achieve advantageous changes in the qualitative and quantitative composition of the photoplankton, preferably in the form of a known preparation containing these substances (e.g. TO).

The first treatment against harmful algae is generally carried out at a water temperature of 4 to 8 ° C, the composition being added in such a way that a higher concentration is formed above the algae to be removed. Then, the phytoplankton is examined by microscopy, and the water is then uniformly concentrated throughout the volume. At a water temperature above 10 ° C, after subsequent visual evaluation, a suitable water treatment is carried out by said composition, which floats on the surface of the water or is already present dissolved in water. After each treatment, both zooplankton and phytoplankton, as well as the oxygen content dissolved in water, should be investigated on several occasions, since in the unfavorable state of these values for the intended use, a new application of the compositions would have to be carried out.

For each treatment, a concentration of active compound of 10 to 500 .mu.g / l, preferably 10 to 300 .mu.g / l, corresponding to 0.01 to 0.5 g / m @ 2, preferably 0.01 to 0.3 g, is required. / m ^. At an average water depth of 1 m, this corresponds to an amount of 0.1 to 5.0 kg / ha.

The number of treatments, dosages and formulation used are determined by the current conditions, and no precise prescription can be given. It is within the skill of the artisan to determine the method of treatment based on the water parameters and to control the parameters.

The active substances Lenacil and / or Terbacil can be used both in themselves and in the form of solutions, suspensions, emulsions, solid powders or granules. Also, the choice of formulation depends on local conditions.

The process according to the invention will be further elucidated by means of examples, but is not limited thereto. In the examples, the active substances or the formulations thereof are used, in the latter case the method of formulation of WSCP, TO being always the same. Internationally used names are used to designate compounds. According to them, Lenaoil and Terbacil are active substances, Lenacil 80 TO and Terbacil 80 TO have 80% powder containing active substances.

Example 1

Toxicity of three algae destroying agents and Lenacil and Terbacil to algal cultures.

Active substances intended to influence the algae flora of free-flowing waters have been investigated for their toxicities prior to their use in the laboratory in algae tests. The test method used was the procedure developed by the US Environmental Protection Agency - Jiller et al.: The Selenastrum Capricomut Printz Algal Assay Bottle Test, Envirometal Protection Agenoy, Envirometal Research Laboratory Corvallis, Oregon, pp. 1-126, 1978; further modified by Crdog according to Ordog V .: Int. Revue ges. Hydrobiol. 67, pp. 127 and 136 (1982).

The useful algae Selenastrum oaprioornutum Printz (Starr str.) Was used. A 500 ml Erlenmeyer flask was filled with 250 ml SABII (Synthetic Algal Nutrient Medium) nutrient solution. The flask cultures were bubbled through a 20 L air and 0.2 L COg per hour air tube. The duration of illumination was 14 hours a day and the luminance was 3,500 and 350 lux. The temperature of the room was 25 - 2 ° C.

At least two experiments were performed with each preparation. Each concetration was tested in three parallel experiments. After four days of culture, the growth of the cultures was determined by the turbidity method at 750 nm. The data were evaluated by a graphical test analysis method according to Ordog V .: Acta hydroohim. hydrobiol. 9,

607-612 (1981). Toxicity is expressed in terms of ΕΟ ^ θ, ie the concentration that causes 50% growth inhibition relative to the control.

According to the results of the first tests, Lenacil and Terbacil were found to be highly toxic to the algae tested. Table 1 compares the toxicity data of three commercially available seaweed killers with the roxicity of Terbacili and Lenacil.

Table 1

Effect of three kelp products, lenacil and Terbaoil on green algae Selenastrum capricornutum Printz (Starr str.)

General name of the product used EC ₅₀ / Jug / 1 / Algizide WSCP (2) 315 Alginex (1) 608 L-lox (2) 933 lenacil 6 Terbacil 22nd

Active substance:

(1): poly (N-oxyethylene-N, N-dimethyl-N'-ethylene-N ', N ^, -dimethyl) -ethylenediaminochloride (2): 2-diohloroacetylamine) -3-chloraaphthoquinone (3): copper- triethanolamine

The data in Table 1 shows that lenacil is 52 times more toxic to the algae tested than the most potent of the commercially available algae killer products, Algizide WSOP. Therefore, first investigations have shown that lenacil and Terbacil show excellent killing effects on algae.

Example 2

Daphnia test.

After a successful experiment with green algae, preparations and one commercially available algae control product have to be investigated for its effects on zooplankton. Daphnia - water fleas were used as representatives of zooplankton because they represent an important link in the food chain. The experiment was performed according to the Hungarian standard MSZ-22902 / 6-81L 09. The LC ₁₀ , L0 ^ q, and ΙΟ ^ θ values determined by assay analysis are summarized in Table 2.

Table 2

Daphnia test results.

^M 10 ^M 50 ICs ₉₀ ^ ig / 1 / Lenacil 80 WP 1 000 3 160 9 540 Terbacil 80 WP 2 630 19 950 144 000 Algizid WSCP 36.3 95.49 263

ar ·: ·

It can be seen from the table that the values for Lenacil 80 WP and Terbaoil 80 WP are extremely low and at concentrations at which these agents already have a beneficial effect on water quality, ie 10 to 300 µg / l of daphnia still representing zooplankton, are not endangered. In contrast, the commercially available Algizid WSCP is toxic to daphnia at a dose that requires algae control.

Example 3

Effect of three algae killers, lenacil and terbacil on fish.

Prior to the actual hydrobiological experiments, fish toxicity tests were performed to compare the toxic effects of lenacil, Terbacil and some commercially available products. The experiments were carried out in the form of static fish tests. The test fish used was mainly carp (Cyprinus carpio), but the effect of Lenacil and Terbacil was nevertheless controlled on small fish Albumus alburnus, Rhodeus serviceus amatus and Rutilus rutilus. The experiments were carried out according to the Hungarian standard 1EZ 22902 / 3-77. The results are summarized in Table 3.

Table 3

Effect of various kelp (Cyprianus carpio) preparations

Product to be used (common name) LC-value / Jug / 1/96 hours Algizid WSCP 5 200 Alginex 750 L-lox 17 400 Lenacil 80 WP 183 000 Terbacil 80 WP 69 700

It is clear from the data in the table that Lenacil 80 WP is harmful to fish up to a concentration of 1 to 2 orders of magnitude higher than commonly available algae control agents. In contrast, Lenacil 80 WP in a concentration that already improves water quality, ie 10 to 300 ₍ µg / l), does not harm the fish at all.

Example 4

The effect of Lenacil 80 WP on the life communities of phytoplankton and zooplankton in ponds.

The experiments were carried out in 100 liter glass aquariums. The aquariums were filled with water from pond No. 1 described in Example 6 and illuminated with Lumoflor-type lighting tubes manufactured in the GDR, with a luminance of 3500 lux. The ambient temperature was maintained at 25 - 2 ° C. The number of phytoplankton and zooplankton subjects was counted on the fourth day after application. There was no difference to the naked eye between applications. The water was heavily overgrown with algae and had a tan color. In microscopic examination, Euglena and Phacus algae of about 100 μα were observed; after treatment with Lenacil at 100 µg / l, no more Mycrocystis colonies could be detected. The detailed results of the experiment are shown in Table 4.

Table 4

Influence of Lenaoil and Terbacil on the composition of phytoplankton and zooplankton

Dose in (Ug / l Number of individuals

Mycrocystis Useful algae Zooplankton (x) total (x) (xx)

untreated fish- water 80.3 23 1 257 10 61.07 14 2 000 20 May 29.95 15 Dec 2 000 50 10,03 20 May 1 857 100 ALIGN! - 33 1 500 200 * 32 1 428

(x): millions of individuals per liter (xx): number of individuals per liter

Are the following conclusions drawn from the results?

- When lenaoil concentration of 80 WP increases, the amount of phytoplankton decreases, due to the disappearance of Miorocystis algae colonies and a change in algal species.

- A dose of 100 µg / l of lenaoil 80 WP was sufficient for the investigated water quality to kill all Miorocystis colonies.

- The number of individuals of zooplankton decreases only insignificantly even with the concentration of 100 to 200 .mu.g / l of active ingredient.

Example 5

Influence of Terbaoil on habitats of phytoplankton and zooplankton in fishponds.

The experiment was carried out in the same manner as described in Example 4, but Terbacil 80 WP was used instead of Lenaoil. The results are organized in taboo 5 ·

Table 5

Effect of Terbacil 80 WP on the representation of phytoplankton and zooplankton in ponds

Dose ₍ ^ g / l Number of individuals

Miorocystis Useful algae Zooplankton (x) total (x) total (xx) untreated fish-

water 80.31 21 1 357 10 72.23 13 1 000 20 May 41.80 15 Dec 1 857 50 25.42 20 May 857 100 ALIGN! - 33 1 500 500 - 32 1 500

Example. 6

Experiments with lenacil 80 WP in breeding ponds.

The experiments were carried out in the ponds, which were created by the establishment of dams and through which the stream flows. Of the two ponds examined, one served as a control. Both fish ponds were artificially put on a mixed fish spawn as a stick. Ponds were known to be infested with algae Miorooystis every year. The dimensions of both ponds were:

Surface Average depth Pond. 1 1.3 ha 0.80 to 0.85 m Pond No. 2 1,5 ha 0.70 to 0.90 m (control)

The aim of both experiments was to determine the influence of lenaoil 80 WP on the qualitative and quantitative composition of phytoplankton and zooplankton and parameters important for fish breeding during the whole reproduction year.

13 samples of water were taken from these ponds during the period from 15 May to 15 October. The oxygen dissolved in the water was measured on site with the AQUACHECE-3, as well as pH and temperature. Water transparency was determined by Secci-glass. Preparations with fixed lugol solution were taken for laboratory tests. E determination of the amount of zooplankton was taken from each pond 20 l of water and poured through a plankton net with a mesh size of 60 µm. Samples were evaluated under a rotating microscope according to the Uthermohl method.

Detailed results are summarized in Tables 6 to 9.

In the case of a treated pond, the date of treatment is given in addition to the amount of composition applied. On-site evaluations of the number of Miorooystis colonies and other visual observations are given in the appendix to the tables.

Table 6

Quality and quantitative composition of plankton in treated pond (phytoplankton in millions of individuals in liter, zooplankton in individuals in liter)

The date of the experiment

15.5. 6.6. 28.6. 2.7. 19.7. Phytoplankton Hormogonales 13.65 7.51 39.24 13.65 6.82 Chroccocoales - 0.68 - Centrales 43.68 10.92 58.01 7.51 40.95 Pennales 4.09 3.41 42.65 7.51 348.04 Volvocales - 2.09 - 0.68 Chlorococoales 79.16 40.26 87.01 12.97 13.65 Desmidiales - -. - 3.41 Cryptomonadales 1.36 13.74 20.47 - 20.47 Zygnematales «· - - w Other algae - 2.05 - 1.36 Eyelashes total 141.95 86.46 246.38 43.68 433.35

Continuation of Table 6

The date of the experiment

15.5. 6.6. 28.6. 2.7. 19.7, Zooplankton Rotatoria 1 769 588 380 450 242 Cladocera - - 207 242 242 Copepoda - 34 311 519 277 Nauplius 77 174 140 104 174 Total Zooplankton 1 846 796 1 338 1 315 935 Treatment · jig / 1 Lenacil - - 360 - 360 80 WP visual number observation 1 2 3 4 5

Table 6 Continued • Date of attempt

2.8. 21.8. 27.8. 5.9. 24.9. 29.9. 6.10. 15.10 17.06 2.73 6.82 15.35 10.57 10.91 5.11 8.35 ’- - - - - - - - 6.82 6.82 2.73 - 1.36 5.45 0.34 0.17 156.96 35.49 55.96 141.61 1.36 1,02 w - - 1.36 2.73 6.82 102, - - 0.34 0.34 3.41 20.47 8.19 10.24 5.11 2.72 1.36 0.34 - - - - - - - 0.17 - 1.36 1.36 6.82 1,02 0.68 - 0.17 - - - - - - - - - - 1.36 - 0.34 0.34 - - 184.25 68.24 79.16 180.85 20.81 21.15 7.16 9.55 796 1 280 80 184 547 756 107 207 34 138 46 45 177 13 242 415 161 - 9 - 54 67 555 521 267 116 341 - - 55 1 800 2 250 646 346 942 177 810 242 345 - 435 - - 360 - 6 7 8 9 10 11 12 13

vBy. ' ^cs 273191 B2

Table 7

Water-chemical data of pond No. 1

Date of removal sample Water temperature ° C dissolved oxygen% pH NB + mg / l NO mg / l ^Γθ Γ mg / 1 Chemical consumption 0 ₂ mg / l (using KMnO ^) May 16th 18.6 8.2 0,124 0,781 16.00 June 6th 21.7 - 8.35 1,656 0,926 - 17.00 June 28th 22.0 - 8.30 0,600 1,840 - 17.60 2 July 21.7 37 8.10 1,600 0,102 0.180 20.80 July 20 21.0 260 8.30 0.385 0.564 - 21,00 2nd of August 22.0 - 8.40 1,430 17.0 2,600 16.00 21st August 21.8 - 8.10 0,045 0.310 - 24,00 August 27th 23.0 61 7.90 0,028 0.300 0,080 22.80 5th of September 20.2 - 8.30 3,280 0.530 0.270 20,00 September 24th 16.0 73 7.90 2,500 3,500 0,080 16.00 September 29th 13.0 86 7.90 0,967 0,967 0.533 11.70 October 6th 13.0 95 7.90 3,063 1,088 0.330 15.00 October 15th 8.0 42 7.80 3,394 1,289 0,127 11.00

Table 8

Qualitative and quantitative planting of plankton in pond δ. 2 (control pond), (phytoplankton in millions of individuals per liter, zooplankton in individuals per liter)

Date attempted

15.5. 6.6. 28.6. 2.7. 19.7. phytoplankton Hormogonales 17.74 19.11 2.73 11.94 Chroococcales 79.97 2.73 0.68 - - Centrales 27.30 17.74 10.92 1.36 92.13 Pennales 4.09 8.19 5.46 2.05 102.37 Volvovales 2.73 5.46 - 2.05 * Chlorococcales - 64.15 32.07 17.06 18.77 Desmidiales 1.36 - - 0.68 3.41 Cryptomonadales 5.46 13.65 2.73 1.37 3.41 Zygnematales Other algae 5.46 1.36 - 3.41 3.41 Eyelashes total 135.12 132.39 51.87 30.71 232.03

Continuation of Table 8

The date of the experiment 15.5. 6.6. 28.6. 2.7. 19.7. Zooplankton Rotatoria 1 885 1 107 138 1 384 588 Cladocera - 34 104. 34 Copepoda - - 35 138 207 Naupliue 104 w 278 556 Zooplankton total , 1 885 1 211 207 1 904 1 385 Treatment Jig / 1 Lenacil 80 WP - - - - - Visual observation number 14 15 · 16 17 18

Continuation of Table 8

The date of the experiment

2.8. 21.8. 27.8. 5.9. 24.9. 29.9. 6.10. 15.10 17.74 9.55 8.87 20.42 18.76 14.67 4.09 2.04 16.38 9.55 2.73 0.34 1.36 0.34 0.34 17.74 8.19 10.24 6.82 0.34 2.04 0.34 0.34 - 2.73 6.82 6.14 1,02 0.34 1.36 4.00 23.20 12.28 5., 46 6.82 3.41 w * - - - 0.34 13.65 17.74 3.41 1.36 0.84 1,02 0.17 - - - 0.68 w 5.46 - « 1.36 1,02 0.34 75.06 70.97 44.36 42.31 28.66 23.54 4.77 4.94 558 761 69 761 368 1 592 889 121 242 207 104 253 72 242 54 242 346 242 46 125 «* 80 228 520 174 116 232 736 177 29 270 1 592 1 488 531 1 292 1 301 · 1 769 1 240 673 19 Dec 20 May 21 22nd 23 24 25 26

Table 9

Pond water chemistry data No. 2

Date of removal sample Water temperature ° C Dissolved kyelík% PH NH + mg / l NO ” mg / l po; ~ mg / l chemical oxygen demand (using KMnO ^) May 16th 18.6 8.20 0.465 0,852 * · 16.0 June 6th 21.7 - 8.35 1,656 0,926 - 16.0 June 28th 22.0 - 8.00 0,800 1,940 - 14.1 2 July 21.7 52 8.00 1,900 0,110 «· 19.7 July 20 21.0 210 8.20 0.414 0.580 ar 20.0 2nd of August 22.0 - 8.10 1,100 3,590 - 16.5 21 August 21.8 - 8.00 0.750 0.530 - 21.7 August 27th 23.0 71 8.00 0.810 0.510 - 20.8 5th of September 20.2 - 8.25 2,800 0.400 0.190 19.0 September 24th 16.0 73 7.90 2,500 3,500 0,080 16.0 September 29th 13.0 88 7.90 1,863 0,967 0.533 11.7 October 6th 13.0 95 7.90 3,063 1,088 0.330 15.0 October 15th 8.0 42 7.80 3,390 1,289 0,127 11.0

Visual observation of the individual Sasha data shown in Table 6

1) 15 th May Occurrence of the first colonies of Microcystis. 2) June 6th Microcystis colonies appear only in minor quantities in pond water. 3) June 28th On the surface of the pond a small number of colonies of Microcystis. After sampling, the pond was treated with 4 kg (360 µg / l) of Lenacil 80 WP. 4) 2 July After the treatment of the Microcystis colonies, the surface of the pond surface practically disappeared. 5) July 19 A small number of Microcystis colonies were observed at the pond level. Therefore, after sampling, the pond was treated on 23 July with 4 kg (360 jig / l) Lenacil 80 WP. 6) 2nd of August Only individual colonies of Microcystis are observed in the pond. 7) 21st August Many Miorooystis colonies appear in the pond, therefore 3.8 kg (345 Jig / l) of Lenacil 80 WP was evenly dispersed in the pond. 8) August 27th Miorooystis colonies on the surface of the pond are almost invisible, with moderate amounts in the water. 9) 5th of September A moderate amount of Microcystis colonies is observed in the water, therefore 4.8 kg (435 µg / l) treatment is performed after sampling. Lenacil 80 WP. 10) September 24th No colonies of Mikrocystis were observed on the surface of the pond; 11) September 29th At one edge of the pond, a cluster of Mikrocystis colonies is observed on an area of about 1.2 m. 12) October 6th No colonies of Microcysis, etc. are observed on the surface of the pond

en 273191 B2 practically none. The pond was treated with 4 kg (360 µg / l) of Lenaoil 60 TO 2 days before.

13) October 15 Miorooystis colonies did not occur on the surface of the pond or were observed under a microscope.

Visual observation of the individual time data given in Table 8.

14) 15 th May Occurrence of the first colonies of Microcystis 15) June 6th Only a small number of Miorooystis colonies are observed in the pond water. 16) June 28th A unique number of Microcystis colonies on the surface. 17) 2 July Same as June 28th. 18) July 29th On the surface of the pond a small number of colonies of Microcystis. 19) 2nd of August The number of Miorooystis colonies is increasing. 20) 21st August In contrast to observations 7 and 8 in the treated pond, a moderate amount of Miorooystis colonies are observed here. 21) August 27th On the surface of the pond almost no colonies of Miorooystis, in the water medium amount. 22) 5th of September Many Miorooystis colonies in the water. 23) 24 · September No Microcystis colonies on pond surface, small amount in microscopic water · 24) 29 · September There are no Miorooystis colonies on the surface of the pond, and there are no practices when microscoping the sample. 25) October 6th No Miorooystis colonies on the surface, determined in a sample under a microscope of about 500. 26) October 15th Microcystis colonies do not occur either on the water surface or in a microscopic sample.

o Evaluation of results:

(a) Number of algae in the weakly flowing pond No 1 after the first treatment carried out

On June 28, it dropped considerably, and at the same time the Miorooystis colonies practically disappeared. As a result of the release of nutrients from dead algae (July 2 NS ions content 1.6 mg / l, PO ³

0.18 mg / l) the number of algae only increased to 400 million per liter by 19 July; Pennales were the main component. Further treatment resulted in a decrease in algae counts and only isolated Miorooystis colonies. After the first treatment, siliceous algae prevailed until the end of the monitored period. Tests on the content of plant protection product studies have shown that Lenaoil 80 WP surprisingly was almost not detectable after only a few days.

(b) The amount of zooplankton in pond No 1 has been favorable in terms of fish farming. The amount of Cladoceres, Copepoda and Nauplius, which serve as food for the fish, was considerable between 6 June and 21 August, and the total number of zooplankton organisms showed an upward trend. This increase was most pronounced among

19, July and 21, sprnem, exactly at a time when the number of algae was relatively small. This small amount is due to the large multiplication of zooplankton, which feed on these algae. Therefore, this phenomenon has nothing to do with the destructive effect of lenaoil 80 TO on algae after pond treatment. It also follows that after August 21, when the amount of zooplankton has already dropped, algae numbers have increased again, although the pond has been treated with Lenaoil 80 WP,

c) The number of algae in the weakly flowing pond No. 1 can be described as low during the monitored period. On September 21, clumps of Microoystis colonies appeared at one edge of the pond. The effect of the treatment of 4 kg Lenacil 80 WP on 4 October resulted in:

- Miorocystis colonies have virtually disappeared from the pond

- the total number of algae decreased again

- the amount of oxygen dissolved in the water has been halved.

The amount of zooplankton increased significantly 2 days after treatment, but this was of no practical importance because in October, when the water is already very cold, the fish almost do not eat.

In summary, the most important objective was achieved by the treatment method according to the invention, since the number of Microoystis colonies in the treated pond decreased sharply. This allowed the growth of other algae, in this case siliceous, which was most pronounced after the first treatment. The amount of zooplankton did not decrease but showed a favorable development. Until 5 September, with four treatments with Lenacil 80 WP in the amount of about 300 µg / l, the number and representation of zooplankton and phytoplankton for fish farming were advantageously changed. This late date can be explained by the treatment carried out in the autumn of the previous year, as it can be assumed that this treatment caused only individual Miorocystis colonies to hibernate in the bottom of the pond.

Claims (1)

SUBJECT OF THE INVENTION Process for treating the biological quality of free-flowing water, characterized in that the water is treated at least once a year with 3-cyclohexyl-5,6-trimethyluracyl or a target. 3-butyl-5-chloro-6-methyluracyl in an amount of 20 to 500 µg / l, preferably in the form of a formulation containing these substances.