| Sponsor |
GERO milieu-technieken P.O. Box 284 5660 AG Geldrop The Netherlands |
| Testing Facility |
NOTOX B.V. Hambakenwetering 3, 5231 DD 's-Hertogenbosch, The Netherlands |
| NOTOX Project | 179292 | NOTOX Substance | 63945 |
| Guidelines |
OECD No. 202 PART I (1984), EEC (Part C.2., 1992). |
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June 10 to June 12, 1996 |
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TEST PROCEDURE AND CONDITIONS |
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| Test substance | The product tested here is a water-based, clear 20% solution of polymerised organic and inorganic solid matter (a.i.). |
| Reference substance | 3,5 - Dichlorophenol (97% , Aldrich). |
| Method of preparation | A final test solution was prepared at a nominal concentration of 500 mg/l corresponding with 100 mg a.i./l. |
| Test Species | Pseudomonas putida, Strain: MIGULA, Berlin 33/2 )DSM 50026). |
| Loading | 10 Daphnia per vessel containing 80 ml test solution. |
| Culture medium (stock) | Nutrient medium: 18 g of agar dissolved in test medium prepared according tot ISO 10712, 1996. |
| Preliminary suspension cultures | A small amount of bacteria from a 7-day old stock culture of Pseudomonas putida was inoculated in pre-culture medium. |
| Exposure | Duplicate test solutions in 100 ml Erlenmeyer flasks coverd with aluminium caps. |
| Equipment | UV/VIS Spectrophotometer, Lambda 5 (Perkin Elmer, the Netherlands), λ = 436 nm, 10 mm layer |
| Calibration solution | Formazin standard suspension. |
| Data handling |
The percentage of cell multiplication inhibition for each tested concentration was calculated as follows: I = [(Bc - Bn) : (Bc - Bo)] * 100 |
| I | Cell multiplication inhibition in % |
| Bn | Measured biomass (extinction - extinction of turbidity control) at the end of the test period for the th concentration of the test material | Bc | Measured biomass (extinction) at the end of the test period in the control batch |
| Bo | Measured biomass (extinction) at the start fo the test (t = o) in the control batch. |
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RESULTS Bacterial toxicity After incubation extinction values were measured and the celle multiplication inhibition for each test concentration was determined (see Table I). Table I: Extinction values of the inoculated test solutions containing 500 mg HYDRO SEAL/1, corresponding with 100 mg a.i./l: |
| Concentration of HYDRO SEAL |
EXTINCTION IN FNU 436 nm series |
MEAN | INHIBITION % |
||||
| (mg/l) | I | II | III | IV | V | ||
| 500 | 1.988 | 2.126 | - | - | - | 2.057 | nil |
| Controls | 2.122 | 2.154 | 2.075 | 1.948 | 2.082 | 2.076 | ca. 0.08 |
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CONCLUSION HYDRO SEAL: Based on the results of the test presently performed, the toxicity threshold value (EC10) of HYDRO SEAL was over 500 mg/I. The EC50 value for the reference substance, 3,5-dichlorophenol, tested during the same experiment was 31 mg/l. Since this was within the accepted range of 10-30 mg/l for the EC50 and the multiplication factor of the bacteria within the test was over 60, it was concluded that the test conditions were optimal and the results obtained were valid. |