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Long-term toxicity to aquatic invertebrates

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Reference
Endpoint:
long-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
key study
Study period:
09 July, 2001 - 21 May, 2002
Dates of Experimental Phase : 01 August - 20 November, 2001
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Qualifier:
according to guideline
Guideline:
OECD Guideline 211 (Daphnia magna Reproduction Test)
Version / remarks:
1998
Deviations:
no
GLP compliance:
yes
Specific details on test material used for the study:
Batch No. 9000421832;
Purity 98.5%;
Expiry Date : 17 April, 2002
Analytical monitoring:
yes
Remarks:
HPLC-UV/VIS detection
Details on sampling:
Semi-static set-up used. The main period of renewal was every 48 hours, with 2 chnages being made after 72 hours (Renewals on Day 2, 5, 7, 9, 12, 14, 16 and 19).

One sample was taken from the freshly prepared stock solution and duplicate samples were taken from the freshly prepared test media of all test concentrations and the Control at the first treatment period (Day 0), at a treatment period in the second week (Day 12) and at a treatment period in the last week (Day 16).
Vehicle:
no
Details on test solutions:
The following Nominal exposure concentrations were prepared :
Control
0.038 mg/L
0.12 mg/L
0.38 mg/L
1.2 mg/L
3.8 mg/L

Prior to the start of the test and prior to each test medium renewal a stock solution of Nominal 10 mg/L was freshly prepared by dissolving 20 mg of test substance completely in 2 L test water by intensive stirring for 20 minutes at room temperature.

Adeuqate volumes of the stock solution were diluted in test water to obtain the desired Nominal test concentration.
Test organisms (species):
Daphnia magna
Details on test organisms:
Daphnia magna Strauss.

DAphnia were acclimated in the same water as that used for the study. At the start of the test the young daphnids used were less than 24 hours old and were not first brood progeny.
Test type:
semi-static
Water media type:
freshwater
Remarks:
Elendt M7
Limit test:
no
Total exposure duration:
21 d
Hardness:
250 mg/L as CaCO3
Test temperature:
20 - 22 °C
pH:
pH 7.5 - 7.9
Dissolved oxygen:
> = 8.0 mg O2/L
Nominal and measured concentrations:
The Nominal and mean measured concentrations were, as follows :

Nominal (mg/L) Mean Msd. (mg/L)
Control < LOD (0.174 mg/L)
1.2 mg/L 0.709 mg/L
3.8 mg/L 2.55 mg/L

These two concentration levels englobe the effects range observed in the study.
Details on test conditions:
No. of Daphnids : 10 per test concentration, each test animal in a separate beaker
Exposure Vessels : 100 mL glass beaker containing 80 mL of media, covered with glass plates.
Water Temperature : 20 - 22°C
Light Conditions : 16 hours light / 8 hours dark, with 30 minute transition period (370 - 380 lux);
Test Duration : 21 days
Test Water : Elendt M7 with initial pH 7.9
Feeding : On each working day, 50% algae / 50% fish food suspension, administered at between 0.10 and 0.25 mg TOC/daphnia/day.

Reference substance (positive control):
no
Key result
Duration:
21 d
Dose descriptor:
NOEC
Effect conc.:
0.71 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
reproduction
Duration:
21 d
Dose descriptor:
EC50
Effect conc.:
1.7 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
reproduction
Details on results:
In all test concentrations the survival rate of the test animals at the end of the test was at least 90% or higher. Thus, the survival rate after 21 days was not signifcantly (< 10%) reduced up to the highest test concentration of 2.6 mg/L (3.8 mg/L Nominal).

The first young offspring released from their parent animals were recorded in the Control and at all test concentrations up to and including 0.71 mg/L (1.2 mg/L Nominal) at the observation on Day 9. At the highest test concentration a delay of the first brood was determined (Day 12).

The mean reproduction rate of the daphnids in the Control was 67.1 +/- 7.5 alive offspring per adult. According to the results of a Williams-Test, no significant toxic effect of the test item on the mean reproduction rate was determined up to and including the test concentration of 0.71 mg/L (1.2 mg/L Nominal).

Number of Surviving Test Animals :



The Total Number of alive, young daphnids reproduced by all adults (cumulative values) :



The number of alive offspring reproduced per surviving adult within 21 days of exposure :







Validity criteria fulfilled:
not specified
Conclusions:
The results of the 21-day OECD 211 Daphnia reproduction study performed with Florhydral are :
21 day NOEC = 0.71 mg/L.

Description of key information

AQUATIC TOXICITY :

Daphnia Reproduction 21-day NOEC = 0.71 mg/L


Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates
Effect concentration:
0.71 mg/L

Additional information

AQUATIC TOXICITY :

Daphnia Reproduction 21-day NOEC = 0.71 mg/L.