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Toxicity to microorganisms

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Reference
Endpoint:
toxicity to microorganisms
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
data from handbook or collection of data
Justification for type of information:
Data is from peer reviewed journal
Qualifier:
according to
Guideline:
other: refer below principle
Principles of method if other than guideline:
In vitro toxicity study of Piperazine citrate on Gyrodactylus sp. infecting rainbow trout Oncorhynchus mykiss
GLP compliance:
not specified
Specific details on test material used for the study:
- Name of test material (as cited in study report): Piperazine citrate / tripiperazine dicitrate- Molecular formula: C12H30N6•Cl2H16O14 - Molecular weight: 642.76 g/mole - Substance type: Organic - Physical state: Solid
Analytical monitoring:
not specified
Details on sampling:
Details on sampling- Concentrations: 200 mg/l
Vehicle:
yes
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)- Method: Gyrodactylus sp. were obtained from rainbow trout placed in Petri dishes containing different concentrations of anthelmintic - Controls: Yes - Chemical name of vehicle (organic solvent, emulsifier or dispersant): Water
Test organisms (species):
other: G. Malmberg as Gyrodactylus salaris
Details on inoculum:
- Laboratory culture: One sample obtained from infested rainbow trout
Test type:
not specified
Water media type:
freshwater
Limit test:
no
Total exposure duration:
60 min
Remarks on exposure duration:
30 and 60 min. study
Hardness:
No data
Test temperature:
No data
pH:
No data
Dissolved oxygen:
No data
Salinity:
No data
Nominal and measured concentrations:
nominal and measured concentration : Measured concentration
Details on test conditions:
TEST SYSTEM- Test vessel: Petri Dishes- Type (delete if not applicable): open - No. of organisms per vessel: 6 to 8 specimens - No. of vessels per concentration (replicates): 2 - No. of vessels per control (replicates): 1 - No. of vessels per vehicle control (replicates): 1 EFFECT PARAMETERS MEASURED (with observation intervals if applicable): Number of dead (immobile) helminths.
Reference substance (positive control):
not specified
Key result
Duration:
60 min
Dose descriptor:
EC0
Effect conc.:
200 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
other: Number of dead (immobile) Gyrodactylus salaries

Oncorhynchus mykiss. Treatment against Gyrodactylus sp. Results obtained under in vitro conditions for the drugs examined. Doses expressed as mg I-'; length of exposure, in min; percentage of reduction gives the number of live Gyrodactylus

Drug

Dose mg/l

Time of exposure (min)

Percentage of reduction

Nos. of Gyrodactylus sp.

total

Dead

Piperazine citrate

200

60

0

8

0

200

30

0

8

0

relative to the initial number; also listed are the number of Gyrodactylusinitially tested and the number of dead worms counted at the end of the treatment. 

Control lots remained unaffected after 60 min in drug-free water under conditions identical to those in the treated lots

Validity criteria fulfilled:
not specified
Conclusions:
EC0 was considered to be 200 mg/l when Gyrodactylus sp. infecting rainbow trout Oncorhynchus mykiss treated with Piperazine citrate.
Executive summary:

In an in - vitro toxicity study, Gyrodactylus sp. infecting rainbow trout Oncorhynchus mykiss treated with Piperazine citrate in the concentration of 0 and 200 mg/l. no effect were observed on Percentage of reduction and number of dead (immobile) Gyrodactylus salaries. Therefore, EC0 was considered to be 200 mg/l when Gyrodactylus sp. infecting rainbow trout Oncorhynchus mykiss treated with Piperazine citrate.

Description of key information

EC0 was considered to be 200 mg/l when Gyrodactylus sp. infecting rainbow trout Oncorhynchus mykiss treated with Piperazine citrate. Based on this result it may be concluded that the substance Piperazine citrate (CAS no. 144-29-6) is non toxic to micro organisms.

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:
200 mg/L

Additional information

Toxicity to micro organisms was assessed for the target compound Piperazine citrate (CAS no. 144-29-6) and its structurally related read- across substance by reviewing a number of studies. The summary of the results are presented below as weight of evidence approach:

Key study from reviewed journal DISEASES OF AQUATIC ORGANISMS, Vol. 10: 39-43, 1991 indicate that thein - vitro toxicity study, Gyrodactylus sp. infecting rainbow trout Oncorhynchus mykiss treated with Piperazine citrate in the concentration of 0 and 200 mg/l. no effect were observed on Percentage of reduction and number of dead (immobile) Gyrodactylus salaries. Therefore, EC0 was considered to be 200 mg/l when Gyrodactylus sp. infecting rainbow trout Oncorhynchus mykiss treated with Piperazine citrate.

Various supporting studies of the read across compound piperazine (CAS no. 110-85-0) obtained from European Union Risk Assessment Report – PIPERAZINE, 3rd Priority List Volume: 56; final Report, 2005 were reviewed and are summarised as below:

The respiration inhibition of nitrifying bacteria was studied in a two hours study (Balk and Meuwsen, 1989c). No guidelines were referred to. The nominal test concentrations were 410,750 and 1,350 mg/L. The test temperature was 20°C, and the pH was kept neutral with HCl.

Further, the inhibition of cell multiplication of Pseudomonas putida was investigated during 18 hours in a study generally in accordance with an ISO Guideline (van Ginkel, 1989). The nominal test concentrations of piperazine were 62.5, 125, 250, 500 and 1,000 mg/L. Test temperature was 25°C, pH was adjusted to neutral by means of titration with H2SO4. Cell density was determined photometrically in single cultures at the beginning of the incubation and after 18 hours. No effect on cell multiplication was observed in any of the tested concentrations compared to the controls. NOEC was determined to be >1,000 mg/L (nominal concentration).

Similarly, an activated sludge respiration inhibition test was performed according to EEC Guidelines (OECD 209) (van Ginkel and Stroo, 1989). Homogenised sludge (0.46 g dw/L) was incubated at 20°C and pH 7.4-7.8 for 30 minutes with nominal test concentrations of 20, 60,180, 540 and 1,620 mg/L plus control. The oxygen depletion was measured in single samples using an oxygen electrode. At the highest test concentration, respiration inhibition was 16% compared to the control. NOEC was determined to be 540 mg/L.

Based on above results for target chemical as well as its read across substance and by applying weight of evidence approach it may be concluded that the substance Piperazine citrate (CAS no. 144-29-6) is non toxic to micro organisms.