5H-Oxazolo[3,2-a]pyridine-5-carbonitrile, hexahydro-3-phenyl-, (3S,5R,8aS)-

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Sept 2013 - Oct 2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: This study has been performed according to OECD and/or EC guidelines and according to GLP principles.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2013

Report date:

2013

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

(3S,5R,8aS)-3-cyclohexyl-hexahydro-2H-[1,3]oxazolo[3,2-a]pyridine-5-carbonitrile

EC Number:

634-598-5

Cas Number:

106565-71-3

Molecular formula:

C14H16N2O1

IUPAC Name:

(3S,5R,8aS)-3-cyclohexyl-hexahydro-2H-[1,3]oxazolo[3,2-a]pyridine-5-carbonitrile

Test material form:

solid: crystalline

Details on test material:

Identification : PAM-Oxazolopiperidine
Chemical name: (3S,5R,8aS)-(+)Hexahydro-3-phenyl-5Hoxazolo[3,2a]pyridine-5-carbonitrile
Batch no: BS12010625
CAS no.: 106565-71-3
Molecular formula: C14H16N2O
BMG sample no.: M1302-00843-01
Physical form: Solid
Purity: 99.7% (w/w)
Test substance storage: At room temperature, protected from light
Stability: Stable under storage conditions
Expiry date: 8 November 2013

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Vehicle:

yes

Test organisms

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Results and discussion

Effect concentrations

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

< 0.1 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Executive summary:

The median growth inhibiting concentration (ErC50/EyC50) and the low-effect concentrations (ErC10/EyC10,ErC20/EyC20), based on the average specific growth rate and the yield (algal biomass production) within 3 days, of PAM-Oxazolopiperidine to the green alga Desmodesmus subspicatus, were investigated over a period of 72 h. Since PAM-Oxazolopiperidine is only partially soluble, the loadings of the test material were prepared by adding the respective amounts of an acetonic stock solution to empty glass vessels. After complete evaporation of the solvent, the algal medium was added, moderately stirred for a minimum of 24 h, followed by filtration. The resulting water saturated solutions were used in the test. The loading rates were 0.100, 0.320, 1.00, 3.20, 10.0 and 32.0 mg/l. Three parallel test vessels were used for each loading rate of the test substance. HPLC analysis of PAM-Oxazolopiperidine was performed at the beginning, after 24 and 48 h and at the end of the exposure (72 h). Measured concentrations for the loading rates of 0.10 and 0.32 mg/l were below the limit of quantification (LOQ) of the analytical method of 0.1 mg/l. The measured concentrations at the beginning of the exposure for the loading rates of 1.00, 3.20, 10.0 and 32.0 mg/l were 0.194, 1.12, 5.26 and 16.9 mg/l, respectively. The concentrations were not satisfactorily maintained over the whole exposure period: mean concentrations after 72 h of exposure were <0.1, 0.525, 3.58 and 16.8 mg/l (not determined, 47, 68 and 99% of initial concentration, respectively). In order to allow for the calculation of a geometric mean concentration (GM0-72h) and for a statistical evaluation, measured values below the limit of quantification (LOQ) of 0.1 mg/l were set at 0.05 mg/l (0.5 LOQ) for the loading rates of 1.0 mg/l and 0.32 mg/l and at 0.025 mg/l for the loading rate of 0.1 mg/l (0.25 LOQ), respectively. Geometric mean concentrations over a period of 0-72 h (GM0-72h) were 0.025, 0.050, 0.082, 0.773, 4.22 and 17.6 mg/l. The effective concentrations of PAM-Oxazolopiperidine were assessed based on the geometric mean (GM0–72h) concentrations. The results of the growth (r) and yield (y) inhibition of PAM-Oxazolopiperidine to green algae are summarized in the following table showing EC-values and 95% confidence limits (cl) based on the geometric mean (GM0–72h) concentrations:

Parameter              ErC10       ErC20       ErC50       NOEC

GM0-72h (mg/l)     0.368        1.04        6.08 <0.10

Lower 95%-cl        0.142        0.547        4.52

Upper 95%-cl        0.667        1.58        8.39

Parameter              EyC10       EyC20       EyC50       NOEC

GM0-72h (mg/l)     0.013        0.047        0.438        <0.10

Lower 95%-cl        0.006        0.027        0.312

Upper 95%-cl        0.023        0.073        0.627