Naltrexone

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2016

Report date:

2016

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Naltrexone

EC Number:

240-649-9

EC Name:

Naltrexone

Cas Number:

16590-41-3

Molecular formula:

C20H23NO4

IUPAC Name:

(1S,5R,13R,17S)-4-(cyclopropylmethyl)-10,17-dihydroxy-12-oxa-4-azapentacyclo[9.6.1.0^{1,13}.0^{5,17}.0^{7,18}]octadeca-7(18),8,10-trien-14-one

Sampling and analysis

Analytical monitoring:

yes

Remarks:

HPLC-UV

Test organisms

Test organisms (species):

Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)

Details on test organisms:

The test organism (P. subcapitata, strain 278/4) was originally obtained from the culture collection of algae and protozoa and is representative species of the freshwater aquatic phytoplankton.
Prior to testing, duplicate starter cultures were prepared and incubated under test conditions to obtain sufficient algal cells in exponential growth and to achieve a starting algae cell density of 1x10e+4 cells/mL.

Study design

Test type:

not specified

Water media type:

other: reverse osmosis water

Limit test:

no

Total exposure duration:

72 h

Post exposure observation period:

Following incubation, the cell density of a single starter culture was established using a particle counter and confirmed manually using a haemocytometer.

Test conditions

Hardness:

Not specified

Test temperature:

21-24°C

pH:

7.77-8.55 (test start)

Dissolved oxygen:

Not specified

Nominal and measured concentrations:

Nominal: 2.56, 6.4, 16, 40 and 100 mg/L
Measured: 2.413, 5.910, 13.968, 33.431 and 77.217 mg/L

Details on test conditions:

Incubation under 4440-8880 lux light intensity

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 77.22 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

ca. 33.434 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 3

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

ca. 59.83 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

biomass

Effect concentrations 4

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

ca. 33.434 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

biomass

Effect concentrations 5

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

ca. 57.73 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

other: yield

Effect concentrations 6

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

ca. 33.434 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

other: yield

Details on results:

Based on geometric mean measured concentrations, the 72-h EyC50 (yield), EbC50 (biomass) and ErC50 (growth rate) values were calculated to be 57.73, 59.83 and > 77.22 mg/L respectively. The corresponding NOEC values for yield, biomass and specific growth rate after 72 hours were 33.434 mg/L respectively.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

As the measured concentrations were outside the range of 80-120% of nominal exposure concentrations of Naltrexone which is required to report the test concentrations in terms of nominal concentrations, the test concentrations therefore, were reported as geometric mean measured concentrations.
Based on geometric mean measured concentrations, the 72-h EyC50 (yield), EbC50 (biomass) and ErC50 (growth rate) values were calculated to be 57.73, 59.83 and > 77.22 mg/L respectively. The corresponding NOEC values for yield, biomass and specific growth rate after 72 hours were 33.434 mg/L respectively.