Acetamide, N-(4-fluorophenyl)-2-hydroxy-N-(1-methylethyl)-

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

March-August 2014

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Qualifier:

according to guideline

Guideline:

ISO 10253 (Water quality - Marine Algal Growth Inhibition Test with Skeletonema costatum and Phaeodactylum tricornutum)

Qualifier:

according to guideline

Guideline:

other: ISO 10253 2006 Water quality - Marine algal growth inhibition test with Skeletonema costatum

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Remarks:

HPLC-UV

Details on sampling:

- Concentrations: all test concentrations and control sampled
- Sample storage conditions before analysis: below 5 °C

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: FOE-hydroxy was characterised as poorly soluble and test solutions were therefore prepared by Water Accommodated Fractions (WAFs).
- Evidence of undissolved material (e.g. precipitate, surface film, etc): Floating particles

Test organisms (species):

Skeletonema costatum

Test type:

static

Water media type:

saltwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

19.1-20.9 °C

pH:

8.06-8.20

Salinity:

36 ‰

Nominal and measured concentrations:

Range finding test: Nominal noncentration (mg/L): 1, 10, 100 and 1000, Analytical concentrations at 0 h(mg/L): <0,1, 9,2, 90 and 360, Analytical concentrations at 72h (mg/L): 1, 9, 91 and 930
Definitive test: Nominal concentrations (mg/L): 10, 32, 100, 320 and 1000 , Analytical concentrations at 0h(mg/L): 9, 30, 95, 320 and 1178, Analytical concentrations at 72h(mg/L): 9, 28, 95, 309 and 930

Details on test conditions:

TEST SYSTEM
The test was conducted in 100 mL borosilicate glass conical flasks, to which 50 mL of test medium seawater was added. Each treatment was inoculated with cells from the pre-cultures (in exponential growth phase) to give an initial cell density of approximately 10,000 cells per mL.
The initial inoculum was checked microscopically using a haemocytometer. Following inoculation, all flasks were loosely covered with aluminium foil caps and mounted on an orbital shaker at approximately 150 rpm. The illumination consisted of 40W cool white tubes (as specified in the ISO guidelines) which were mounted at a distance of approximately 40 cm directly above the test area. Light intensity values were measured daily during the test. Flasks were assigned positions on the shaker. The controlled temperature room temperature was 20 +-2 °C.
Range finding tests were conducted over 72h to determine the approximate concentrations at which effects were observed. Rangefinding tests employ four concentrations and one replicate per concentration with four controls.
Definitive tests were conducted over 72h at concentrations determined from the results of the Range finding tests. Definitive tests employ five concentrations and three replicates per concentration and six controls. A reference test with 3,5-Dichlorophenol was conducted within the previous three months.
In the definitive test, counts of algal cell numbers were carried out daily by microscope using either haemocytometer or Sedgewick-Rafter chamber, depending upon cell numbers present or by Fluorometer measurements. Three readings were performed on each test vessel

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: The seawater used for this study was supplied by a submersible pump situated on Sutherland’s pier on the west side of Flotta in Scapa Flow, Orkney, Scotland. The site can be referenced from Latitude 58°50'8.02"N, Longitude 3° 8'10.80"W. It is pumped continuously from a depth of two metres below low water spring tide level, before passing up 1.8 kilometres of plastic pipe to a 20,000 litre storage tank. Two smaller pumps move the water to three
settlement tanks situated nine metres above floor level. The seawater temperature varies between 6ºC in the winter and 15ºC in the summer. The salinity is between 36‰ and 38‰.

Culture medium is prepared from natural seawater supplied by pump from Scapa Flow, Orkney. All seawater was UV sterilised and filtered to 0.2 ìm. The filtered treated seawater was then enriched with nutrients and vitamins in accordance with ISO guidelines. The salinity of the enriched natural seawater at 0h was 36‰+- 4‰.

OTHER TEST CONDITIONS
- Sterile test conditions: no
- Adjustment of pH: At pre 0h or 0h, the pH of the culture medium was adjusted if required, by adding 1M HCl, or NaOH to give a pH of 8+-0.2. If, at 0h the pH of the test material stock(s) was outwith the pH range of 8+-0.2 then the pH was returned to within these limits by adjustment with either 1M HCl or NaOH as was appropriate. If the pH requires adjustment, a stirring period was required to ensure the pH remained constant.
- Photoperiod:
- Light intensity and quality: 6100-9250 Lux
- Salinity (for marine algae): 36‰

EFFECT PARAMETERS MEASURED (with observation intervals if applicable):
- Determination of cell concentrations: counts of algal cell numbers were carried out daily by microscope using either haemocytometer or Sedgewick-Rafter chamber, depending upon cell numbers present or by Fluorometer measurements.


TEST CONCENTRATIONS
- Range finding study yes
- Test concentrations: 1, 10, 100 and 1000 mg/L (nominal)
- Results used to determine the conditions for the definitive study:

Reference substance (positive control):

yes

Remarks:

3,5-Dichlorophenol

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

582 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

95 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

growth rate

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- EC50: 2.04 mg/L

Validity criteria fulfilled:

yes

Conclusions:

In the definitive test after 72 h FOE-hydroxy exhibited an ErC50 value of 582 mg/L and a NOEC of 95 mg/L(Water Accommodated Fractions (WAFs)) to the marine phytoplankton Skeletonema costatum in the aqueous phase.

Executive summary:

In the definitive test after 72 h FOE-hydroxy exhibited an ErC50 value of 582 mg/L and a NOEC of 95 mg/L(Water Accommodated Fractions (WAFs)) to the marine phytoplankton Skeletonema costatum in the aqueous phase.

Description of key information

In the definitive test after 72 h FOE-hydroxy exhibited a ErC50 value of 582 mg/L and a NOEC of 95 mg/L(Water Accommodated Fractions (WAFs)) to the marine phytoplankton Skeletonema costatum in the aqueous phase.

Key value for chemical safety assessment

EC50 for marine water algae:

582 mg/L

EC10 or NOEC for marine water algae:

95 mg/L