Hydroxylammonium chloride

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

07 - 09 June 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

adopted 2004

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

The department of health of the government of the United Kingdom

Analytical monitoring:

yes

Details on sampling:

- Concentrations: control, 1.0, 1.8, 3.2, 5.6 and 10 mg/L
- Sampling method: at the start of the test and at media renewal at 24 h, 10 mL samples of freshly prepared test media were taken from the control and each test media preparation flask for chemical analysis. At 24 and 48 h, 10 mL samples were taken for chemical analysis from the pooled test media.
- Sample storage conditions before analysis: stability of stored samples was not demonstrated for hydroxylamine hydrochloride in Elendt M4 medium and un-derivatised samples were not considered to be stable. A derivatised batch of samples with their associated calibration standards could be stored refrigerated or frozen for as long as the method criteria are met. The derivatised samples were shown to be stable under refrigerated conditions for a period of 3 d.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: 50 mg of test substance was dissolved in 500 mL of Elendt medium to give a 100 mg/L stock solution. 100 mL was diluted in a final volume of 1000 mL of Elendt medium to give the 10 mg/L test concentration. Aliquots (280, 160, 90 and 50 mL) of the 10 mg/L test concentration were each separately diluted in a final volume of 500 mL of Elendt medium to give the 5.6, 3.2, 1.8 and 1.0 mg/L test concentrations, respectively. A control group was prepared only with Elendt medium.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flea
- Source: laboratory culture. Culture was originally obtained from MicroBio Tests Inc., Belgium
- Age of parental stock: < 24 h old Daphnids (juveniles were collected from the second brood onwards)
- Feeding during test: no

CULTURING
- Culturing conditions: in beakers with 1 L Elendt M4 medium. New cultures were initiated with juvenile Daphnia magna (< 24 h old), at a density of 15-20 daphnids/vessel. The cultures were fed daily with a concentrated suspension of Chlorella vulgaris. The media was renewed twice weekly. Juveniles were
removed using a sieve. Cultures were maintained up to a maximum of 4 to 5 weeks. The light conditions were the same as during the test.

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

-

Test temperature:

19.0 - 19.7 °C

pH:

7.45 - 7.90

Dissolved oxygen:

8.15 - 10.05 mg/L

Salinity:

-

Conductivity:

-

Nominal and measured concentrations:

Nominal concentrations: control, 1.0, 1.8, 3.2, 5.6 and 10 mg/L
Time-weighted mean measured test concentrations:

Details on test conditions:

TEST SYSTEM
- Test vessel: 100 mL beakers
- Type (delete if not applicable): vessels were covered with a clear lid
- Material, size, headspace, fill volume: Material: glass, Fill volume: 50 mL
- Renewal rate of test solution (frequency/flow rate): every 24 h
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Elendt M4 medium
- Ca/Mg ratio: CaCl2.2H2O 1 mg/L / MgSO4.7H2O 0.5 ml/L
- Culture medium different from test medium: no
- Intervals of water quality measurement: the pH, dissolved oxygen concentration and temperatures were determined in freshly prepared test media and in the old media at 24 and 48 h (replicates were pooled in old media). Temperatures was measured continuously using a digital thermometer in an additional vessel maintained in the study area.

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16-h light: 8-h dark
- Light type: fluorescent lighting

EFFECT PARAMETERS MEASURED: mobility was observed after 24 and 48 h

RANGE-FINDING STUDY
- Test concentrations: control, 0.10, 1.0, 10 and 100 mg/L (nominal)
- Results used to determine the conditions for the definitive study: the results of the range-finding/limit test suggested that the 48-h EC50 value would be between 1.0 and 10 mg/L.

Reference substance (positive control):

yes

Remarks:

Regular tests are conducted in the laboratory using a reference toxicant to ensure that Daphnia magna cultures are of the highest quality and sensitivity.

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

1.1 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% CI 0.79 – 2.1

Details on results:

- Mortality of control: no mortality
- The test preparations were observed to be colourless solutions throughout the duration of the test.

VALIDITY CRITERIA:

Table 1: Validity criteria.

Criterion from the guideline	Outcome	Validity criterion fulfilled
In the control, including the control containing the solubilising agent, not more that 10% of the daphnids should have been immobilized.	0% immobilizition	yes
The dissolved oxygen concentration at the end of the test should be ≥ 3 mg/L in control and test vessels.	8.15 – 8.9 mg/L	yes

BIOLOGICAL RESULTS:

Table 2: % immobilization of Daphnids after 48 h exposure.

Nominal concentration (mg/L)	% Immobility at 48 h
Control	0
1	0
1.8	15
3.2	75
5.6	100
10	100

Table 3: Further biological results.

Effect value	TWA concentration (mg/L) 48 h
LOEC	0.74
NOEC	0.29

ANALYTICAL RESULTS

Table 4: Analytical results.

Nominal concentration (mg/L)	Measured concentration (mg/L)
	0 h (New media)	% nominal	24 h (Old media)	% nominal	24 h (New media)	% nominal	48 h (Old media)	% nominal	Time weighted mean measured concentration (mg/L)
Control	-	-	-	-	-	-	-	-	-
1	0.844	84	-	-	0.943	94	-	-	0.29
1.8	2.22	123	0.124	7	1.91	106	0.192	11	0.74
3.2	3	94	0.369	12	3.36	105	0.531	17	1.4
5.6	6.26	112	0.789	14	5.25	94	-	-	2.6
10	10.8	108	3.49	35	10.5	105	-	-	6.5

Where measured concentrations were <LOQ, a value of half LOQ (0.5 mg/L) was used to calculate the time-weighted mean measured concentration. Calculated using 0 (fresh media) and 24 (old media) h results only for the 5.6 and 10 mg/L test concentrations given that the daphnids were not transferred to new media at 24 h due to 100% immobilisation.

Validity criteria fulfilled:

yes

Remarks:

For further details please refer to “Any other information on results incl. tables”.

Description of key information

EC50 (48 h) = 1.1 mg test item/L (TWA, D. magna, OECD 202)

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

1.1 mg/L

Additional information

One study is available, in which the short term toxicity of the substance hydroxylammonium chloride (CAS 5470-11-1) to aquatic invertebrates is tested. The study was performed according to OECD guideline 202 and GLP. The water flea, Daphnia magna was exposed in a semi-static test regime to nominal test item concentrations of 1.0, 1.8, 3.2, 5.6 and 10 mg/L and a control (corresponding to time-weighted mean measured concentrations of 0.29, 0.74, 1.4, 2.6 and 6.5 mg/L) for 48 h. The test item was analytically monitored during the test by LC-TOF/MS. Due to the decline of the measured concentrations over each 24-h period, the results were based on time-weighted mean measured concentrations. All validity criteria given by the guideline were fulfilled. The test resulted in an EC50 (48 h) of 1.1 mg/L (TWA).