Manganese sulphide

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:

2010-03-10 to 2010-04-26

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Study was conducted according to GLP and to current guidelines. A single temperature during the range-finding test was observed to be slightly in excess of the range given in the protocol of 20 ± 1°C. This deviation was considered not to have affected the outcome or the validity of the test as the temperature range was within guideline specification.

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

Water samples were taken from the control (replicates R1 – R4 pooled) and the 100% v/v saturated solution test group (replicates R1 – R2 and R3 – R4 pooled) at 0 and 48 hours for quantitative analysis. Duplicate samples were taken and stored at approximately -20°C for further analysis if necessary.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION:

- Method: The test concentration to be used in the definitive test was determined by a preliminary range-finding test. In the range-finding test Daphnia magna were exposed to a series of nominal test concentrations of 0.10, 1.0, 10 and 100% v/v saturated solution.
An amount of test item (200 mg) was dispersed in 2 litres of reconstituted water with the aid of magnetic stirring at approximately 100 rpm for 48 hours. After 48 hours the stirring was stopped and any undissolved test item was removed by filtration through a 0.2 µm Gelman AcroCap filter (first approximate 500 mL discarded in order to pre-condition the filter) to give the 100% v/v saturated solution test concentration. A series of dilutions was made from this saturated solution to give further test concentrations of 10, 1.0 and 0.10% v/v saturated solution. Each prepared concentration was inverted several times to ensure adequate mixing and homogeneity. A sample of the control and 100% v/v saturated solution were taken for chemical analysis at 0 hours to determine the concentration of manganese in the saturated solution

In the definitive test an amount of test item (250 mg) was dispersed in 2.5 litres of reconstituted water with the aid of magnetic stirring at approximately 100 rpm for 48 hours. After 48 hours the stirring was stopped and any undissolved test item was removed by filtration through a 0.2 µm Gelman AcroCap filter (first approximate 500 ml discarded in order to pre-condition the filter) to give the 100% v/v saturated solution test concentration (equivalent to a mean measured test item concentration of 6.1 mg/L). The concentration of the test item in the test preparations was verified by chemical analysis at 0 and 48 hours.

- Controls: The control group was maintained under identical conditions but not exposed to the test item. A positive control (Harlan Laboratories Ltd Project No: 0039/1133) conducted approximately every six months used potassium dichromate as the reference item at concentrations of 0.32, 0.56, 1.0, 1.8 and 3.2 mg/L.

- Evidence of undissolved material: The test preparations were observed to be clear, colourless solutions throughout the duration of the test.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna
- Source: in-house laboratory cultures
- Age at study initiation (mean and range, SD): less than 24 hours old
- Method of breeding: parthenogenesis
- Feeding during test: no

ACCLIMATION
- Acclimation conditions: the same as test conditions
- Type and amount of food: a suspension of algae (Chlorella sp.)
- Feeding frequency: daily

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Post exposure observation period:

no

Hardness:

250 mg/L as CaCO₃

Test temperature:

20°C

pH:

7.8± 0.2

Dissolved oxygen:

8.5 - 9.4 mg O₂/L

Salinity:

not reported

Nominal and measured concentrations:

nominal concentration: 100% v/v saturated solution
measured concentration: from 6.0 to 6.1 mg/L as test item, no decline in measured concentration was observed over the test period, therefore it was considered appropriate to calculate the results based on the mean measured test item concentration which was determined to be 6.1 mg/L as test item

Details on test conditions:

TEST SYSTEM
- Test vessel: 250 mL glass jars containing approximately 200 mL of test preparation
- Type: open, covered to avoid evaporation
- Aeration: no
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: reconstituted water
- Conductivity: <5 µS cm-1
- Culture medium different from test medium: no

OTHER TEST CONDITIONS
- Photoperiod: 16 hours light and 8 hours darkness cycle with 20 minute dawn and dusk transition periods
- Light intensity: not reported

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Any immobilisation or adverse reactions to exposure were recorded at 24 and 48 hours after the start of exposure. The criterion of effect used was that Daphnia were considered to be immobilised if they were unable to swim for approximately 15 seconds after gentle agitation.

TEST CONCENTRATIONS
- Justification for using less concentrations than requested by guideline: Based on the results of the range-finding test a "Limit test" was conducted at a concentration of 100% v/v saturated solution to confirm that at the highest attainable test concentration no immobilisation or adverse reactions to exposure were observed.
- Range finding study: yes
- Test concentrations: In the range-finding test Daphnia magna were exposed to a series of nominal test concentrations of 0.10, 1.0, 10 and 100% v/v saturated solution. Based on the results of the range-finding test a "Limit test" was conducted as a definitive study.
- Results used to determine the conditions for the definitive study: No immobilisation was observed at the test concentrations of 0.10, 1.0, 10 and 100% v/v saturated solution.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 other: % v/v saturated solution

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

100 other: % v/v saturated solution

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 6.1 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

6.1 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

In the range-finding test no immobilisation was observed at the test concentrations of 0.10, 1.0, 10 and 100% v/v saturated solution (results from the study are provided in Table 1). Based on the results of the range-finding test a "Limit test" was conducted. There was no immobilisation in 20 daphnids exposed to a test concentration of 100% v/v saturated solution for a period of 48 hours (results from the definitive test are given in Table 2). The No Observed Effect Concentration after 24 and 48 hours exposure was 100% v/v saturated solution (equivalent to a mean measured test item concentration of 6.1 mg/L). No other abnormalities in behaviour were observed.

Results with reference substance (positive control):

- Results with reference substance valid? yes
- EC50: 0.77 mg/L (sd = 0.20)
- NOEC: 0.32 mg/L

Reported statistics and error estimates:

The slope and its standard error of the response curve at 24 hours was 7.7 (SE = 1.6). Due to the unsuitable nature of the data it was not possible to calculate the slope and error of response curve at 48 hours.

Results from range-finding test:

Cumulative immobilisation data from the exposure of Daphnia magna to the test item during the range-finding test are given in Table 1. No immobilisation was observed at the test concentrations of 0.10, 1.0, 10 and 100% v/v saturated solution.

Table 1            Cumulative Immobilisation Data in the Range-finding Test

Nominal Concentration (% v/v Saturated Solution)	Cumulative Immobilised Daphnia (Initial Population: 10 Per Replicate)
	24 Hours	48 Hours
Control	0	0
0.10	0	0
1.0	0	0
10	0	0
100	0	0

Results from the definitive test:

Cumulative immobilisation data from the exposure of Daphnia magna to the test item during the definitive test are given in Table 2.

There was no immobilisation in 20 daphnids exposed to a test concentration of 100% v/v saturated solution for a period of 48 hours. Inspection of the immobilisation data gave the following results:

Time (h)	EC50(% v/v Saturated Solution)	EC50(mg/L as test item)
24	>100	>6.1
48	>100	>6.1

The No Observed Effect Concentration after 24 and 48 hours exposure was 100% v/v saturated solution (equivalent to a mean measured test item concentration of 6.1 mg/L). The No Observed Effect Concentration is based upon zero immobilisation at this concentration.

Table 2. Cumulative Immobilisation Data in the Definitive Test

Mean Measured Test Item Concentration (mg/L)		Cumulative Immobilised Daphnia (Initial Population: 5 Per Replicate)
		24 Hours			48 Hours
		No. Per Replicate	Total	%	No. Per Replicate	Total	%
Control	R1	0	0	0	0	0	0
	R2	0			0
	R3	0			0
	R4	0			0
6.1	R1	0	0	0	0	0	0
	R2	0			0
	R3	0			0
	R4	0			0

 

R₁– R₄= Replicates 1 to 4

Appendix 2      Physico-Chemical Measurements

Mean Measured Test Item Concentration (mg/L)		0 Hours				24 Hours	48 Hours
		pH	mg O2/L	%*	T°C	TºC	pH	mg O2/L	%*	T°C
Control	R1	7.8	9.4	101	19	21	7.8	9.0	101	21
	R2	7.8	9.4	101	19	20	7.9	9.0	101	21
	R3	7.8	9.4	101	19	21	7.9	8.8	99	21
	R4	7.8	9.3	100	19	21	7.9	8.9	100	21
6.1	R1	7.7	8.5	96	21	21	7.8	8.9	98	20
	R2	7.7	8.5	96	21	21	7.9	8.9	100	21
	R3	7.7	8.5	96	21	20	7.9	8.8	97	20
	R4	7.7	8.5	96	21	20	7.9	8.9	98	20

 

*ASV= Dissolved oxygen concentration expressed as a percentage of Air Saturation Value

R₁– R₄= Replicates 1 to 4

Validity criteria fulfilled:

yes

Conclusions:

48-Hour EC50 was estimated to be greater than 6.1 mg/L.

Executive summary:

The short-term toxicity of the test material to aquatic invertebrates was assessed according to OECD Test Guideline 202 and EU Method C.2 and in compliance with GLP.

There was no immobilisation in 20 daphnids exposed to a test concentration of 100 % v/v saturated solution for a period of 48 hours. The No Observed Effect Concentration after 24- and 48-hours exposure was 100 % v/v saturated solution (equivalent to a mean measured test item concentration of 6.1 mg/L). No other abnormalities in behaviour were observed.

Under the conditions of the study the 48-Hour EC50 was estimated to be greater than 6.1 mg/L. 

Description of key information

The 48-Hour EC50 was estimated to be greater than 6.1 mg/L.  

Additional information

The short-term toxicity of the test material to aquatic invertebrates was assessed according to OECD Test Guideline 202 and EU Method C.2 and in compliance with GLP.

There was no immobilisation in 20 daphnids exposed to a test concentration of 100 % v/v saturated solution for a period of 48 hours. The No Observed Effect Concentration after 24- and 48-hours exposure was 100 % v/v saturated solution (equivalent to a mean measured test item concentration of 6.1 mg/L). No other abnormalities in behaviour were observed.

Under the conditions of the study the 48-Hour EC50 was estimated to be greater than 6.1 mg/L.