m-phenylenediamine

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

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:

no guideline followed

Principles of method if other than guideline:

Animals from commercial supplier acclimated in 100% dilution water. Temperature 18.2 - 19.0 ºC. Dissolved oxygen maintained above 6.9 mg/L. Fed once or twice daily before test. Static screening test was followed by flow-through test. Test temperature was 18 ± 1 ºC with five concentrations of test substance and a dilution water control. Twenty amphipods equally distributed among 2 replicates of each treatment. Concentrations monitored every 24 hours with HPLC. Used computer program to calculate LC50.

GLP compliance:

yes

Analytical monitoring:

yes

Vehicle:

no

Details on test solutions:

Stock solution was used; 40.8 g of test substance was dissolved in deionized water and diluted to 1000 mL.

Test organisms (species):

Gammarus fasciatus

Details on test organisms:

TEST ORGANISM
- Common name: amphipod
- Source: Aquatic Research Organisms division of Resource Analysts, Inc.
- Feeding during test: no food 48 h prior and during the test
- Average wet weight (blotted dry): 0.02 g

ACCLIMATION
- Acclimation period: more than 14 days
- Acclimation conditions : in 100% dilution water, in glass aquarium, under flow-through conditions, temp 18.2-10 ºC, DO above 6.9 mg/L
- Type and amount of food: Tetra-min dry fish food
- Feeding frequency: once or twice daily
- Health during acclimation (any mortality observed): free of apparent sickness, injury and abnormalities

Test type:

flow-through

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Test temperature:

17.1 - 18.5 ºC

pH:

8.2 -8.4

Dissolved oxygen:

8.5 - 9.0 mg/L

Nominal and measured concentrations:

Nominal: 0, 3.6, 6.0, 9.6, 14.4, 24.0 mg/L
Measured: ND, 3.8, 5.3, 8.5, 13.0, 23.4 mg/L
- static screening test used nominal concentrations: 0.2, 2.0, 20, 200, and 2000 mg/L
- flow-through screening test used nominal concentrations 3.6 and 24.0 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 4 Liter glass vessels
- Aeration: no
- Type of flow-through (e.g., peristaltic or proportional diluter): intermittent flow proportional diluter
- Renewal rate of test solution (frequency/flow rate): 16.1 volume exchanges per test vessel per day
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 1
- Biomass loading rate: 0.08 g/L


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: well water collected at EnviroSystems in Hampton, New Hampshire
- adjusted to hardness of 160 mg/L as CaCO3
- stored in 500-gallon polyethylene tanks and aerated
- Total organic carbon: <1.0 mg/L
- TSS: <10 mg/L
- Pesticides: Not detected
- Conductivity: 1200 micromhos/cm

OTHER TEST CONDITIONS
- Photoperiod: 16 h light/ 8 h dark
- Type: cool white fluorescent light
- Light intensity: 10 uEs-1m-2

TEST CONCENTRATIONS
- static screening test used nominal concentrations: 0.2, 2.0, 20, 200, and 2000 mg/L
- flow-through screening test used nominal concentrations 3.6 and 24.0 mg/L

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

4.6 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Basis for effect:

mortality

Remarks on result:

other: 95% CL 4.3 - 5.1 mg/L

Duration:

72 h

Dose descriptor:

LC50

Effect conc.:

5.5 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Basis for effect:

mortality

Remarks on result:

other: 95% CL 4.9-6.3 mg/L

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

7.8 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Basis for effect:

mortality

Remarks on result:

other: 95% CL 6.8-8.8 mg/L

Duration:

24 h

Dose descriptor:

LC50

Effect conc.:

> 23.4 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Basis for effect:

mortality

Details on results:

- amphipods exposed to 13 mg/L were lethargic and those exposed to 23.4 mg/L were immobilized at 24 hours
- all surviving amphipods exposed to 8.5 mg/L were lethargic at 48 hours and immobilized at 72 hours
- 8 of the 12 surviving amphipods exposed to 5.3 mg/L were immobilized at 72 hours and all survivors were immobilized at 96 hours
- Any observations (e.g., precipitation) that might cause a difference between measured and nominal values: no insoluble material was observed.

Affected/Survival (%)

	0 hr		24 hr		48 hr		72 hr		96 hr
Measured Concentration (mg/L)	Rep 1	Rep 2	Rep 1	Rep 2	Rep 1	Rep 2	Rep 1	Rep 2	Rep 1	Rep 2
ND	0/100	0/100	0/100	0/100	0/100	0/100	0/100	0/100	0/100	0/90
3.8	0/100	0/100	0/100	0/90	0/100	0/90	0/90	0/90	0/90	0/90
5.3	0/100	0/100	0/90	0/100	0/90	0/100	40/40	40/80	10/10	30/30
8.5	0/100	0/100	0/100	0/90	60/60	30/30	10/10	-	-	-
13	0/100	0/100	100/100	90/90	-	-	-	-	-	-
23.4	0/100	0/100	100/100	90/90	-	-	-	-	-	-

Dashes represent vessels with no surviving amphipods. Affected amphipods exposed to 13.0 mg/L were lethargic and those exposed to 23.4 mg/L were immobilized. All surviving amphipods exposed to 8.5 mg/L were affected at 48 hours and immobilized at 72 hours. Affected amphipods exposed to 5.3 mg/L were immobilized.

Validity criteria fulfilled:

yes

Conclusions:

Exposure of amphipods to the test substance resulted in a 96 h LC50 of 4.6 mg/L, with 95% confidence interval of 4.3 - 5.1 mg/L.

Executive summary:

Exposure of amphipods to the test substance resulted in a 96 hour LC50 of 4.6 mg/L, with a 95 percent confidence interval of 4.3 - 5.1 mg/L.

Static range test produced 100% survival at 0.2 and 2.0 mg/L and 0% survival at all higher tested concentrations. Test was performed under unaerated, flow through conditions with 5 concentrations at 18 ºC. Amphipods were acclimated for more than 14 days. Amphipods exposed to 13 mg/L were lethargic and those exposed to 23.4 mg/L were immobilized at 24 hours. All surviving amphipods exposed to 8.5 mg/L were lethargic at 48 hours and immobilized at 72 hours. Eight of the 12 surviving amphipods exposed to 5.3 mg/L were immobilized at 72 hours and all survivors were immobilized at 96 hours.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

4.6 mg/L