4-aminophenol

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:

March 21 to April 16, 1997

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

HLPC at the start of exposure, 3 hours and 24 hours afterwards. Sample was taken from the middle section of each test solution.

Vehicle:

no

Details on test solutions:

Based on preliminary work that preceded this study, the maximum testing concentration was set at 1.00 mg/L (considered 100% immobilisation concentration). 5 concentrations were established with a common ratio of 1.8 ( 1.00, 0.556, 0.309, 0.171 and 0.0953 mg/L).

Test organisms (species):

Daphnia magna

Details on test organisms:

juvenile daphnia born no later than 24 hours beforehand were used. Species bred and rasied from supply from EPA Laboratory USA.

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Remarks on exposure duration:

test solution changed after 24 hours

Hardness:

55.6 mg/l as CaCO3

Test temperature:

20.0-20.2 C

pH:

7.6-7.7

Dissolved oxygen:

8.6 to 8.8 mg/l

Salinity:

37.5 mg/l

Nominal and measured concentrations:

measured concentrations of the test article were 103-106% of the labeled concentrations at the start of exposure, 51.4 % -65.3% after 3 hours ad 0.0to14.0% at the time the solution was changed (24 hours).

Details on test conditions:

see below

Reference substance (positive control):

no

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

0.089 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

act. ingr.

Remarks:

arithmatic mean of the first 24 h and measures at t=0. 3 and 24h; RR 6% after 24 hours

Basis for effect:

mobility

Remarks on result:

other: 95% CL; Values based on mean measured concentrations calculated directly from data in the study report.

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

0.064 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

Values based on mean measured concentrations calculated directly from data in the study report.

Reported statistics and error estimates:

see below

- Measured Concentrations: The test concentrations were measured three times (0, 3, 24th hour) during the test period using HPLC.

Nominal Conc.　(mg/L)	Measured Concentration (mg/L)			Geometric mean*
	0 hour	3 hour	24 hours
Control	n.d.	n.d.	n.d.	---
0.0953	0.0979	0.0622	n.d.	0.024
0.171	0.177	0.111	0.0240	0.065
0.309	0.329	0.174	0.0243	0.089
0.556	0.588	0.286	0.0376	0.15
1.00	1.04	0.522	n.d.	0.077

n.d.: <0.00567 mg/L

*: Geometric mean of measured concentration at the initial and 24th-hour (before water replacement).

Nominal Conc.　(mg/L)	% of Nominal concentration (%)
	0 hour	3 hour	24 hours	Geometric mean
Control	---	---	---	---
0.0953	103	65.3	---	25.2
0.171	104	65.0	14.0	38.0
0.309	106	56.4	7.9	28.8
0.556	106	51.4	6.8	27.0
1.00	104	52.2	---	7.7

- Water chemistry (pH, DO, and temperature in test): Water chemistry and temperature were measured for control and each concentration at the start and before water replacement (24th-hour) of the test.
pH: 7.6 - 7.7
DO: 8.6 - 8.8 mg/L
Water Temperature: 20.0 - 20.2 C

-Effect Data:
EC50 (48hr) 0.182mg/L (mc)
95% Confidence Interval: 0.085 – 0.11 mg/L
mc: based on measured concentrations
 
-Mortality or Immobility: None of test organisms were immobilized the behaviours at control.

Nominal Conc. (mg/L)	Measured Conc. (mg/L)	Cumulative Number of Immobilized Daphnia (Percent Immobility, %)
		24　hour	(%)	48 hours	(%)
Control	---	0	0	0	0
0.0953	0.024	0	0	1	5
0.171	0.065	0	0	1	5
0.309	0.089	4	20	10	50
0.556	0.15	14	70	17	85
1.00	0.077	17	85	20	100

Validity criteria fulfilled:

yes

Conclusions:

EC50 at 48 hours was 0.182 mg/l for nominal measured concentration. Nominal NOEC at 48 hours was 0.177 mg/L and LOEC 0.313 mg/L for nominal measured concentrations. Values based on mean measured concentrations calculated directly from data in the study report.
The substance degrades very fast in the test with a (>65% loss after 24hr) therefore results are expressed as the mean goemetric mean values which would result in a LD50 of 0.089 mg/L. Based on the tables it would seem that the gemoetric mean NOEC value in this instance would be 0.064 mg/L

Description of key information

The short-term toxicity in daphnia magna is from one key study with results calculated as mean measured concentrations of EC50 (48 hours) 0.089 mg/l and NOEC of 0.064 mg/L.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

0.089 mg/L

Additional information

The key study is an Acute Toxicity in Daphnia magna completed in 1997 based on OECD method 202 with a reported EC50 (48 hours) mean measured values as 0.0.089mg/l, NOEC as 0.064 mg/L. Values were based on mean measured concentrations calculated directly from data in the study report. The measured concentrations of the test article were 103 -106% of the labeled concentrations at the start of exposure, 51.4 % -65.3% after 3 hours and 0.0 to14.0% at the time the solution was changed (24 hours). One supporting study was included with klimisch of 4: daphnia magna - EC50 (48 h): 0.24 mg/L. As the substance degrades rapidly an additional study was conducted to determine the toxicity of the degradation products versus the parent molecule. The results of this study show that the parent molecue is significanty more toxic that the degradation products.