Cyclohexyldimethylamine

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:

1989

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study, GLP

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

GLP compliance:

yes

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
Not relevant

Analytical monitoring:

yes

Details on sampling:

Sampling times: 0, 24, 48 hours

Vehicle:

yes

Details on test solutions:

A 600 mg/mL stock solution was prepared by diluting 17.67 mL of test substance to 25 mL with distilled acetone. The exposure was initiated by adding appropriate aliquots of stock solution to test vessels and adding additional dilution water to give a final volume of 200 mL.

Test organisms (species):

Daphnia magna

Details on test organisms:

- Strain:  Daphnia magna straus
- Source/supplier: lab-reared
- Breeding method: illumination (2500 lux): 16 h light, temperature 20±1°C 
- Age: <24 hours
- Feeding: three times weekly with algae - Selanastrum capricornutum.
- Feeding during test: no

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

Not applicable

Hardness:

166 mg/L as CaC03

Test temperature:

19.8 - 20.9 °C

pH:

7.6-9.4

Dissolved oxygen:

>93% of air saturation value (8.6 mg/L)

Salinity:

Not applicable

Nominal and measured concentrations:

- Nominal concentrations (mg/L): 0 (control), 0 (solvent control), 39, 65, 108, 180, 300
- Measured concentrations (mean (mg/L)): 0, 45.0, 65, 75, 150, 241

Details on test conditions:

- Control group: vehicle and untreated control

STOCK AND TEST SOLUTION AND THEIR PREPARATION
- Vehicle, solvent: acetone
- Concentration of vehicle/ solvent: max. 0.12 mL/L

DILUTION WATER - Source: Lake Huron water
- Alkalinity: 54 mg/L
- TOC: 1.6 mg/L
- Ca/Mg ratio: 6/1
- Na/K ratio: 2/1
- TSS: 2.3 mg/L
- Conductance: 340 umhos/cm

TEST SYSTEM
- Exposure vessel type: 250 mL glass vessels containing 200 mL of medium
- Number of daphnids: 10/beaker, 3 beakers/treatment
- photoperiod: 16 hours

PHYSICAL MEASUREMENTS
- Measuring times: daily

TEST PARAMETER: 
immobility

OBSERVATION TIMES: at 0, 24 and 48 hours

Dilution water - Daphnid dilution water is prepared by adjusting Lake Huron water, obtained from the City of Midland Water Treatment Plant before treatment, to a hardness of approximately 170 mg/L as CaC03 which is achieved after autoclaving. at 121°C and 18 psi for 35 minutes. The water is cooled and aerated before use. Daphnid dilution water is monitored weekly for pH, alkalinity, conductivity, and hardness; quarterly for selected inorganics, total suspended solids, total dissolved solids and total organic carbon (TOC); and twice annually for selected organics, pesticides and PCBs.

Reference substance (positive control):

no

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

75 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: 95% CI 65-150 mg a.i./L

Duration:

48 h

Dose descriptor:

LC0

Effect conc.:

65.3 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mortality

Duration:

48 h

Dose descriptor:

LC100

Effect conc.:

150 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mortality

Details on results:

RESULTS: 
- Effect data (Mortality): 0, 0, 0, 50, 100, 100 for concentration s of 0, 39, 65, 108, 180, 300 mg/L (nominal), respectively.

ANALYTICAL RESULTS
Linear response (r2 0.982) from 30-340 mg/L. Precision 5-26%.
The measured concentration ranged between 69-116% of nominal with a relative standard deviation of 19-48%.

Results with reference substance (positive control):

Not applicable

Reported statistics and error estimates:

The acute concentration-mortality data were analysed for daily LC50 values. A computer program was used to calculate the LC50 values and corresponding 95% confidence intervals. This program has three methods available: probit analysis, moving average angle analysis and binomial probability.

Analytical results

Nominal conc. (mg/L)	Measured concentration (mg/L)			Mean measured conc. (mg/L)
	0 hours	24 hours	48 hours
Control	nd	nd	nd	-
38.9	53.5	61.3	20.3	45.0
64.8	72.1	73.1	50.7	65.3
108	95.5	64.3	64.9	74.9
180	117.5	174.5	156.7	149.6
300	241.3	325.9	156.3	241.2

 

Daphnia mortality results

Nominal conc. (mg/L)	Number dead Daphnia		% mortality
	24 hours	48 hours	24 hours	48 hours
Control	0	0	0	0
Solvent control	0	0	0	0
45	0	0	0	0
65.3	0	0	0	0
74.9	15	15	50	50
150	30	30	100	100
241	30	30	100	100

 

Validity criteria fulfilled:

yes

Conclusions:

Three groups, each of ten Daphnia magna were exposed under static conditions to DMCHA.  The results of the study were based on mean measured exposure concentrations. The 48 hour LC50 value was calculated to 75 mg/L (with 95% confidence limits of 65 to 150 mg/L). The no-observed effect concentration was observed to be 65 mg/L. 

Executive summary:

Three groups, each of ten Daphnia magna were exposed under static conditions to cyclohexyldimethylamine (DMCHA). Nominal exposure concentrations were control, control, solvent control, 38.9, 64.8, 108, 180 and 300 mg/L, mean measured concentrations were 45.0, 65.3, 74.9, 150 and 241 mg/L. The results of the study were based on mean measured exposure concentrations. After 48 hours 100% mortality was observed in the 150 and 241 mg/L treatment, there was 50% mortality at 75mg/L and no mortality in any of the other treatments or controls.

The 48 hour LC50 value was calculated to 75 mg/L (with 95% confidence limits of 65 to 150 mg/L). The no-observed effect concentration was observed to be 65 mg/L. 

Description of key information

Three groups, each of ten Daphnia magna were exposed under static conditions to cyclohexyldimethylamine (DMCHA). Nominal exposure concentrations were control, control, solvent control, 38.9, 64.8, 108, 180 and 300 mg/L, mean measured concentrations were 45.0, 65.3, 74.9, 150 and 241 mg/L. The results of the study were based on mean measured exposure concentrations. After 48 hours 100% mortality was observed in the 150 and 241 mg/L treatment, there was 50% mortality at 75mg/L and no mortality in any of the other treatments or controls.
The 48 hour LC50 value was calculated to 75 mg/L (with 95% confidence limits of 65 to 150 mg/L). The no-observed effect concentration was observed to be 65 mg/L. 

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

75 mg/L

Additional information

Three groups, each of ten Daphnia magna were exposed under static conditions to cyclohexyldimethylamine (DMCHA).  The results of the study were based on mean measured exposure concentrations. The 48 hour LC50 value was calculated to 75 mg/L (with 95% confidence limits of 65 to 150 mg/L). The no-observed effect concentration was observed to be 65 mg/L (Mayes et al, 1989). 

Additional acute aquatic toxicity data are also provided. One study from 1988 was given a Klimisch 2 as it was not a GLP compliant study. This study had a 24 -hour EC50 of 79.9 mg/L. The third study was given Klimisch 4 as there was insufficient information given in the report to determine reliability. This study had an EC₅₀ of 75 mg/L.