Reaction mass of 1,3-diisopropylbenzene and 1,4-diisopropylbenzene

Long-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: study conducted according to guideline (literature not available), the data, however, were evaluated in the frame of the OECD SIDS program and therefore regarded as valid

Qualifier:

according to guideline

Guideline:

OECD Guideline 211 (Daphnia magna Reproduction Test)

Version / remarks:

Cited as OECD Guide-line 202, part 2 (Daphnia sp., Reproduction Test)

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

Analytical Procedure: The test concentrations were measured for both new and old test solution at the start of test and 1st, 7th 8th, 14th and 15th day.

Vehicle:

yes

Details on test solutions:

a) Stock Solutions: Diisopropylbenzene of 100 mg/L was prepared for stock solution according to the following method. 50 mg test substance was dissolved in 8000 mg Dimethyl formamide(DMF) with 300 mg HCO-40. The solution was diluted with pure water in 500 mL.
b) Vehicle/Solvent and Concentrations: DMF and HCO-40 were used for solvent. DMF 20.0 mg/L and 60.0 mg/L HCO-40 were contained in each test solution and solvent control.

Test organisms (species):

Daphnia magna

Details on test organisms:

a) Age: < 24 hours old
b) Supplier/Source: Test organisms were obtained from National Institute for Environmental Studies (JAPAN) and reproduced by the testing laboratory for four years and six months.
c) Any pretreatment: Parental daphnids were acclimated for at least 27 days on test conditions before testing, the mortality of the parental daphnids for two weeks before testing was 0% and any male dapnid was not born. During acclimination, test daphnids were fed with Chlorella vulgaris, 0.2 mg carbon/day/individual.

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

21 d

Hardness:

Water chemistry and temperature were measured for control and each concentration at the start of test and before and after renewal of the test solutions. Total hardness: 220 - 245 mg/L

Test temperature:

Water chemistry and temperature were measured for control and each concentration at the start of test and before and after renewal of the test solutions. Water Temperature: 20.0 - 20.5 degrees C

pH:

Water chemistry and temperature were measured for control and each concentration at the start of test and before and after renewal of the test solutions. pH: 7.3 - 8.6

Dissolved oxygen:

Water chemistry and temperature were measured for control and each concentration at the start of test and before and after renewal of the test solutions. DO: 7.7 - 9.1 mg/L

Salinity:

Dilution Water Source: Elendt M4 medium (OECD guideline 211)

Nominal and measured concentrations:

Nominal Concentrations: control, solvent control, 0.012, 0.032, 0.085, 0.230 and 0.600 mg/L
Method of Calculating Mean Measured Concentrations (i.e. arithmetic mean, geometric mean, etc.): Time-weighted Mean

Details on test conditions:

a) Dilution Water Source: Elendt M4 medium (OECD guideline 211)
b) Exposure Vessel Type: A 80 mL test solution in a 100 mL heat-resistance glass jar with glass screw cap
c) Nominal Concentrations: control, solvent control, 0.012, 0.032, 0.085, 0.230 and 0.600 mg/L
d) Stock Solutions: Diisopropylbenzene of 100 mg/L was prepared for stock solution according to the following method. 50 mg test substance was dissolved in 8000 mg Dimethyl formamide(DMF) with 300 mg HCO-40. The solution was diluted with pure
water in 500 mL.
e) Vehicle/Solvent and Concentrations: DMF and HCO-40 were used for solvent. DMF 20.0 mg/L and 60.0 mg/L HCO-40 were contained in each test solution and solvent control.
f) Number of Replicates: 10
g) Individuals per Replicates: 10
h) Renewal Rate of Test Water: Every 24 hours
i) Water Temperature: 20+/-1 degrees C
j) Light Condition: 16:8 hours, light-darkness
k) Feeding: 0.15 mg carbon/day/individual (Chlorella vulgaris: Green Algae)

Reference substance (positive control):

not specified

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

0.063 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

reproduction

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

0.168 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

reproduction

Duration:

21 d

Dose descriptor:

LC50

Effect conc.:

0.22 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: 0.156-0.346 mg/L

Duration:

21 d

Dose descriptor:

EC50

Effect conc.:

0.154 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Reported statistics and error estimates:

a) Data Analysis: Dunnett multiple comparison for NOEC and LOEC; Probit method, binomial or Moving average for EC50
b) Method of Calculating Mean Measured Concentrations (i.e. arithmetic mean, geometric mean, etc.): Time-weighted Mean

Calculation of toxicity values: The calculation of toxicity values was the mean measured concentrations. The reason is that some of the error ranges of measured concentration were not less than
+/-20% of nominal concentration

Cumulative Number of Died Parental Daphnids: No test organism was killed at control and solvent control.  The
lowest concentration that test organisms were dead was at 0.012 mg/L after 7days.  All test organisms were dead at
0.600 mg/L after 8days.

---------------------------------------------------------
Measured          Cumulative Number of Dead Parental
Daphnids
Conc.                                (days)(mg/L)
                1   2   3   4   5   6   7   8   9   10
---------------------------------------------------------
Control          0   0   0   0   0   0   0   0   0    0
Solvent Control  0   0   0   0   0   0   0   0   0    0
0.009            0   0   0   0   0   0   1   1   1    1
0.024            0   0   0   0   0   0   0   0   0    1
0.063            0   0   0   0   0   0   0   0   0    0
0.168            0   0   0   0   0   1   1   1   1    1
0.431            0   0   1   9   9   9   9   10  10  10
---------------------------------------------------------

---------------------------------------------------------
Nominal       Cumulative Number of Dead Parental Daphnids
Conc.                             (days)
(mg/L)         11  12  13  14  15  16  17  18  19  20  21
---------------------------------------------------------
Control         0   0   0   0   0   0   0   0   0   0   0
Solvent 
 Control        0   0   0   0   0   0   0   0   0   0   0
0.009           1   1   1   1   2   2   2   2   2   2   2
0.024           1   1   1   1   1   1   1   1   1   1   2
0.063           1   1   1   1   1   1   1   1   1   1   1
0.168           1   1   1   1   1   1   1   1   1   1   1
0.431          10  10  10  10  10  10  10  10  10  10  10
---------------------------------------------------------

Cumulative numbers of juveniles produced per adult alive for 21 days
---------------------------------------------------------
                            Nominal Conc., mg/L
                         (Measured Conc.*1, mg/L)
---------------------------------------------------------
Vessel Cont.** Solv*** 0.012  0.032  0.085  0.230  0.600
No.            Cont.  (0.009)(0.024)(0.063)(0.168)(0.431)
---------------------------------------------------------
1       152    135     138      D     151     45      D
2       133    152     149      D     145     11      D
3       129    131     152     144     D      67      D
4       110    152     123     149    145     D       D
5       148    135     151     140    149     37      D
6       135    133     128     139    146     28      D
7       120    154      D      137    125     70      D
8       132    135     129     149    151     54      D
9       116    140     145     151    154     37      D
10      130    136      D      147    140     71      D
---------------------------------------------------------
Mean  130.5   140.3   139.4   144.5  145.1   46.7   0.0
S.D.   13.1    8.8     11.5     5.3    8.6   20.7  
---------------------------------------------------------
Inhibition
rate(%)                0.7    -3.0    -3.4   66.7   0.0
--------------------------------------------------------
Significant 
difference            ---      ---    ---    **     ++
--------------------------------------------------------
*1: Time-wighted mean measured concentration
**: Indicates a significant difference (alpha = 0.01) from the solvent control.
++: Statistical comparison test could not be performed for this concentration because adult alive after 21 days was
none.
D: Were not included for calculation because the parental daphnids were dead during a 21-day testing period.
---: Indicates no significant difference.

Effect Data(reproduction): Juveniles were first producted
on the 7th day control and all concentrations.

---------------------------------------------------------
Measured             Mean Cumulative Numbers of
Conc.              Juveniles Produced per Adult (days)
(mg/L)  0 -- 6    7    8     9     10    11    12    13
---------------------------------------------------------
Control 0 -- 0   4.1   9.6   9.6   18.9  45.0  45.1  45.1
Solvent Control
        0 -- 0   9.5   10.7  10.7  29.3  45.3  48.2  48.2
0.009   0 -- 0   8.5   11.5  11.5  18.7  47.5  47.5  47.5
0.024   0 -- 0   14.0  14.0  14.0  14.1  56.4  60.9  60.9
0.063   0 -- 0   12.0  12.0  12.0  11.9  49.0  53.7  53.7
0.168   0 -- 0   1.7    3.0   4.0   1.5  17.0  17.0  17.0
0.431   0 -- 0   ---    ---   ---   ---  ---   ---   ---
---------------------------------------------------------

---------------------------------------------------------
Measured                 Mean Cumulative Numbers of
Conc.                 Juvenieles Produced per Adult (days)
(mg/L)  14    15   16    17    18     19     20      21
---------------------------------------------------------
Control 78.6  78.6  78.6  101.6  106.6  106.6  110.0 130.5
Solvent Control 
        83.2  83.2  83.2  114.8  115.1  115.1  122.7 140.3
0.009   83.4  83.4  83.4  115.6  115.6  115.6  119.8 139.4
0.024   92.4  92.4  92.4  121.9  122.0  122.0  127.8 144.5
0.063   86.1  86.1  89.9  120.9  120.9  120.9  142.7 145.1
0.168   18.7  20.3  26.9   40.1   42.4   42.4   44.6  46.7
0.431   ---   ---   ---    ---    ---    ---    ---    ---
---------------------------------------------------------
---: The parental Daphnids were dead during a 21-day testing period

Effect Data:
LC50 (21day) = 0.220 (mc) (95 C. I.: 0.156-0.346 mg/L)
EC50 (21day) = 0.154 mg/L (mc)
NOEC (21day) = 0.063g/L (mc)
LOEC (21day) = 0.168 mg/L (mc)
mc: based on measured concentrations

    

NOEC was determined based on the cumulative number of juveniles produced per adult alive for 21 days.

Measured Concentration as a Percentage of Nominal
---------------------------------------------------------
Nominal Measured Concentration as a Percentage of
Nominal
Concentration ------------------------------------------
mg/L Days 0 1 7 8 14 15
Fresh Old Fresh Old Fresh Old
---------------------------------------------------------
0.012 100 58 83 67 83 58
0.032 88 59 81 69 91 72
0.085 88 61 81 64 88 65
0.230 87 62 84 62 83 63
0.600 81 63 81 64 * *
---------------------------------------------------------
Fresh: Start of renewal period
Old: End of renewal period
*1: Time-weighted mean of measured concentration during 21 days
*: No measured was made because all dapnids were dead at this time.

Water chemistry (pH and DO) and temperature in test:
Water chemistry and temperature were measured for control and each concentration at the start of test and before and after renewal of the test solutions.
pH: 7.3 - 8.6 DO: 7.7 - 9.1 mg/L
Water Temperature: 20.0 - 20.5 degrees C
Total hardness: 220 - 245 mg/L

Effect: reproduction
Measured Concentrations : The test concentrations were measured for both renewal and old test solution at the start of test and 1st, 7th 8th, 14th and 15th day. For some of them, the deviation from the nominal were not less than +/-20%.

---------------------------------------------------------
Nominal Measured Conc., mg/L
Conc.
---------------------------------------------------------
mg/L Date 0 1 7 8 14 15 TWM*1 % of Fresh Old Fresh Old Fresh Old mg/L
Nominal
---------------------------------------------------------
Control <0.002 <0.002 <0.002 <0.002 <0.002 <0.002 -- --
Solvent
Control
<0.002 <0.002 <0.002 <0.002 <0.002 <0.002 -- --
0.012 0.012 0.007 0.010 0.008 0.010 0.007 0.009 75
0.032 0.028 0.019 0.026 0.022 0.029 0.023 0.024 75
0.085 0.075 0.052 0.069 0.054 0.075 0.055 0.063 74
0.230 0.199 0.143 0.193 0.143 0.190 0.146 0.168 73
0.600 0.486 0.380 0.483 0.383 * * 0.431 72
---------------------------------------------------------
Fresh: Start of renewal period
Old: End of renewal period
*1: Time-weighted mean of measured concentration during 21 days
*: No measured was made because all dapnids were dead at this time.

Validity criteria fulfilled:

no

Remarks:

All toxic signs above water solubility limits

Conclusions:

In a study conducted according to OECD Guideline 211 (Daphnia magna Reproduction Test; cited as OECD Guide-line 202, part 2: Daphnia sp., Reproduction Test), Daphnia magna were exposed to diisopropylbenzene for 21 d and NOEC, LOEC, LC50 and EC50 determined. The test was conducted using solvent ( mixture of a dispersant of HCO40 and DMF). The 21 d NOEC and LOEC in respect to reproduction rate were determined to be 0.063 and 0.168 mg/L (measured concentrations), respectively. The 21 d LC50 and EC50 were determined to be 0.22 mg/L (95% C.L.: 0.156 -0.346 mg/L) and 0.154 mg/L (measured concentrations), respectively. All toxicity signs were observed above both isomers water solubility limits (0.0405 and 0.072 mg/l).
The LOEC = 0.168 mg/l is clearly above both isomers solubility limits (0.0405 mg/l for p-DIPB and 0.072 mg/l for m-DIPB). The weighted mean solubility (ca.40 % p-DIPB and ca.60% m-DIPB) is around 0.06 mg/L and therefore the NOEC value shows that there was no effect at this limit of water solubility.

Executive summary:

In a study conducted according to OECD Guideline 211 (Daphnia magna Reproduction Test; cited as OECD Guide-line 202, part 2: Daphnia sp., Reproduction Test), Daphnia magna were exposed to diisopropylbenzene for 21 d and NOEC, LOEC, LC50 and EC50 determined. The test was conducted using solvent ( mixture of a dispersant of HCO40 and DMF), however, analytical monitoring was done. The 21 d NOEC and LOEC in respect to reproduction rate were determined to be 0.063 and 0.168 mg/L (measured concentrations), respectively. The 21 d LC50 and EC50 were determined to be 0.22 mg/L (95% C.L.: 0.156 -0.346 mg/L) and 0.154 mg/L (measured concentrations), respectively. All toxicity signs were observed above both isomers water solubility limits (0.0405 and 0.072 mg/l).

The LOEC = 0.168 mg/l is clearly above both isomers solubility limits (0.0405 mg/l for p-DIPB and 0.072 mg/l for m-DIPB). The weighted mean solubility (ca.40 % p-DIPB and ca.60% m-DIPB) is around 0.06 mg/L and therefore the NOEC value shows that there was no effect at this limit of water solubility.

Reference 2

Endpoint:

long-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

1992

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Results of an study conducted in accordance with generally accepted scientific principles. Possible deficiencies in the reporting of the endopoint do not affect the quality of relevant results.

Qualifier:

according to guideline

Guideline:

OECD Guideline 211 (Daphnia magna Reproduction Test)

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

yes

Remarks:

DMSO:HCO-40 = (:1 (100 mg/l) and laboratory water control

Test organisms (species):

Daphnia magna

Details on test organisms:

40 daphnids (4 replicates; 10 organisms per replicate)

Test type:

semi-static

Water media type:

freshwater

Total exposure duration:

21 d

Nominal and measured concentrations:

5 nominal concentrations (0.3-30 mg/l)

Details on test conditions:

40 daphnids (4 replicates; 10 organisms per replicate) were exposed to 5 nominal concentrations (0.3-30 mg/l)

Reference substance (positive control):

yes

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

7.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

immobilisation

Remarks on result:

other: 95% confidence level: 5.4-9.8 mg/L

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

immobilisation

Remarks on result:

other: 95% confidence level: 4.5-8.0 mg/l

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

4.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

immobilisation

Remarks on result:

other: 95% confidence level: 3.2-5.4 mg/l

Duration:

7 d

Dose descriptor:

EC50

Effect conc.:

3.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

immobilisation

Remarks on result:

other: 95% confidence level: 2.4-4.1 mg/l

Duration:

14 d

Dose descriptor:

EC50

Effect conc.:

2.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

immobilisation

Remarks on result:

other: 95% confidence level: 1.9-3.5 mg/l

Duration:

21 d

Dose descriptor:

EC50

Effect conc.:

2.4 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

immobilisation

Remarks on result:

other: 95% confidence level: 1.8-3.2 mg/l

Duration:

14 d

Dose descriptor:

EC50

Effect conc.:

1.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Remarks on result:

other: 95% confidence level: 0.66-1.7 mg/l

Duration:

21 d

Dose descriptor:

EC50

Effect conc.:

1.3 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Remarks on result:

other: 95% confidence level: 0.97-1.8 mg/l

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

0.93 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Remarks on result:

other: p<0.05

Duration:

21 d

Dose descriptor:

LOEC

Effect conc.:

3 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Remarks on result:

other: p<0.05

Validity criteria fulfilled:

yes

Conclusions:

21d EC50 (immobility) =2.4 mg/L and EC50 (reproduction) =1.3 mg/L
21d NOEC = 0.93 mg/L (reproduction)
21d LOEC = 3 mg/L (reproduction)

Executive summary:

The aim of the study was to assess the long term toxicity of 1,4 -diethylbenzene toward daphnia according to OECD Guideline 211. Mortality and reproduction were monitored at different intervals. The results after 21 days were EC50 (immobility)=2.4 mg/L and EC50 (reproduction)=1.3 mg/L which resulted into a NOEC of 0.93 mg/L (21days, basis for effect reproduction) and a LOEC of 3 mg/L.

Concentrations were based on nominal concentrations and were not analytically verified (but water solubility - 50 mg/L- was above the tested concentrations).

Description of key information

In a study conducted according to OECD Guideline 211 (Daphnia magna Reproduction Test; cited as OECD Guideline 202, part 2: Daphnia sp., Reproduction Test), Daphnia magna were exposed to diisopropylbenzene for 21 d and NOEC, LOEC, LC50 and EC50 determined. The test was conducted using solvent (mixture of a dispersant of HCO40 and DMF), however analytical monitoring was done. The 21 d NOEC and LOEC in respect to reproduction rate were determined to be 0.063 and 0.168 mg/L (measured concentrations), respectively. The 21 d LC50 and EC50 were determined to be 0.22 mg/L (95% C.L.: 0.156 -0.346 mg/L) and 0.154 mg/L (measured concentrations), respectively.

The LOEC = 0.168 mg/l is clearly above both isomers solubility limits (0.0405 mg/l for p-DIPB and 0.072 mg/l for m-DIPB). The weighted mean solubility (ca.40 % p-DIPB and ca.60% m-DIPB) is around 0.06 mg/L and therefore the NOEC value shows that there was no effect at this limit of water solubility.

Another long term daphnia study performed on the analog 1,4-Diethylbenzene also showed toxicity above DIPB solubility limits.