p-phenylene diisocyanate

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

11/12/2017-18/05/2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

GLP compliance:

yes

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material:
UpChem Co. Ltd., 170329
- Expiration date of the lot/batch: 28-03-2018
- Purity test date:
06-04-2017

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: at room temperature, away from moisture
- Stability under test conditions: stable
- Solubility and stability of the test substance in the solvent/vehicle: not soluble
- Reactivity of the test substance with the solvent/vehicle of the cell culture medium: not observed

Analytical monitoring:

not specified

Vehicle:

not specified

Details on test solutions:

Test medium was algal medium as described in the OECD test guideline 201 (OECD, 2006) and the preparation details are given in Appendix 5.

Chemical Batch No. Manufacturer
MgCl2. 6H2O MF6M 561553 Merck Specialities Private Limited, Mumbai, India
ZnCl2 B0755316248
CaCl2. 2H2O D14A/1314/0804/31 s.d. fine chem. Limited
Mumbai, India
NH4Cl D14A/2314/2103/31
MgSO4. 7H2O H14A/1813/1707/31
Na2EDTA. 2H2O J08W/2908/2209/31
MnCl2. 4H2O E13A/1613/1204/13
CoCl2. 6H2O H09Z/1709/2203/31
CuCl2. 2H2O G09Z/2109/0106/31
Na2MoO4. 2H2O L15A/3315/0912/31
H3BO3 A16A/1115/0705/31
NaHCO3 D14A/1414/0702/31
KH2PO4 0000136538 Himedia Laboratories Private Limited, Mumbai, India
FeCl3. 6H2O 161215 Central Drug House (P) Limited, New Delhi, India

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Details on test organisms:

Pseudokirchneriella subcapitata ATCC 22662

This algal species was used as the test system as it is a recommended algal species in the guideline.
6.1.2.1 Source
American Type Culture Collection
P.O.Box 1549
Manassas, VA 20108
USA
6.1.2.2 Culture Maintenance
Algal cells were maintained at the test facility through sub-culturing once in 5 to 10 days from the continuous culture into fresh medium in a conical flask. These conical flasks were incubated between 21 and 25°C (±2°C) under a continuous illumination of 8000±1600 Lux.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Reference substance (positive control):

yes

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

25.46 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Validity criteria fulfilled:

yes

Conclusions:

The EC50 value calculated for growth rate is 25.46 mg/L

Executive summary:

The effect of P-phenylene diisocyanate was tested on the growth of freshwater single cell green algaPseudokirchneriella subcapitata.

 

Range finding test was carried out to select the test concentrations for the definitive test. In the range finding test, the tested concentration was 0.00001, 0.0001, 0.001, 0.01, 0.1, 1, 10 and 100 mg/L with single replicate. The test item exhibited 15.91, 0.65, 2.92, 10.39, 20.45, 33.44, 51.30 and 100 % reduction in cell biomass at the tested concentrations of 0.00001, 0.0001, 0.001, 0.01, 0.1, 1, 10 and 100 mg/L at 72 h.

 

The alga was exposed to the test item at the nominal concentrations of 0.4, 1.2, 3.6, 10.8, 32.4 and 97.2 mg/L (factor of about 3) along with a negative control and a reference substance (Potassium dichromate) at 0.9 mg/L. The cell growth was measured at 24, 48 and 72 hours after the initiation of the test.

 

The concentration/effect relationship was determined using two factors namely growth rate and yield at the end of the test (72 hours). The per cent inhibition of growth rate was 1.65, 4.94, 12.37, 15.03, 45.35 and 100% and the percent yield inhibition was 6.99, 19.53, 42.06, 48.50, 87.13 and 100% at the nominal concentrations of 0.4, 1.2, 3.6, 10.8, 32.4 and 97.2 mg/L, respectively, when compared to the negative control. There was 23.34 % and 64.48 % inhibition of average growth rate and yield of alga, respectively, in the reference substance group at 0.9 mg/L. Observed cells were found morphologically normal.

 

The EC values calculated for growth rate and yield on the basis of the nominal concentration of the test item are presented below:

 

At 72 hours	EC values (mg/L)
ErC50	25.46
ErC20	7.1449
ErC10	3.6767
EyC50	5.98
EyC20	1.4846
EyC10	0.7166

 

Note: E_rCrefers to growth rate and E_yC refers to yield

Description of key information

The EC50 value calculated for growth rate is 25.46 mg/L

Key value for chemical safety assessment

EC50 for freshwater algae:

25.46 mg/L