Reaction products of phosphoryl trichloride and 2-methyloxirane

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:

2004

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

GLP

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Product name: TCPP

Analytical monitoring:

yes

Details on sampling:

Samples of the test solutions were collected at approximately 0 and 72 hours to measure concentrations of the test substance. Samples at test initiation were collected from the individual batches of test solution prepared for each treatment and control group prior to distribution to the test chambers. At test termination, samples were collected from the pooled replicates of each treatment and control group. All samples were collected in glass scintillation vials and analyzed immediately without storage.

Vehicle:

no

Test organisms (species):

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

Details on test organisms:

Original algal cultures were obtained from the University of Toronto Culture Collection (UTCC), and had been maintained in culture medium at
Wildlife International, Ltd., Easton, Maryland. Algal cells used in this test were obtained from Wildlife International, Ltd. cultures that had been actively growing in culture medium for at least two weeks prior to test initiation, and had been transferred to fresh medium four days prior to test initiation.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

23.2 - 24.6

pH:

7.8 - 7.9 at the beginning of the test
and ranged from 8.0 - 8.9 at test termination.

Nominal and measured concentrations:

Nominal test concentrations selected were: 6.3, 13, 25, 50, 100 and 200 mg/L
Measured test concentrations were determined from samples of test medium collected from each treatment and control group at the beginning and
end of the test. Mean conc.: 6.5, 13, 25, 46, 88 and 200 mg/L

Reference substance (positive control):

no

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

13 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

42 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

82 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: (95 % CL) 76 - 89 mg/l

Details on results:

Results are expressed relative to nominal concentrations because measured concentrations were within 80-120% of nominal.

Table - Measured Concentrations of TCPP in Freshwater Algal Medium Samples

Nominal Test Concentration (mg/L)	Sampling Time (Day)	Measured Concentration (mg/L)^	Percent of Nominal	Mean Measured Concentration (mg/L)	Mean Measured Percent of Nominal
0	0 3	<LOQ <LOQ	- -	-	-
6.3	0 3	6.64 6.29	105 99.8	6.5	103
13	0 3	13.8 13.0	106 100	13	100
25	0 3* 3	25.9 8.95 25.0	104 35.8 100	25	100
50	0 3	48.8 43.1	97.6 86.1	46	92
100	0 3	96.0 80.0	96.0 80.0	88	88
200	0 3	197 203	98.6 101	200	100

^ Limit of Quantification (LOQ)
* Due to a sampling error, sample reanalyzed and not included in calculation

Table - Mean Growth Rate and % Inhibition

Nominal Test Concentration (mg/L)	0-24h		0-48h		0-72h
	Mean Growth Rate	Percent Inhibition	Mean Growth Rate	Percent Inhibition	Mean Growth Rate	Percent Inhibition
0	0.0450	-	0.0646	-	0.0674	-
6.3	0.0432	4.0	0.0623	3.6	0.0738	-9.5
13	0.0288	36	0.0586	9.4	0.0679	-0.68
25	0.0387	14	0.0560	13	0.0618*	8.3
50	0.0212	53	0.0465	28	0.0518*	23
100	0.0000	100	0.0237	63	0.0267*	90
200	0.0000	100	0.0022	97	0.0023*	67

 

Table - EC Values over the 72-Hour Growth Period

Time	Growth Rate
	ErC10 (95 % Confidence Interval)	ErC20 (95 % Confidence Interval)	ErC50 (95 % Confidence Interval)
24 hours	NA	NA	47 mg/L (35 -65 mg/L)
48 hours	NA	NA	81 mg/L (74 - 88 mg/L)
72 hours	42 mg/L (36 - 50 mg/L)	53 mg/L (46 - 61 mg/L)	82 mg/L (76 - 89 mg/L)

Validity criteria fulfilled:

yes

Remarks:

1) Mean cell density in the control flasks increased by a factor greater then 16 within three days. 2) The pH of the control did not deviate by more than 1.5 units during the test, and 3) Coefficient of variationof growth rate in control replicates < 35%

Conclusions:

A toxicity of TCPP on algae (Pseudokirchnerella subcapitata) of 72 h EC50 of 82 mg/L and an EC10 of 42 mg/L based on growth rate were determined.

Executive summary:

A study on toxicity to the freshwater algae Pseudokirchnerella subcapitata of TCPP was performed according to OECD Guideline 201 (Alga, Growth Inhibition Test) with analytical monitoring. The test gave an EC50 and an EC10 value for effects on growth of 82 mg/L and 42 mg/l, respectively and a NOEC of 13 mg/l after a test duration of 72 hours, relating to nominal concentrations as the test concentrations were analytically confirmed (Desjardins, 2004). Temperature, pH and ligt intensity were monitored during the study.

Description of key information

OECD 201 (Desjardins, 2004): 72h ErC50 = 82 mg/L (meas.), 72h ECrC10 = 42 mg/L (meas.)

Key value for chemical safety assessment

EC50 for freshwater algae:

82 mg/L

EC10 or NOEC for freshwater algae:

42 mg/L

Additional information

A single key study is submitted for this endpoint, a study on toxicity to the freshwater algae Pseudokirchnerella subcapitata of TCPP performed according to OECD Guideline 201 (Alga, Growth Inhibition Test) with analytical monitoring (Desjardins, 2004). The test gave an EC50 and an EC10 value for effects on growth of 82 mg/L and 42 mg/l, respectively and a NOEC of 13 mg/l after a test duration of 72 hours, relating to nominal concentrations as the test concentrations were analytically confirmed (Desjardins, 2004). Temperature, pH and ligt intensity were monitored during the study.