Phosphonic acid, monoethyl ester, sodium salt (1:1)

Toxicity to soil macroorganisms except arthropods

Link to relevant study record(s)

Reference

Endpoint:

toxicity to soil macroorganisms except arthropods: short-term

Type of information:

experimental study

Adequacy of study:

key study

Study period:

5 Dec 2016 - 4 Jan 2017

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 207 (Earthworm, Acute Toxicity Tests)

Version / remarks:

1984

GLP compliance:

yes

Analytical monitoring:

no

Vehicle:

no

Details on preparation and application of test substrate:

- Method of mixing into soil (if used): The direct addition method was adopted to prepare the test medium. First, a fixed quantity of the test substance was mixed with the dry test soil, total quantity 10 g, then it was added to the test container and mixed thoroughly with 550 g artificial soil (dry soil), and finally deionised water was used to adjust the soil moisture content to approximately 35% (soil dry weight). See details in Table 1 under any other information on materials and methods incl. tables.
- Controls: negative control without test material

Test organisms (species):

Eisenia fetida

Animal group:

annelids

Details on test organisms:

TEST ORGANISM
- Common name: earthworm
- Source: Nanjing Earthworm Farm, Pudong Community, Changlu Street, Dachang District, Nanjing City, (batch no.: E20160318E)
- Age at test initiation (mean and range, SD): two months with clitellum
- Weight at test initiation (mean and range, SD): 385-431 mg

ACCLIMATION
- Acclimation period: 277 d, before the test started the test earthworms were cultivated for 24 h in the test soil environment. Prior to use, they were rinsed clean with deionised water and surface water was wiped off with filter paper
- Acclimation conditions (same as test or not): pre-cultivated in pollution-free soil under test conditions

Study type:

laboratory study

Substrate type:

artificial soil

Limit test:

yes

Total exposure duration:

14 d

Test temperature:

19.3-20.6 °C

pH:

6.24-6.78

Moisture:

27-35% of soil dry weight

Details on test conditions:

TEST SYSTEM
- Test container (material, size): 1 L specimen bottle, plastic film was used to seal the opening of the specimen bottle, and the plastic film was pierced with several small holes for ventilation
- Amount of soil or substrate: 560 g
- No. of organisms per container (treatment): 10
- No. of replicates per treatment group: 4
- No. of replicates per control: 4

SOURCE AND PROPERTIES OF SUBSTRATE (if soil)
- Artificial soil: 1) 10% peat (Sphagnum palustre) (Denmark Pindstrup (Group) C pH value 6.00, no obvious plant residue, finely ground, air dried);
2) 20% kaolin clay (CAS: 1332-58-7, batch no.: 20160118, Sinopharm Group Chemical Reagents Co., Ltd., 30% kaolinite content);
3) 70% quartz sand (CAS: 14808-60-7, batch no.: 20160520, Sinopharm Group Chemical Reagents Co., Ltd., 80% 50-200 μm grain diameter fine sand content)

OTHER TEST CONDITIONS
- Photoperiod: continuous light
- Light intensity: 478-563 lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : At 7 d of exposure, the test medium in the culture bottle was gently poured into a stainlesssteel plate, the earthworms were removed, the response of the anterior tail of the earthworm to mechanical stimulus was tested, and symptoms and number of deaths were recorded. If the anterior tail of the earthworm had no obvious response to gentle mechanical stimulus, then it was judged dead. Earthworms that disappeared were also counted among the number of deaths. The test medium was again placed in a culture bottle, and surviving earthworms were placed on the surface of the test medium to continue culturing. At 14 d, the same test was performed again. At the same time as the mortality rate tests on 7 d and 14 d, we observed symptoms of pathology and abnormal behaviour in the earthworms (for example, weakness and stiffness). Bodyweight of the eartworms was measured on days 0 and 14. The pH was measured at days 0 and 14. Test medium soil moisture content was measured at days 0 and 14.

TEST CONCENTRATIONS
- Range finding study: yes
- Test concentrations: 100, 500, and 1000 mg/kg (soil dry weight) and blank control
- Results used to determine the conditions for the definitive study: No deaths at any tested concentration after 14 days of exposure

Reference substance (positive control):

yes

Remarks:

2-chloroacetamide, reference compound test is performed three times each year, to confirm that the test conditions meet the test requirements and there have been no significant changes, test dates of last testing: 2016-11-10 to 2016-11-24

Duration:

14 d

Dose descriptor:

LC50

Effect conc.:

> 1 000 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Details on results:

- Mortality at end of exposure period: In the pretesting and the limit test processes, no deaths occurred in the control group; at 14 d, there were no earthworm deaths in the 1000 mg/kg (soil dry weight) concentration group
- Other biological observations: At the start of the test, after the earthworms came into contact with the pesticide in soil they quickly burrowed into the soil and were active in the soil during the entire test.

Results with reference substance (positive control):

- Relevant effect levels: The reference compound’s 7d-LC50 was 35.1 mg/kg and 14d-LC50 was 27.2 mg/kg. The results of this test were valid.

Reported statistics and error estimates:

LC50 and 95% confidence interval were calculated using the trimmed Spearman-Karber method (version 1.5, USEPA). Because the test substance had low toxicity to earthworms, the method was only used for calculating the reference compound LC50 and the 95% confidence interval.

Table 1.Average Earthworm Body Weight at Start and End of Exposure Period

Treatment dose (mg/kg (soil dry weight))	0 d average body weight (mg)	14 d average body weight (mg)
0	417	386
0	423	375
0	431	385
0	425	377
1000	385	352
1000	406	372
1000	428	381
1000	411	374
Minimum value	385	352
Maximum value	431	386

 

Table 2.Results of Measurement of Fosetyl-Na Acute Toxicity to Earthworms (Limit test)

Treatment dose (mg/kg (soil dry weight))	Earthworm count (each)	Death count (each)
		7 d	14 d
0	10	0	0
0	10	0	0
0	10	0	0
0	10	0	0
1000	10	0	0
1000	10	0	0
1000	10	0	0
1000	10	0	0

 

Table 3. Validity criteria OECD 207

Criterion from the guideline	Outcome	Validity criterion fulfilled
The mortality in the controls should not exceed 10 per cent at the end of either test.	0%	Yes

 

Validity criteria fulfilled:

yes

Remarks:

see Table 3 in 'any other information on results incl. tables'

Description of key information

LC50 (14 d) > 1000 mg/kg dw  for Eisenia fetida (OECD 207)

Key value for chemical safety assessment

Short-term EC50 or LC50 for soil macroorganisms:

1 000 mg/kg soil dw

Additional information

A GLP study according to OECD guideline 207 on the acute toxicity to earthworms (Eisenia fetida) using artificial soil was performed with Fosetyl-Sodium. Two months old earthworms with clitellum were exposed to a nominal limit concentration of 1000 mg/kg dry weight and an untreated control at 19.3 - 20.6 °C for 14 days. Appropriate concentrations were obtained by mixing the test substance directly into the dry test substrate. No analytical verification was performed. A test with the reference compound 2-chloroacetamide is performed three times each year, to confirm that the test conditions meet the test requirements and there have been no significant changes. The test dates of the last testing were: 2016-11-10 to 2016-11-24.

After 14 days of exposure, no mortalities were observed in the control or at the test concentration. No significant difference was observed for mean body weight between the control group and the limit concentration. No behavioral alterations or physical abnormalities were observed in the control or in the exposed group after 7 or 14 days exposure to the test substance. Thus, the 14-day LC50 was in excess of the limit concentration of 1000 mg/kg soil dry weight (nominal). The reference compound’s 7d-LC50 was 35.1 mg/kg and 14d-LC50 was 27.2 mg/kg. The results of the test with the reference compound were valid. Since the mortality in the controls did not exceed 10 percent at the end of the test (0%), the test was valid according to the OECD guideline 207 validity criteria.