O,O,O-triphenyl phosphorothioate

Toxicity to soil macroorganisms except arthropods

Link to relevant study record(s)

Reference

Endpoint:

toxicity to soil macroorganisms except arthropods: long-term

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 222 (Earthworm Reproduction Test (Eisenia fetida/Eisenia andrei))

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Vehicle:

yes

Details on preparation and application of test substrate:

- Method of mixing into soil : The water solubility is not enough to prepare a sufficient stock solution with deionized water. The test substance was weighed into a 50 mL volumetric flask. The test substance was dissolved by addition of acetone as solvent. After short stirring, the solution was filled up to the mark with acetone. The test substance was completely dissolved. The solution was colourless and clear.
The required aliquots of the stock solution were added to 25 g quartz sand (10 g quartz sand/kg dry weight). The mixtures were blended thoroughly and the organic solvent was removed by evaporation afterwards. No odour of the organic solvent was noticeable.
The required amounts of artificial soil were weighed into a mixing bowl. The test substance / quartz sand mixtures were added and thoroughly mixed with the soil. Amounts of deionized water were dosed in order to adjust the water content to about 50% WHCmax. and mixed once again. The test mixtures were distributed to the test units.

- Controls: with quartz sand and solvent control with quartz sand and solvent
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): acetone
- Concentration of vehicle in test medium (stock solution and final test solution): removed by evaporation before exposure period

Test organisms (species):

Eisenia fetida

Animal group:

annelids

Details on test organisms:

TEST ORGANISM
- Source: Agricultural Center Limburgerhof of BASF SE, D-67056 Ludwigshafen, Germany
- Age at test initiation: Only adult worms (with clitellum) with a fresh weight between 250 and 600 mg were used. age ca 10 months
- Worm weight at start of exposure: In a range of 257- 598 mg

ACCLIMATION
- Acclimation conditions: A transport box filled up with approx. 1.2 kg wet test substrate was provided to the supplier. A sufficient number of adult worms were sorted out from the breeding boxes into the transport box. The worms selected for the test, were acclimatized in the test substrate in the transport box under test conditions overnight under permanent light without feeding before starting the test.

Study type:

laboratory study

Substrate type:

artificial soil

Limit test:

no

Total exposure duration:

56 d

Test temperature:

20.7-21.3°C

pH:

6.4 (start of exposure), 5.9-6.7 at the end of exposure

Moisture:

50 % ± 10% WHCmax
water content of dry test substrate 0.7 % (mean of 2 single values 0.7%/0.7%)
content water of the artificial soil at start of exposure: 48.5-50.0
content of water of the artificial soil at the end of exposure: 55.0-64.3
In several replicates the content of water was slightly out of the required range. An influence to the test result can be excluded.

Details on test conditions:

TEST SYSTEM
- Test container (material, size): Bellaplast plastic container were used as test vessels. The containers consist of inert and non-toxic plastic. The test vessels have a bottom area of 11 × 15.5 cm and a height of 6 cm. The test vessels were covered with perforated transparent lids. Plastic dishes with a volume of about 1.0 L.
- Amount of soil or substrate: Approx. 675 g artificial soil (wet weight), equivalent to 550 g dry weight
- No. of organisms per container (treatment): 10
- No. of replicates: 8 for the solvent control, 4 for the control and for each test- and reference substance concentration

SOURCE AND PROPERTIES OF SUBSTRATE (if soil)
- Composition (if artificial substrate):
18.5 kg quartz sand (73.5 % of total substrate mass)
5.3 kg kaolin clay (21.1 % of total substrate mass)
1.3 kg sphagnum peat (5.2 % of total substrate mass), finely grounded.
72.0 g CaCO3, p.A. (0.2 % of total substrate mass)
- Organic carbon (%): 5.2% The availability of lipophilic test item (ingredients) in soil and therefore their toxicity to earthworms depends on the organic matter content of the soil. For chemicals with log Kow >2, adsorption is expected to be linearly related to soil organic matter content. With respect to the properties of the test item (log Kow >2) 5 % instead of 10 % peat were used, considering the influence on bioavailability (OECD 222 and EPPO 2003).
- Water holding capacity (in % dry weigth): 45.6 g/100g Dw (mean value)

FEEDING:
The adult worms were fed with finely ground cow manure (free of growth promoters, nematicides or similar veterinary pharmaceuticals). After the start of the experiment, food was first provided one day after application of the test substance and introduction of the adult worms. Thereafter, the adult worms were fed weekly during the first 4 weeks of the test. An amount of 5 g moistened with about 5-6 mL deionized water was spread on the test substrate surface of each test container. If food remained unconsumed, the ration was reduced on demand. After removing the adults on day 28 further 5 g of food moistened with about 5-6 mL deionized water was mixed with the test substrate of each test vessel.

OTHER TEST CONDITIONS
- Illumination: Light/day cycles of 16:8 hours, over the exposure period
- Measurement of light intensity, once at start of exposure: 563 Lux, (mean of 5 single measurements: 715, 526, 517, 519 and 537 [Lux])
- Measurement of light intensity, once at start of adaption: 645 Lux
- Temperature: two times a week during the exposure in a separate vessel

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- consumption of feed: weekly in the first 28 days
- mortality of adult worms: after 28 days
- biomass of adult worms: start of exposure and after 28days of the test
- number of juvenile: at the end of exposure (56d)

VEHICLE CONTROL PERFORMED: yes

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2

Nominal and measured concentrations:

250, 500, 1000, 2000, 4000 mg/kg dw

Reference substance (positive control):

yes

Remarks:

Carbendazim CAS 10605-21-7

Duration:

28 d

Dose descriptor:

EC10

Effect conc.:

900 mg/kg soil ww

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

mortality

Remarks on result:

other: adult worms

Key result

Duration:

56 d

Dose descriptor:

EC10

Effect conc.:

199.6 mg/kg soil ww

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

reproduction

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

2 000 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: adult worms

Duration:

28 d

Dose descriptor:

EC10

Effect conc.:

3 264 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: adult worms

Duration:

56 d

Dose descriptor:

NOEC

Effect conc.:

500 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Duration:

56 d

Dose descriptor:

EC10

Effect conc.:

724 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

reproduction

Details on results:

No abnormalities were observed up to 28d exposure.
No morphological and behavioral changes of the survived worms were observed after 28d exposure.
Dead worms were found at the test container with the highest test concentrations (28d).
At the test container with 4000mg/kg dw, no cocoons were observed after 28d.
No morphological and behavioral changes of the juveniles were observed after 56d.

Results with reference substance (positive control):

The reference substance BAS 346 F (Carbendazim) was tested by a non-GLP project 68E0902/00G024 (start of exposure 21 January 2016). The raw data and the report are archived. The result of the reference substance is presented below.
ECx values [mg/kg soil (dw)], reproduction, conf. limits 95%
EC10: 1.30 LCL: 1.17 UCL: 1.46
EC50: 1.93 LCL: 1.82 UCL: 2.05
These observed effects are within the expected range from the test guideline (1-5 mg/kg carbendazim/kg soil (dw)) and hence acceptable sensitivity of the test system is assured.

Validity criteria fulfilled:

yes

Conclusions:

All validity criteria were met. After 28 days, no adult worm in the control assay was dead. A number of about 200 juveniles were counted in the test units of the control assay. The coefficient of variation concerning to the offspring juvenile worms in the solvent control assay was 10.7 %.

Description of key information

NOEC (56h) = 199.6 mg ai/kg soil dw for reproduction of Eisenia fetida (OECD 222)

Key value for chemical safety assessment

Long-term EC10, LC10 or NOEC for soil macroorganisms:

199.6 mg/kg soil dw

Additional information

One study is available investigating the long-term toxicity of O,O,O-triphenyl phosphorothioate in a lower purity (purity > 25%) to terrestrial macroorganisms. The study was performed according to OECD guideline 222 and in compliance with GLP criteria using Eisenia fetida as test organism (BASF 2016). Concentrations of 0, 250, 500, 1000, 2000 and 4000 mg/kg d.s. (dry soil) were tested. The surviving worms were removed after 28 days of exposure and the produced cocoons were allowed to hatch for a period of 28 days. Biomass of adult animals at day 0 and 28, mortality of adult worms at day 28 and reproduction at day 56 were recorded. The 56d-EC10 for reproductive output were determined to be 724 mg test substance/kg soil dw based on nominal concentrations. No information is available which constituents contribute to these observed adverse effects. Thus, in a worst case approach the effects were attributed to O,O,O-triphenyl phosphorothioate and the effect value was recalculated to 100 % O,O,O-triphenyl phosphorothioate: 56d-EC10 = 199.6 mg a.i./kg soil dw.