Tetrasodium (1-hydroxyethylidene)bisphosphonate

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:

other: Analogy

Adequacy of study:

key study

Study period:

19 March 2014 - 15 May 2014

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))

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

Eisenia fetida

Animal group:

annelids

Study type:

laboratory study

Substrate type:

artificial soil

Limit test:

no

Total exposure duration:

28 d

Remarks:

Cocoons and offspring were incubated under the same conditions for further 4 weeks.

Test temperature:

20 ± 2 °C

pH:

6.0 ± 0.5

Moisture:

52% of the maximum water holding capacity

Nominal and measured concentrations:

62.5 – 125 – 250 – 500 – 1000 mg test item/kg soil dry weight

Reference substance (positive control):

yes

Remarks:

Carbendazim

Key result

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

500 mg/kg soil dw

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

reproduction

Duration:

28 d

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/kg soil dw

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

reproduction

Results with reference substance (positive control):

Significant effects between 1 and 5 mg a.i./kg soil dry weight.

Validity criteria fulfilled:

yes

Conclusions:

Under the conditions of this study, Etidronic acid hydrate did not induce evident mortality, pathological symptoms or changes of the behaviour of adult earthworms after 28 days of exposure in all tested concentrations. The adult earthworm biomass increased in the control and in all application rates without any statistically significant differences. After eight weeks of exposure the earthworm reproduction was not statistically significantly reduced at the test item concentrations 62.5, 125, 250 and 500 mg test item/kg soil dry weight. However, at 1000 mg test item/kg soil dry weight the reproduction rate was statistically significantly reduced.
The EC50 - value for reproduction was determined to be > 1000 mg test item/kg soil dry weight.

Thus, the No Observed Effect Concentration (NOEC) for Etidronic acid hydrate summarizing the endpoints mortality and body weight and reproduction of Eisenia fetida fetida after 8 weeks of exposure in artificial soil was determined to be 500 mg test item/kg soil dry weight.

Executive summary:

Effects ofEtidronicacidhydrate(Batch no.A3495) on mortality, biomass and the reproductive potential of the earthworm species Eisenia fetida (Annelida, Lumbricidae) were determined according to the Guidelines DIN ISO 11268-2 (1998), OECD 222 (2004) and BBA (1994). The study was conducted under static conditions over 8 weeks with the test item concentrations 62.5, 125, 250, 500 and 1000 mg test item/kg soil dry weight, which were mixed into artificial soil containing 10 % peat and a control using untreated artificial soil. 80 test organisms were inserted into 8 control replicates and 40 test organisms were divided into 4 replicates for each treatment (10 earthworms per replicate). They had an individual body weight between 0.32 and 0.54 g at experimental starting.

After 28 days of exposure in soil, no evident earthworm mortalities (< 10%) as well as no evident pathological symptoms or changes in the behaviour of adult earthworms were observed in all treatments. Moreover, no statistically significant differences in earthworm body weights were observed at all test item concentrations compared to the control. After further four weeks the reproduction rate (average number of juveniles produced) was 88 in the control and ranged between 46 and 115 in the test item treatment rates. Compared to the control, no statistically significant reduction of reproduction was observed at the test item concentrations 62.5, 125, 250 and 500 mg test item/kg soil dry weight. However, at 1000 mg test item/kg soil dry weight the reproduction was statistically significantly reduced. Overall, the NOEC of the test item concerning mortality, biomass and reproduction of earthworms was determined to be 500 mg test item/kg soil dry weight. The EC₅₀- value for reproduction was determined to be > 1000 mg test item/kg soil dry weight.

 

Key value for chemical safety assessment

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

714 mg/kg soil dw

Additional information

An earthworm study following OECD Guideline 222 (Earthworm Reproduction Test (Eisenia fetida/Eisenia andrei)) was conducted with etidronic acid (CAS 2909-21-4). The overall NOEC for etidronic acid was determined as 500 mg/Kg. This corresponds to a NOEC of 714 mg/kg for tetrasodium (1-hydroxyethylidene)bisphosphonate (CAS 3794-83-0) after molecular weight correction. The results of the new study well support the previously available results of a reliability 2 study on earthworm toxicity which determined a 14 d LC50 value of >1000 mg/kg for the effects of HEDP sodium salt on the terrestrial worm E. foetida. It is also informative regarding the validity of the equilibrium partitioning approach for similar substances.