Sodium Salts of (1-Hydroxyethylidene)bisphosphonic acid (1-2:1)

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to microorganisms, other

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods with acceptable restrictions

Remarks:

It was not compliant with GLP.

Qualifier:

equivalent or similar to guideline

Guideline:

DIN 38412-8 (Pseudomonas Zellvermehrungshemmtest)

Version / remarks:

Test uses P phosphoreum. Also cites draft DIN Leuchtbakterientest.

Principles of method if other than guideline:

Short term test using luminosity of P phosphoreum as an indicator of inhibition. Test using microtox reactor

GLP compliance:

not specified

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

Photobacterium phosphoreum

Test type:

not specified

Water media type:

freshwater

Limit test:

no

Total exposure duration:

30 min

Reference substance (positive control):

no

Key result

Duration:

30 min

Dose descriptor:

IC0

Effect conc.:

> 250 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: luminescence

Remarks on result:

other: IC0 estimates derived from tests conducted at 3 concentrations

Conclusions:

A reliable IC0 value of >250 mg/l has been determined for the effects of HEDP-xNa on the bioluminescence of the bacterium Photobacterium phosphoreum.

Reference 2

Endpoint:

toxicity to microorganisms, other

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods with acceptable restrictions

Qualifier:

no guideline followed

Principles of method if other than guideline:

Non-quantitative study of effect of increasing concentration of test substance on the sewage treatment process

GLP compliance:

not specified

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

activated sludge

Test type:

not specified

Water media type:

not specified

Limit test:

no

Total exposure duration:

30 d

Reference substance (positive control):

no

Key result

Duration:

30 d

Dose descriptor:

NOEC

Effect conc.:

200 mg/L

Nominal / measured:

nominal

Conc. based on:

not specified

Basis for effect:

other: sewage gas production volume

Duration:

30 d

Dose descriptor:

LOEC

Effect conc.:

500 mg/L

Nominal / measured:

nominal

Conc. based on:

not specified

Basis for effect:

other: sewage gas volume reduced and fermentation delayed

Details on results:

At 50 mg/L HEDP showed no effects.
At 100 and 200 mg/L the start of fermentation was delayed, but constant gas volume was achieved in the same period as in the control.
At 500 mg/L HEDP, the system was strongly disturbed, as indicated by a late beginning of fermentation, and greatly reduced sewage gas production volume.

Conclusions:

A non-standard study of effects on sewage treatment plant micro-organisms was conducted according to generally accepted scientific principles but lacks detail in the study report. The result of a lack of effects on respiration up to 200 mg/L provides reliable evidence.

Reference 3

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

The full report was not available.

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Version / remarks:

DIN 38412

GLP compliance:

no

Analytical monitoring:

no

Test organisms (species):

Pseudomonas putida

Details on test conditions:

Type: aquatic

Key result

Duration:

30 min

Dose descriptor:

EC0

Effect conc.:

960 mg/L

Result expressed as nominal concentration. Properties of the
test substance and evidence from other studies (where
concentrations were measured) indicate that nominal and
measured concentrations are likely to be in good agreement.

Reference 4

Endpoint:

toxicity to microorganisms, other

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Remarks:

The study was well documented and meets generally accepted scientific principles, but was not conducted in compliance with GLP.

Qualifier:

no guideline followed

Principles of method if other than guideline:

Non-quantitative study of effect of increasing concentration of test substance on the sewage treatment process

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

activated sludge

Test type:

flow-through

Water media type:

freshwater

Limit test:

no

Total exposure duration:

70 d

Remarks on exposure duration:

With stepwise increase of test substance concentration

Reference substance (positive control):

no

Duration:

53 d

Dose descriptor:

NOEC

Effect conc.:

300 mg/L

Nominal / measured:

nominal

Conc. based on:

not specified

Basis for effect:

other: MBAS reduction

Duration:

54 d

Dose descriptor:

LOEC

Effect conc.:

400 mg/L

Nominal / measured:

nominal

Conc. based on:

not specified

Basis for effect:

other: MBAS reduction

Details on results:

A artifical sewage treatment plant was continuously fed with nutrient and anionic surfactant plus increasing concentrations of HEDP. Up to a concentration of 300 mg/l the MBAS reduction (methylene blue substance - analytical parameter for anionic surfactants) was not impaired. After increase of HEDP concentration to 400 mg/L the MBAS reduction was reduced but recovered within 5 days. The MBAS reduction was reduced again after an increase of the HEDP concentration in the inflow to 600 mg/l.

Conclusions:

A non-standard study of effects on aerobic sewage treatment process micro-organisms was conducted according to generally accepted scientific principles but lacks detail in the study report. The result of a lack of effects on respiration up to 300 mg/L provides reliable evidence.

Description of key information

The available data provide a general weight of evidence of a lack of inhibition of aerobic and anaerobic WWTP micro-organisms at concentrations up to ca. 200 mg active acid/L, equivalent to 243 mg HEDP-2Na/L and 286 mg HEDP-4Na/L.

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:

200 mg/L

Additional information

A respiration inhibition test with aerobic bacteria P. putida following the test guideline DIN 38412 part 27 showed the result EC₀ = 580 mg/L within a contact time of 30 minutes. However full details are not available. The general test principle was comparable to the OECD 209 method (Henkel, unpublished data, pers.comm.).

A non-standard reliable study of effects on anaerobic sewage treatment plant micro-organisms was conducted according to generally accepted scientific principles but lacks detail in the study report. The result of a lack of effects on bio-gas production up to at least 200 mg active acid/L after 11 days exposure in a simulation study provides reliable evidence (Henkel 1972).

A non-standard reliable study of effects on aerobic sewage treatment plant micro-organisms was conducted according to generally accepted scientific principles but lacks detail in the study report. The result of a lack of effects on MBAS reduction up to 300 mg active acid/l after 53 days exposure in a simulation study provides reliable evidence (Henkel, 1972).

A reliable IC₀ value of >250 mg/l has been determined for the effects of HEDP-xNa on the bioluminescence of the bacterium Photobacterium phosphoreum (Grohmann and Horstmann, 1989).

These studies have been used as weight of evidence to demonstrate the low toxicity of HEDP and its salts to micro-organisms toxicity.

Other data of non-assignable reliability have determined the low toxicity of HEDP and its salts towards aquatic micro-organisms.

Aquatic effects data determined with HEDP acid (2809-21-4) can be read across to HEDP salts. The main assumption is that sodium is not significant in respect of all the properties under consideration (and would not influence effects on micro-organisms). In dilute aqueous conditions of defined pH a salt will behave no differently to the parent acid, at identical concentration of the particular speciated form present and will be fully dissociated. Hence some properties (measured or expressed in aqueous media, e.g. ecotoxicity) for a salt can be directly read across (with suitable mass correction) to the parent acid and vice versa.

Here, the value of 200 mg active acid/L may be directly read-across. It is convenient to convert the result into units of mg HEDP-2Na salt/L and mg HEDP-4Na salt/L.

 

The NOEC for HEDP 2809-21-4 is 200 mg/L, which is equivalent to a NOEC value of 200 * 1.21 = 243 mg/L HEDP-2Na (CAS 7414 -83-7)

  Using: MW(HEDP-2Na)/MW(HEDP) = 249.99 / 206.03 = 1.21

The NOEC for HEDP 2809-21-4 is 200 mg/L, which is equivalent to a NOEC value of 200 * 1.43 = 286 mg/L HEDP-4Na (CAS 3794-83-0)

 Using: MW(HEDP-4Na)/MW(HEDP) = 293.96 / 206.03 = 1.43