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Ecotoxicological information

Toxicity to soil macroorganisms except arthropods

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Administrative data

Endpoint:
toxicity to soil macroorganisms except arthropods: short-term
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Justification for type of information:
REPORTING FORMAT FOR THE ANALOGUE APPROACH
See read-across justification report under Section 13 ‘Assessment Reports’.

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
In accordance with REACH Annex XI, Section 1.5, of Regulation (EC) No. 1907/2006 (REACH) the standard testing regime may be adapted in cases where a grouping or read-across approach has been applied.

The similarities may be based on:
(1) a common functional group
(2) the common precursors and/or the likelihood of common breakdown products via physical or biological processes, which result in structurally similar chemicals; or
(3) a constant pattern in the changing of the potency of the properties across the category

1. Both substances are inorganic salts of a monovalent cation from Group 1A of the periodic table, sodium or potassium, and phosphoric acid. Thus, they all share the Na+ or K+ cation and the PO43- anion as common functional groups. 2. All members of the group will ultimately dissociate into the common breakdown products of the Na+ or K+ cations and the PO43- anion. 3. Sodium and potassium orthophosphates have been shown to have a similar toxicological profile and physicochemical nature and therefore this data is considered to be adequate and reliable for use in read-across. Any further testing would not be scientifically justified as all substances will dissociate to their anionic and cationic forms in natural waters and these ions (Na+, K+ and PO43-) are all ubiquitous and are not considered to pose a risk of ecotoxicity

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
See read-across justification report under Section 13 ‘Assessment Reports’.

3. ANALOGUE APPROACH JUSTIFICATION
See read-across justification report under Section 13 ‘Assessment Reports’.

4. DATA MATRIX
See read-across justification report under Section 13 ‘Assessment Reports’.
Cross-reference
Reason / purpose:
read-across: supporting information

Data source

Reference
Reference Type:
publication
Title:
A comparison of the relative toxicity of bone meal and other P sources used as remedial treatments to the earthworm
Author:
Atuah L & Hodson ME
Year:
2011
Bibliographic source:
Pedobiologica - International Journal of Soil Biology

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 207 (Earthworm, Acute Toxicity Tests)
GLP compliance:
no
Remarks:
Study was not performed for the purpose of REACH registration.

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): potassium hydrogen phosphate (KH2PO4)

Test substrate

Vehicle:
no
Details on preparation and application of test substrate:

- Controls: unamended soil

Test organisms

Test organisms (species):
Eisenia fetida
Animal group:
annelids
Details on test organisms:
TEST ORGANISM
- Common name: earthworm
- Source: Blades biological Ltd, Cowden, Edenbridge, Kent, UK
- Age at test initiation (mean and range, SD): no data
- Weight at test initiation (mean and range, SD): 340 +/- 3.7 mg

ACCLIMATION
- Acclimation period: no data

Study design

Study type:
laboratory study
Substrate type:
natural soil
Limit test:
no
Total exposure duration:
28 d

Test conditions

Test temperature:
20°C
pH:
7-7.2
Moisture:
60% water holding capacity
Details on test conditions:
TEST SYSTEM
- Test container (material, size): no data
- Amount of soil or substrate: 500 g
- No. of organisms per container (treatment): 10
- No. of replicates per treatment group: 4
- No. of replicates per control: 8


SOURCE AND PROPERTIES OF SUBSTRATE (if soil)
- Geographic location: Jetting Loam - bought
- Soil texture (if natural soil): sieved to less than 2mm

Properties are similar to the OECD standard soil.

OTHER TEST CONDITIONS
- Photoperiod: performed in dark


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : mortality


TEST CONCENTRATIONS
- Spacing factor for test concentrations: 1.8
Nominal and measured concentrations:
15,000 mg P/kg with concentrations decreasing by a factor of 1.8 downwards to 441 mg P/kg
Reference substance (positive control):
not specified

Results and discussion

Effect concentrationsopen allclose all
Duration:
14 d
Dose descriptor:
LC50
Effect conc.:
> 3 500 other: mg P/ kg
Nominal / measured:
nominal
Conc. based on:
act. ingr.
Basis for effect:
mortality
Duration:
28 d
Dose descriptor:
LC50
Effect conc.:
> 3 500 other: mg P / kg
Nominal / measured:
nominal
Conc. based on:
act. ingr.
Basis for effect:
mortality

Applicant's summary and conclusion

Validity criteria fulfilled:
not specified
Conclusions:
LC50 (14 day and 28 day values) of potassium dihydrogen phosphate was found to be > 3500 mg P / kg.