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Toxicity to soil macroorganisms except arthropods

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toxicity to soil macroorganisms except arthropods: short-term
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
1998-10-22 to 1998-11-25
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
comparable to guideline study
Justification for type of information:
Supporting for waiving of "Toxicity to soil macroorganisms except arthropods" with Guanidinium thiocyanate.
according to guideline
OECD Guideline 207 (Earthworm, Acute Toxicity Tests)
GLP compliance:
Specific details on test material used for the study:
Identification : Ammonium thiocyanate
Description : White crystalline solid
Chemical name :Thiocyanic acid, ammonium salt
Cas - no : 1762-95-4
Batch :0609810070729
Purity :See Certificate of Analysis
Test substance storage: In refrigerator in the dark
Expiry date 14 October 2001
Density 1300 kg/m3
Bulk density 600-700kg/m3
Specific Gravity: 1.3
Stability in water: At least 96 h

The sponsor is responsible for the completeness and GLP Compliance of all test substance data
Analytical monitoring:
Details on preparation and application of test substrate:
Since the test substance was soluble in water, the test media were prepared using a stock solution o f 10 g / l (stock A) or 100 mgll (stock B) i n
MilliPore water ( tap water purified by reverse osmosis). The dissolved stock solution was added to the artificial soil to achieve the desired spiked
concentration. The mixture was blended for 10 minutes to achieve a homogenious dispersion of the test substance. Concentration were spiked at
0.1,1.0,10,100,1000 mg/kg Dry soil.
Test organisms (species):
Eisenia fetida
Animal group:
Details on test organisms:
Species Earthworm (Eisenia foetida / foetida )
Source Earthworms were bred a t the NOTOX B.V.facilities .
Age and mass o f earthworms : At least two months old with clitellum , with an individual wet mass o f 300-600 mg.
Study type:
laboratory study
Substrate type:
artificial soil
Limit test:
Total exposure duration:
14 d
Post exposure observation period:
Worms were observed for movement and were considered dead if no movement was observed after light mechanical stimulation
Test temperature:
20-22ºc ( one day reached 24 ºc)
The water content of the soil at the start of the test was 35 %. At the end of the test the water content was 34 %.
Details on test conditions:
combined range finding plus limit test was performed to provide information about the range of concentrations to be used in an optional
test . The concentrations ranged from 0.1 t o 1000 mg/kg artificial soil (dry mass), differing by a factor 10. At concentrations o f 0 . 1 t o 100 mglkg 10 earthworms were exposed, whereas a t 0 and 1000 mglkg ( limit test concentration) 40 earthworms were exposed. Since no toxic effects were
observed a t 1000 mg/kg, no additional testing was performed.
Nominal and measured concentrations:
0.1,1.0,10,100,1000 mg/kg Dry soil. (Nominal)
Reference substance (positive control):
Key result
14 d
Dose descriptor:
Effect conc.:
>= 1 000 mg/kg soil dw
Nominal / measured:
Conc. based on:
test mat.
Basis for effect:
Details on results:
No mortalities were observed at any of the test concentrations and reduction in mass also did not drop significantly. NOEC = >1000mg/l
Results with reference substance (positive control):
Conducted as part of laboratory maintainence and reported in full results satisfactory. Chloroacetamide.
Reported statistics and error estimates:
No effects, No statistical analysis was conducted.

General Remarks

Test was conducted to the guidelines with no significant modifications or deviations. Lacking chemical analysis however this is not mentioned as a criteria in the guidelines. Photoperiod not reported


Validity Criteria

Mortality in the control did not exceed 10 % at the end of the test

Validity criteria fulfilled:
Despite lack of chemical analysis this study complies fully to the OECD guideline for this test. It is however still important to consider possible biodegredation of the substance during the test which may have affected the exposure to the test animals. Due to the ready biodegradable nature of this substance the actual exposure is likey to be significantly less than the nominals reported here. This study is therefore reliable with restrictions
Executive summary:



Acute toxicity study in the earthworm with AMMONIUM THIOCYANATE according to OECD guidelines for Testing of Chemicals, guideline No. 207: "Earthworm Acute Toxicity Tests, Adopted April 4, 1984, European Economic Community (EEC), Directive 87/302/EEC Annex VIII of the EEC Directive 79/831/EEC, Toxicity for Earthworms. EEC Publication no. L 133 and International Standard IS0 11268-1 (1993), Soil quality-Effects of pollutants on earthworms (Eisenia fetida)-Part 1: Determination of acute toxicity using artificial soil substrate.


Earthworms of the species Eisenia foetida foetida were exposed to AMMONIUM THIOCYANATE in artificial soil for 14 days. A combined range-finding/limit test was performed in which the concentrations of AMMONIUM THIOCYANATE were nominally 0.1, 1.0, 10, 100 and 1000 mg/kg dry weight of soil (further referred to as dry soil). For the preparation of test media stock solutions were prepared in milli-RO water and subsequently mixed with the artificial soil.

40 Earthworms were exposed to the blank and the highest concentration, i.e. 10 earthworms per vessel. To the other concentrations 10 earthworms were exposed.


No mortality or other effects to the earthworms were recorded at any of the concentrations tested throughout the whole 14-day period of exposure. The average loss of biomass of the earthworms in the control and at all

concentrations did not exceed 20%.  Since all criteria for acceptability of the test were met, this study was considered to be valid.


Under the conditions of the present study AMMONIUM THIOCYANATE did not induce mortality of Eisenia foetida foetida at or below 1000 mg/kg dry soil after 14 days of exposure. Hence, the NOEC is >1000 mg/kg dry soil.


toxicity to soil macroorganisms except arthropods: short-term
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:

Description of key information

According to REACH Annex IX (section R. and table R.7.11-2) of the Guidance on Information Requirements and Chemical Safety Assessment, Chapter R.7c: Endpoint specific guidance, Version 3.0 – June 2017, standard information requirements according to Annex IX can be waived based on the physicochemical properties and aquatic toxicity data when there is no sufficient soil organism toxicity data available. If the substance is expected to have a low potential for adsorption (log KOW < 5), low persistence (DT50 < 180 days / readily biodegradable) and low aquatic toxicity (EC/LC50 >1 mg/L for algae, daphnia or fish) (as indicated in table R.7.11-2; column 1), the Equilibrium Partitioning Method (EPM) can be used for screening assessment using PEC/ PNECscreen. If comparison of a PNECsoil derived by EPM from the aquatic PNEC, shows a PEC:PNEC ratio <1, then the information available may be sufficient to conclude the soil assessment.


The terrestrial endpoints of the target substance Guanidine Thiocyanate can be waived due to following physiochemical properties:

  1. The target substance Guanidine Thiocyanate (log Kow = -1.11) and all source substances exhibit a log Kow below 0 (Guanidine Nitrate (-1.7), Guanidine Hydrochloride (-1.7), Ammonium Thiocyanate (-2.29), Sodium Thiocyanate (-2.52) and Potassium Thiocyanate (-2.29)) indicating a low adsorption potential of the substances.  

  2. The source substances Ammonium Thiocyanate, Sodium Thiocyanate and Potassium Thiocyanate are assumed to be readily biodegradable in soil. For Guanidine Hydrochloride the half-life in soil is 2.5-8 d. Thus, for the target substance Guanidine Thiocyanate assuming a worst-case scenario a half-life in soil of 8 d can be assumed which indicates low persistence.

  3. Guanidine Thiocyanate reveals a low aquatic toxicity; the most sensitive organism group are aquatic invertebrates which revealed an EC50 of 42.4 mg/L for acute toxicity. Data of the source substances Guanidine Nitrate and Ammonium Thiocyanate shows the EC50 for the target substance is in-between the two source substances and all are EC/LC50 >1 mg/L.


These properties lead to a classification into hazard category 1 based on table R.7.11-2. As the risk assessment based on the EPM method did not indicate any risk (PEC/PNECscreen < 1 for soil), no further testing on soil organisms is required.

Further, there is a study available for the source substance Ammonium thiocyanate (CAS-No 1762-95-4). The data clearly shows low toxicity for the tested endpoint and supports the data waiving approach for this terrestrial endpoint:


Toxicity to soil macroorganisms except arthropods

For Ammonium Thiocyanate, there is a short-term GLP study with earthworms (OECD 207) revealing a LC50 > 1000 mg/kg soil dw. Under the conditions of the study Ammonium Thiocyanate did not induce mortality of Eisenia foetida at or below 1000 mg/kg dry soil after 14 days of exposure. Hence, the NOEC is >1000 mg/kg dry soil.

Key value for chemical safety assessment

Short-term EC50 or LC50 for soil macroorganisms:
1 000 mg/kg soil dw

Additional information