Dipotassium peroxodisulphate

Long-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

adult fish: sub(lethal) effects

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Justification for type of information:

JUSTIFICATION FOR DATA WAIVING
The study does not need to be conducted for the reasons of adaptation rules of section 1 Annex XI (scientifically not necessary) as well as column 2, section 9.1 Annex IX.

As stated by ECHA in the Compliance Check Decision (CCH-D-2114340956-41-01/F): “There were no indications in the dossier from the short-term toxicity studies on aquatic species that the fish would be substantially more sensitive than Daphnia.” Therefore, the long-term toxicity testing on fish is considered scientifically not necessary, as it is clearly shown in the technical dossier that Daphnia magna is the most sensitive species towards the registered substance.

Additionally, “ECHA has indicated in both long-term aquatic toxicity testing that according to integrated testing strategy (ITS) the long-term toxicity testing on aquatic invertebrates (Daphnia) should be conducted first and that the results of this test should be considered together with other information as part of the chemical safety assessment to identify whether further long-term testing on fish is needed. This ensures that the Daphnia study is undertaken first to ensure no vertebrate animals are tested, unnecessarily. Following the Daphnia study, and the application of a relevant assessment factor, if no risks are observed (PEC/PNEC<1), no long-term fish testing may need to be conducted.” The suggested approach in the Compliance Check Decision (CCH-D-2114340956-41-01/F) was followed and first a long-term test with Daphnia was performed. Based on the results of this study, the PNECs were derived and the risk was assessed. All Risk characterisation Ratios were below 1 (RCR<1), therefore, long-term toxicity testing on fish was considered unnecessary.

This strategy was supported by ECHA with their statement in the final decision: “According to ECHA Guidance on information requirements and chemical safety assessment (version 2.0, November 2014), Chapter R7b (Section R.7.8.5., including Figure R.7.8-4), if based on acute aquatic toxicity data neither fish nor invertebrates are shown to be substantially more sensitive, long-term studies may be required on both. In such case, according to the integrated testing strategy, the Daphnia study is to be conducted first. If based on the results of the long-term Daphnia study and the application of a relevant assessment factor, no risks are observed (PEC/PNEC<1), no long-term fish testing may need to be conducted. However, if a risk is indicated, the long-term fish study needs to be conducted.”
Column 2, section 9.1., Annex IX states that “Long-term toxicity testing shall be proposed by the registrant if the chemical safety assessment according to Annex I indicates the need to investigate further the effects on aquatic organisms.” The chemical safety assessment does not indicate the need to further investigate effects on aquatic organisms as outlined in the following. This is also in line with the rule of information requirement adaptation due to no scientific necessity as stated in Annex XI section 1.

The substance was investigated in OECD and GLP compliant studies for its acute toxicity to algae, daphnia, and fish, respectively. The acute toxicity of the Persulfate Category to fish was tested in four studies. Three studies were available for diammonium persulfate (APS) and one for disodium persulfate (SPS). The studies were in accordance to FIFRA guideline 72-1 of the pesticide assessment guidelines, OECD guideline 203 and EU Method C.1. The most sensitive LC50 (96 h) value for freshwater was determined at 76.3 mg/L for Rainbow trout (Oncorhynchus mykiss) and for marine water at 107.6 mg/L for Turbot (Scophthalmus maximus).

The acute toxicity of the Persulfate Category to aquatic invertebrates was tested in eight studies. Six studies were available for diammonium persulfate (APS) and two for disodium persulfate (SPS). The studies were in accordance to FIFRA guideline 72-2 and 72-3 of the pesticide assessment guidelines, OECD guideline 202 and EU Method C.2. The most sensitive LC50 (48 h) value for freshwater was determined at 120 mg/L for Daphnia magna and for marine water at 11 mg/L (5 d) for Abra alba.

The acute toxicity of the Persulfate Category to aquatic algae was tested in four studies. One study was available for disodium persulfate (SPS) and three for diammonium persulfate (APS). The studies were in accordance to OECD guideline 201 and EU Method C.3. The most sensitive EC50 (72 h) value for marine water was detected at 320 mg/L with a NOEC of 32 mg/L for Phaeodactylum tricornutum.

The long-term toxicity of the Persulfate Category to aquatic invertebrates was tested with diammonium peroxodisulphate (APS). Based on the results of this 21-day chronic toxicity study, the test item had significant influence on the reproductive output of Daphnia magna. The determined NOEC based on nominal concentrations for reproduction was 20.8 mg/L. An EC10 and EC50 of 25.9 mg/L and 44.0 mg/L for reproduction were observed, respectively. For mortality a NOEC value of 39.5 mg/L was observed.

Taken together, the most sensitive species when exposed to any of the members of the Persulfate Category was determined to be the Daphnia magna when exposed for longer periods. NOEC values for a long-term fish test are expected to be well above the NOEC value from the long-term toxicity to aquatic invertebrates test. Therefore, long-term toxicity studies in fish are not expected to provide more relevant information in regards to hazard conclusion and would, therefore, not improve chemical safety assessment. Furthermore, based on the chemical safety assessment the environmental risk is considered to be adequately controlled. There are no concerns regarding the safe use of the substances. For the aquatic environment RCR values are below the threshold of 1. This information is additionally supported from ECHA as cited in the Compliance Check Decision (CCH-D-2114340956-41-01/F) and further long-term toxicity test on fish are not necessary to be performed (rf. ECHA Guidance on information requirements and chemical safety assessment (version 2.0, November 2014), Chapter R7b).
Another point of consideration is the fact that Persulfates dissociate in water to the corresponding cation and persulfate anion. Hydrolysis is temperature and pH dependent. The persulfate anion, independent from the cation, undergoes decomposition in normal water or acid conditions, readily oxidising water to oxygen, producing acid conditions. All degradation products are ubiquitous to the environment. Hydrolysis half-life was determined to be 80.4 days at 12 °C and pH 7. Water solubility of the substance was determined to be 52.77 g/L at 20 °C. Due to these properties the substance is expected to be distributed or disintegrated rapidly and, therefore, well diluted in the compartment water. Thus, aquatic life is not expected to be exposed to higher concentrations of the test item over a longer period. This further supports the point that acute toxicity studies together with the available chronic daphnia study already provide sufficient information for chemical safety assessment.

Taken together the points outlined above, it is concluded, that the criteria of Annex XI section 1 are fulfilled justifying the adaptation of the information requirements, accordingly. Therefore, and considering animal welfare reasons, further studies on long-term toxicity to fish are neither scientifically, nor from a regulatory point of view justified.

This is also in line with the rule of information requirement adaptation as stated in Annex IX Section 9.1 column 2. Further testing does not appear to be scientifically necessary.

Description of key information

Based on the low toxicity in acute studies with fish, physical-chemical properties and hydrolysis behaviour of dipotassium persulfate, long term toxicity testing of fish was considered not scientifically justified.

Additional information

The study does not need to be conducted for the reasons of adaptation rules of column 2, section 9.1 Annex IX as well as section 1 Annex XI (scientifically not necessary).

Column 2, section 9.1., Annex IX states that “Long-term toxicity testing shall be proposed by the registrant if the chemical safety assessment according to Annex I indicates the need to investigate further the effects on aquatic organisms.” The chemical safety assessment does not indicate the need to further investigate effects on aquatic organisms as outlined in the following. This is also in line with the rule of information requirement adaptation due to no scientific necessity as stated in Annex XI section 1.

The substance was investigated in OECD and GLP compliant studies for its acute toxicity to algae, daphnia, and fish, respectively. The acute toxicity of the Persulfate Category to fish was tested in four studies. Three studies were available for diammonium persulfate (APS) and one for disodium persulfate (SPS). The studies were in accordance to FIFRA guideline 72-1 of the pesticide assessment guidelines, OECD guideline 203 and EU Method C.1. The most sensitive LC50 (96 h) value for freshwater was determined at 76.3 mg/L for Rainbow trout (Oncorhynchus mykiss) and for marine water at 107.6 mg/L for Turbot (Scophthalmus maximus).

The acute toxicity of the Persulfate Category to aquatic invertebrates was tested in eight studies. Six studies were available for diammonium persulfate (APS) and two for disodium persulfate (SPS). The studies were in accordance to FIFRA guideline 72-2 and 72-3 of the pesticide assessment guidelines, OECD guideline 202 and EU Method C.2. The most sensitive LC50 (48 h) value for freshwater was determined at 120 mg/L for Daphnia magna and for marine water at 11 mg/L (5 d) for Abra alba. The acute toxicity of the Persulfate Category to aquatic algae was tested in four studies. One study was available for disodium persulfate (SPS) and three for diammonium persulfate (APS). The studies were in accordance to OECD guideline 201 and EU Method C.3. The most sensitive EC50 (72 h) value for marine water was detected at 320 mg/L with a NOEC of 32 mg/L for Phaeodactylum tricornutum. The long-term toxicity of the Persulfate Category to aquatic invertebrates was tested with diammonium peroxodisulphate (APS). Based on the results of this 21-day chronic toxicity study, the test item had significant influence on the reproductive output of Daphnia magna. The determined NOEC based on nominal concentrations for reproduction was 20.8 mg/L. An EC10 and EC50 of 25.9 mg/L and 44.0 mg/L for reproduction were observed, respectively. For mortality a NOEC value of 39.5 mg/L was observed.

Taken together, the most sensitive species when exposed to any of the members of the Persulfate Category was determined to be the Daphnia magna when exposed for longer periods. NOEC values for a long-term fish test are expected to be well above the NOEC value from the long-term toxicity to aquatic invertebrates test. Therefore, long-term toxicity studies in fish are not expected to provide more relevant information in regards to hazard conclusion and would, therefore, not improve chemical safety assessment. Furthermore, based on the chemical safety assessment the environmental risk is considered to be adequately controlled. There are no concerns regarding the safe use of the substances. For the aquatic environment RCR values are below the threshold of 1. This information is additionally supported from ECHA as cited in the Compliance Check Decision (CCH-D-2114340958-37-01/F) and further long-term toxicity test on fish are not necessary to be performed (rf. ECHA Guidance on information requirements and chemical safety assessment (version 2.0, November 2014), Chapter R7b).

Another point of consideration is the fact that Persulfates dissociate in water to the corresponding cation and persulfate anion. Hydrolysis is temperature and pH dependent. The persulfate anion, independent from the cation, undergoes decomposition in normal water or acid conditions, readily oxidising water to oxygen, producing acid conditions. All degradation products are ubiquitous to the environment. Hydrolysis half-life was determined to be 130 h at 50 °C and pH 7. Water solubility of the substance was determined to be 730 g/L at 20 °C. Due to these properties the substance is expected to be distributed or disintegrated rapidly and, therefore, well diluted in the compartment water. Thus, aquatic life is not expected to be exposed to higher concentrations of the test item over a longer period. This further supports the point that acute toxicity studies together with the available chronic daphnia study already provide sufficient information for chemical safety assessment.

Taken together the points outlined above, it is concluded, that the criteria of Annex IX Section 9.1 column 2 are fulfilled justifying the adaptation of the information requirements, accordingly. Therefore, and considering animal welfare reasons, further studies on long-term toxicity to fish are neither scientifically nor from a regulatory point of view justified.

This is also in line with the rule of information requirement adaptation as stated in Annex XI section 1. Further testing does not appear to be scientifically necessary.