Reaction mass of calcium hydrogen phosphonate and dialuminium tricalcium hexaoxide

Endpoint summary

Additional information

Acute aquatic toxicity

Reliable, relevant and adequate data to assess the aquatic toxicity of substance "reaction mass of calcium hydrogen phosphonate and dialuminium tricalcium hexaoxide" are available from studies performed on algae, invertebrates, fish and activated sludge microorganisms in accordance with the respective OECD and EU guidelines.

In a 72-h acute toxicity study according to OECD guideline 201, adopted June 7, 1984 and EU Method C.3, dated December 29, 1992, cultures of Scenedesmus subspicatus (new name: Desmodesmus subspicatus) CHODAT were exposed at nominal concentrations of 0 (control), 1.0, 3.2, 10, 32, and 100 mg/L (the three last mentioned concentrations correspond to measured concentrations of 8.6 (86 % of nominal), 21. 6 (67 % of nominal), and 67.2 (67 % of nominal) mg/L, respectively) under static conditions. The NOEC, EC₅₀, and EC₁₀ values based on measured concentrations and biomass were 8.6 (nominal 10), 16.0 (nominal 21.9), and 9.7 (nominal 12.3) mg/L, respectively. The NOEC, LOEC, EC₅₀, and EC₁₀ values based on measured concentrations and growth rate µ were 8.6 (nominal 10), 21.6 (nominal 32), 19.9 (nominal 28.9), and 14.6 (nominal 19.7) mg/L, respectively. The microscopic examination of the shape of the algal cells after 72 hours in the second highest nominal test substance concentration of 32 mg/L showed no difference in comparison to the cells in the control. Thus, the shape of the algal cells was not affected by the test item up to and including this concentration. In the control the cell density increased from N= 1x10exp4 cells/mL at the start of the test (hour-0) to N= 119x10exp4 cells/mL (mean value) after 72 hours. Thus, algal growth in the control was sufficiently high under the test conditions.

The 48-h acute toxicity to invertebrates was studied under static conditions according to OECD Guideline 202, adopted April 4, 1984 and EU method C-2, adopted September 19, 1984. Daphnids were exposed at nominal concentrations of 0 (control), 5.6, 10, 18, 32, 56, and 100 mg/L for 48 hours. Based on immobilization, the 24-h EC₅₀ was 38.0 mg/L with 95 % confidence interval ranging from 29.8 to 51.8 mg/L, and the 48-h EC₅₀ was 26.3 mg/L with 95 % confidence interval ranging from 22.8 to 32.2 mg/L. The 48–h NOEC based on immobilization was 10 mg/L. 

In a 96-h acute toxicity study according to OECD Guideline 203, adopted April 4, 1984 and EU method C-1, adopted September, 1984, carp (Cyprinus carpio) were exposed at nominal concentrations of 0 (control), 97, 174, 309, 541, and 1010 mg/L under static conditions. The 96-h LC₅₀ was 409 mg/L (95 % confidence interval: 309 to 541 mg/L). The NOEC value was 309 mg/L, based on mortality. At the next higher tested concentration of 541 mg/L the mortality was 100 %. No other effects besides mortality were observed. 

The toxicity to aerobic wastewater microorganisms of activated sludge was assessed in a 3-h respiration inhibition test according to OECD guideline 209, April 04, 1984 and EU method C11, May 05, 1988. The substance was tested up to and including a nominal concentration of 1000 mg/L which is well above the water solubility limit. In comparison to the inoculum controls, the respiration rate of the activated sludge was not significantly inhibited (< 15 %) at any of the nominal substance concentrations in the range from 10 to 1000 mg/L. Concentrations exceeding 1000 mg/L nominal were not tested. From the appearance of substance "reaction mass of calcium hydrogen phosphonate and dialuminium tricalcium hexaoxide" (90 - 95 % a.i.) in the final test medium, an obvious excess of test article on the surface of the test media was present at 100, 320, and 1000 mg/L. At the two lower concentrations of 32 and 10 mg/L, white suspensions were noted. Thus, the saturation concentration (equilibrium) under the present test conditions was reached. The 3-h EC₂₀ and EC₅₀ are clearly higher than the limit of water solubility under the present test conditions, or > 1000 mg/L nominal. From the results of this test it can be stated that the substance poses no hazard to the microbiological activity in sewage treatment plants.

Chronic aquatic toxicity

No data are available for the long-term toxicity to invertebrates or fish for these substances. Algal studies report both acute and chronic endpoints and therefore the data collected from the algal growth inhibition study will be used to provide chronic data for this trophic level.

The NOEC, LOEC, EC50, and EC10 values based on measured concentrations and growth rate µ were 8.6 (nominal 10), 21.6 (nominal 32), 19.9 (nominal 28.9), and 14.6 (nominal 19.7) mg/L, respectively.

ECHA REACH TGD R.7b (2017) states that chronic aquatic ecotoxicity testing may be triggered if the CSA indicates that there is a need to investigate further the effects on the environment. Testing may be triggered if additional testing could alter the conclusions on classification, PBT assessment or the level of concern.

Reliable, relevant and adequate acute studies according to the respective OECD Guidelines and EU methods are available for fish and aquatic invertebrates. The 96-h LC50 for carp (Cyprinus carpio) is 409 mg/L (95 % confidence interval: 309 to 541 mg/L). The test was run by adding 97, 174, 309, 541, and 1010 mg/L. The 48-h EC50 for daphnia magna is 26.3 mg/L with 95 % confidence interval ranging from 22.8 to 32.2 mg/L. The test was run by adding 5.6, 10, 18, 32, 56, 100 mg/L. Noticed toxicity for fish and invertebrates at>541 mg/L and>18 mg/L, respectively, was most probably triggered by a pH effect. Dissociation of the reaction mass under the conditions of OECD Guidelines 112 or 105, resulted in an pKa of 10.1 and pH of 11.4, respectively. The substance does only comprise of common environmental elements – calcium, phosphate and aluminium. A temporary pH effect as toxicodynamic reason for aquatic toxicity of alkaline substances dissolving in common environmental constituents has been discussed in detail in the EU Risk Assessment on sodium hydroxide and in several OECD HPV SIDS documents on alkaline inorganic substances. In general, natural waters do have a sufficient buffering capacity to overcome this effect (c.f. EU RAR sodium hydroxide, 2007; http://echa.europa.eu/documents/10162/0ded9c53-4082-405b-b09a-e16e57e158af ). Therefore, substance "reaction mass of calcium hydrogen phosphonate and dialuminium tricalcium hexaoxide" is not expected to have a relevant intrinsic toxic activity to aquatic organisms and PNECs were not derived.

Further on, the substance does not fulfill the PB or vPvB criteria. The concept of “biodegradability” has been developed for organic substances and is not applicable to inorganic substances. Notwithstanding, for classification of chronic aquatic effects and the PBT assessment information on degradation is needed. As a surrogate approach for assessing “degradability” of inorganic substances, the concept of “removal from the water column” has been developed to assess whether or not a respective metal ion, or inorganic substance would remain present in the water column upon addition (and thus, be able to exert a chronic effect) or would be rapidly removed from the water column. In this concept, “rapid removal” (defined as >70 % removal within 28 days) can be considered equivalent to “rapid degradation”. For structurally related substances to substance "reaction mass of calcium hydrogen phosphonate and dialuminium tricalcium hexaoxide" - so called nanoclays - the environmental fate has been assessed on behalf of a national authority. In consideration of this assessment, most probably, if released to the environment, the inorganic, sparingly soluble crystalline solid of lamellar clay mineral (hydrocalumite)-like substance will end up in the sediment or soil compartment by sedimentation comparable to natural clay minerals. This fate is not expected to result in any negative environmental impact (c.f. G.E. Batley and M.J. McLaughlin CSIRO Niche Manufacturing Flagship Report, Fate of Manufactured Nanomaterials in the Australian Environment, prepared for the Australian Department of the Environment, Water, Heritage and the Arts (March 2010), available via Internet available via Internet (https://www.environment.gov.au/system/files/pages/371475a0-2195-496d-91b2-0a33f9342a6d/files/manufactured-nanomaterials.pdf).

Transformation by normal environmental processes (e.g. diagenesis or dissolution) is not expected to result in any negative environmental impact either, as the substance does only comprise of nonhazardous common environmental elements. Calcium and phosphate are essential for almost all living organisms including fresh- and saltwater organisms and natural constituents of their habitats. Aluminium as most abundant metallic element of the earth´s crust, and thus together with the further moieties of the reaction mass also a natural component in environmental habitats. Thus, "reaction mass of calcium hydrogen phosphonate and dialuminium tricalcium hexaoxide" is considered as equivalent to being ‘rapidly degradable‘ in the context of classification for chronic aquatic effects and the PBT assessment. Based on the physicochemical properties, substance "reaction mass of calcium hydrogen phosphonate and dialuminium tricalcium hexaoxide" can be expected not to have a relevant potential for bioaccumulation at all. Data on partition coefficient n-octanol/water are not available as the substance is inorganic. However, measurement of solubility in standard fat HB 307 indicates on missing affinity to organic material. Further on, if dissoluted in water, the dissoluted moieties - calcium, phosphate, aluminium - are not considered to be bioaccumulative. As normal constituents of aquatic organisms they are effectively processed and regulated in the body by natural physiological mechanisms.

Furthermore, the use of the substance on workplaces is controlled and widespread exposure to the environment is not expected. In service life, the substance is embedded in polymer matrices from which there is no release of substance “reaction mass of calcium hydrogen phosphonate and dialuminium tricalcium hexaoxide”.

In conclusion, substance "reaction mass of calcium hydrogen phosphonate and dialuminium tricalcium hexaoxide" is not classified for aquatic toxicity and not considered to be PBT/vPvB. Additional chronic testing is not required to refine this assessment. Further long-term toxicity testing on aquatic invertebrates and/or fish is therefore not triggered and this data requirements are waived in accordance with REACH Regulation, Annex IX, 9.1.5 and 9.1.6, column 2.

Sediment toxicity

No data are available for the toxicity to sediment organisms.

Data on toxicity to sediment organisms is not a data requirement at the registered tonnage band. The dissociation of the substance in water will result in common environmental constituents - calcium, aluminium, phosphate. Calcium and phosphate are essential for almost all living organisms including sediment organisms and natural constituents of their habitats. Aluminium as most abundant metallic element of the earth´s crust, is also a natural component in environmental habitats. Therefore, the substance is not expected to have a relevant intrinsic toxic activity to sediment organisms. Furthermore, the use of the substance on workplaces is controlled and widespread exposure to the environment is not expected. In service life, the substance is embedded in polymer matrices from which there is no release of substance "reaction mass of calcium hydrogen phosphonate and dialuminium tricalcium hexaoxide". Sediment exposure to the substance is unlikely. In addition, substance "reaction mass of calcium hydrogen phosphonate and dialuminium tricalcium hexaoxide" is an inorganic, sparingly soluble crystalline solid of lamellar clay mineral (hydrocalumite) -like substance. Although, if released to the environment, the substance most probably will end up in the sediment or soil compartment by sedimentation comparable to natural clay minerals, this fate is not expected to result in any negative environmental impact (c. f. G. E. Batley and M. J. McLaughlin CSIRO Niche Manufacturing Flagship Report, Fate of Manufactured Nanomaterials in the Australian Environment, prepared for the Australian Department of the Environment, Water, Heritage and the Arts (March 2010), available via Internet https://www.environment.gov.au/system/files/pages/371475a0-2195-496d-91b2-0a33f9342a6d/files/manufactured-nanomaterials.pdf).

In accordance with REACH Regulation, Annex X, 9.5.1, column 2 as well as Annex XI, 1., the performance of sediment toxicity studies is not justified due to exposure as well as toxicological considerations.