Reaction mass of diisobutyl hydrogen phosphate and isobutyl dihydrogen phosphate

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

no hazard identified

Marine water

Hazard assessment conclusion:

no hazard identified

STP

Hazard assessment conclusion:

no hazard identified

Sediment (freshwater)

Hazard assessment conclusion:

no hazard identified

Sediment (marine water)

Hazard assessment conclusion:

no hazard identified

Hazard for air

Air

Hazard assessment conclusion:

no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:

no hazard identified

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

no potential for bioaccumulation

Additional information

The short term toxicity of the reaction mass (IBAP) on aquatic organisms is assessed by using a read-across with its potassium salt. The main assumption is that the potassium cation is not significant in respect of the toxicological effect on aquatic organisms which are expected to be related to the IBAP. In experimental dilute aqueous conditions at environmental pH (5-9), the salt will be completely dissociated and will not behave differently to the parent acid, at identical concentration of the particular speciated form present.

One reliable key study performed according to standard guidelines and under GLP is available for all the trophic levels (algae, invertebrates, fish and micro-organisms). The test item was a potassium salt of the reaction mass having a similar composition than the target substance and no toxic effects were measured on any of the organisms. The 96h LC50 for fish, 72h ErC50 for algae and 48h EC50 for daphnids are above 100mg/L and the 3h EC50 for micro-organisms in STP is above 1000 mg/L.

The 72h NOErC for the algae was determinate at 100 mg/L, the highest concentration tested. Due to the absence of any effect on any of the tested organisms in the acute tests, the long-term toxicity of registered substance to aquatic organisms was not further investigated.

Therefore, as no acute effect was identified on these organisms and no chronic data are available on fish or the invertebrates, no PNECs for pelagic aquatic organisms were derived.

In the absence of both sediment organisms’ data and a PNEC for pelagic organisms, no PNEC sediment could be derived. However, the reaction massis highly soluble in water and does not have potential for adsorption so it will be found mainly in pore water. The equilibrium partitioning method is based on the assumption that, the sensitivity of pelagic and sediment organisms is comparable therefore in the absence of toxicity on aquatic organisms, toxicity on sediment organisms is unlikely to occur.

In the absence of both terrestrial organisms data and a PNEC for pelagic organisms, no PNEC soil could be derived. However, the reaction mass is highly soluble in water and does not have potential for adsorption so it will be found mainly in pore water. The equilibrium partitioning method is based on the assumption that, the sensitivity of pelagic and terrestrial organisms is comparable therefore in the absence of toxicity on aquatic organisms, toxicity on terrestrial organisms is unlikely to occur.

No data were available for the air compartment however due to the low volatilization potential of the reaction mass, this compartment is not consider of concern and no PNEC was derived.

No data was available for secondary poisoning assessment but the reaction mass has a low potential for adsorption, a low partition coefficient and is highly soluble in water, therefore no potential for bioaccumulation is expected.

Conclusion on classification

The short term toxicity of the reaction mass (IBAP) on aquatic organisms is assessed by using a read-across with its potassium salt. The main assumption is that the potassium cation is not significant in respect of the toxicological effect on aquatic organisms which are expected to be related to the IBAP. In experimental dilute aqueous conditions at environmental pH (5-9), the salt will be completely dissociated and will not behave differently to the parent acid, at identical concentration of the particular speciated form present.

One reliable key study performed according to standard guidelines and under GLP are available for all the trophic levels (algae, daphnids, fish). The test item was a potassium salt of the reaction mass having a similar composition than the target substance and no toxic effects were measured on any of the organisms. For the purpose of classification and labeling, the concentrations were not corrected for the target substance because the molecular weight of potassium was assessed to be negligible compared to the molecular weight of the other constituents of the reaction mass.

The following toxicity values are available for the substance:

Fish Acute: 96h-LC50 > 100 mg/L (based on nominal concentration, limit test)

Aquatic invertebrates: 48h-EC50 > 100 mg/L (based on nominal concentration)

Algae: 72h-ErC50 > 100 mg/L (based on nominal concentration)

No toxicity effects are observed in these studies and all acute aquatic toxicity values are higher than 100 mg/L.

Except the 72h NOErC of 100 mg/L (the highest concentration tested) for the algae, the long-term toxicity of registered substance to aquatic organisms was not further investigated.

The degradation of the reaction mass was assessed by reliable tests performed according to OECD Guidelines under GLP:

The two main constituents, the mono-ester and the di-ester, were found stable to hydrolysis at all pHs: DT50> 1 year (according to OECD 111).

The registered reaction mass was found not readily biodegradable (0% of biodegradation at Day 28 based on O2 consumption) under the conditions of a close bottle test (according to OECD Guideline 301D).

Therefore, the substance is considered as not rapidly degradable in aquatic system.

Information on bioaccumulation potential of the registered reaction mass:

No fish BCF is available.

Log Kow ranges between < -1.83 and -1.67 based on experimental values for the two main constituents, the mono-ester and the di-ester (according to OECD guideline).

Log Koc ranges between 1.15 and 2.21 based on calculated values for the two main constituents, the mono-ester and the di-ester (with KOCWIN).

The reaction mass is highly soluble based on the experimental values for the two mains constituents, the mono-ester and the di-ester, determinated according to the OECD guideline.

All these data indicate a low potential for bioaccumulation.

CLP Classification proposal according to CLP environmental criteria laid down in CLP Regulation (including 2nd Adaptation to Technical Progress, Com Reg No 286/2011):

Acute aquatic hazard: not classified based on acute aquatic toxicity higher than 100 mg/L.

Chronic aquatic hazard: not classified based on adequate chronic toxicity data on algae above 1 mg/L (NOErC > 100 mg/L), acute E(L) C50 higher than 100 mg/L, non-rapidly degradable substance, no potential of bioaccumulation and readily soluble. The determination of M-Factor is not applicable.

DSD Classification proposal:

Not classified based on acute E(L) C50 higher than 100 mg/L, non-readily biodegradable substance, not potentially bioaccumulable and readily soluble.