reaction mass of calcium bis(dihydrogenorthophosphate) and calcium hydrogenorthophosphate

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

Derivation of PNECs for sodium, potassium, calcium and magnesium orthophosphates:

 

READ-ACROSS

 

The following substances are considered to be similar enough to facilitate read-across for aquatic toxicity and subsequently for the derivation of PNEC’s:

 

Sodium and potassium orthophosphates:

 

Sodium dihydrogenorthophosphate

Disodium hydrogen phosphate

Trisodium orthophosphate

Potassium dihydrogenorthophosphate

Dipotassium hydrogenorthophosphate

Tripotassium orthophosphate

Potassium pentahydrogen bis(phosphate)

Tripotassium trihydrogen diphosphate dihydrate.

 

Calcium and magnesium orthophosphates:

 

Calcium bis(dihydrogenorthophosphate)

Calcium hydrogen orthophosphate

Tricalcium bis(orthophosphate)

Tricalcium phosphate

Magnesium hydrogenorthophosphate

Trimagnesium bis(orthophosphate)

Magnesium bisdihydrogenorthophosphate

 

All members of the group are structurally similar ionic inorganic compounds with the anion only changing by the number of hydrogen atoms to account for changes in charge due to increase in cation numbers.

Progression through each group sees an increase in cation number from one to three followed by a change in cation.

Cations are group 1 alkali metals sodium and potassium and group 2 alkaline earth metals calcium and magnesium. Na and K are in the +1 ionic state and Ca and Mg are in the +2 state. All cations are ubiquitous in natural waters and therefore the different cations are not considered to be of relevance for assessing the ecotoxicity of the aforementioned substances. The strategy is therefore designed to asses the toxicity of the phosphate ion.

 

All potassium and sodium orthophosphates are highly soluble and therefore represent a worst case in terms of bioavailability in natural waters. The magnesium and calcium orthophosphates are less soluble but are expected to dissociate to the ionic forms in water and therefore the toxicity results can be read across on the basis that all cations (Na+, K+, Ca2+ and Mg2+) are abundant in natural waters and are unlikely to contribute to toxicity.

 

The aforementioned substances differ in their acid or alkaline nature when dissolved in water, with pH values ranging from ca. pH3 to pH >14.These pH differences are not expected to be manifest in the natural environment, because of dilution and pH buffering by other compounds resulting in an ambient pH not dependent on the phosphate compound and therefore when taking in to account the substance to be tested; it was decided to test one which results in a solution of around pH 7 and therefore any pH-related effects will be discounted.

 

  

 

 

 

 

Data relevant for the derivation of PNECs:

 

1. Short-term toxicity to fish (Reliability 2, GLP):LC₅₀= 100 mg/L substance tested = tripotassium trihydrogen diphosphate dihydrate

 

2. Short-term toxicity to daphnia (Reliability 2, GLP):LC₅₀= 100 mg/L substance tested = tripotassium trihydrogen diphosphate dihydrate

 

3. Algal growth inhibition study (Reliability 2, GLP):EC₅₀= 100 mg/L substance tested = tripotassium trihydrogen diphosphate dihydrate

 

4. ASRI: (Reliability 2, GLP):EC₅₀= 1000 mg/L , substance tested = dipotassium hydrogenorthophosphate

 

 

 

PNEC_{aqua (freshwater)}

 

• Assessment factors:

Use of short-term data only	1000
Use of data on analogous substance (read-across)	2
TOTAL	2000

 

• Lowest value from short-term studies: 100 mg/L

 

PNEC_{aq freshwater}= 100/2000 = 0.05

 

No long-term toxicity studies are available and therefore the PNEC is based on the lowest value from the short-term studies (100 mg/L), the assessment factor used takes the use of short-term data and read-across data into account. (AF for use of short-term data = 1000, AF for use of data on an analogue material = 2. Overall AF = 2000)

 

 

 

 

PNEC_{aqua (marine)}

 

• Assessment factors:

Use of short-term data only	10000
Use of data on analogous substance (read-across)	2
TOTAL	20000

 

• Lowest value from short-term studies: 100 mg/L

 

 

PNEC_{aq marine}= 100/20000 =0.005mg/L

 

No reliable studies are available on marine species. The PNEC is therefore based on the short-term studies conducted on freshwater species.The assessment factor used takes the use of short-term data in freshwater species and read-across data into account. (AF for use of short-term freshwater data = 10000, AF for use of data on an analogue material = 2. Overall AF = 20000)

 

 

 

PNEC_{intermittent release}

 

• Assessment factors:

Use of short-term data only	100
Use of data on analogous substance (read-across)	2
TOTAL	200

• Lowest value from short-term studies: 100 mg/L

 

 

PNEC_{intermittent release}= 100/200 =0.5 mg/L

 

The PNEC is based on the lowest value from the short-term studies (100 mg/L), the assessment factor used takes the use of read-across data into account. (AF for intermittent release = 100, AF for use of data on an analogue material = 2. Overall AF = 200)

 

 

 PNEC_stp

·        Assessment factors:

 

Standard AF for use with NOEC from ASRI study	10
Use of data on analogous substance (read-across) [not relevant for dipotassium hydrogenorthophosphate]	2
TOTAL	20

 

·        NOEC from ASRI study : 1000 mg/L

 

 

Calculated for read across substances and for tested substance (dipotassium hydrogenorthophosphate)

 

READ ACROSS:

 

PNEC_stp= 1000/20 =50 mg/L

 

DIPOTASSIUM HYDROGENORTHOPHOSPHATE:

 

PNEC_stp= 1000/10 =100 mg/L

 

 

The PNEC is based on the NOEC from the ASRI study. The assessment factor used takes the use of read-across data into account and uses the assessment factor appropriate for use of a NOEC value. (AF for use of NOEC = 10, AF for use of data on an analogue material = 2. Overall AF = 20)

 

 

PNEC_{freshwater sediment}

 

No data is available for freshwater sediments. Na⁺, K⁺, Mg²⁺, Ca²⁺and PO4^3- ions are ubiquitous in the environment and are found naturally in soil, water and sediment. All are assimilated by species residing in the sediment, water or soil and are essential for maintaining a good chemical balance. It is therefore unlikely that inorganic phosphates of this nature would be toxic to sediment organisms and hence toxicity studies are scientifically unjustified.

 

PNEC_{marine sediment}

No data is available for marine sediments. Na⁺, K⁺, Mg²⁺, Ca²⁺and PO4^3- ions are ubiquitous in the environment and are found naturally in soil, water and sediment. All are assimilated by species residing in the sediment, water or soil and are essential for maintaining a good chemical balance. It is therefore unlikely that inorganic phosphates of this nature would be toxic to sediment organisms and hence toxicity studies are scientifically unjustified.

 

 

 

PNEC_soil

 

No data is available for soil macroorganisms. Na⁺, K⁺, Mg²⁺, Ca²⁺and PO4^3- ions are ubiquitous in the environment and are found naturally in soil, water and sediment. All are assimilated by species residing in the sediment, water or soil and are essential for maintaining a good chemical balance. Furthermore inorganic phosphate fertilizers (containing Na⁺, K⁺, Mg²⁺, Ca²⁺and PO4^3- ions) are often added to soils to improve soil quality. Given the extensive use of inorganic phosphates as soil fertilizers and the natural occurrence of the ions in the environment it is unlikely that inorganic phosphates of this nature would have a detrimental effect on soil macroorganisms and plants and hence toxicity studies are scientifically unjustified.

 

 

PNEC_oral

 

Inorganic phosphates are not considered to pose a risk of secondary poisoning as they are unlikely to bioaccumulate due to the fact that they are not lipophillic and will therefore not accumulate in fatty tissues. It not considered necessary to derive a PNEC to take into account the risk of secondary poisoning and no further testing is considered necessary.

Conclusion on classification

The following substances are not considered to pose a risk to the environment and as such are neither classified as harmful nor dangerous to the environment, in accordance with Regulation (EC) No. 1272/2008 (EU CLP):

 

Sodium and potassium orthophosphates:

 

Sodium dihydrogenorthophosphate

Disodium hydrogen phosphate

Trisodium orthophosphate

Potassium dihydrogenorthophosphate

Dipotsasium hydrogenorthophosphate

Tripotassium orthophosphate

Potassium pentahydrogen bis(phosphate)

Tripotassium trihydrogen diphosphate dihydrate.

 

Calcium and magnesium orthophosphates:

 

Calcium bis(dihydrogenorthophosphate)

Calcium hydrogen orthophosphate

Tricalcium bis(orthophosphate)

Tricalcium phosphate

Magnesium hydrogenorthophosphate

Trimagnesium bis(orthophosphate)

Magnesium bis(dihydrogenorthophosphate)