Magnesium potassium fluoride silicate (Mg2.7K0.7Si4O10F2)

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Cross-reference

Reason / purpose for cross-reference:

data waiving: supporting information

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

20 Nov 2018 - 20 Dec 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Deviations:

not specified

GLP compliance:

yes

Type of method:

flask method

Specific details on test material used for the study:

Chemical name: Magnesium potassium fluoride silicate (Mg2.7K0.7Si4O10F2)
Previously known as: magnesium potassium silicon fluoride hydroxide oxide, and referenced as CAS number 273730-58-8
Trade name: MICROMICA
Composition formula: K₀.₇Mg₂.₇Si₄O₁₀F₂
Molecular weight: 403.33 g/mol
Purity of test item: ≥95%
Impurity: <5% water
Lot number: 776A

Key result

Water solubility:

ca. 1.02 mg/L

Conc. based on:

element (dissolved fraction)

Remarks:

total silcon content

Loading of aqueous phase:

1 g/L

Incubation duration:

>= 6 - <= 8 d

Temp.:

20 °C

pH:

ca. 6.6

Agitation period (days)	Sample	pH	Measured silicon content of the test solution (mg/L)	Concentration of test item in test solution* (mg/L)		Maximum measured difference (%)
					Mean
4	1a	6.3	0.194	0.731	-	24.6	-	-
	1b	6.3	0.195	0.732
5	2a	6.7	0.226	0.849			22.1
	2b	6.5	0.225	0.845
6	3a	6.6	0.246	0.924	1.02			14.9
	3b	6.6	0.258	0.970
7	4a	6.3	0.283	1.06		-
	4b	6.3	0.289	1.09
8	5a	6.8	0.278	1.05			-
	5b	6.9	0.281	1.05

*The silicon content of the test item was 26.6% so the measured silicon content of the test solution was multiplied by 3.76 (100/26.6) to calculate the concentration of test item in test solution.

As the maximum difference in silicon content between test solutions 3, 4 and 5 (a and b) was less than 15% (14.9%), it was judged that the silicon concentrations of these test solution reached equilibrium and are therefore valid. Samples 1 and 2 (a and b) are discounted.

Conclusions:

Aqueous samples, with a 1 g/L loading, were incubated for 6, 7 and 8 days at 30 °C and silicon content measured via ICP-AES. As the silicon content of the test item was 26.6%, the aqueous solubility of the test item was determined to be 1.02 mg/L at 20 °C.

Executive summary:

The aqueous solubility of the test item was measured in a GLP study performed using method OECD 105. Aqueous samples, with a 1 g/L loading, were incubated for 6, 7 and 8 days at 30 °C and silicon content measured via ICP-AES. As the silicon content of the test item was 26.6%, the aqueous solubility of the test item was determined to be 1.02 mg/L at 20 °C.