Silicomanganese manufacturing fumes dedusting solid residues

Additional information on environmental fate and behaviour

Administrative data

Endpoint:

additional information on environmental fate and behaviour

Type of information:

experimental study

Adequacy of study:

key study

Study period:

The study was conducted between 15 January 2015 and 30 June 2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2015

Report date:

2015

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: OECD Environment, Health and Safety Publications, Series on Testing and Assessment, No.29, Environment Directorate, OECD, April 2011; Annex 10, Guidance on Transformation/Dissolution of Metals and Metal Compounds in Aqueous Media

Deviations:

yes

Remarks:

See 'Deviations from study plan' comments in overall remarks section

GLP compliance:

yes (incl. QA statement)

Type of study / information:

The purpose of this study is to evaluate the transformation/dissolution of the test item in aqueous media.

Test material

Test material information

Constituent 1

Reference substance name:

Silicomanganese manufacturing fumes dedusting solid residues

EC Number:

930-776-4

IUPAC Name:

Silicomanganese manufacturing fumes dedusting solid residues

Test material form:

other: granular solid

Details on test material:

Identification: SiMn fumes
Appearance/Physical State: Dark brown granular solid
Batch: 04042012
Purity: Not supplied
Expiry / Retest Date: Not supplied
Storage Conditions: Room temperature, in the dark

Results and discussion

Any other information on results incl. tables

Screening Test:

The pH, dissolved oxygen content and TOC of the aqueous media prior to addition of test item are shown in the following table:

Control Sample	pH	Dissolved Oxygen (mg/L)	TOC (mg/L)
pH 5.5 Control	5.45	8.71	1.14
pH 6.0 Control	6.01	8.54	0.547
pH 7.0 Control	7.02	8.53	1.49
pH 8.5 Control	8.47	8.54	0.912

Results summary (screening test):

The concentrations of dissolved silicon and manganese in the aqueous media at a single loading of 100 mg/L shaken over a period of 24 hours are shown in the following table:

Aqueous Media	Mean Concentration (mg/L)
	Silicon	Manganese
pH 5.5	0.426	2.56 x 10^-2
pH 6.0	0.410	1.68 x 10^-2
pH 7.0	0.451	0.288
pH 8.5	0.301	6.57 x 10^-2

 

Full Test - 28 Day:

The pH, dissolved oxygen content and TOC of the aqueous media prior to testing are shown in the following table:

Control Sample	pH	Dissolved Oxygen (mg/L)	TOC (mg/L)
pH 5.5 Control	5.5	8.54	0.867
pH 7.0 Control	7.0	8.52	0.484

The concentrations of silicon and manganese of the control samples are shown in the following table:

Solution	Silicon (mg/L)		Manganese (mg/L)
	Concentration	Mean	Concentration	Mean
pH 5.5 Control 1	5.38 x 10^-3	8.99 x 10^-3	3.32 x 10^-3	3.35 x 10^-3
pH 5.5 Control 2	2.16 x 10^-2		3.41 x 10^-3
pH 5.5 Control 3	None detected		3.31 x 10^-3
pH 7.0 Control 1	None detected	None detected	None detected	None detected
pH 7.0 Control 2	None detected		None detected
pH 7.0 Control 3	None detected		None detected

 

The pH, dissolved oxygen, and temperature of the sample solutions after 28 days shaking are shown in the following table:

                                         

Sample	pH	Dissolved Oxygen (mg/L)	Temperature (°C)
pH 5.5 Sample 1	6.2	7.53	24.1
pH 5.5 Sample 2	3.9	8.17	24.1
pH 5.5 Sample 3	4.4	8.14	24.1
pH 7.0 Sample 1	4.7	8.11	24.2
pH 7.0 Sample 2	3.7	7.97	24.2
pH 7.0 Sample 3	3.6	8.02	24.2

The concentrations of dissolved silicon and manganese in pH 5.5 and pH 7.0 aqueous media at a loading of 1 mg/L, shaken over a period of 28 days are shown in the following table:

Solution	Silicon (mg/L)			Manganese (mg/L)
	Conc	Mean	Mean Corrected for Control	Conc	Mean	Mean Corrected for Control
pH 5.5 Control	None detected	-	-	None detected	-	-
pH 5.5 Sample 1A	4.45 x 10^-2	5.43 x 10^-2	5.43 x 10^-2	6.15 x 10^-2	6.16 x 10^-2	6.16 x 10^-2
pH 5.5 Sample 1B	6.41 x 10^-2			6.17 x 10^-2
pH 5.5 Sample 2A	0.173	0.170	0.170	8.60 x 10^-2	8.55 x 10^-2	8.55 x 10^-2
pH 5.5 Sample 2B	0.167			8.50 x 10^-2
pH 5.5 Sample 3A	7.48 x 10^-2	6.48 x 10^-2	6.48 x 10^-2	0.115	0.115	0.115
pH 5.5 Sample 3B	5.49 x 10^-2			0.115
pH 7.0 Control	None detected	-	-	None detected	-	-
pH 7.0 Sample 1A	0.231	0.236	0.236	0.114	0.114	0.114
pH 7.0 Sample 1B	0.241			0.114
pH 7.0 Sample 2A	0.278	0.272	0.272	0.229	0.230	0.230
pH 7.0 Sample 2B	0.266			0.231
pH 7.0 Sample 3A	0.315	0.312	0.312	0.132	0.132	0.132
pH 7.0 Sample 3B	0.309			0.132

 

Results summary (main test):

The concentrations of dissolved silicon and manganese in the aqueous media at a single loading of 1 mg/L shaken over a period of 28 days are shown in the following table:

Aqueous Media	Mean Concentration (mg/L)
	Silicon	Manganese
pH 5.5	9.65 x 10^-2	8.73 x 10^-2
pH 7.0	0.273	0.159

Validation:

Linearity:

The calibration curves for the analyses were second order. The concentrations of each analyte in the sample solutions were interpolated from the respective calibration curve for each analysis.

Precision (Reproducibility):

Five individual samples were prepared in pH 6.0 aqueous media as part of the screening test to determine the precision (reproducibility) of the test. 

Accuracy (Recovery):

The recovery was determined using pH 6.0 aqueous media fortified with analyte (Si and Mn) at two levels; 0.1 and 1.0 mg/L.

Limit of Quantification:

The limit of quantification (LOQ) was based on the lowest validated level of each analyte.

Limit of Detection:

The limit of detection (LOD) was based on the background equivalent concentration (BEC) for calibration curves used for the accuracy (recovery) analysis.

Results:

The results of the method validation in support of the analysis are shown in the following table:

Parameter	Analyte
	Silicon	Manganese
Linearity	2^ndorder response	2^ndorder response
Precision (reproducibility)
Mean Concentration (mg/L)	0.410	1.68 x 10^-2
RSD (%)	5.45	11.8
Accuracy (% recovery):
Fortification at 0.1 mg/L	117	98.3
Fortification at 1.0 mg/L	105	110
Limit of Quantification (mg/L)	0.10	0.10
Limit of Detection (mg/L)	2.6 x 10^-2	5.9 x 10^-2

Discussion:

Accuracy data obtained for the silicon and manganese analyses were acceptable at levels of 0.10 mg/L and 1.0 mg/L. 

Precision (reproducibility) data obtained for the silicon and manganese analyses were acceptable using pH 6 aqueous media. This demonstrated that inter-vessel variation is <20% for both silicon and manganese, indicating that duplicate samples from triplicate vessels is sufficient to give a representative result for the main test.

No specificity testing was possible due to the non-chromatographic nature of the method. The method (ICP-MS) was an elemental method that quantified each analyte through the intensity of a specific, discrete wavelength which resulted from the transition of gaseous atoms between excitation states.

Conclusion:

The analytical method for the determination of silicon and manganese in the aqueous media has been validated with the respect to accuracy (recovery), precision (reproducibility), limit of detection and limit of quantification. The results of the validation demonstrated that the method was acceptable for the study.

Applicant's summary and conclusion

Conclusions:

The concentrations of dissolved silicon and manganese observed in the main test (28-day: 1 mg/L) are:

Aqueous media pH 5.5:
Silicon concentration: 9.65 x 10-2 mg/L
Manganese Concentration: 8.73 x 10-2 mg/L

Aqueous media pH 7.0:
Silicon concentration: 0.273 mg/L
Manganese Concentration: 0.159 mg/L