The product from the burning of a combination of carbonaceous materials.

Water solubility

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

transformation / dissolution of metals and inorganic metal compounds

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

April 2010

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: non-GLP, guideline analysis

Qualifier:

according to guideline

Guideline:

other: SFS-EN 12457-3. Characterisation of waste. Leaching. Compliance test for leaching of granular waste materials and sludges.

Deviations:

no

GLP compliance:

no

Type of method:

other: Leaching test; two-stage shaking test

Type of test:

other: Two-stage shaking test

Mean dissolved conc.:

77 other: mg/kg (dw)

Element analysed:

Barium

Incubation duration:

8 h

Type of test:

other: Two- stage shaking test/SFS-EN 12506, ISO 11885

Mean dissolved conc.:

23 other: mg/kg (dw)

Element analysed:

Barium

Incubation duration:

6 h

Details on results:

Barium was found to be the most leachable metal. Molybdenium, lead, selenium and zinc leached to a minor extent. Of heavy metals, lead leached in detectable amount. The most leachable ions were chloride and sulphate, of which chloride leached ten times more than sulphate. Some Dissolved Organic Carbon was found in the leachate.

Table 2. Results and uncertainties of the leaching test.

Element	Unit	Result L/S 2	Result L/S 10 (cumulative)	Expanded Uncertainty (95% confidence)	Method	Remarks
Arsenic, As	mg/kg (d.w.)	<0.03	<0.15	-	SFS-EN 12506, ISO11885 (ICP-OES)	aa
Barium, Ba	mg/kg (d.w.)	23	77	±16%	SFS-EN 12506, ISO11885 (ICP-OES)	aa
Cadmium, Cd	mg/kg (d.w.)	<0.003	<0.015	-	SFS-EN 12506, ISO11885 (ICP-OES)	aa
Cobalt, Co	mg/kg (d.w.)	<0.01	<0.05	-	SFS-EN 12506, ISO11885 (ICP-OES)	aa
Chromium, Cr	mg/kg (d.w.)	<0.02	<0.1	-	SFS-EN 12506, ISO11885 (ICP-OES)	aa
Copper, Cu	mg/kg (d.w.)	<0.02	<0.1	-	SFS-EN 12506, ISO11885 (ICP-OES)	aa
Molybdenum, Mo	mg/kg (d.w.)	0.042	0.12	±25%	SFS-EN 12506, ISO11885 (ICP-OES)
Nickel, Ni	mg/kg (d.w.)	<0.02	<0.1	-	SFS-EN 12506, ISO11885 (ICP-OES)	aa
Lead, Pb	mg/kg (d.w.)	0.16	0.64	±25%	SFS-EN 12506, ISO11885 (ICP-OES)	aa
Antimony, Sb	mg/kg (d.w.)	<0.01	<0.05	-	ISO11885 (ICP-OES), GFAAS	aa,**
Selenium, Se	mg/kg (d.w.)	0.017	0.053	±25%	ISO11885 (ICP-OES), GFAAS	aa,**
Tin, Sn	mg/kg (d.w.)	<0.03	<0.15	-	ISO11885 (ICP-OES)
Vanadium, V	mg/kg (d.w.)	<0.01	<0.05	-	SFS-EN 12506, ISO11885 (ICP-OES)	aa
Zinc, Zn	mg/kg (d.w.)	0.021	0.23	±25%	SFS-EN 12506, ISO11885 (ICP-OES)	aa
Mercury, Hg	mg/kg (d.w.)	<0.001	<0.005	-	SFS-EN 13370, SFS-EN 1483:en (CVAAS)
Fluoride, F^-	mg/kg (d.w.)	<1	<5	-	SFS-EN 13370, SFS-EN 10304-1 and 2 (IC)
Chloride, Cl^-	mg/kg (d.w.)	490	500	±25%	SFS-EN 13370, SFS-EN 10304-1 and 2 (IC)
Sulphate, SO4^2-	mg/kg (d.w.)	<10	<50	-	SFS-EN 13370, SFS-EN 10304-1 and 2 (IC)
DOC	mg/kg (d.w.)	6.8	14	±20%	SFS-EN 13370, SFS-EN 1484	sb
Phenol index	mg/kg (d.w.)	<0.1	<0.5	-	SFS-EN 13370, SFS-EN ISO 14402:en	sb

Concentrations are expressed on a dry weight (d.w.) basis. L / S = liquid to solid ratio. **) = If ICP-OES result is below the method quantitation limit, determination is made using GFAAS. ICP-OES = Inductively coupled plasma optical emission spectrometry. GFAAS = Graphite furnace atomic absorption spectrometry. CVAAS = Cold vapour atomic absorption spectrometry. IC = Ion Chromatography. sb = subcontracted

Conclusions:

The most leachable metal from Ash was barium. Molybdenium, lead, selenium and zinc leached to a minor extent. The most leachable ions were chloride and sulphate, of which chloride leached ten times more than sulphate. Some Dissolved Organic Carbon was found in the leachate.

Executive summary:

Leaching properties of Ash was studied in a non-GLP compliant study according to European standard SFS-EN 12457-3. Ash was homogenised to particle size <4 mm followed by two phase extraction with ultraclean water (18 MΩ/cm, pH 5 - 7.5) in L/S = 2 and L/S = 10. The filtrate was analysed with atomic absorption, ICP-OES and liquid chromatigraphic methods. The most leachable metal from Ash was barium. Molybdenium, lead, selenium and zinc leached to a minor extent. The most leachable ions were chloride and sulphate, of which chloride leached ten times more than sulphate. Some Dissolved Organic Carbon was found in the leachate.

Reference 2

Endpoint:

transformation / dissolution of metals and inorganic metal compounds

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

September 2010

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: non-GLP, non-guideline analysis

Qualifier:

no guideline available

Principles of method if other than guideline:

Acid (pH 4.65) ammonium acetate extraction including analysis with ICP-OES.

GLP compliance:

no

Type of method:

other: Acid ammonium acetate extraction

Type of test:

other: Acetate extraction

Mean dissolved conc.:

2 190 other: mg/kg (d.w.)

Element analysed:

Potassium

Incubation duration:

1 h

Type of test:

other: Acetate extraction

Mean dissolved conc.:

4 470 other: mg/kg (b.w.)

Element analysed:

Silicon

Incubation duration:

1 h

Type of test:

other: Acetate extraction

Mean dissolved conc.:

6 100 other: mg/kg (d.w.)

Element analysed:

Sulphur

Incubation duration:

1 h

Type of test:

other: Acetate extraction

Mean dissolved conc.:

6 170 other: mg/kg (d.w.)

Element analysed:

Magnesium

Incubation duration:

1 h

Type of test:

other: Acetate extraction

Mean dissolved conc.:

158 000 other: mg/kg (d.w.)

Element analysed:

Calcium

Incubation duration:

1 h

Details on results:

The most soluble metal in acidic ammonium acetate was calcium. Other macronutrients, which extracted at higher amounts, were magnesium, sulphur, silicon and potassium. The most extracted trace metals were zinc and copper. Of the most toxic components, lead extracted most followed by nickel, arsenic and cadmium.

Table 1 Acid ammonium acetate soluble elements

Element	Unit	Result
Aluminum	mg/kg (d.w.)	120
Calcium	mg/kg (d.w.)	158000
Iron	mg/kg (d.w.)	5.0
Magnesium	mg/kg (d.w.)	6170
Phosphorus	mg/kg (d.w.)	74
Potassium	mg/kg (d.w.)	2190
Silicon	mg/kg (d.w.)	4470
Sodium	mg/kg (d.w.)	490
Titanium	mg/kg (d.w.)	1.5
Sulphur	mg/kg (d.w.)	6100
Manganese	mg/kg (d.w.)	170
Arsenic	mg/kg (d.w.)	3.5
Barium	mg/kg (d.w.)	69
Cadmium	mg/kg (d.w.)	1.5
Cobalt	mg/kg (d.w.)	0.87
Chromium	mg/kg (d.w.)	3.3
Copper	mg/kg (d.w.)	50
Molybdenium	mg/kg (d.w.)	3.0
Nickel	mg/kg (d.w.)	4.2
Lead	mg/kg (d.w.)	8.3
Antimony	mg/kg (d.w.)	2.4
Selenium	mg/kg (d.w.)	1.5
Vanadium	mg/kg (d.w.)	0.89
Zinc	mg/kg (d.w.)	190
Mercury	mg/kg (d.w.)	<0.1

Conclusions:

The most soluble metal in acidic ammonium acetate was calcium. Other macronutrients, which extracted at higher amounts, were magnesium, sulphur, silicon and potassium. The most extracted trace metals were zinc and copper. Of the most toxic components, lead extracted most followed by nickel, arsenic and cadmium.

Executive summary:

Ammonium acetate soluble metals from Ash were analysed in non-GLP compliant laboratory with a non-guideline method. The aim of this study was to simulate long term leaching properties of metals from Ash. Extraction ratio was 1:10 (V/V) and extraction time was 1 h. pH of the test was 4.65. Before determination, the extract was separated from the solid residue by filtration. The element concentrations of the extracts were determined with inductively coupled plasma optical emission spectrometer (ICP-OES). Of nutriets, calcium was clearly the most extractable element. Also magnesium, sulphur, silicon and potassium obtain remarkable long-term leaching properties, but approx. 25 times less than calcium. Zinc, copper and barium extracted as amounts of over 10 mg/kg (d.w.). Of the most toxic components, lead extracted most followed by nickel, arsenic and cadmium. Mercury was not found to be acidic ammonium acetate soluble element.

Reference 3

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: A non-GLP, guideline analysis with modifications.

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

other: EN 12457-3

Deviations:

yes

Principles of method if other than guideline:

Bottom ash (aged for five years) was studied with sequential batch leaching from L/S 1 to L/S 3 using the modified EN 12457-3 (two stage batch test) method. The modified method included three subsequently steps of leaching at cumulative liquid to solid (L/S) ratios of 1, 2 and 3 L/kg.

GLP compliance:

no

Remarks on result:

other: Results presented in "details of results" section

Details on results:

The validation parameters are shown in Table 7. In the leaching test pH was between 8.0-8.1 in all the leachates. The stabile pH indicates that the material has been well aged during the storing and that hydroxides have been converted to carbonates due to the exposure to air (CO2). Conductivity was found to decrease from 803 to 373 mS/m and redox potential varied between 280 and 315 mV.

Study results are presented in table 8. The ash contained a considerable amount of salts with high solubility, shown by the initial high concentrations of e.g. Na, K and Cl. The highest metal concentrations in leachate L/S 1 were found for Na, Ca, K, Mg and Si. The concentration of Na, K and Cl was reduced by 75 %, 65 % and 90% from L/S 1 to L/S 3, respectively. The concentration of Ca, Al and Zn was stabile during all studied L/S-ratios, while the concentration of Cu was reduced by 50% from L/S 1 to L/S 3. The concentration of DOC decreased simultaneously with decreasing copper concentration (approx. 35% from L/S 1 to L/S 3). Concentrations of Cd and Mn were found to slightly increase from L/S1 to L/S 3. All the studied elements showed high precision; the standard deviation was in general lower or equal to the analytical error of the individual elements.

Table 7. Parameters of validation measured at termination of leaching

Validitetsparametrar	L/S	1	2	3
pH		8.0 (±1%)	8.1 (±1%)	8.1 (±0%)
Ledningsförmåga	mS/m 25 °C	803 (±1%)	506 (±2%)	373 (±5%)
Redox Eh	mV	284 (±3%)	280 (±11%)	315 (±2%)

Table 8. Concentrations of compounds in leachates (sampled at L/S 1, 2 and 3) together with concentrations in solution used for dilution in the ecotox-tests. Samples were filtrated through 0.45 μm pore-filter prior analyses. For comparison, concentrations in natural water sampled at the location Landsortsdjupet in the Baltic See are also shown. This sample is assumed to be comparable with the origin of the water used for dilution (Askö).

Halt i lakvatten vid L/S 1, 2 och 3							Halt i spädningsmedia
		L/S 1 n=2	Stdv %	L/S2 n=2	Stdv %	L/S3	Spädningsmedia* ofiltrerad	Spädnings-media*	Stdv %	Landsort s-djupet**
Metaller
Ca	mg/l	526	2	520	2	525	89	96,8	4	92
Fe	mg/l	<0,007		<0,004		0,005	<0,004	0,0187	112	0,0016
K	mg/l	210	12	114,5	2	77,4	70,2	74,7	13	70,8
Mg	mg/l	62,8	2	44,45	1	38,2	224	237	6	223
Na	mg/l	1435	2	695	0	377	1940	1980	4	1847
Si	mg/l	2,855	3	2,845	3	2,63
Al	μg/l	200,5	1	196,5	5	209	5,68	10,4	50
As	μg/l	3,245	15	<2,7		<1	2,31	2,31	74
Ba	μg/l	42,4	1	32,5	4	29,5	38,4	37,4	2
Cd	μg/l	<0,095		<0,071		0,077	<0,05	<0,05		0,021
Co	μg/l	0,9945	12	0,826	26	0,592	<0,05	0,09	63
Cr	μg/l	6,215	1	3,32	0	2,11	<0,5	0,842	24
Cu	μg/l	79,4	16	50,3	3	39,3	2,67	3,55	13	0,55
Hg	μg/l	<0,02		<0,02		<0,02	<0,02
Mn	μg/l	15,85	2	25	3	27,4	2,5	1,59	82	1,7
Mo	μg/l	221,5	6	174	6	134
Ni	μg/l	5,41	4	5,09	25	3,41	5,86	7,14	25	0,69
Pb	μg/l	0,4115	10	<0,02		0,22	<0,20	0,24	24
Sb	μg/l	37,5	10	24,45	0	18,2
Se	μg/l	3,46	11	1,645	9	0,897
V	μg/l	1,05	0	1,055	6	0,888
Zn	μg/l	27,65	5	26,9	23	26,1	12,8	14,1	16	0,38
Övriga
Cl	mg/l	936	4	337	17	106	4730	3915	19
F	mg/l	<0,2		0,41		<0,2	<0,4
S-tot	mg/l	1220	1	822	12	741	185	188	6	161
SO4	mg/l	3470	5	2500	7	2180	661	550	17
DOC	mg/l	13,3	3	5,855	15	4,43	3,48	4,48	33	3 -5
DIC	mg/l	22,7	1	21,75	7	18,6				2***

*Data för spädmedium hämtad ur rapport av Värmeforsk (2011). Spädmedium är filtrerat och upphettat brackvatten hämtat utanför Stockholms universitets fältstation på Askö.

**Data gällande för Landsortsdjupet från Forsberg (2005) med undantag för DOC där data är hämtade från Österlund (2010) och är representativa för Bottniska viken och Gotlandsdjupet.

*** Förväntad halt i Havsvatten.

Conclusions:

The highest metal concentrations in the first leachate were found for Na, Ca, K, Mg and Si. The concentration of Na, K and Cl was reduced by 75 %, 65 % and 90 % from L/S 1 to L/S 3, respectively. The concentration of Ca, Al and Zn was stabile during all studied L/S-ratios, while the concentration of Cu was reduced by 50% from L/S 1 to L/S 3. The concentration of DOC decreased simultaneously with decreasing copper concentration (approx. 35% from L/S 1 to L/S 3). Concentrations of Cd and Mn were found to slightly increase from L/S1 to L/S 3.

Executive summary:

A modified two stage batch leaching test (EN 12457-3) was used to analyse leaching of metals and salts from 5 -years aged bottom ash in a non-GLP study. Metal analyses were performed for both ash and leachates. The leachates were analyzed for the following elements Ca, Fe, K, Mg, Na, Si, Al, As, Ba, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, Sb, Se, V, Zn (mod. EPA-200.7 and EPA-200.8) and Hg (EN ISO 17852:2008), anions chloride, fluoride, sulphate (mod. EN ISO 10304-1 and EN ISO 10304-2) together with dissolved organic carbon (DOC) and total inorganic carbon (TIC) (EN 1484). The most readily leached metals were Na, Ca, K, Mg and Si. The concentration of Na, K and Cl was reduced by 75 %, 65 % and 90% from L/S 1 to L/S 3, respectively. Of the trace metals, concentrations of Mo and Al were highest in the first eluate (L/S 1). Release of Cd and Mn was slower as their concentration increased during the test. Continuous, more steady leaching was found for Ca, Al and Zn. The concentration of DOC decreased simultaneously with decreasing copper concentration (approx. 35% from L/S 1 to L/S 3). pH was approx. 8 during the different test sequences.

Reference 4

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

other: A non-GLP, non-guideline analysis.

Principles of method if other than guideline:

Analysis of leaching properties of metals from wood, peat, mixed biofuel and Recycled Fuel (REF) ashes originating from four different types of power plants. The used liquid-solid fractions were L/S 2 and 10.

GLP compliance:

no

Remarks on result:

other: Detailed results are presented in "Details of results" section

Details on results:

Limit values of As, Cd, Cr, Cu, Mo, Pb, Sb, Zn or Sulphate for unpaved and paved constructions were not exeeded.

Table 1 presents leaching properties of different ashes produced with different kind of fuels (mg/kg). Limit values for utilisation presented in the table 2 are not exceeded in the studied ashes (Table 1).

Table 1. Leaching properties of selected metals (i.e. critical components, see Environmental fate properties) from different ashes produced with different kind of fuels (mg/kg).

Sample	REF; Grate firing	REF; Grate firing (washed)	REF; BFC bottom ash	REF; BFC fly ash	Mixed biofuel; BFC bottom ash	Mixed biofuel; BFC fly ash	Mixed biofuel, incl. REF; BFC bottom ash	Mixed biofuel, incl. REF; BFC fly ash	Limit value of utilisation I	Limit value of utilisation II
	L/S2 / L/S10	L/S2 / L/S10	L/S2 / L/S10	L/S2 / L/S10	L/S2 / L/S10	L/S2 / L/S10	L/S2 / L/S10	L/S2 / L/S10	L/S10	L/S10
pH	9.5 / 10.2	9.7 / 10.5	11.2 / 11.8	11.0 / 11.5	11.1 / 11.1	12.1 / 11.7	11.6 / 11.4	12.7 / 12.5
Conductivity	560 / 55	79 / 19	176 / 195	2570 / 290	48 / 39	499 / 138	104 / 70	1497 / 719
As				<0.02 / <0.2					0.14	0.85
Cd				<0.02 / <0.02	<0.02 / <0.02	<0.02 / <0.02			0.011	0.015
Cu	0.02 / 0.1	<0.02 / <0.1	<0.02 / <0.1	<0.02 / <0.1	<0.02 / <0.1	<0.02 / <0.1			1.1	2.0
Pb					<0.02 / <0.1	<0.02 / <0.1			1.0	1.8
Sb				<0.06 / 0.2			0.05 / 0.14	<0.01 / <0.05	0.12	0.4
Sulphate				130 / 340					1500

BFC = Bubbling Bed Combustion

REF = Recovered Fuel

Limit value I for unpaved constructions, limit value II for paved constructions (Mroueh et al. 2000).

Table 2. Minor (mg/kg) and major (%) components in ashes related to Table 1.

Minor (mg/kg)	Wood ash	Peat ash	REF; Grate firing	REF; BFC bottom ash	REF; BFC fly ash	Mixed biofuel; BFC bottom ash	Mixed biofuel; BFC fly ash	Mixed biofuel, incl. REF; BFC bottom ash	Mixed biofuel, incl. REF; BFC fly ash
Sb	N/A	N/A	12	27	94	N/A	N/A	N/A	N/A
As	0.2-60	31-116	40	21	51	<30	<30	<30	<50
Cd	0.4-40	0.5-5	3.9	0.05	15	<10	<10	<10	<10
Cr	40-250	43-130	150	120	230	22	63	48	100
Cu	15-300	60-160	850	1200	2200	29	120	120	180
Pb	15-1000	160-970	93	55	790	<40	55	<40	91
Major (%)	Wood ash	Peat ash	REF; Grate firing	REF; BFC bottom ash	REF; BFC fly ash	Mixed biofuel; BFC bottom ash	Mixed biofuel; BFC fly ash	Mixed biofuel, incl. REF; BFC bottom ash	Mixed biofuel, incl. REF; BFC fly ash
Al	3.03	11.2	12	4.25	8.7	6.47	8.52	4.88	8.91
K	4.7	0.7	12.4	2.5	2.48	3.49	2.14	N/A	N/A
Ca	12	6.78	8.17	6.78	18.7	3.19	10	6.21	13.8
Mg	1.24	0.6	N/A	N/A	N/A	N/A	N/A	N/A	N/A
Na	0.69	0.3	2.31	1.04	1.39	1.87	1.13	N/A	N/A
Si	13.7	18.6	N/A	N/A	N/A	N/A	N/A	N/A	N/A
Fe	3.16	7.44	6.61	1.9	6.02	0.91	2.84	0.84	2.66
Sulphate	4.01	0.79	2.1	0.2	8.31	N/A	N/A	N/A	N/A

References

Mroueh, U.-M. et al. 2000. Sivutuotteet maarakenteissa. Tekes-teknologiakatsaus 93/2000. 87 s. (In Finnish)

Conclusions:

Limit values of As, Cd, Cu, Pb, Sb, or Sulphate for unpaved and paved constructions were not exeeded in the leachates of different ashes.

Executive summary:

Leaching tests with L/S 2 and L/S 10 were performed for wood, peat, mixed biofuel and Recycled Fuel (REF) ashes originating from four different types of power plants in a non-GLP study. Results were compared to limit values of unpaved and paved constructions (Mroueh et al. 2000). Limit values of As, Cd, Cu, Pb, Sb, or Sulphate were not exeeded in the leachates of different ashes. Although concentrations of these metals were clearly higher in REF ashes than in mixed biofuel ashes, there was no remarkable difference in leaching test results.

Reference 5

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Study was conducted between 2 June 2010 and 4 June 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP compliant guideline study.

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

25 February 2009

Type of method:

column elution method

Water solubility:

< 1 mg/L

Temp.:

30 °C

pH:

ca. 12

Remarks on result:

other: pH range was 12.48-12.54. Water solubility value is estimated.

Details on results:

Unable to detect on the UV spectrometer - no peak absorbance obtained. Therefore HPLC and UV spectrometry unsuitable methods of determination.
Owing to the fact that the column elution method did not produce any useable results the flask method was attempted. 5.1757g was added to flask 1, 5.5255g to flask 2 & 5.0365g to flask 3. The flasks were then shaken for 1 day, 2 days and 3 days at 30°C. After leaving the flasks to settle overnight, a sample of the supernatant was removed, filtered and scanned using the UV spectrophotometer. No peak absorbance was observed, the only option to determine the water solubility was to provide an estimated value. 1mg of sample was weighed into a 1000ml volumetric flask which was shaken vigorously. Small particles were apparent after several periods of shaking, hence an estimated value of <1 mg/l.

Table 1. Preliminary (Estimated) Analysis

Mass of sample (mg)	Volume of water in which  sample dissolve (ml)	Estimated solubility (g/L)	Analysis method
1	1000	0	Column Elution Method

Comment: Unable to detect on the UV spectrometer - no peak absorbance obtained. Therefore HPLC and UV spectrometry unsuitable methods of determination.

Table 2. Formal Analytical Determination

UV- Analytical Determinations

Flask No.	pH	Absorbance 1	Absorbance 2	Mean concentration (g/L)
1	12.50	0	0	N/A
2	12.48	0	0	N/A
3	12.54	0	0	N/A

Conclusions:

Interpretation of results: slightly soluble (0.1-100 mg/L) <1mg/l
The Ash was found to be slightly water soluble (< 1 mg/l).

Executive summary:

The water solubility of Ash was studied in a GLP compliant laboratory according to Method A.6. in Comission Regulation No 440/2008. The preliminary shaking test with a flask method showed very low water solubility. Thus, column elution method was used for more detailed study. The column elution showed no UV peak absorbance, which together with the shaking test led to the conclusion of water solubility lower than 1 mg/l.

Description of key information

The water solubility of Ash was studied in a GLP compliant laboratory according to Method A.6. in Commission Regulation No 440/2008. The water solubility was found to be < 1 mg/l. Despite the major proportion of Ash is non-soluble minerals, salts and some metals leach from it. Leaching properties were studied with four different leaching tests. 

Key value for chemical safety assessment

Water solubility:

1 mg/L

at the temperature of:

20 °C

Additional information

Ash typically consists of minerals mainly as oxides and trace metals (Isännäinen &Huotari (1994)). This leads to a difficulty to measure water solubility as required according to REACH information requirements in Annex VII (7.7.). Low solubility observed in the guideline compliant study reflects the physical property of Ash. Council directive 1999/31/EC on the landfill waste regulates of establishing criteria and procedures for the acceptance of waste at landfills. One tool to assess environmental impacts of inert materials is to study leaching properties of them. The leaching test i.e. water extraction performed for this dossier is accordant to national legislation and compliant with an European standard. Extraction of metals in water shows short term leachability properties.

Of the analysed ions in water leachate, Chlorine was most abundant. Additionally, some dissolved organic compounds were detected, but no phenol compounds were present.

Since environmental pH is typically below neutral, acid (pH 4.5) ammonium acetate extraction was performed to describe solubility in the longer term. Table 1 presents the concentrations of certain leached heavy metals in leaching test and in acetate extraction of Ash.

Table 1. Concentrations of leached heavy metals from Ash (mg/kg (d.w.)). Leaching test describes quickly water soluble fraction and acetate extraction reflects long term leachability from Ash.

	Unit	Leaching test		Acetate extraction
		Result L/S 2	Result L/S 10 (cumulative)	Result
Arsenic, As	mg/kg (d.w.)	<0.03	<0.15	3.5
Barium, Ba	mg/kg (d.w.)	23	77	69
Cadmium, Cd	mg/kg (d.w.)	<0.003	<0.015	1.5
Copper, Cu	mg/kg (d.w.)	<0.02	<0.1	50
Lead, Pb	mg/kg (d.w.)	0.16	0.64	8.3
Antimony, Sb	mg/kg (d.w.)	<0.01	<0.05	2.4

In ammonium acetate extraction, major components were found to leach followingly: Ca>Mg>Si>K>Na>Al>P>Fe. Of these, Ca leached 25 fold more than Mg, Si and K, to which the difference of the amounts of Na and Al was approx. 10 fold. P was leached 5 -10 fold less than the previous group and Fe 15 times less than P. Aim of Ash use in fertilisation is to release main nutrients. Aluminium, however, can have adverse effects due to its toxic properties. Mobility and toxic effects of aluminium in environment are pH dependent. Binding at humic substances typically decrease toxicity.

Table 2 presents leaching properties of different ashes produced with different kind of fuels (mg/kg) (Ranta & Wahlström (2002)). Limit values for utilisation presented in the table 2 are exceeded neither in Ash (Table 1) nor in the studied ashes (Table 2).

Table 2. Leaching properties of different ashes produced with different kind of fuels (mg/kg) according to Ranta & Wahlström (2002).

Sample	REF; Grate firing	REF; Grate firing (washed)	REF; FBC bottom ash	REF; FBC fly ash	Mixed biofuel; BFC bottom ash	Mixed biofuel; BFC fly ash	Mixed biofuel, incl. REF; BFC bottom ash	Mixed biofuel, incl. REF; BFC fly ash	Limit value of utilisation I	Limit value of utilisation II
	L/S2 / L/S10	L/S2 / L/S10	L/S2 / L/S10	L/S2 / L/S10	L/S2 / L/S10	L/S2 / L/S10	L/S2 / L/S10	L/S2 / L/S10	L/S10	L/S10
pH	9.5 / 10.2	9.7 / 10.5	11.2 / 11.8	11.0 / 11.5	11.1 / 11.1	12.1 / 11.7	11.6 / 11.4	12.7 / 12.5
Conductivity	560 / 55	79 / 19	176 / 195	2570 / 290	48 / 39	499 / 138	104 / 70	1497 / 719
As				<0.02 / <0.2					0.14	0.85
Cd				<0.02 / <0.02	<0.02 / <0.02	<0.02 / <0.02			0.011	0.015
Cu	0.02 / 0.1	<0.02 / <0.1	<0.02 / <0.1	<0.02 / <0.1	<0.02 / <0.1	<0.02 / <0.1			1.1	2.0
Pb					<0.02 / <0.1	<0.02 / <0.1			1.0	1.8
Sb				<0.06 / 0.2			0.05 / 0.14	<0.01 / <0.05	0.12	0.4
Sulphate				130 / 340					1500

FBC = Fludised Bed Combustion; BFB = Bubbling Bed Combustion

REF = Recovered Fuel

Limit value I for unpaved constructions, limit value II for paved constructions (Mroueh et al. 2000).

Table 3. Minor (mg/kg) and major (%) components in ashes related to Table 2 (Ranta & Wahlström (2002)).

Minor (mg/kg)	Wood ash	Peat ash	REF; Grate firing	REF; FBC bottom ash	REF; FBC fly ash	Mixed biofuel; BFC bottom ash	Mixed biofuel; BFC fly ash	Mixed biofuel, incl. REF; BFC bottom ash	Mixed biofuel, incl. REF; BFC fly ash
Sb	N/A	N/A	12	27	94	N/A	N/A	N/A	N/A
As	0.2-60	31-116	40	21	51	<30	<30	<30	<50
Cd	0.4-40	0.5-5	3.9	0.05	15	<10	<10	<10	<10
Cr	40-250	43-130	150	120	230	22	63	48	100
Cu	15-300	60-160	850	1200	2200	29	120	120	180
Pb	15-1000	160-970	93	55	790	<40	55	<40	91
Major (%)	Wood ash	Peat ash	REF; Grate firing	REF; FBC bottom ash	REF; FBC fly ash	Mixed biofuel; BFC bottom ash	Mixed biofuel; BFC fly ash	Mixed biofuel, incl. REF; BFC bottom ash	Mixed biofuel, incl. REF; BFC fly ash
Al	3.03	11.2	12	4.25	8.7	6.47	8.52	4.88	8.91
K	4.7	0.7	12.4	2.5	2.48	3.49	2.14	N/A	N/A
Ca	12	6.78	8.17	6.78	18.7	3.19	10	6.21	13.8
Mg	1.24	0.6	N/A	N/A	N/A	N/A	N/A	N/A	N/A
Na	0.69	0.3	2.31	1.04	1.39	1.87	1.13	N/A	N/A
Si	13.7	18.6	N/A	N/A	N/A	N/A	N/A	N/A	N/A
Fe	3.16	7.44	6.61	1.9	6.02	0.91	2.84	0.84	2.66
Sulphate	4.01	0.79	2.1	0.2	8.31	N/A	N/A	N/A	N/A

In a sequential leaching test (Breitholz M. et al. (2012)) with L/S 1, 2, and 3, Na, Ca, K, Mg and Si were the most leached major components. The concentration of Na, K and Cl was reduced by 75 %, 65 % and 90% from L/S 1 to L/S 3, respectively. Of the minor components, concentrations of As, Ba, Cr, Cu, Pb ad Sb decreased between 30% and 70%. The concentration of DOC decreased simultaneously with decreasing copper concentration (approx. 35% from L/S 1 to L/S 3). Concentrations of Cd and Mn were found to slightly increase from L/S1 to L/S 3 and concentrations of Ca, Al and Zn were stabile during all studied L/S-ratios.

REFERENCES

Isännäinen S, Huotari H (1994) Tuhkan ja metsäteollisuuden muiden jätejakeiden prosessointi lannoitekäyttöön soveltuvaksi. Esiselvitys. VTT Energia, Jyväskylä, 1994. In Finnish.

Mroueh, U.-M. et al. 2000. Sivutuotteet maarakenteissa. Tekes-teknologiakatsaus 93/2000. 87 s. In Finnish.