Registration Dossier

Diss Factsheets

Administrative data

Endpoint:
toxicity to terrestrial plants: long-term
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:
other:
Justification for type of information:
JUSTIFICATION FOR DATA WAIVING
According to Column 2 of Information Requirement 9.4., Annex X, Commission Regulation (EU) 1907/2006 ”Long-term toxicity testing shall be proposed by the registrant if the results of the chemical safety assessment according to Annex I indicates the need to investigate further the effects of the substance and/or degradation products on terrestrial organisms. The choice of the appropriate test(s) depends on the outcome of the chemical safety assessment. These studies do not need to be conducted if direct and indirect exposure of the soil compartment is unlikely.”

According to Section 8.4.2 of ECHA Guidance on IR & CSA, Part B: Hazard assessment (Version 2.1; ECHA, 2011), “For substances which are classified as harmful, toxic or very toxic to aquatic life (i.e. H412, H411, H410 and H400), an aquatic PNEC can be derived. In these circumstances there are unclassified hazards to the sediment and soil compartments because toxicity to aquatic organisms is used as an indicator of concern for sediment and soil organisms, and a screening risk characterisation is undertaken using the equilibration partitioning method (EPM) to derive PNECs for sediment and soil. Hence quantitative exposure assessment, i.e. derivation of PECs, is mandatory for the water, sediment and soil environmental compartments.

Substances with the only environmental classification as ‘May cause long lasting harmful effects to aquatic life’ (i.e. H413) have been established as persistent in the aquatic environment and potentially bioaccumulative on the basis of test or other data. There are also potential hazards for these substances for the sediment and soil compartments, because these substances are potentially bioaccumulative in all organisms and are also potentially persistent in sediment and soil. Hence exposure assessment is mandatory for the water, sediment and soil environmental compartments, which may be quantitative or qualitative as appropriate. PBT and vPvB substances have been established as persistent and bioaccumulative (and the former also as toxic) in the environment as a whole. Hence qualitative exposure assessment is mandatory for the water, sediment and soil environmental compartments…

If there are ecotoxicity data showing effects in aquatic organisms, but the substance is not classified as dangerous for the aquatic environment, an aquatic PNEC can nevertheless be derived thus indicating a hazard to the aquatic environment. In these circumstances there are also unclassified hazards to the sediment and soil compartments because toxicity to aquatic organisms is used as an indicator of concern for sediment and soil organisms and a screening risk characterisation is undertaken using the equilibration partitioning method (EPM) to derive PNECs for sediment and soil. Hence quantitative exposure assessment, i.e. derivation of PECs, is mandatory for the water, sediment and soil environmental compartments.”

High-temperature calcination products of diiron trioxide and amorphous silica resulting in a glassy silica matrix can be considered environmentally and biologically inert due to the characteristics of the synthetic process (calcination at a high temperature of approximately 1000°C), rendering the substance to be of a unique, stable crystalline structure in which all atoms are tightly bound and not prone to dissolution in environmental and physiological media. This assumption is supported by available transformation/dissolution data (Grané, 2010) that indicate a very low release of pigment components. Transformation/dissolution of High-temperature calcination products of diiron trioxide and amorphous silica resulting in a glassy silica matrix (24-screening test according to OECD Series 29, loading of 100 mg/L, pH 6 and 8) resulted in mean dissolved iron concentrations of 0.131 µg/L Fe and 0.002 µg/L Fe, silicon concentrations of 215.7 µg/L Si and 204 µg/L Si at pH 6 and 8, respectively. Dissolution of iron and silicon is highest at pH 6, therefore pH 6 is considered as pH that maximised metal release. Metal release at the 1 mg/L loading and pH 6 remained below the respective LOD for iron and silicon (<0.22 µg/L Fe and <0.07 µg/L Si). After 28 days at the 1 mg/L loading and pH 6 iron concentrations of 0.29 µg/L were measured whereas silicon concentrations remained below the LOD (< 0.07 µg/L Si). Thus, the rate and extent to which High-temperature calcination products of diiron trioxide and amorphous silica resulting in a glassy silica matrix produces soluble (bio)available ionic and other silicon- and iron-bearing species in environmental media is limited. Hence, the pigment can be considered as environmentally and biologically inert during short- and long-term exposure. The poor solubility of High-temperature calcination products of diiron trioxide and amorphous silica resulting in a glassy silica matrix is expected to determine its behaviour and fate in the environment, and subsequently its potential for ecotoxicity.

Proprietary studies are not available for High-temperature calcination products of diiron trioxide and amorphous silica resulting in a glassy silica matrix. The poorly soluble substance High-temperature calcination products of diiron trioxide and amorphous silica resulting in a glassy silica matrix is evaluated by comparing the dissolved metal ion levels resulting from the transformation/dissolution test after 7 and 28 days at a loading rate of 1 mg/L with the lowest acute and chronic ecotoxicity reference values (ERVs) as determined for the (soluble) metal ions. The ERVs are based on the lowest EC50/LC50 or NOEC/EC10 values for algae, invertebrates and fish. Acute and chronic ERVs were obtained from the Metals classification tool (MeClas) database as follows: For iron ions, the acute and chronic ERVs are above 1 mg/L, respectively, and a concern for short-term (acute) and long-term (chronic) toxicity was not identified (no classification). An acute as well as chronic ERV for silicon has not been derived since a concern for short-term (acute) and long-term (chronic) toxicity of silicon ions was not identified (see also OECD, 2004). According to ECHA Guidance on the Application of the CLP Criteria (Version 5.0, July 2017), “Where the acute ERV for the metal ions of concern is greater than 1 mg/L the metals need not be considered further in the classification scheme for acute hazard.” Further, ”Where the chronic ERV for the metal ions of concern corrected for the molecular weight of the compound (further called as chronic ERV compound) is greater than 1 mg/l, the metal compounds need not to be considered further in the classification scheme for long-term hazard.” Due to the lack of an acute and chronic aquatic hazard potential for soluble silicon and iron ions and the fact that dissolved silicon and iron concentrations were below the LOD (<0.22 Fe and <0.07 µg/L Si) after 7 days and below 0.5µg/L (0.29 Fe and <0.07 µg/L Si) after 28 days at pH 6 in the T/D test, respectively, it can be concluded that the substance High-temperature calcination products of diiron trioxide and amorphous silica resulting in a glassy silica matrix is not sufficiently soluble to cause short- or long-term toxicity at the level of the acute or chronic ERVs (expressed as EC50/LC50 or NOEC/EC10, respectively).

In accordance with Figure IV.4 “Classification strategy for determining acute aquatic hazard for metal compounds” and Figure IV.5 „Classification strategy for determining long-term aquatic hazard for metal compounds “of ECHA Guidance on the Application of the CLP Criteria (Version 5.0, July 2017) and section 4.1.2.10.2. of Regulation (EC) No 1272/2008, the substance High-temperature calcination products of diiron trioxide and amorphous silica resulting in a glassy silica matrix is poorly soluble and does not meet classification criteria for acute (short-term) and chronic (long-term) aquatic hazard.

High-temperature calcination products of diiron trioxide and amorphous silica resulting in a glassy silica matrix is not classified as dangerous for the aquatic environment, an aquatic PNEC cannot be derived, thus not indicating a hazard to the aquatic environment. In these circumstances there are also not unclassified hazards to the soil compartment because toxicity to aquatic organisms is used as an indicator of concern for soil organisms and a screening risk characterisation (using the equilibration partitioning method to derive a PNEC for soil) cannot be undertaken. Thus, High-temperature calcination products of diiron trioxide and amorphous silica resulting in a glassy silica matrix does not have a “non-classified hazard” potential.

Silicon, at about 28%, is the second most abundant element in the Earth’s crust after oxygen, and is mainly found in silica or silicate forms. It is a major constituent of nearly all rocks. Quartz, SiO2, is the most resistant mineral in soil. Quartz, because of its very low aqueous solubility, may be considered unreactive, and it is one of the residual minerals remaining in soil after other minerals have altered or dissolved.

Monitoring data for elemental silicon background concentrations in soil are provided by the FOREGS Geochemical Baseline Mapping Programme that offers high quality, multi-purpose homogeneous environmental geochemical baseline data for Europe (Salminen et al. 2005). The FOREGS dataset for EU-27 countries plus UK and Norway reports silicon concentrations for 833 topsoil samples. Baseline silicon levels in topsoil range from 6,874.4 to 452,307.1 mg/kg with 5th, 50th and 95th percentiles of 159,055.5, 317,531.2 and 415,680.6 mg/kg, respectively.

Additionally, silicon concentrations in soils were determined in the GEMAS project (Geochemical Mapping of Agricultural and Grazing land Soil), that offers high quality harmonized, freely and interoperable geochemical data for the regularly ploughed top layer of agricultural and grazing land soil (Reimann et al. 2014). For the EU-27, UK and Norway, 1,867 and 1,781 samples of agricultural and grazing land soil were analysed. Silicon levels of agricultural soil range from 11,499.0 to 448,274.0 mg/kg with 5th, 50th and 95th percentiles of 156,447.5, 311,829.0 and 417,708.0 mg/kg, respectively. In grazing land, soil concentrations of silicon range from 7,058.0 to 450,293.0 mg/kg with 5th, 50th and 95th percentiles of 133,489.0, 299,650.0 and 409,396.0 mg/kg, respectively.

Based on the FOREGS dataset, the 95th percentile of 415,680.6 mgSi/kg can be regarded as representative background concentration of silicon in topsoil of EU countries. Representative silicon concentrations (95th percentile) of agricultural and grazing land soil (i.e. ambient levels) amount to 417,708.0 and 409,396.0 mgSi/kg, respectively, according to the GEMAS dataset.

Iron is the fourth most abundant element and the second most abundant metal in the Earth’s crust (after aluminium). It is present mostly as ferrous iron (Fe2+) in ferro-magnesian silicates, such as olivine, pyroxene, amphibole and biotite, and as ferric iron (Fe3+) in iron oxides and hydroxides, as the result of weathering (Salminen et al. 2005). Ferrous iron is more soluble and bioavailable to plants than ferric iron. Iron is an abundant element in rocks and soils, but it is also one of the most commonly deficient micronutrients due to the extremely insoluble nature of certain compounds of ferric iron (US EPA, 2003).

The FOREGS dataset for EU-27, UK and Norway reports iron concentrations of 825 topsoil samples, and baseline iron levels in topsoil range from 0.7 to 152.4 g Fe/kg with 5th, 50th and 95th percentiles of 3.5, 19.6 and 44.3 g Fe/kg, respectively.

Additionally, iron concentrations in soils were determined in the GEMAS project for the EU-27 plus UK and Norway, i.e. 1,867 samples of agricultural land soil and for 1,781 samples of grazing land soil. Iron levels of agricultural soil range from 404.5 to 133,926.1 mg Fe/kg with 5th, 50th and 95th percentiles of 3,223.4, 17,165.1 and 36,998.8 mg Fe/kg, respectively. In grazing land, soil concentrations of iron range from 510.3 to 94,759.1 mg Fe/kg with 5th, 50th and 95th percentiles of 3,448.0, 16,949.0 and 38,345.0 mg Fe/kg, respectively.

Based on the FOREGS dataset, the 95th percentile of 44.3 g Fe/kg can be regarded as representative background concentration of iron in topsoil of EU countries. Representative iron concentrations (95th percentile) of agricultural and grazing land soil (i.e. ambient levels) amount to 36,998.8 and 38,345.0 mg Fe/kg, respectively, according to the GEMAS dataset.

Regarding essentiality, “Silicon is considered necessary for various functions in some species, including diatom algae, gastropods and mammals. Silicon deficiency in animals may lead to delays in growth, bone deformations and abnormal skeletal development, and one of the symptoms of silicon deficiency is aberrant connective and bone tissue metabolism (Pérez-Granados and Vaquero, 2002).

Iron is an essential trace element for living organisms including animals, plants and microorganisms. It serves as a cofactor in a variety of enzymes involved in the electron transport processes of various metabolic pathways, i.e., photosynthesis, respiration, and nitrogen fixation. It is a structural component of the metalloenzyme nitrogenase, which is the key enzyme in the nitrogen fixation process performed by different microorganisms. Due to its involvement in the synthesis and maintenance of chlorophyll, iron is a vital factor for the photosynthetic performance of plants. As an essential component of the haemoglobin of red blood cells, iron functions as a carrier of oxygen in the blood and muscles of animals (e.g. US EPA, 2003; Colombo et al. 2014).

Considering abundance, essentiality and bioavailability, the potential of silicon and iron ions for toxicity to terrestrial organisms can be expected to be low.

High-temperature calcination products of diiron trioxide and amorphous silica resulting in a glassy silica matrix is not classified as harmful, toxic or very toxic to aquatic life or may cause long lasting harmful effects to aquatic life High-temperature calcination products of diiron trioxide and amorphous silica resulting in a glassy silica matrix is also not an unclassified hazard to the aquatic environment. Based on the poor solubility, bioavailability, lack of a potential for bioaccumulation and toxicity to aquatic organisms and considering ubiquitousness and bioavailability of silicon and iron in soil as well as essentiality of silicon and iron, High-temperature calcination products of diiron trioxide and amorphous silica resulting in a glassy silica matrix is also not considered an unclassified hazard to the soil compartment. Results of the chemical safety assessment do not indicate the need to investigate further the effects of High-temperature calcination products of diiron trioxide and amorphous silica resulting in a glassy silica matrix on soil organisms. Therefore, the study on the long-term toxicity to terrestrial plants does not need to be conducted in accordance with Column 2 of Information Requirement 9.4.6., Annex X, Commission Regulation (EU) 1907/2006.

References:

Colombo et al. (2014) Review on iron availability in soil: interaction of Fe minerals, plants, and microbes. Journal of Soils and Sediments 14: 538–548.

US EPA (2003) Ecological Soil Screening Level for Iron, Interim Final, OSWER Directive 9285.7-69.

Reimann et al. (2014) Chemistry of Europe’s agricultural soils - Part A: Methodology and interpretation of the GEMAS data set.

Salminen et al. (2005) Geochemical Atlas of Europe - Part 1: Background information, Methodology and Maps. EuroGeoSurveys.

Pérez-Granados and Vaquero (2002) Silicon, aluminium, arsenic and lithium: Essentiality and human health implications. The Journal of Nutrition Health and Aging 6/2:154-62.
Cross-referenceopen allclose all
Reason / purpose for cross-reference:
data waiving: supporting information
Reference
Endpoint:
monitoring data
Type of information:
other: report
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
data from handbook or collection of data
Qualifier:
no guideline required
Principles of method if other than guideline:
Evaluation and summary of high quality environmental geochemical data for Europe, which is provided by the Forum of European Geological Surveys (FOREGS) and the European Geochemical Mapping of Agricultural and Grazing Land Soil (GEMAS), with respect to silicon concentrations in stream water, stream sediment and topsoil, as well as in agricultural soil and grazing land.
GLP compliance:
no
Type of measurement:
other: Geochemical background and ambient silicon concentrations in different environmental compartments across Europe
Media:
other: Natural stream water, stream sediment and topsoil, as well as agricultural and grazing land soils
Details on sampling:
FOREGS and GEMAS data for EU-27 countries plus UK and Norway were considered, i.e. data from non-EEA countries such as Albania, Bosnia and Switzerland were excluded from further analysis.

FOREGS:
- The FOREGS sampling grid was based on GTN grid cells developed for Global Geochemical Baseline mapping. This grid divides the entire land surface into 160 km x 160 km cells covering an area of 4,500,000 km2.
- Sampling methodology, preparation and analysis are described by Salminen et al. (2005).
- FOREGS data for EU-27 countries plus UK and Norway were considered, i.e. data from non-EEA countries such as Albania and Switzerland were excluded from further analysis.
- A total of 795 stream water samples of silicon dioxide and 839 sediment samples of silicon dioxide were processed in the FOREGS-program, including 743 paired samples, i.e. samples with the same coordinates for the sampling location of stream water and sediment.
- The FOREGS dataset reports silicon/silicon dioxide concentrations for 833 topsoil samples sampled on a grid across Europe. A topsoil sample was taken at each site from 0-25 cm (excluding material from the organic layer where present).
- Reported silicon dioxide concentrations were converted into silicon concentrations.
- High quality and consistency of the obtained data were ensured by using standardised sampling methods and by treating and analysing all samples in the same laboratory of each country.

GEMAS:
- Samples from 33 out of 38 European countries were analysed to develop a suitable harmonised geochemical data base for soils. The sampling started in the spring 2008 and the first four months of 2009.
- The whole GEMAS project area of 5,600,000 km2 was divided into a grid with 50 km x 50 km cells.
- To generate harmonised data sets, all project samples were processed by a central sample preparation facility in Slovakia.
- GEMAS data for EU-27 countries plus UK and Norway were considered, i.e. data from non-EEA countries such as Bosnia and Switzerland were excluded from further analysis.
- The GEMAS dataset reports silicon concentrations of 1,867 samples from the regularly ploughed layer (Ap-horizon) of agricultural land (arable land; 0 - 20 cm) and of 1,781 samples from the top layer of grazing land (soil under permanent grass cover; 0 - 10 cm) sampled on a grid across Europe.

FOREGS DATABASE STREAM WATER/SEDIMENT:

- Sampled stream water and sediments cover a wide range of environmental conditions. Water parameters such as pH, hardness and organic carbon concentrations extend over several magnitudes. Silicon water levels range from 0.05 to 33.7 mg/L with 5th, 50th and 95th percentiles of 0.8, 3.7 and 8.7 mg/L, respectively.

- In the sediment, silicon concentrations range from 11,691.1 to 439,586.6 mg/kg with 5th, 50th and 95th percentiles of 161,384.4, 290,875.4 and 385,246.2 mg/kg, respectively (Table 1).

- Taking into account the high quality and representativeness of the data set, the 95th percentile of 8.7 mg/L can be regarded as representative background concentration for dissolved silicon in European surface waters and the 95th percentile of 385,246.2 mg/kg as representative background concentration of silicon in European stream sediments.

- Regarding the partitioning of silicon in the water column, stream water/sediment partition coefficients range from 7,056 to 5,290,000 L/kg. Since FOREGS sampled on a grid aiming to equally represent geochemical baseline concentrations across Europe, a European median log Kp value of 4.87 is derived.

Table 1: Water parameters and silicon/silicon dioxide concentrations of stream sediment and stream water and respective partitioning.

Parameter

#

Unit

Min.

Max.

5th P

50th P

water

pH 1

735 2

-

9.80

4.50

8.50

7.70

water

Ca

743

mg/L

0.23

592.00

1.64

42.70

water

Cl

743

mg/L

0.14

4,560.00

0.49

9.32

water

HCO3

741 3

mg/L

0.69

1,804.42

5.36

131.67

water

K

743

mg/L

< 0.01

182.00

0.15

1.64

water

Mg

743

mg/L

0.05

230.00

0.46

6.22

water

Na

743

mg/L

0.23

4,030.00

1.00

6.76

water

NO3

743

mg/L

< 0.04

107.00

< 0.04

3.10

water

DOC

741 4

mg/L

< 0.50

57.94

0.60

4.79

water

SO42-

743

mg/L

< 0.30

2,420.00

1.18

17.10

water

SiO2

743

mg/L

0.10

72.00

1.66

8.00

water

Si 5

743

mg/L

0.05

33.67

0.78

3.74

sediment

SiO2

743

%

2.50

94.00

34.51

62.20

sediment

Si 5

743

mg/kg

11,691.13

439,586.58

161,384.39

290,875.37

Partitioning (Kp)

Si (sed/water)

743

L/kg

7,056

5,290,000

26,762

73,789

Log Kp

Si (sed/water)

743

-

3.85

6.72

4.43

4.87

Statistics are based on H+ concentrations rather than pH.

Removal of 2 outliers < pH 4.3 and 6 negative values.

Removal of 2 outliers < 0.01.

Removal of 1 outlier > 70 mg/L and 1 negative values.

5 Values converted from SiO2.

FOREGS DATABASE Background soil concentrations

- Sampled soils cover a wide range of environmental conditions. Soil parameters, including pH and TOC, cover several magnitudes.

- Baseline silicon levels in topsoil range from 6,874.4 to 452,306.5 mg/kg with 5th, 50th and 95th percentiles of 159,055.5, 317,531.2 and 415,680.6 mg/kg, respectively (see Table 2)

- Taking into account the high quality and representativeness of the data set, the 95th percentile of 415,680.6 mg/kg can be regarded as representative background concentration of silicon in topsoil of EU countries.

Table 2: Concentrations of silicon/silicon dioxide in topsoil samples.

Parameter

Unit

#

Min.

Max.

5th P

50th P

95th P

pH 1

-

802

7.55

3.38

7.31

5.49

4.28

TOC

%

799

0.07

46.61

0.56

1.72

5.86

SiO2

%

833

1.47

96.72

34.01

67.90

88.89

Si 2

mg/kg

833

6,874.4

452,306.5

159,055.5

317,531.2

415,680.6

1 Statistics are based on H+ concentrations rather than pH.

2 Values converted from SiO2.

GEMAS DATABASE AGRICULTURAL AND GRAZING LAND SOIL CONCENTRATIONS:

- Silicon levels of agricultural soil range from 11,499.0 to 448,274.0 mg/kg with 5th, 50th and 95th percentiles of 156,447.5, 311,829.0 and 417,708.0 mg/kg, respectively (see Table 3). In grazing land, soil concentrations of silicon range from 7,058.0 to 450,293.0 mg/kg with 5th, 50th and 95th percentiles of 133,489.0, 299,650.0 and 409,396.0 mg/kg, respectively (see Table 4)

Table 3: Agricultural soil concentrations.

Parameter

Unit

Method

#

Min.

Max.

5th P

50th P

95th P

CEC

meq/100g

AAS

1,867

1.80

48.30

6.10

15.80

33.30

pH (CaCl2)

pH

pH-meter

1,867

3.32

7.98

4.14

5.71

7.45

TOC

%

IR

1,854

0.40

46.00

0.70

1.70

5.67

Silicon

mg/kg

XRF

1,867

11,499.00

448,274.00

156,447.50

311,829.00

417,708.00

Table 4: Grazing land soil concentrations.

Parameter

Unit

Method

#

Min.

Max.

5th P

50th P

95th P

CEC

meq/100g

AAS

1,781

2.54

49.88

8.27

17.96

37.74

pH (CaCl2)

pH

pH-meter

1,780

3.26

8.06

4.03

5.38

7.45

TOC

%

IR

1,780

0.41

49.00

0.94

2.80

11.05

Silicon

mg/kg

XRF

1,781

7,058.00

450,293.00

133,489.00

299,650.00

409,396.00

Conclusions:
Representative background or ambient concentrations of silicon/silicion dioxide in environmental compartments are tabulated below.

compartment, unit, concentration (50th P), concentration (95th P)
background stream water, mg/L SiO2, 8.0, 18.6
background stream water, mg/L Si, 3.7*, 8.7*
background stream water sediment, % SiO2, 62.2, 82.4
background stream water sediment, mg/kg Si, 290,875.4*, 385,246.2*
background topsoil, % SiO2, 67.9, 88.9
background topsoil, mg/kg Si, 317,531.2*, 415,680.6*
agricultural soil, mg/kg Si, 311,829.0, 417,708.0
grazing land soil, mg/kg Si, 299,650.0, 409,396.0
* based on measured SiO2.

Based on the FOREGS dataset, the 95th percentile of 8.7 mg/L can be regarded as representative background concentration of dissolved silicon in European surface waters and the 95th percentile of 385,246.2 mg/kg as representative background concentration of European stream sediments. Regarding the respective partitioning between sediment and water, a European median log Kp value of 4.87 is derived.

Based on the FOREGS dataset, the 95th percentile of 415,680.6 mg/kg can be regarded as representative background concentration of silicon in topsoil of EU countries. Representative silicon concentrations (95th percentile) of agricultural and grazing land soil (i.e. ambient levels) amount to 417,708.0 and 409,396.0 mg/kg, respectively, according to the GEMAS dataset.
Reason / purpose for cross-reference:
data waiving: supporting information
Reference
Endpoint:
monitoring data
Type of information:
other: report
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
data from handbook or collection of data
Qualifier:
no guideline required
Principles of method if other than guideline:
Evaluation and summary of high quality environmental geochemical data for Europe, which is provided by the Forum of European Geological Surveys (FOREGS) and the European Geochemical Mapping of Agricultural and Grazing Land Soil (GEMAS), with respect to iron concentrations in stream water, stream sediment and topsoil, as well as in agricultural soil and grazing land.
GLP compliance:
no
Type of measurement:
other: Geochemical background and ambient iron concentrations in different environmental compartments across Europe
Media:
other: Natural stream water, stream sediment and topsoil, as well as agricultural and grazing land soils
Details on sampling:
FOREGS and GEMAS data for EU-27 countries plus UK and Norway were considered, i.e. data from non-EEA countries such as Albania, Bosnia and Switzerland were excluded from further analysis.

FOREGS:
- The FOREGS sampling grid was based on GTN grid cells developed for Global Geochemical Baseline mapping. This grid divides the entire land surface into 160 km x 160 km cells covering an area of 4,500,000 km2.
- Sampling methodology, preparation and analysis are described by Salminen et al. (2005).
- FOREGS data for EU-27 countries plus UK and Norway were considered, i.e. data from non-EEA countries such as Albania and Switzerland were excluded from further analysis.
- A total of 795 stream water samples and 832 sediment samples were processed in the FOREGS-program, including 737 paired samples, i.e. samples with the same coordinates for the sampling location of stream water and sediment.
- The FOREGS dataset reports iron concentrations for 825 topsoil samples. A topsoil sample was taken at each site from 0-25 cm (excluding material from the organic layer where present).
- High quality and consistency of the obtained data were ensured by using standardised sampling methods and by treating and analysing all samples in the same laboratory of each country.

GEMAS:
- Samples from 33 out of 38 European countries were analysed to develop a suitable harmonised geochemical data base for soils. The sampling started in the spring 2008 and the first four months of 2009.
- The whole GEMAS project area of 5,600,000 km2 was divided into a grid with 50 km x 50 km cells.
- To generate harmonised data sets, all project samples were processed by a central sample preparation facility in Slovakia.
- GEMAS data for EU-27 countries plus UK and Norway were considered, i.e. data from non-EEA countries such as Bosnia and Switzerland were excluded from further analysis.
- The GEMAS dataset reports iron concentrations of 1,867 samples from the regularly ploughed layer (Ap-horizon) of agricultural land (arable land; 0-20 cm) and of 1,781 samples from the top layer of grazing land (soil under permanent grass cover; 0-10 cm) sampled on a grid across Europe.

FOREGS DATABASE STREAM WATER/SEDIMENT:

- Sampled stream water and sediments cover a wide range of environmental conditions. Water parameters such as pH, hardness and organic carbon concentrations extend over several magnitudes. Iron water levels range from < 1.0 (< LOQ) to 4,820.0 µg/L with 5th, 50th and 95th percentiles of 4.1, 65.4 and 1,120.0 µg/L, respectively.

- In the sediment, iron concentrations range from 0.6 to192.4 g/kg with 5th, 50th and 95th percentiles of 5.8, 20.1 and 45.3 g/kg, respectively (Table 1).

- Taking into account the high quality and representativeness of the data set, the 95th percentile of 1,120.0 µg/L can be regarded as representative background concentration for dissolved iron in European surface waters and the 95th percentile of 45.3 g/kg as representative background concentration of iron in European stream sediments.

- Regarding the partitioning of iron in the water column, stream water/sediment partition coefficients range from 1,413 to 294,000,000 L/kg. Since FOREGS sampled on a grid aiming to equally represent geochemical baseline concentrations across Europe, a European median log Kp value of 5.48 is derived.

Table 1: Water parameters and iron concentrations of stream sediment and stream water and respective partitioning.

 

Parameter

#

Unit

Min.

Max.

5th P

50th P

95th P

water

pH 1

729 2

-

9.80

4.50

8.50

7.70

6.10

water

Ca

737

mg/L

0.23

592.00

1.61

42.44

143.52

water

Cl

737

mg/L

0.14

4,560.00

0.49

8.97

68.37

water

HCO3

735 3

mg/L

0.69

1,804.42

5.35

128.02

371.20

water

K

737

mg/L

< 0.01

182.00

0.14

1.62

9.81

water

Mg

737

mg/L

0.05

230.00

0.46

6.15

38.11

water

Na

737

mg/L

0.23

4,030.00

1.00

6.66

48.28

water

NO3

737

mg/L

< 0.04

107.00

< 0.04

3.09

39.91

water

DOC

735 4

mg/L

< 0.50

57.94

0.60

4.80

23.10

water

SO42-

737

mg/L

< 0.30

2,420.00

1.18

16.80

164.01

water

Fe

737

µg/L

< 1.00

4,820.00

4.10

65.40

1,120.00

sediment

Fe

737

g/kg

0.60

192.40

5.78

20.10

45.28

Partitioning (Kp)

Fe

(sed/water)

737

L/kg

1,413

294,000,000

14,317

303,282

6,805,391

Log Kp

Fe

(sed/water)

737

-

3.15

8.47

4.16

5.48

6.83

Statistics are based on H+ concentrations rather than pH

Removal of 2 outliers < pH 4.3 and 6 negative values.

Removal of 2 outliers < 0.01.

Removal of 1 outlier > 70 mg/L and 1 negative values.

FOREGS DATABASE Background soil concentrations

- Sampled soils cover a wide range of environmental conditions. Soil parameters, including pH and TOC, cover several magnitudes.

- Baseline iron levels in topsoil range from 0.7 to 152.4 g/kg with5th, 50th and 95th percentiles of 3.5, 19.6 and 44.3 g/kg, respectively (see Table 2).

- Taking into account the high quality and representativeness of the data set,the 95th percentile of 44.3 g/kg can be regarded as representative background concentration of iron in topsoil of EU countries.

Table 2: Concentrations of iron in topsoil samples.

Parameter

Unit

#

Min.

Max.

5th P

50th P

95th P

pH 1

-

798

7.55

3.38

7.31

5.49

4.29

TOC

%

805

0.07

46.61

0.55

1.72

5.87

Fe

g/kg

825

0.70

152.40

3.52

19.60

44.30

1 Statistics are based on H+ concentrations rather than pH.

GEMAS DATABASE AGRICULTURAL AND GRAZING LAND SOIL CONCENTRATIONS:

- Iron levels of agricultural soil range from 404.5 to 133,926.1 mg/kg with 5th, 50th and 95th percentiles of 3,223.4, 17,165.1 and 36,998.8 mg/kg, respectively (see Table 3). In grazing land, soil concentrations of iron range from 510.3 to 94,759.1 mg/kg with 5th, 50th and 95th percentiles of 3,448.0, 16,949.0 and 38,345.0 mg/kg, respectively (see Table 4).

Table 3: Agricultural soil concentrations.

Parameter

Unit

Method

#

Min.

Max.

5th P

50th P

95th P

CEC

meq/100g

AAS

1,867

1.80

48.30

6.10

15.80

33.30

pH (CaCl2)

pH

pH-meter

1,867

3.32

7.98

4.14

5.71

7.45

TOC

%

IR

1,854

0.40

46.00

0.70

1.70

5.67

Iron

mg/kg

AR

1,867

404.50

133,926.10

3,223.35

17,165.05

36,998.83

Iron

mg/kg

XRF

1,867

909.00

154,715.00

5,595.00

24,620.00

48,499.00

Iron

mg/kg

MMI

1,867

0.50

2,200.00

7.00

35.00

249.00

Table 4: Grazing land soil concentrations.

Parameter

Unit

Method

#

Min.

Max.

5th P

50th P

95th P

CEC

meq/100g

AAS

1,781

2.54

49.88

8.27

17.96

37.74

pH (CaCl2)

pH

pH-meter

1,780

3.26

8.06

4.03

5.38

7.45

TOC

%

IR

1,780

0.41

49.00

0.94

2.80

11.05

Iron

mg/kg

AR

1,781

510.31

94,759.13

3,447.99

16,948.95

38,344.67

Iron

mg/kg

XRF

1,781

979.00

114,422.00

5,665.00

24,129.00

49,727.00

Conclusions:
Representative background or ambient concentrations of iron in environmental compartments are tabulated below:

compartment, unit, concentration (50th P), concentration (95th P)
background stream water, µg/L Fe, 65.4, 1,120.0
background stream water sediment, g/kg Fe, 20.1, 45.3
background topsoil, g/kg Fe, 19.6, 44.3
agricultural soil, mg/kg Fe, 17,165.1, 36,998.8
grazing land soil, mg/kg Fe, 16,949.0, 38,344.7

Based on the FOREGS dataset, the 95th percentile of 1,120.0 µg/L can be regarded as representative background concentration for dissolved iron in European surface waters and the 95th percentile of 45.3 g/kg as representative background concentration of European stream sediments. Regarding the respective partitioning between sediment and water, a European median log Kp value of 5.48 is derived.

Based on the FOREGS dataset, the 95th percentile of 44.3 g/kg can be regarded as representative background concentration of iron in topsoil of EU countries. Representative iron concentrations (95th percentile) of agricultural and grazing land soil (i.e. ambient levels) amount to 36,998.8 and 38,344.7 mg/kg, respectively, according to the GEMAS dataset.

Data source

Materials and methods

Results and discussion

Applicant's summary and conclusion