Registration Dossier

Administrative data

Endpoint:
toxicity to soil microorganisms
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 IX, Commission Regulation (EU) 1907/2006 ”These studies do not need to be conducted if direct and indirect exposure of the soil compartment is unlikely. In the absence of toxicity data for soil organisms, the equilibrium partitioning method may be applied to assess the hazard to soil organisms. Where the equilibrium partitioning method is applied to nanoforms, this shall be scientifically justified. The choice of the appropriate tests depends on the outcome of the chemical safety assessment. In particular for substances that have a high potential to adsorb to soil or that are very persistent, the registrant shall consider long-term toxicity testing instead of short-term.”

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.”

Chromium iron hematite 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 (Pardo Martinez, 2010) that indicate a very low release of pigment components. Transformation/dissolution of chromium iron hematite (24-screening test according to Oecd Series 29, loading of 100 mg/L, pH 6 and 8) resulted in metal concentrations that are below the respective LODs for iron and chromium (< 0.5 µg/L). Dissolved metal concentrations remained also below the respective LOD after 7 days with 1 mg/L (and also 100 mg/L) and after 28 days with 1 mg/L at pH 6. Thus, the rate and extent to which chromium iron hematite produces soluble (bio)available ionic and other chromium- 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 chromium iron hematite is expected to determine its behaviour and fate in the environment, and subsequently its potential for ecotoxicity.

Proprietary studies are not available for chromium iron hematite. The poorly soluble substance chromium iron hematite 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 trivalent chromium and 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). 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 trivalent chromium and iron ions and the fact that dissolved chromium and iron concentrations were below the LOD of 0.5 µg/L after 7 and 28 days at pH 6 in the T/D test, respectively, it can be concluded that the substance chromium iron hematite 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 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 chromium iron hematite is poorly soluble and does not meet classification criteria for acute (short-term) aquatic hazard. In accordance with 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 chromium iron hematite is poorly soluble and does not meet classification criteria for acute (short-term) and chronic (long-term) aquatic hazard.

Chromium iron hematite 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, chromium iron hematite does not have a “non-classified hazard” potential.

Chromium is ubiquitous in soil and a constituent of several rock forming minerals. According to the EU RAR on chromates (ECB, 2005), “Chromium (III) has generally been shown to be less toxic than chromium (VI) to soil organisms…Since chromium (III) adsorbs more strongly onto soil than chromium (VI), it would again be expected that in soils, chromium (III) would be less toxic than chromium (VI)”. Monitoring data for elemental chromium 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 chromium concentrations for 825 topsoil samples. Baseline chromium levels in topsoil range from 1.0 to 2,340.0 mg Cr/kg with 5th, 50th and 95th percentiles of 5.0, 22.0 and 69.8 mg Cr/kg, respectively.

Additionally, chromium 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 for chromium. Chromium levels of agricultural soil range from 0.40 to 696.02 mg Cr/kg with 5th, 50th and 95th percentiles of 4.16, 19.87 and 67.16 mg Cr/kg, respectively. In grazing land, soil concentrations of chromium range from 0.78 to 576.74 mg Cr/kg with 5th, 50th and 95th percentiles of 3.87, 19.75 and 67.82 mg Cr/kg, respectively.

Based on the FOREGS dataset, the 95th percentile of 69.8 mg Cr/kg can be regarded as representative background concentration of chromium in topsoil of EU countries. Representative chromium concentrations (95th percentile) of agricultural and grazing land soil (i.e. ambient levels) amount to 67.16 and 67.82 mg Cr/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, “Chromium(III) is required by only some microorganisms for specific metabolic processes, such as glucose metabolism and enzyme stimulation. Chromium(III), in trace amounts, has been reported to be an essential component of animal nutrition and is most notably associated with glucose and fat metabolism (WHO, 2009).”

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 chromium (III) and iron ions for toxicity to terrestrial organisms can be expected to be low.

Chromium iron hematite is not classified as harmful, toxic or very toxic to aquatic life or may cause long lasting harmful effects to aquatic life. Chromium iron hematite 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 chromium and iron in soil as well as essentiality of chromium and iron, chromium iron hematite 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 chromium iron hematite on soil organisms. Therefore, the study on effects on soil microorganisms does not need to be conducted in accordance with Column 2 of Information Requirement 9.4.2., Annex IX, 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.

ECB (2005) European Union Risk Assessment Report: Chromium trioxide, sodium chromate, sodium dichromate, ammonium dichromate and potassium dichromate. EUR 21508 EN.

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.

WHO (2009) Concise International Chemical Assessment Document 76 (CICAD). Inorganic chromium (III) compounds. International Programme of Chemical Safety (IPCS), WHO, Geneva.
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 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.
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 chromium 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 chromium 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 734 paired samples, i.e. samples with the same coordinates for the sampling location of stream water and sediment.
- The FOREGS dataset reports chromium 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 chromium 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. Chromium water levels range from < 0.01 (< LOQ) to 43.0 µg/L with 5th, 50th and 95th percentiles of 0.06, 0.4 and 1.8 µg/L, respectively.

- In the sediment, chromium concentrations range from 2.0 to 1,748.0 mg/kg with 5th, 50th and 95th percentiles of 6.0, 21.0 and 63.0 mg/kg, respectively (Table 1).

-Taking into account the high quality and representativeness of the data set, the 95th percentile of 1.8 µg/L can be regarded as representative background concentration for dissolved chromium in European surface waters and the 95th percentile of 63.0 mg/kg as representative background concentration of chromium in European stream sediments.

-Regarding the partitioning of chromium in the water column, stream water/sediment partition coefficients range from 1,080 to 4,800,000 L/kg. Since FOREGS sampled on a grid aiming to equally represent geochemical baseline concentrations across Europe,a European median log Kp value of 4.75 is derived.

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

Parameter

#

Unit

Min.

Max.

5th P

50th P

95th P

water

pH 1

726 2

-

9.80

4.50

8.50

7.70

6.10

water

Ca

734

mg/L

0.23

592.00

1.60

42.28

144.21

water

Cl

734

mg/L

0.14

4,560.00

0.49

8.95

69.08

water

HCO3

7323

mg/L

0.69

1,804.42

5.34

128.01

370.00

water

K

734

mg/L

< 0.01

182.00

0.14

1.62

9.80

water

Mg

734

mg/L

0.05

230.00

0.46

6.15

36.81

water

Na

734

mg/L

0.23

4,030.00

1.00

6.66

48.30

water

NO3

734

mg/L

< 0.04

107.00

< 0.04

3.05

39.91

water

DOC

732 4

mg/L

< 0.50

57.94

0.60

4.84

23.11

water

SO42-

734

mg/L

< 0.30

2,420.00

1.18

16.79

164.56

water

Cr

734

µg/L

< 0.01

43.03

0.06

0.38

1.81

sediment

Cr

734

mg/kg

2.00

1,748.00

6.00

21.00

63.00

Partitioning (Kp)

Cr (sed/water)

734

L/kg

1,080

4,800,000

8,570

56,119

390,841

Log Kp

Cr (sed/water)

734

-

3.03

6.68

3.93

4.75

5.59

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 chromium levels in topsoil range from 1.0 to 2,340.0 mg/kg with5th, 50th and 95th percentiles of 5.0, 22.0 and 69.8 mg/kg, respectively (see Table 2).

- Taking into account the high quality and representativeness of the data set, the 95th percentile of 69.8 mg/kg can be regarded as representative background concentration of chromium in topsoil of EU countries.

Table 2: Concentrations of chromium 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

Cr

mg/kg

825

1.00

2,340.00

5.00

22.00

69.80

Statistics are based on H+ concentrations rather than pH.

GEMAS DATABASE AGRICULTURAL AND GRAZING LAND SOIL CONCENTRATIONS:

- Chromium levels of agricultural soil range from 0.40 to 696.02 mg/kg with 5th, 50th and 95th percentiles of 4.2, 19.9 and 67.2 mg/kg, respectively (see Table 3). In grazing land, soil concentrations of chromium range from 0.8 to 576.7 mg/kg with 5th, 50th and 95th percentiles of 3.9, 19.8 and 67.8 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

Chromium

mg/kg

AR

1,867

0.40

696.02

4.16

19.87

67.16

Chromium

mg/kg

XRF

1,867

2.00

6,133.00

14.00

58.00

191.00

Chromium

mg/kg

MMI

1,867

< 0.001

1.30

0.01

0.07

0.26

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

Chromium

mg/kg

AR

1,781

0.78

576.74

3.87

19.75

67.82

Chromium

mg/kg

XRF

1,781

2.00

6,594.00

13.00

59.00

187.00

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

compartment, unit, concentration (50th P), concentration (95th P)
background stream water, µg/L Cr, 0.4, 1.8
background stream water sediment, mg/kg Cr, 21.0, 63.0
background topsoil, mg/kg Cr, 22.0, 69.8
agricultural soil, mg/kg Cr, 19.9, 67.2
grazing land soil, mg/kg Cr, 19.8, 67.8

Based on the FOREGS dataset, the 95th percentile of 1.8 µg/L can be regarded as representative background concentration for dissolved chromium in European surface waters and the 95th percentile of 63.0 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 4.75 is derived.

Based on the FOREGS dataset, the 95th percentile of 69.8 mg/kg can be regarded as representative background concentration of chromium in topsoil of EU countries. Representative chromium concentrations (95th percentile) of agricultural and grazing land soil (i.e. ambient levels) amount to 67.2 and 67.8 mg/kg, respectively, according to the GEMAS dataset.


Data source

Materials and methods

Results and discussion

Applicant's summary and conclusion