Chromium iron oxide

Monitoring data

Administrative data

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

Data source

Reference

Reference 1

Reference Type:

publication

Title:

Unnamed

Year:

2005

Report date:

2005

Reference 2

Reference Type:

other: GEMAS database

Title:

Chemistry of Europe’s agricultural soils - Part A: Methodology and interpretation of the GEMAS data set.

Author:

Reimann et al.

Year:

2014

Reference 3

Reference Type:

study report

Title:

Unnamed

Year:

2021

Report date:

2021

Materials and methods

Test guideline

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

Test material

Test material information

Constituent 1

Reference substance name:

not applicable

IUPAC Name:

not applicable

Test material form:

other: elemental concentrations

Details on test material:

natural occuring chromium

Study design

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.

Results and discussion

Any other information on results incl. tables

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 5^th, 50^th and 95^th 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 5^th, 50^th and 95^th 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 95^th percentile of 1.8 µg/L can be regarded as representative background concentration for dissolved chromium in European surface waters and the 95^th 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.	5^thP	50^thP	95^thP
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	732^3	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	SO4^2-	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

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

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

³ Removal of 2 outliers < 0.01.

⁴ 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 with5^th, 50^th and 95^th 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 95^th 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.	5^thP	50^thP	95^thP
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

¹ 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 5^th, 50^th and 95^th 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 5^th, 50^th and 95^th 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.	5^thP	50^thP	95^thP
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.	5^thP	50^thP	95^thP
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

Applicant's summary and conclusion

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.