Lake Sediment

This environmental certified reference material (CRM) was developed and certified by the National Institute for Environmental Studies (NIES) for the determination of multi-elements in lake sediment and in materials of similar matrix. This CRM supersedes NIES CRM No. 2 Pond Sediment. Certified values and reference values are given for the whole material as supplied, and for the HCl/HNO3/HClO4 extract, determined according to “The Methods for Sediment surveillance ” of the Ministry of the Environment, Japan (August, 2012).

Certified values of NIES CRM No.31 in the whole material as supplied

Element Mass fraction Analytical method
Unit Certified value Uncertainty
Na % 0.882  0.063  AAS, ICP-OES, INAA, XRF
Al % 9.17  0.86  AAS, ICP-OES, ICP-MS, INAA, XRF
Ca %  1.25  0.12  ICP-OES, ICP-MS, XRF
Ti %  0.442  0.044  ICP-OES, ICP-MS, XRF
Fe %  5.38  0.55  ICP-OES, ICP-MS, INAA, XRF
P mg/kg  925  60  AAS, ICP-OES, XRF
V mg/kg  154  11  ICP-OES, ICP-MS, INAA
Cr mg/kg  43.3  3.0  ICP-OES, ICP-MS, INAA, XRF
Mn mg/kg  978  92  ICP-OES, ICP-MS, INAA, XRF
Ni mg/kg  25.3  2.8  ICP-OES, ICP-MS
Cu mg/kg  53.1  4.6  ICP-OES, ICP-MS, INAA, XRF
 Zn  mg/kg  121  13  ICP-OES, ICP-MS, INAA, XRF
 Pb  mg/kg  25.1  2.5  ICP-OES, ICP-MS

AAS: atomic absorption spectroscopy
ICP-OES: inductively coupled plasma optical emission spectrometry
ICP-MS: inductively coupled plasma mass spectrometry
ID-ICP-MS: isotope dilution-ICP-MS
INAA: instrumental neutron activation analysis
XRF: X-ray fluorescence spectroscopy

Reference values of NIES CRM No.31 in the whole material as supplied

Element Mass fraction Analytical method
Unit Reference value Uncertainty
Mg % 0.836 0.068  AAS, ICP-OES, ICP-MS, INAA, XRF
K % 0.991 0.134  AAS, ICP-OES, ICP-MS, INAA, XRF
Sc mg/kg 19.1 3.4  ICP-OES, ICP-MS, INAA
Co mg/kg 18.1 1.9  ICP-OES, ICP-MS, INAA
As mg/kg 13.9 1.5  ICP-MS, INAA
Sr mg/kg 125 14  ICP-OES, ICP-MS, XRF
Ba mg/kg 338 49  ICP-OES, ICP-MS, INAA, XRF
La mg/kg 20.4 2.2  ICP-OES, ICP-MS, INAA
Cd mg/kg 0.342 0.043  ICP-MS, ID-ICP-MS

 

Certified values of NIES CRM No.31 in the HCl/HNO3/HClO4 extract

Element Mass fraction Analytical method
Unit Certified value Uncertainty
 V mg/kg  133 23  ICP-OES, ICP-MS
 Mn mg/kg  881  85  AAS, ICP-OES, ICP-MS
 Ni mg/kg  22.2  2.3  ICP-OES, ICP-MS
 Cu mg/kg  50.6  8.1  ICP-OES, ICP-MS
 Zn mg/kg  110  13  AAS, ICP-OES, ICP-MS
 Pb mg/kg  22.0  3.0  ICP-OES, ICP-MS

AAS: atomic absorption spectroscopy
ICP-OES: inductively coupled plasma optical emission spectrometry
ICP-MS: inductively coupled plasma mass spectrometry

Reference values of NIES CRM No.31 in the HCl/HNO3/HClO4 extract

Element Mass fraction Analytical method
Unit Reference value Uncertainty
 Cr mg/kg 33.7 6.1 ICP-OES, ICP-MS 
 Cd mg/kg  0.285  0.067 ICP-OES, ICP-MS

 

Characterization

The property values of the material were statistically determined based on chemical analyses by 13 organizations (including 20 laboratories) using a wide range of methods. A property value satisfying the following conditions was accepted as a certified value: 1) the relative standard deviation associated with the mean of the laboratory means was under 10 %; 2) the number of laboratories contributing to the mean of the laboratory means was at least ten; 3) the number of analytical methods contributing to the mean of the laboratory means was at least two. The uncertainty attached to the certified values is the expanded uncertainty using a coverage factor k = 2, corresponding to a confidence interval of approximately 95 %. A property value failing to satisfy one or two of the NIES criteria for certification but supplying valuable additional information about the material is given as a reference value. All certified and reference values were determined based on dry mass.

Description of the Material

The CRM is supplied as fine powder in an amber glass bottle. It is dark grayish-yellow in color.

Preparation of the CRM

The origin of this material is sediment collected at Lake Kasumigaura, Japan in February 1999. The raw sediment was dried in the sun at NIES and the clods that formed were crushed, sieved through a 2 mm sieve, and dried at 105 ºC overnight. This dry material was then ground in an alumina ball mill, and passed first through a 212 µm sieve and then through a 75 µm sieve. The sieved material was homogenized with a V-blender to yield 12.2 kg of powder suitable for use as the CRM. The final material was placed in amber glass bottles (20 g in each bottle, 560 bottles), and sterilized by 60Co irradiation (20 kGy). All procedures complied with ISO GUIDE 34.

Homogeneity

Mass fractions of multi-elements, including those for which certified values are given, were determined by XRF in material taken from 10 bottles selected from the total 560 bottles by stratified random sampling. The between-bottle variation evaluated by a one-way analysis of variance (ANOVA) showed the relative standard deviations between bottles for the analytes to be less than 1 %. The material, therefore, is sufficiently homogeneous for its intended use as a reference material.

Instructions for Use

  1. Care should be taken to avoid contamination when opening the bottles. It is desirable to use up the contents as quickly as possible after opening.
  2. This CRM should be kept tightly closed in its original bottle and stored in a desiccator at room temperature (≤30 ºC).
  3. Prior to weighing portions for analysis, the contents of the bottle should be shaken gently.
  4. It is recommended that a sample intake of 0.05 g is the minimum for convenient handling.
  5. Precautions should be taken to avoid inhalation of the material.
  6. This CRM should not be used for purposes other than research. When disposing of the material, local laws concerning processing and disposal of waste materials should be strictly adhered to.
  7. The mass fractions of elements in this CRM are reported on a dry mass basis. This CRM, as received, has less than 1 % water as measured in NIES by drying for 4 h at 105 ºC. Correction to dry mass should be determined by drying a separate sub-sample.

Expiry Date of Certification

The expiry date for the certified values of this CRM is December 2024 assuming that the recommended storage conditions are adhered to. NIES will notify via its website if any changes in the contents are recognized within the term of validity.

Collaborating Laboratories in Analysis

The certified and reference values for this CRM were based on analytical values from the following 13 participating organizations:
National Institute for Environmental Studies; China Institute of Atomic Energy; Elemental Analysis, Inc.; Environmental Control Center Co., Ltd.; Environmental Research Center Co., Ltd.; IDEA Consultants, Inc.; Japan Environment Sanitation Center; Japan Food Research Laboratories; Kanagawa Industrial Technology Center; Murata Keisokuki Service Co., Ltd.; Naitoh Environmental Science Co., Ltd.; Nippon Steel & Sumikin Technology Co., Ltd.; Shimadzu Techno-Research Inc.

Appendices




Appendix 1: Schematic flow-chart of the HCl/HNO3/HClO4 extraction method according to “The Methods for Sediment surveillance” (in Japanese) of the Ministry of the Environment, Japan (public notice, August 2012).


Appendix 2: Information values of Mass fractions of C, N, Si and S in NIES CRM No.31 Lake Sediment

Element Unit Mass Fraction Analytical Method
 C % 3.22 EA
 N % 0.373 EA
Si % 25.1 Gravimetry, XRF
S % 0.391 ICP-OES

EA: elemental analysis
XRF: X-ray fluorescence spectroscopy
ICP-OES: inductively coupled plasma optical emission spectrometry