Test conditions should be optimized to address specific analytes. However, it is not always possible to specify test conditions which are suitable for the measurement of inorganic and organic substances at the same time. Such conditions can also vary especially for various groups of organic constituents. Test requirements for organic constituents are generally more decisive for the quality of the analysis and test conditions which are appropriate for measuring the release of organic substances will mostly be applicable to inorganic constituents also.
In the figures below, the relationship between the concentration and relative repeatability standard deviation (RSDr) and relative reproducibility standard deviation (RSDR) is given for the content analysis of inorganic substances in soils, sludge, waste, biowaste and construction products. Apart from some obvious outliers, there is a clear increase in RSDr and RSDR as the concentration decreases. This matches with the relationship defined by Horwitz and Albert (2006). The consistency of the performance across fields indicates that comparison of performance data in tabulated form does not sufficiently consider the role of concentration level in validation studies.
Figure 1. Relative repeatability and reproducibility standard deviations for validation studies for As and Cd content in soil, sludge, biowaste (Project Horizontal abbreviation HOR, CEN/TC400; now TC444 – EN16171), waste (CEN/TC292; now TC444 – EN13657) and construction products (CEN/TC351 – EN17201).
Figure 2. Relative repeatability and reproducibility standard deviations for validation studies on Cr and Cu content in soil, sludge, biowaste, (Project Horizontal abbreviation HOR, CEN/TC400; now TC444 – EN16171), waste (CEN/TC292; now TC444 – EN13657) and construction products (CEN/TC351 – EN17201).
Figure 3. Relative repeatability and reproducibility standard deviations for validation studies on Hg and Mo content in soil, sludge, biowaste (Project Horizontal abbreviation HOR, CEN/TC400; now TC444 – EN16171), and construction products (CEN/TC351 – EN17201).
Figure 4. Relative repeatability and reproducibility standard deviations for validation studies on V and Zn content in soil, sludge, waste, biowaste (Project Horizontal abbreviation HOR, CEN/TC400; now TC444 – EN16171), waste (CEN/TC292; now TC444 – EN13657) and construction products (CEN/TC351 – EN17201).
The above information can be used to judge individual test results. In case of critical evaluations, it is recommended to perform the needed analysis at least in duplicate.
Observations:
In the figures below, the relationship between the concentration and relative repeatability standard deviation (RSDr) and relative reproducibility standard deviation (RSDR) is given for the content analysis of organic contaminants in soils, sludge, waste, biowaste and construction products. Apart from some obvious outliers, there is a clear increase in RSDr and RSDR as the concentration decreases. This matches with the relationship defined by Horwitz and Albert (2006). The consistency of the performance across fields indicates that comparison of performance data in tabulated form does not sufficiently consider the role of concentration level in in performance.
Figure 1. Relative repeatability and reproducibility standard deviations for validation studies for PAH (polyaromatic hydrocarbons) content in soil, sludge, biowaste, waste and construction products.
Figure 2. Relative repeatability and reproducibility standard deviations for validation studies for PCB (polychlorobiphenyls) content in soil, sludge, biowaste, waste and construction products.
Figure 3. Relative repeatability and reproducibility standard deviations for validation studies for DL-PCB (dioxin like
polychlorobiphenyls) content in soil, sludge and biowaste.
Figure 4. Relative repeatability and reproducibility standard deviations for validation studies for PCDD-PCDF (dibenzofurans and polychlorinated dibenzo-p-dioxins) content in soil, sludge and biowaste.
Figure 5. Relative repeatability and reproducibility standard deviations for validation studies of the content of phtalates (DMP, DBP, DEHP) in soil, sludge and biowaste (Project Horizontal – abbreviation HOR and BAM study using CEN/TS 16183) and construction products (sealants in TC 351 Robustness) using CEN/TS 16183.
Figure 6. Relative repeatability and reproducibility standard deviations for validation studies of the content of different phenols (phenol, nonylphenol NP, nonylphenol monoethoxylate and diethoxylate, bisphenol A, chlorophenols) in soil, sludge and biowaste (Project Horizontal – abbreviation HOR) and construction products (render and waterproofing sheets in TC 351 Robustness) using CEN/TS 16182.
Figure 7. Relative repeatability and reproducibility standard deviations for validation studies of the content of polybrominated diphenyl ethers (PBDE) in soil, sludge and biowaste (Project Horizontal – abbreviation HOR) and construction products (polyethylene reference in TC 351 Robustness) using EN ISO 22032.
Observations:
Leaching tests are not suitable for the determination of the release of substances that are volatile under ambient conditions.
Eluates obtained by leaching procedures such as ISO 21286 series (soil), EN 12457 series (various solid matrices such as waste, soil, compost, biowaste etc., to be adapted for the analysis of organic substances), CEN/TS 16637 series (construction products) can be used for subsequent testing of ecotoxicological effects of the released substances.
For guidance on ecotoxicological testing see ISO 15799, ISO 17616, CEN/TS 17459.
In the framework of the EU Project Harmonisation of leaching test, pH dependence tests were performed on a wide range of materials and products. The list is given in the table below. The tests were carried out in duplicate and covered per element a wide range of concentrations due to the fact that the pH in the test varies from around 2 to 13. The repeatability of the analysis is derived from the duplicate test and presented in graphs by element as the variation of the relative standard deviation versus the average of the measured eluate concentrations. For a number of elements the information has been grouped according to largely inorganic materials vs. materials with a relatively high content of organic matter. This factor can lead to higher uncertainties due to variability in DOC level. In other cases, samples show heterogeneity (Contaminated sediment MAL, stabilized waste, galvanic sludge).
| Code No | Materials | Short Description |
| SOI 1 | Soil | Loamy soil Horizon A |
| SOI 2 | Soil | Loamy soil Horizon B |
| CSO 1 | Contaminated soil | Metal contamination intermediate |
| CSO 2 | Contaminated soil | Metal contamination high -sewage sludge amended |
| SED 1 | Sediments | Relatively clean |
| SED 2 (MAL) | Sediments | Elevated metal leachability |
| CW 1 | Compost | “clean compost” from putricibles only |
| CW 5 | Compost | MSW compost |
| SEW 1 (RWZI) | Sewage sludge | Rural sewage sludge |
| SEW 2 (IPF) | Sewage sludge | Contaminated urban sewage sludge |
| GAL | Waste | Filtercake from industrial waste treatment-galvano sludge |
| MFA | Waste | MSWI fly ash |
| SSI | Waste | Ash from sewage sludge incineration |
| STG | Stabilized waste materials | Stabilized product from waste 1 |
| STF | Stabilized waste materials | Stabilized product from waste 2 |
| CFA | Construction material | Concrete with additives/admixtures (coal fly ash) |
| ABA | Construction material | Asphalt with MSWI Bottom ash |
| BRI | Construction material | Sintered bricks |
| MBA | Aggregates | Granulated slag e.g. sieved,aged MSWI Bottom ash |
| RDW | Aggregates | Recycled demolition waste |
| DWP | Drinking water pipes | Cement mortar |
| IWO 1 | Impregnated wood | Metal salt impregnated wood |
| IWO 2 | Impregnated wood | Metal salt impregnated wood |
Origin:
Harmonization of leaching/extraction tests, 1997. Studies in Environmental Science, Volume 70. Eds H.A. van der Sloot, L. Heasman, Ph Quevauviller, Elsevier Science, Amsterdam, 292 pp.
Additional information for all other major, minor and trace elements is given here: All elements repeatability eluate analysis
In the framework of the Robustness validation of analysis methods for construction products in CEN/TC 351 ICP-OES and ICP-MS measurements were done on a selection of construction product eluates (CEN/TC 351 Robustness validation of the draft methods for eluate and content analysis of inorganic substances – FINAL REPORT on substances other than As, Sb and Se, ALS Global for NEN Standards, December 2016 – https://wpn.acceptatie.nen.nl/en/cen-tc-351 and Vanhoof, C., Tirez, K., Robustness validation of the draft methods for eluate and content analysis of As, Sb and Se, VITO Report 2016/SCT/R/665. Available from www.centc351.org).
For the robustness study, measurements were performed with ICP-SFMS as well as ICP-OES. The eluates were preserved with 1% HNO3. Each eluate was analysed 10-fold and the average and repeatability standard deviation calculated. The results have been sorted by method and condition and the relative repeatability standard deviation (RSDr) was plotted against the average concentration in the respective eluate sample. The LOD of ICP-OES is generally higher than for ICP-MS. The relative repeatability standard deviation increases as the concentration decreases in a typical curve with a different end point depending on the LOD of the specific measurement option. At measurement levels well above the LOD the methods perform very similarly.
Table of tested eluates
| Code No | Materials | Short Description |
| CFA E1 | Coal fly ash | CEN/TS 16637-3 Fraction 1-3 Cumulative L/S=0.5 |
| CFA E2 | Coal fly ash | CEN/TS 16637-3 Fraction 7 Cumulative L/S=10 |
| CMU E1 | Clay masonry unit | CEN/TS 16637-2 Fraction 1 |
| CMU E2 | Clay masonry unit | CEN/TS 16637-2 Fraction 3 |
| ECL E1 | Expended clay | CEN/TS 16637-3 Fraction 1-3 Cumulative L/S=0.5 |
| ECL E2 | Expended clay | CEN/TS 16637-3 Fraction 7 Cumulative L/S=10 |
| MAS E1 | Masonry product | CEN/TS 16637-3 Fraction 1-3 Cumulative L/S=0.5 |
| MAS E2 | Masonry product | CEN/TS 16637-3 Fraction 7 Cumulative L/S=10 |
| MSS E1 | Steel slag | CEN/TS 16637-2 Fraction 1 |
| MSS E2 | Steel slag | CEN/TS 16637-2 Fraction 3 |
| NAG E1 | Natural aggregate | CEN/TS 16637-3 Fraction 1-3 Cumulative L/S=0.5 |
| NAG E2 | Natural aggregate | CEN/TS 16637-3 Fraction 7 Cumulative L/S=10 |
| SRM1 | Standard reference material | Solution |
| TILE E1 | Tiles or ceramic tiles | CEN/TS 16637-2 Fraction 1 |
| TILE E2 | Tiles or ceramic tiles | CEN/TS 16637-2 Fraction 3 |
Figure 1. Repeatability standard deviations for Al and As derived from tenfold analysis of eluates from CEN/TS 16637-2 and CEN/TS 16637-3 by ICP-OES and ICP-MS.
Figure 2. Repeatability standard deviations for Ba and B derived from tenfold analysis of eluates from CEN/TS 16637-2 and CEN/TS 16637-3 by ICP-OES and ICP-MS.
Figure 3. Repeatability standard deviations for Cr and Cd derived from tenfold analysis of eluates from CEN/TS 16637-2 and CEN/TS 16637-3 by ICP-OES and ICP-MS.
Figure 4. Repeatability standard deviations for Mo and Zn derived from tenfold analysis of eluates from CEN/TS 16637-2 and CEN/TS 16637-3 by ICP-OES and ICP-MS.
Figure 5. Repeatability standard deviations for As, Sb and Se derived from fivefold analysis of eluates from CEN/TS 16637-2 and CEN/TS 16637-3 by HG-ICP-OES and ICP-MS.
Conclusions:
In the figure below the performance of ICP OES vs ICP MS is shown for Cr and Cu. The sensitivity if ICP MS is obviously greater than ICP OES for these elements. The pattern of repeatability vs concentration is very similar reflecting that as concentrations start to approach the detection limit if the method the repeatability goes up. Several data far outside the range of expected behaviour point at sample heterogeneity, as the sensitivity should be more than enough to obtain more reproducible results at concentrations larger than 0.01 mg/l.
Black and blue points reflect repeatability data obtained by ICP MS from CEN/TC 351 robustness on eluates from a range of construction products. Orange dots: repeatability data from replicates of the pH dependence test on a wide range of soils, sludges, wastes and construction products.
In the figures below, the relationship between the concentration and relative repeatability standard deviation (RSDr) and relative reproducibility standard deviation (RSDR) is given for the eluate analysis of organic contaminants from leaching of soils, sediments and construction products. Apart from some obvious outliers, there is a clear increase in RSDr and RSDR as the concentration decreases. This matches with the relationship defined by Horwitz and Albert (2006). The consistency of the performance across fields indicates that comparison of performance data in tabulated form does not sufficiently consider the role of concentration level in performance.
Figure 1. Relative repeatability and reproducibility standard deviations for validation studies of PAH in eluates from leaching of soil, sediments and construction products.
Observations:
References
TC351 validation study JRC
Horwitz, R. Albert (2006) The Horwitz ratio (HorRat): A useful index of method performance with respect to precision. Mathematics, Medicine, Journal of AOAC International.
BAM studies on DIN 19528
