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DIN Standards Committee Water Practice

Overview

This document has been developed upon existing International Standards for the pretreatment of soils of specified particle fractions. In previous standards, analysis of organic compounds has been specified for samples after pretreatment according to, for example, ISO 14507. Standards specifying pretreatment for chemical and physico-chemical parameters, for example ISO 11464, historically have divided the samples into fractions < 2 mm and > 2 mm where the fraction < 2 mm was taken for testing. By this the concentrations determined and reported for organic compounds could be related to another part of the sample than those of the chemical and physico-chemical parameters. This European Standard does not stem from the assumption, however, that the same part of the original sample is used for all parameters to be analysed. For environmental investigation it is assumed that generally the whole sample is of interest and will be pretreated. Only extraneous materials may need to be removed under specific circumstances (and usually then will be reported accordingly). The pretreatment procedures described in this European Standard are not applicable if they affect the results of the determinations to be made. For example, the properties of the parameters to be analysed may differ greatly depending on chemical species: - they can range from non-volatile to very volatile compounds (low to high vapour pressure); - they may be labile or reactive at ambient or elevated temperatures; - they may be biodegradable or UV-degradable; - they may have considerable different solubilities in water. - they require different analytical procedures. Because of these differences, it is not possible to specify one general pretreatment procedure to fit all materials and goals of investigation. The aim of a pretreatment procedure is to prepare a test sample of which the content of a substance or a characteristic is equal to the original material, provided that the applied pretreatment procedure does not considerably alter the characteristic or the chemical nature of the substance to be analysed. It should be noted that every type of pretreatment will have an influence on certain material properties. Important for both sampling and pretreatment are the particle size distribution and form and the degree of chemical heterogeneity of the sample in relation to the minimum required mass of the sample. In general it can be stated that the smaller the particle size and form, and the less the chemical heterogeneity of the original material, the less sample mass is required for a reliable test or - the other way around - the coarser the particle size or the greater the range of particle size and forms, and the greater the chemical heterogeneity might be, the bigger the (sub)sample mass needs to be in order to perform a reliable test. The preparation of this document by CEN is based on a mandate by the European Commission (Mandate M/330), which assigned the development of standards on sampling and analytical methods for hygienic and biological parameters as well as inorganic and organic determinants, aiming to make these standards applicable to sludge, treated biowaste and soil as far as this is technically feasible. So far, the test methods for the determination of material properties in the environmental sector have been prepared in the technical committees (TCs) responsible for the individual products or materials (for example, soil, waste, sludge). It has been established, however, that single steps of test methods can also be used for analysis of various other materials. By thorough preparation of such steps and the selection of special questions within these steps, parts of the test methods can be specified in a way which allows for application for other matrices and materials within certain limits. This optimization is made together with the users of standards. The majority of routine inspections in the environmental sector are carried out by bodies and laboratories where the field of operation is not limited to one environmental matrix but covers a large variety of matrices. The availability of standards covering several matrices provides for optimization of workflows in laboratories and running expenses, for example, for accreditation and approval. A horizontal, modular approach has been developed in the project "Horizontal". "Modular" means that a standard prepared in accordance with this approach applies for a certain level during the evaluation of a property and not for the entire "measurement chain" (ranging from sampling to the individual analyses). An advantage of this approach is the replacement of individual "modules" by more suitable modules without the entire standardized "chain" becoming void.

Document: references other documents

Document: referenced in other documents

Responsible national committee

NA 119-01-02-01 UA - Sampling  

Responsible european committee

CEN/TC 444/WG 6 - Cross cutting issues