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Fly ash is produced in massive quantities by fossil fuel based power plants and waste incinerators, and contains high levels of potentially toxic chemicals. Various leaching tests exist to determine the available fractions, but the outcome is strongly dependent on the experimental conditions, and these have not yet been harmonised at the international level. In order to test existing protocols for heavy metals, several intercomparisons were organised within the framework of an EU-INCO project "ANALEACH", in which seven institutes from five countries participated. Two existing reference materials were made available for the project and test batches of two new fly ash reference materials were produced. Availability tests, leaching tests and pH-stat tests were studied and critical steps in the procedures were identified. Fly ashes can also contain large amounts of inorganic sulphur and nitrogen compounds, and the determination and leaching behaviour of these compounds were also studied. In one intercomparison for metals, inorganic S and N-compounds were also included. A five-step leaching test was optimised for fly ash in order to link metal fractions to different types of binding. Column leaching experiments were carried out to investigate leaching from fly ash into soil, mimicking the effects of (acid) rain on fly ash deposited on topsoil after atmospheric transport. The major fraction of the leached metal ions was retained by the soil. Also large numbers of organic compounds (including many toxic ones) were identified in fly ash extracts, especially in city waste incinerator ash. Leaching procedures based on ultrasonic extraction were developed for organic compounds and an intercomparison exercise was organised. In a field study at the river Nitra(Slovakia) numerous organic pollutants were found at elevated levels downstream from a major fly ash dump site.

A comparison of five different leaching/extraction tests, each characterized by different parameters such as liquid/solid ratio, pH, leachant, stirring conditions, duration time, has been performed on a highly homogenized fly ash reference material. Eight different elements (As, Cd, Cr, Cu, Ni, Pb, Se, Zn) have been considered in this study. The results show that, among all the considered experimental parameters, pH seems to have the greatest influence on metal release.

The Standards, Measurements and Testing Programme (SM&T) of the European Commission (continuation of the BCR and Measurements and Testing Programmes) aims to contribute to the harmonization and improvement of methods and measurements carried out within the European Union and hence to the comparability of data necessary for e.g. trade activities, monitonng of environment, food and health, etc. One of the tool currently used to achieve this goal is the organization of interlaboratory studies (intercomparisons and certifications of reference materials) in which laboratories may collaborate to improve the measurement or analysis concerned. Other activities are related to development of new methods and prenormative research. Examples of projects undertaken within the Measurements and Testing Programme (1990-94) are given in this paper, covering different aspects, namely interlaboratory study on modern pesticides in freeze dried water, certification of Cr-species in water and welding dust, evaluation o...

Analytical procedures for the determination of organotin compounds in sea water, sediments and mussels have been adopted in our laboratory, intercomparison/certification exercises with other European laboratories giving satisfactory results. The characteristics of the different methodologies are discussed, the balance between practical and analytical aspects leading to the selection of the following procedures. For water samples two alternative extraction techniques are used: liquid/liquid extraction (0.3% tropolone in methylene chloride) or liquid/solid extraction (C18- or Carbopack B-loaded extraction tubes). Solid-phase extraction ensures good results and is more suitable in the field, avoiding high volumes of organic solvents and transport of fragile glassware. Extraction rubes can be easily stored, and problems with the transfer of whole samples to the laboratory, and storage and conservation problems are prevented. For sediments and mussels, sonication (0.05% tropolone in methanol) can be u...