Research strategies and methods for contaminated soils in Finland

摘要

Geological Survey of Finland has completed a project, the objective of which was to find reliable investigation strategies and methods for contaminated soils. The applicability of the ISO-standard Draft, the Dutch prestandard and U.S. EPA recommendations to Finnish geological and hydrogeological environment was studied. Standard drafts turned out to be complicated and expensive to carry out in practice. However, the basic principles in strategies were found applicable also in Finland. During the project a new Finnish practice was created. Investigations on contaminated sites are divided into three phases: preliminary survey, field investigation and additional investigations. Based on the preliminary survey the site is either "probably uncontaminated" or "potentially contaminated". The distribution of the contaminants is always supposed to be heterogeneous in Finnish geological environment. Quality control samples reveal the quality of sampling and analyses. The local baselines (background values) must always be verified in any assessment of contaminated sites. The sampling pattern is determined after the preliminary survey and it is designed primarily case-by-case. The sampling intensity is recommended for both probably uncontaminated or potentially contaminated sites. The inventory of polluted soil masses is mainly based on the chemical analyses results that are compared with limits set by the authorities. Various leaching and test methods have been used in chemical laboratories making the comparison of test results difficult. Standardization of testing methods and active interaction between the authorities and the laboratories is therefore very important.