Om de effecten te voorspellen van giftige stoffen die zich diffuus in het milieu verspreiden is het nodig om de lokale milieucondities in kaart te brengen. Dit blijkt uit een evaluatie van resultaten uit het Nederlandse Stimuleringsprogramma Systeemgericht Ecotoxicologisch Onderzoek (SSEO) die uitgevoerd is onder leiding van het RIVM.<br>De afgelopen zes jaar zijn op drie verontreinigde locaties in Nederland de effecten onderzocht van giftige stoffen op milieu, planten en dieren. De locaties betroffen de uitwaarden van een grote rivier (de Waal), een getijdegebied (de Biesbosch) en een veenweidegebied (nabij Vinkeveen). Op deze plekken hebben zich giftige stoffen verspreid over de omgeving. Van deze diffuse verontreinigingen werden de omvang en effecten gemeten en geanalyseerd.<br>Uit het onderzoek blijkt dat de effecten varieerden tussen niet-waarneembaar of zeer gering tot waarneembaar en groot. De grootte van de effecten hing af van de aanwezige stoffen en hun concentraties, de eigenschappen van bodem, water of sediment op de locatie, en de gevoeligheid van planten en dieren die werden blootgesteld aan de stoffen. Dit maakt duidelijk dat milieucondities voor een deel de effecten van de stoffenmengsels bepalen.<br>De meetmethoden en modelanalyses van het SSEO-programma blijken bruikbaar voor het beheersen van lokale risico's van verontreinigingen. Voor Nederland is het heel belangrijk om deze instrumenten op grotere schaal toe te passen gezien de vele diffuus verontreinigde locaties. Saneren is op die plekken geen oplossing. Om de risico's van deze verontreinigingen te beheren adviseert het RIVM een risicotoolbox te ontwikkelen. Toepassing daarvan is nodig voor een betere op ecologie gebaseerde effectbepaling. Dit kan uiteindelijk leiden tot een koppeling tussen stoffenbeleid en gebiedsbeheer.<br>

Soils contaminated with volatile substances can affect the air quality in buildings located in the vicinity of these substances. This guidance describes measurement techniques and the corresponding risk assessment of volatile substances in air caused by soil pollution. The results form the basis for soil decision-making on remediation by the local authorities. The guidance describes in seven steps how health risks from volatile substances in contaminated soil can be assessed using air measurements in and around the house. Possible areas for taking measurements are the living room, the area under the ground floor and in the soil itself. For this, an effective study strategy is important. Before risk assessors begin measuring, they need to first determine whether it is worthwhile. Subsequently, they need to determine target and pre-condition prior to proceeding with measurement. This method is more effective than first measuring and subsequently adjusting target and pre-conditions. The report provides general instructions for the interpretation of obtained data. This guidance is not meant as a rigid protocol but as an aid for all who have to carry out the measurements and interpret results. Furthermore, the guidance can help those who have to decide about taking remedial measures based on risk assessment.

RIVM has developed an approach which allows human health risks of vegetable consumption from contaminated sites to be assessed. A tiered approach was used to guarantee the scientific basis and efficient use in practice. The underlying principle is: simple when possible and complex when necessary. If the risk can be eliminated in an early step, the assessment can be stopped. If not, assessment continues in the next tier, becoming more site-specific with each tier. This results in a more realistic, but also more time-consuming, assessment. The approach consists of four tiers that are laid out as follows. Tier 0, which precedes the calculation and measurement tiers, investigates the possibilities for experiencing adverse human health effects due to vegetable consumption. Subsequently, the soil concentrations of pollutants are measured in Tier 1 and compared with so-called Critical soil concentrations (for which vegetable consumption from contaminated sites is safe). Tier 2 offers the possibility for a detailed assessment of the site-specific risks for human health on the basis of calculation. Finally, Tier 3 shows a standardized measurement protocol. This protocol offers guidance and advice on the type and amount of crops that can be sampled in the field, thereby providing an indication for human health risks.

The National Institute for Public Health and the Environment has derived Reference Values for maximum permissible soil pollution. The Netherlands Ministry of Housing, Spatial Planning and the Environment (VROM) used these values as a basis for the maximum values for soil pollution. The ministry set these values down according to a proposal for an update of soil policy and the Soil Protection Act in 2003. Reference values refer to allowed concentrations of pollutants in soil, depending on the land use. The soil concentrations of pollutants with values below these concentrations meet all the requirements. The risks for humans, the ecosystem and agriculture were analyzed as critical factors, with risk thresholds derived for different types of land use, such as playgrounds, gardens, and agricultural and nature areas. Furthermore, an accelerated procedure was used to compile a complete list of reference values in 2006. The RIVM used state-of-the-art knowledge to complete the 'old' knowledge for information on toxicity of substances; figures were used where knowledge gaps occurred. A recommendation for the coming years is to address resulting inconsistencies in the list of reference values.