SURICATES : demonstration through pilots of sediment reuse for coastal defence or climate change mitigation

The SURICATES project is a research initiative funded by the European Union regional funds (INTERREG NWE), aimed at increasing the reuse of dredged sediments

The effects of floods and flood-induced pollution on ecosystem health

Flooding not only induces a risk which is related to direct loss of life for humans, animals and plants. During flooding, toxicants which are normally stored or otherwise unavailable might be released. The spreading of these pollutants during the flooding or, often more important, the persistent presence of toxicants in the soil or sediment after the flooding poses an environmental risk. Within Task 10 of FLOODsite, the effect of toxic stress induced by flooding was studied in a case study (Western Scheldt). For this case study, a relation between toxic concentration levels in water and sediment and acute and chronic toxic stress levels on organisms was needed. The scientific principle on which the EU Water Framework Directive (WFD) is based is that relationships between the biological state and physical and chemical properties of surface waters dictate the ecological state of the water system. Toxic stress is part of the chemical properties of the water system. Within the EU 6th framework programme REBECCA (Contract SSP1-CT-2003-502158) the relation between concentration levels of individual toxicants and their potential total toxic effect was researched. This knowledge can then be used within FLOODsite to calculate ecotoxicological stress during and after flooding. The aim of this research was to develop a model framework in which the ecotoxicological stress levels in the water phase can be predicted (OMEGA). The model includes insights in how to combine the toxic risk of different toxicants. This model was used in a case study for the Western Scheldt for an area with nature reserve areas which is regularly flooded to predict the toxic risk for different groups of organisms. Also, a case study for a simulated dike breach flooding in the Western Scheldt area (nearby the city of Middelburg) was carried out to establish the spreading of pollutants during a flood. The source and 'fingerprint' of the pollutants was diverse and based on land use (farming, industry, etc.), urban area and background concentrations in the water. By 'fingerprint' is meant that each source had a different mixture of toxic components. The results of this case study were maps with areas of high and low pollution after a spreading, which could thereafter be used for toxic risk prediction.Floodsit

Variation in the availability of metals in surface water, an evaluation based on the dissolved, the freely dissolved and Biotic Ligand Model bioavailable concentration

In this study the spatial distribution of dissolved metals in surface water is studied at nine locations in Lake Ketelmeer (the Netherlands). The measured dissolved metal concentrations are combined with the local water quality parameters for salinity, pH, alkalinity and DOC to calculate a FIAM Free Ion Activity Model (FIAM) and the Biotic Ligand Model (BLM) based bioavailable metal concentration. The BLM model is used for Cu, Ni, Pb and Zn and the FIAM model for Cd, Cr, Cu, Ni, Pb and Zn. To be able to compare the dissolved metal concentration with the FIAM or BLM based bioavailable metal concentration, an accepted reference standard can be used which is also corrected for the bioavailable concentration. Here the Water Framework Directive (WFD) Annual Average Quality Standard (AA-QS) is used, corrected for the FIAM and BLM based bioavailable metal concentration under reference conditions. This yielded a site specific Risk Characterization Ratio (RCRFIAM/RCRBLM). The FIAM model shows an exceedance of the site specific AA-QS for Cu (RCRFIAM of 1.8) and Pb (RCRFIAM of 1.5) in the northern middle part of the lake. This is due to a lower pH in this part of the lake. The BLM model was inconclusive with regard to spatial trends for Cu and Ni due to out of boundary conditions for the model. For locations where the BLM model was within the model boundary conditions, the RCRBLM could be as high as 7.5 for Cu and 3.2 for Ni. The main water quality parameter causing the high RCRBLM was the low DOC concentration. To establish if the locally increased RCR for Cu and Pb (FIAM) or Cu and Ni (BLM) poses an ecotoxicological risk to organisms the multi substances Potentially Affected Fraction (ms-PAF) model is used. The FIAM based ms-PAF indicates that the northern middle part of the lake has the highest chronic metal exposure risk, with an ms-PAF of 27%. The BLM based ms-PAF has a maximum of 45%, but lacks a spatial trend due to the missing BLM corrected Cu and Ni concentrations for some locations.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Geo-engineerin

Handleiding uitloging en verspreiding vanuit Depots: Naar een nieuw toetsingskader

De noodzaak om te baggeren in Nederland is evident. Dit werd onlangs opnieuw bevestigd door het in juli 2005 verschenen Kabinetstandpunt Waterbodems [1]. Hierin wordt aangegeven dat het uit economisch oogpunt (scheepvaart) noodzakelijk is om de baggerachterstand in Nederland op korte termijn weg te werken. Om de veiligheid in Nederland te kunnen waarborgen, zullen in de komende decennia bovendien grote hoeveelheden uiterwaardmateriaal vrijkomen in het kader van de projecten Ruimte voor de Rivier [2] en Zandmaas/Grensmaas [3]. Daarnaast is een aantal waterbodems zodanig vervuild dat in het kader van de Wet bodembescherming [4] sanering noodzakelijk is vanwege onaanvaardbare risico’s voor het oppervlaktewater, de natuur, de mens en het grondwater. Daarbij worden tevens de doelstellingen van de Kaderrichtlijn Water [5] in ogenschouw genomen. De ervaringen in de afgelopen decennia hebben geleerd dat verwerking en toepassing van alle vrijkomende baggerspecie niet haalbaar is. Dit heeft niet alleen te maken met de kosten van verwerking en toepassing, maar ook met de civieltechnische eigenschappen van baggerspecie. In het Kabinetstandpunt baggerspecie wordt ingezet op kosteneffectieve bestemmingen. Niet langer wordt een verwerking van 20% van het vrijkomende volume aan baggerspecie nagestreefd. Nadrukkelijker wordt ingezet op berging van baggerspecie in depots

From sediments to soils: changes in pore water metal bioavailability

Abstract: The use of sediments as soils is an area of interest for Beneficial Use of dredged sediments. In this study the impact of the transition from sediments to soils is researched by looking at the seasonal and long year (10 year) change in pore water metal chemistry of sediments which are considered clean (class A) according to the Dutch soil directive. This study is based on a combination of geohydrological, geochemical and ecotoxicological risk models and validated against measured pore water concentrations for metals over an dry/wet period. The pore water metal concentrations are compared against standards and expressed as at Risk Characterization Ratio’s (RCR) values. The RCR values are high (> 1) during the first 3 years after the application of sediments as soil, especially at the end of the summer. The multi substances Potentially Affected Fraction (ms-PAF) shows a similar trend as the RCR values, although it takes 5 years before the combined calculated potential ecotoxicity is below the legal 40% threshold level. Translated to land use, it is advised to restrict land use for farming on soils where these clean (class A) sediments are applied for a five-year transition period. Article Highlights: Beneficial Use of sediments should take into account the different conditions when used as soils.Use of sediments as soils lead to a predicable seasonal and multiple year trend in metal concentrations in pore water.The predicted results in metal pore water concentrations are translated into an advice for temporal land use.Geoscience and Engineerin