Water for utilities: climate change impacts on water quality and water availability for utilities in Europe

This report provides an assessment of the consequences of changing water availability for production of drinking water, the manufacturing industry and power production in Europe, due to climate change and socio-economic developments. The report is based up on projections of demographic and socio-economic trends and climate change impacts, according to the SRES A2 and B1 scenario’s also used by IPC

Opname van PCB's door vis in uiterwaardplassen

Veel uiterwaardplassen en andere oppervlaktewateren in Nederland worden gedomineerd door bodemwoelende vissen, zoals brasem. Door hun voedselgedrag komen deze vissen rechtstreeks in aanraking met het sediment, inclusief de daarin nog steeds aanwezige organische verontreinigingen. Ondanks het feit dat de PCB's al jaren in het sediment aanwezig zijn en wellicht met de tijd veel minder beschikbaar zijn geworden, wijzen onderzoeksresultaten erop dat de opname van PCB's uit uiterwaardsedimenten door vis nog steeds substantieel is. Tevens bleek dat de Tenax-methode een betere correlatie oplevert met PCB-opname door bodemwoelende vissen dan meting van het totaalgehalte van PCB's in sedimen

Geochemistry of trace metals in the Scheldt estuary

The distribution of trace metals has been studied in abiotic compartments of the ScheIdt estuary (water column and sediments). Seasonal surveys, carried out in 1987-1988, indicate that the geochemistry of dissolved trace metals (Cd, Cu, Zn) is determined by the redox status of the upper estuary, and by primary production in the lower estuary. During the warmer period (spring till autumn), the incoming river water is anoxic, leading to very low dissolved metal concentrations due to precipitation of metal sulphides. During winter, the river water is usually not completely devoid of oxygen (although highly undersaturated), precluding metal sulphide precipitation. Therefore, the dissolved metal concentrations in the incoming river water are much higher during winter

Klimaatbestendigheid van de drinkwatervoorziening in Nederland gebaseerd op oppervlaktewater

Deltares werkt momenteel in opdracht van RWS-Waterdienst aan de opzet van het project "Klimaatbestendigheid van Nederland Waterland". In dit project wordt onderzocht wat de klimaatbestendigheid is van het hoofdwatersysteem van Nederland. In het project staan twee vragen centraal: 1. Waar liggen de omslagpunten die leiden tot een ander waterbeleid en/of -beheer, en op wat voor termijn gaat dit spelen? 2. Welke alternatieve strategieen zijn er als het omslagpunt bereikt is, en wat zijn daarvan de voor- en nadelen

Dissolved and particulate trace metal geochemistry in the Scheldt estuary, S.W. Netherlands (water column and sediments)

The geochemistry of dissolved and particulate trace metals has been studied in the water column and the sediments of the Scheldt estuary between 1987 and 1990. A strong seasonal influence on the behaviour af dissolved Cd, Cu and Zn is observed, related to the redox conditions in the upper estuary and phyto- plankton activity in the lower estuary (which are both seasonally dependent variables). The dissolved trace metal concentrations in the fresh water end-member are remarkably low during spring and summer, due to metal sulphide precipitation in the anoxic Scheldt river. However, the dissolved concentrations increase rapidly with increasing salinity, due to oxidation of metal sulphides that are present in the suspended matter, accompanied by (e.g. chloro-complexation of the released metals. Reabsorption of Cd and Zn occurs in the lower estuary during the spring phytoplankton bloom. During winter, when the Scheldt river is not completely anoxic, much higher dissolved trace metal concentrations are observed in the fresh water end-member since metal sulphide precipitation in the water column is precluded. Rapid trace metal removal is observed in the low salinity, high turbidity zone, due to absorption onto suspended matter and freshly precipitated iron and manganese oxyhydroxides. Upon further mixing, desorption is apparent, due to a similar oxidation-complexation mechanism as observed during spring and summer. Pore water infusion may also contribute to the enrichment of dissolved Cd, Cu and Zn in the mid-estuarine region. The trace metal contents of the suspended matter and the sediments show a continuous decrease with increasing salinity. This behaviour is to a very large extent due to physical mixing of contaminated fluvial particulates and relatively unpolluted marine particulates. Desorption of Cd, Cu and Zn can be identified but is of minor importance compared to the conservative mixing process. The distribution of dissolved Cd, Cu and Zn in the pore waters of the mid-estuarine region reflects the impact of early diagenetic processes. Trace metal peaks are observed near the sediment-water interface, and at greater depth in the manganese and iron reduction zones. These peaks are attributed to oxidation of reduced trace metal compounds (e.g. sulphides) and reduction of the (iron and manganese) oxide carrier phases, respectively. At greater depth, the dissolved trace metal concentrations are much lower due to metal sulphide precipitation in the sulphate reduction zone. Analysis of a large sediment dataset indicates severe trace metal pollution of the Scheldt estuary at the end of the fifties. A major reduction of the pollution by As, Cr, Hg, Pb, and Zn has occurred in the seventies, and of Cd and Cu in the eighties. The Ni pollution has increased over the time period considered. In spite of this improvement, the present-day pollution status of the Scheldt estuary is still reason for concern

Geochemistry of major elements and trace metals in suspended matter of the Scheldt estuary, southwest Netherlands

The geochemistry of suspended matter from the Scheldt estuary has been studied in eight surveys in 1987–1988. Samples were analyzed for major elements (Al, Ca, Fe, K, Mg, Na, Si, Ti, POC, N, P, S) and trace metals (Ag, Ba, Be, Cd, Co, Cr, Cu, Li, Mn, Ni, Pb, Sn, Sr, V, Zn). Physical mixing of fluvial and marine particulates leads to a continuous decrease in the trace metal content of the suspended matter with increasing salinity. Principal component analysis shows that the effect of desorption processes (e.g., of Cd, Cu, and Zn) on the suspended matter composition is relatively minor as compared to that of particle mixing. A particulate S maximum is present in the upper estuary, reflecting resuspension of reduced sediments. Pore water infusion into the (suboxic) upper estuary is a major source of Fe and Mn to the suspended matter. Due to differences in oxidation kinetics, precipitation of dissolved Mn occurs later (in the lower estuary) than that of Fe (in the upper estuary). Coprecipitation with Mn (hydr)oxides is observed for Ni and Co, but not for the other metals studied. Phytoplankton activity leads to a seasonal shift in the suspended matter composition in the lower estuary. During the spring bloom, the contents of trace metals and lithogenic elements are decreased, in favour of biogenic elements (POC, N, P). This observation is attributed to dilution of mineral particles by phytoplankton which, apparently, has lower trace metal levels. However, the Ba content of the suspended matter is increased during the bloom, which is ascribed to biological formation of barite. Another effect of the spring bloom is depletion of dissolved Cd and Zn (but not of Cu), leading to an increase in their distribution coefficients in the lower estuary. Phytoplankton may both directly (through biological uptake) and indirectly (by increasing the pH) be involved in the seasonal shift of Cd and Zn from the dissolved to the particulate phase. Comparison of recent data on suspended matter composition with historical data shows that the trace metal burden of the Scheldt river has decreased considerably between 1980 and 1995. The decrease in trace metal levels of the fluvial suspended matter amounts to 88% for Cd, 85% for Hg, 74% for As, 59% for Cu, and 50–54% for Cr, Ni, Pb and Zn over the time span considered. However, the Mn content of the fluvial suspended matter has doubled from the early 1970s until the mid 1990s, reflecting the gradual increase in the dissolved oxygen concentration of the river water over the last 20 years

Black Carbon and Ecological Factors affect in situ biota sediment accumulation factors for hydrophobic organic compounds in flood plain lakes

Ecological factors may play an important role in the bioaccumulation of polychlorobiphenyls (PCBs) and polyaromatic hydrocarbons (PAHs). Geochemical and bioaccumulation behavior of these chemicals also appears to be related to the presence of black carbon (BC) in sediment. In situ PCB and PAH biota to sediment accumulation factors (BSAF) for benthic invertebrates, as well as 6h Tenax-extractable (fast-desorbing) concentrations and lake characteristics (including BC in sediment), were determined for different seasons in chemically similar but ecologically different lakes (fish-dominated turbid, algae-dominated turbid, and macrophyte-dominated). BSAFs could be explained with a model including a term for Freundlich sorption to BC and a term for uptake from fast-desorbing concentrations in ingested sediments. Freundlich coefficients for in situ sorption to BC (KF) were calculated from slow desorbing fractions and BC contents and agreed well with literature values for K F. Furthermore, in contrast to BSAFs based on total extracted concentrations, Tenax-based BSAF showed a strong positive correlation with log K0W. We therefore argue that BC caused slow desorption and limited BSAFs in these lakes. Seasonal and lake effects on BSAFs were detected, while the differences between oligochaetes and other invertebrates were small for PCBs and within a factor of 10 for PAHs. BSAFs for pyrogenic PAHs were much lower than for PCBs, which was explained by stronger sorption to BC and lesser uptake from ingested sediment