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Bij een bodemverontreiniging kunnen de schadelijke stoffen 'doorwerken' in de voedselketen. De concentraties van de verontreiniging kunnen in een organisme groter worden naarmate het hoger in de voedselketen staat. Zo kan een stof in de bodem worden opgenomen in een worm, die vervolgens wordt opgegeten door een mol, die op zijn beurt gegeten wordt door een roofvogel. Hoewel de roofvogel niet in direct contact komt met de bodemverontreiniging, kan deze via zijn voedsel gevolgen ondervinden van de verontreiniging. Het RIVM beschrijft in dit rapport de modellen waarmee de doorvergiftiging wordt beoordeeld, en benoemt de ervaringen in de praktijk, de knelpunten daarin en mogelijke oplossingen. Er zijn twee routes om rekening te houden met de doorvergiftiging: in de normstelling van stoffen, en bij de risicobeoordeling van stoffen op een verontreinigde locatie. Voor de risicobeoordeling van stoffen op een locatie wordt de kans op een doorvergiftiging in de voedselketen beoordeeld door individuele experts. Hiervoor zijn verschillende rekenmodellen beschikbaar, zoals BERISP, OMEGA 6.0 en SEDIAS. Een veel geopperde wens vanuit de praktijk is een eenduidige werkwijze om doorvergiftiging te beoordelen. Ook is beschreven voor welke stoffen in de huidige normstelling rekening is gehouden met doorvergiftiging. Tot 2008, toen de bodemkwaliteitsnormen in het Besluit bodemkwaliteit zijn ingevoerd, was het niet gebruikelijk om bij de normstelling voor bodem rekening te houden met doorvergiftiging. Voor een aantal stoffen (onder andere de pesticiden aldrin, dieldrin en endrin en DDT, DDD en DDE) worden momenteel de risicogrenzen geëvalueerd waarbij dat wel gebeurt.

Het RIVM heeft beschikbare gegevens over ophopingen van polycyclische aromatische koolwaterstoffen (PAK's) in waterorganismen geevalueerd. Naar aanleiding hiervan is de indeling van deze stoffen voor regelgeving aangepast. Fenantreen en fluoranteen worden nu niet meer als 'zeer bioaccumulerend' beschouwd in vis, maar als 'bioaccumulerend'. De mate waarin stoffen in organismen ophopen (bioaccumulatie) is een belangrijk criterium voor regelgeving. Het is een indicatie dat hoger in de voedselketen hogere concentraties van de stof worden aangetroffen die schadelijk kunnen zijn. Gegevens van individuele PAK's, waaronder bioaccumulatiegegevens, worden gebruikt voor de risicobeoordeling van stoffen(mengsels) waarin PAK's een belangrijk bestanddeel zijn, zoals bijvoorbeeld olie en olieachtige stoffen. Als maat voor de ophoping wordt de bioconcentratiefactor (BCF) van een stof gebruikt. Dat is de ratio tussen de snelheid waarmee het organisme de stof vanuit water opneemt en de snelheid waarmee het naar water wordt uitgescheiden. Op grond hiervan worden stoffen in de Europese REACH-regelgeving ingedeeld in drie categorieen: niet bioaccumulerend (de BCF is kleiner dan 2000), bioaccumulerend (de BCF ligt tussen 2000 en 5000) en zeer bioaccumulerend (de BCF is hoger dan 5000). Vissen zijn in staat om PAK's om te zetten in stoffen die beter in water oplosbaar zijn waardoor ze makkelijker kunnen worden uitgescheiden. Hierdoor worden in vissen vaak lagere BCF-waarden gemeten. Mosselen en andere ongewervelden kunnen PAK's veel minder goed omzetten waardoor PAK's in deze organismen meer ophopen.

Within the framework of the project "Evaluation of decontaminated soil", the applicability of bioassays with earthworms and plants for the quality assessment of decontaminated soil is investigated. In order to establish a reference system for "normal" levels of metals in earthworms, radish and lettuce, bioassays with these organisms were applied to relatively unpolluted soils from nature reserve areas in the Netherlands. Such reference levels can be used to evaluate the results bioassays on decontaminated soils. Nineteen elements were analysed: As, Ba, Ca, Cd, Co, Cr, Cu, Hg, K, Mg, Mo, Na, Ni, Pb, Sb, Se, Sn, V, Zn. The concentrations of these elements (except for As, Cu, Hg, Ni en Pb) and the content of clay and the pH of the soils were lower compared to a study of Edelman (1983) on the same soils. The content of organic carbon was, however, higher. The soil concentrations of all elements appeared to be significantly correlated with the pH and the contents of clay and organic carbon of the soils. Also the availability, expressed as the concentrations in pore water sampled after the bioassays with earthworms, appeared to be correlated with a combination of these three soil characteristics. For most elements, bioavailability determined as the concentrations in earthworms, radish roots, radish tops and lettuce was also significantly correlated with a combination of these soil characteristics. The results of the Microtox-test, which was applied to the soil pore water, could not be explained by the pore water characteristics (pH, conductivity). These results and data gathered from the literature were used to formulate a proposal for a reference system of "normal" concentrations of elements in earthworms, radish roots and radish tops. Growth of lettuce was severely hampered, especially on acid soils; therefore lettuce was considered to be less suitable as a test plant. It is concluded, that the soil type correction presently used in the Dutch soil protection policy needs to be expanded with soil pH in addition to the contents of clay and organic matter presently used.

A model for risk assessment was built for simultaneous, congener-specific PCB bioaccumulation from sediment to fish to otters (Lutra lutra). Toxic equivalence factors (TEFs) were used to sum individual congeners in otters to a toxic equivalent concentration (TEQ) relative to 2,3,7,8-tetrachlorodibenzo-p-dioxin. Microbial dechlorination and burial in sediments and bioac-cumulation are modeled to predict time trends of PCB concentrations in otters. Effects of accumulated PCBs on otters were assessed for vitamin A metabolism and reproduction, taking model uncertainty into account. Three locations in The Netherlands were modeled with PCB levels in sediment of 1 to 171 pg TEQ/g organic carbon (OC). Almost 100% reduction in litter size was predicted for the most polluted area in 1996. Due to large associated uncertainty, a period of 25 to 80 years may be needed for recovery of otter vitamin A levels and litter size at this site. Calculated median sediment quality criteria (SQC) range between 1 and 12 pg TEQ/g OC, depending on the chosen effect criterion. Uncertainty in calculated effects and SQCs is substantial and is mainly caused by uncertainty in PCB congener 126 accumulation.

Plannen om een deel van de Biesbosch opnieuw in te richten kunnen effecten hebben voor sedimentatie-processen. Om inzicht te krijgen in de risico's van dit soort ingrepen is Alterra een onderzoek gestart naar effecten van verontreiniging op kleine zoogdieren in de Biesbosch

The effects of sediment-bound toxicants to aquatic invertebrates may vary due to differences in bioavailability, food quality, or food structure. The equilibrium partitioning theory (EPT) assumes that organic matter content of sediments and not structure of organic matter is relevant for biological effects of polycyclic aromatic hydrocarbons. To test this hypothesis effects of benzo(a)pyrene (B(a)P) and size of sediment organic matter particles on the bioaccumulation and growth of the waterlouse Asellus aquaticus were studied in laboratory microcosms. Sediments and A. aquaticus were both sampled in an unpolluted, spring-fed pond. The sampled sediment was divided into two portions. From one portion the size of the organic matter particles was mechanically reduced. One set of each sediment fraction (fine and coarse) was spiked with B(a)P and incubated for 3 weeks resulting in a concentration of 70 mg B(a)P per kg sediment. Bioassays of 32 days were performed in a 2 × 2 factorial design with four replicas of each treatment. The results showed that the growth of A. aquaticus was mainly influenced by the size of organic matter particles. Growth was significantly less (27%) on finer sediments than on coarser sediments. The increase in length was 9–14% lower in the spiked sediments, but this difference was not significant. The reduced growth of A. aquaticus on finer sediments may be due to a change in the availability and/or quality of food together with a change in feeding behavior. The coarse and fine spiked sediment types did not differ significantly with respect to the sediment water partition coefficient, the organic carbon water partition coefficient, and the bioconcentration factor. In contrast, the biota to sediment accumulation factors were significantly 15% higher in the cosms with coarse sediments than in cosms with fine sediments. However, this difference is too small to conflict with EPT.

In the present investigation the influence of exposure duration and lipophilicity on the lethal body burdens (LBBs) of thirteen organophosphorus insecticides are investigated. The LBBs are found to differ widely between compounds, varying from 0.011 to 29 μmol·g−1 wet weight. Compounds of high hydrophobicity (log Kow > 4) tend to have high LBBs (2–29 μmol·g−1 wet weight) which are not dependent on exposure concentrations. Some, but not all, of the less hydrophobic compounds had lower LBBs which were dependent on the exposure concentration. The use of LBBs for the interpretation of aquatic toxicity data of specifically acting chemicals is discussed. The wide variation in the observed LBBs makes the solely use of LBBs for toxicity assessment far from straightforward for more specificically acting compounds.

Klassieke verontreinigingen zoals hydrofobe organische verbindingen (HOCs) komen uiteindelijk vaak in waterbodems terecht. Deze waterbodems kunnen hierdoor zelf een bron van verontreiniging worden en zo een risico vormen voor aquatische organismen en voor de mens. Traditionele manieren om waterbodems te reinigen, zoals baggeren en in situ capping, zorgen voor een grote verstoring van het benthische milieu en zijn niet altijd effectief, terwijl zij wel hoge kosten met zich meebrengen. Daarom is het nodig om nieuwe methoden voor reiniging van waterbodems te ontwikkelen die makkelijker zijn, minder kosten en minder verstorend zijn dan de bestaande methoden. De afgelopen jaren is de mogelijkheid onderzocht om adsorberende materialen zoals actieve kool (AC) toe te voegen aan verontreinigde waterbodems om zo de HOC concentratie in het water te verminderen. Dit onderzoek heeft als doel om het effect van toevoegen van AC op HOC blootstelling en toxiciteitsafname voor bentische organismen en gemeenschappen beter te begrijpen, om zo het gat tussen laboratorium en veld te dichten.

This study assessed the suitability of seven species of soil invertebrates for toxicologically testing pesticides in water. Requirements were that the organisms must survive in water, be easy to handle, be easy to breed, be sensitive to pesticides, and show unambiguous toxicological effects. The organisms tested were the nematodes Plectus parietinus and Globodera rostochiensis, the white pot-worms Enchytraeus buchholzi and Enchytraeus albidus, the manure worm Eisenia fetida, the mite Caloglyphus mycophagus, and the springtail Folsomia candida. The springtail met all the requirements and proved to be the most suitable of the organisms tested for soil quality assessment with soil pore water.

The project "Catch up manoeuvre old pesticides" has resulted in a summary of the environmental aspects of 152 pesticides being marketed in the Netherlands before 1975. In addition to the summary an environmental brieflet was prepared. The underlying report describes the procedure followed and the results obtained in evaluating the environmental impacts of the pesticides. Pesticides are evaluated with respect to their behaviour in soil and in water, effects on organisms in the environment, such as birds, aquatic organisms (algae, crustaceans, and fish), bees, and earth worms, and the bioaccumulating potency. Proposals are put forward for classification systems of some environmental characteristics of pesticides in general. Especially for persistence a classification system is badly needed for a comparison of the pesticides. Carrying out the project several data essentially necessary for the evaluation appeared to be lacking. In the report additional proposals are included to develop the evaluation system for pesticides for example with respect to behaviour in water and air, risk for terrestrial organisms and biomagnification.

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The project "Catch up manoeuvre old pesticides" has resulted in a summary of the environmental aspects of 152 pesticides being marketed in the Netherlands before 1975. In addition to the summary an environmental brieflet was prepared. The underlying report describes the procedure followed and the results obtained in evaluating the environmental impacts of the pesticides. Pesticides are evaluated with respect to their behaviour in soil and in water, effects on organisms in the environment, such as birds, aquatic organisms (algae, crustaceans, and fish), bees, and earth worms, and the bioaccumulating potency. Proposals are put forward for classification systems of some environmental characteristics of pesticides in general. Especially for persistence a classification system is badly needed for a comparison of the pesticides. Carrying out the project several data essentially necessary for the evaluation appeared to be lacking. In the report additional proposals are included to develop the evaluation system for pesticides for example with respect to behaviour in water and air, risk for terrestrial organisms and biomagnification.

The ordination techniques principal component analysis (PCA) and redundancy analysis (RDA) are considered to be useful tools for evaluating community responses in experimental ecotoxicology. Concepts and interpretation of these techniques are summarized. Application of PCA and RDA is illustrated in a case study. In this study, the effects of a single application of the insecticide Dursban(®) 4E (a.i. chlorpyrifos) on an aquatic macroinvertebrate community in microcosms were analysed. Four treatment (nominal chlorpyrifos concentration: 35 μg l(-1)) and four control microcosms were used. PCA visualized a change in species composition with time. Immediately after treatment, a major shift in species composition occurred in treated microcosms. RDA demonstrated that this shift was due to the treatment. RDA also showed that non-arthropods were generally insusceptible to chlorpyrifos; most arthropods were affected. Dynamics of separate taxa were visualized, giving indications of possible primary and secondary effects for these taxa. A Monte Carlo permutation test was used to decide whether treatment had a significant effect on the species composition and to investigate the state of recovery in time. In general, the RDA results gave an adequate condensation of detailed information on abundance and effects obtained by more conventional univariate statistical analysis for some individual taxa of the community. In combination with toxicity and ecological data, ordination techniques can provide insight into effects of toxic substances in complex biological communities.

The ordination techniques Principal Component Analysis (PCA) and Redundancy Analysis (RDA) are considered to be useful tools for evaluating community responses in experimental ecotoxicology. Concepts and interpretation of these techniques are summarized. Application of PCA and RDA is illustrated in a case-study.

In the Rhine-delta, accumulation of microcontaminants in floodplain foodwebs has received little attention in comparison with aquatic communities. To investigate organochlorine and metal concentrations in a terrestrial foodchain, samples of soil, earthworms (Lumbricus rubellus), and shrew (Crocidura russula, Sorex araneus) livers and kidneys were taken from two moderately to heavily polluted floodplains. Chlorobiphenyl residues in earthworm fat were 0.10 to 3.5 times the concentrations in soil organic matter, whereas ratios for other organochlorines varied between 0.87 and 8.8. These ratios are one order of magnitude lower than expected from laboratory experiments with earthworms, and laboratory and field studies on aquatic invertebrates. Bioconcentration ratios for heavy metals are in accordance with literature values for other locations, confirming the high potential for cadmium accumulation in Lumbricidae. Concentrations of organochlorines in shrew liver lipids were 1.0 to 13 times the residues in earthworm fat. These values are higher than lipid-corrected biomagnification ratios for laboratory rodents, but equal to those measured for benthivorous birds in the Rhine-delta. On a dry weight basis, kidney-earthworm ratios for cadmium were about one order of magnitude lower than previously reported values for insectivores. Soil concentrations of many compounds in both floodplains did not meet Dutch quality standards. Yet, hexachlorobenzene, chlorobiphenyl 153 (PCB153), gamma-hexachlorocyclohexane, sigma DDT, and dieldrin residues in earthworms and shrews did not exceed diet levels expected to be safe for endothermic species. An exception was noted for cadmium in worms and shrew kidneys. Heavy metal pollution in soil was close to levels that are critical to earthworms in laboratory studies. Cadmium concentrations in shrew kidneys were below levels suggested to be safe for Sorex araneus, but above those that were critical to the rat.

Standards for pesticide concentrations in water are based on the laboratory toxicity of the most susceptible standard test organisms (algae, crustaceans or fish). Field studies have shown that the standards for the insecticide chlorpyrifos and the herbicide atrazine will protect aquatic ecosystems at both species and community levels. This study was aimed at evaluating the chronic effects of the standards for chlorpyrifos and atrazine in experimental freshwater model ecosystems. It is concluded that standards based on acute exposure are not simply transferable to chronic exposure.

In a literature study the results of published research projects concerning the ecological and toxicological properties of NTA as a detergent builder during its whole life cycle have been evaluated

Voor het in kaart brengen van de vervuiling van schubvis met dioxines, dioxineachtige PCB's en niet dioxineachtige PCB's en zware metalen zijn op 10 locaties in Nederland brasem, voorn en snoekbaars bemonsterd en geanalyseerd. De resultaten laten zien dat de gehalten dioxines voor alle soorten onder de geldende Europese norm liggen. Hetzelfde geldt voor de gehalten aan zware metalen. Brasem gevangen in de Nieuwe Maas bij Pernis was het meest gecontamineerd en benadert de norm

Voor het in kaart brengen van de vervuiling van schubvis met dioxines, dioxineachtige PCB's en niet dioxineachtige PCB's en zware metalen zijn op 10 locaties in Nederland brasem, voorn en snoekbaars bemonsterd en geanalyseerd. De resultaten laten zien dat de gehalten dioxines voor alle soorten onder de geldende Europese norm liggen. Hetzelfde geldt voor de gehalten aan zware metalen. Brasem gevangen in de Nieuwe Maas bij Pernis was het meest gecontamineerd en benadert de norm

Oligochaete communities were monitored under semi-natural conditions in experimental ditch mesocosms. Twelve ditches were used in a Before-Control-After-Impact (BACI) experiment to study the effect of the insecticide chlorpyrifos. Another eight ditches were used in a randomized experiment to study the effect of eutrophication. Oligochaete communities were sampled by deploying trays of substratum for colonization over a 20-week period. The experiments were analyzed by multivariate analysis using redundancy analysis and Monte Carlo permutation to assess statistical significance. These novel methods have the advantage over classical multivariate analysis of variance (MANOVA) of being distribution-free and of having no restrictive upper limit on the number of species that can be analyzed simultaneously. In the BACI-experiment no significant effect of chlorpyrifos on oligochaete communities was detected. Eutrophication effects were observed at the higher eutrophication levels in clay ditches. Oligochaete abundances decreased in those ditches. Considerable variation was attributed to stochastic factors given that the ditches were in an early developmental stage when the experiments were initiated. Large-scale experiments such as the ones that we describe require time to develop and stabilize before parameters of community structure like population abundance, can be employed to detect changes associated with water quality manipulations.

The variation of acute toxicity data among nematode species belonging to different taxonomic and ecological groups was investigated. Twelve different nematode species were extracted from the soil and directly exposed to cadmium and pentachlorophenol. LC50-values were estimated after 24, 48, 72, and 96 h of exposure in aqueous solutions. The species exhibited large differences in sensitivity. LC50-values (72 h) for pentachlorophenol ranged from 0.5 to more than 34.5 mumol/L and for cadmium from 29 to more than 800 mumol/L. These toxicity data could be described by a log-logistic distribution function. LC50-values for cadmium were not correlated with those for pentachlorophenol. Species of the subphylum Secernentia were less sensitive to pentachlorophenol than species of the subphylum Penetrantia, while no differences were observed for cadmium. In addition, no relationship was found between toxicity data and life-history strategies. Slow colonizers (K-strategists, sensu lato) were not more sensitive to cadmium and pentachlorophenol than opportunistic species (r-strategists, sensu lato). Nematodes appeared to be as sensitive to pentachlorophenol as other soil invertebrates. Nematodes were generally tolerant to cadmium.

Regime shifts in shallow lakes may significantly affect partitioning of sediment-bound hydrophobic organic chemicals (HOCs) such as polychlorobiphenyls (PCB) and polycyclic aromatic hydrocarbons (PAH). In replicated experimental model ecosystems mimicking the alternative stable states ‘macrophyte-dominated’ and ‘suspended solid – phytoplankton dominated’, we tested the effects of macrophytes and benthivorous fish presence on mass distribution and bioaccumulation of hexachlorobenzene, PCBs and PAHs. HOC mass distributions and lipid-normalized concentrations in sediment (Soxhlet- and 6-h Tenax-extractable), suspended solids, macrophytes, periphyton, algae, zooplankton, invertebrates and carp revealed that mobile, i.e. less hydrophobic or less aged HOCs were more susceptible to ecological changes than their sequestered native counterparts. Macrophytes were capable of depleting considerable percentages of the bioavailable, fast desorbing HOC fractions in the sediment upper (bioactive) layer, but did not have a significant diluting effect on lipid-normalized HOC concentrations in carp. Carp structured invertebrate communities through predation and stimulated partitioning of HOCs to other system compartments by resuspending the sediment. These results show that shifts in ecosystem structure have clear effects on fate, risks and natural attenuation of sediment-bound organic contaminants.

Kwik is een metaal dat door zijn toxische eigenschappen al jaren in de aandacht staat van milieumonitoring. Het metaal werd en wordt gebruikt voor vele toepassingen, en door zowel de natuurlijke als menselijke emissie komt het overal in het milieu voor. De voornaamste bronnen van kwikverontreiniging van water en land bestaan uit atmosferische depositie, aanvoer via zwevend stof in waterstromen en door specifieke industriële bronnen. Meer specifiek wordt ingegaan op die parameters die van invloed kunnen zijn in het beheer van het Zwarte Water en waterbodems in het algemeen

Kwik is een metaal dat door zijn toxische eigenschappen al jaren in de aandacht staat van milieumonitoring. Het metaal werd en wordt gebruikt voor vele toepassingen, en door zowel de natuurlijke als menselijke emissie komt het overal in het milieu voor. De voornaamste bronnen van kwikverontreiniging van water en land bestaan uit atmosferische depositie, aanvoer via zwevend stof in waterstromen en door specifieke industriële bronnen. Meer specifiek wordt ingegaan op die parameters die van invloed kunnen zijn in het beheer van het Zwarte Water en waterbodems in het algemeen

This report provides a proposal for a framework for risk assessment of bioaccumulative substances, either from produced water discharges or present as background contamination. The proposed framework is such that it is compatible to the current EIF risk assessment models that are used in the Norwegian offshore oil and gas industry. The risk assessment approach selected for this framework is based on the use of critical body residues (CBR); i.e., body-tissue concentrations above which adverse effects are expected. A three-tiered risk assessment approach is distinguished: tier 1 for worst-case screening purposes; tier 2 based on probabilistic risk assessment using species sensitivity distributions and tier 3 focusing on population modelling for specific species. The latter tier is, because of its specific characteristics, not elaborated in detail. It is proposed to use a food-chain accumulation model to translate species sensitivity thresholds on the basis of CBR into external threshold concentrations, those external thresholds could then be used to either derive an ecosystem PNEC (tier I) or Species Sensitivity Distribution (tier II). This would provide a pragmatic approach to risk assessment of bioaccumulative substances in the context of the EIF modelling framework. Finally, an outline is provided for a research project in which the a risk assessment model for bioaccumulative substances is developed. This model will then be applied to two cases for purposes of demonstration and evaluation. An indication of workload and planning is provided.

This report provides a proposal for a framework for risk assessment of bioaccumulative substances, either from produced water discharges or present as background contamination. The proposed framework is such that it is compatible to the current EIF risk assessment models that are used in the Norwegian offshore oil and gas industry. The risk assessment approach selected for this framework is based on the use of critical body residues (CBR); i.e., body-tissue concentrations above which adverse effects are expected. A three-tiered risk assessment approach is distinguished: tier 1 for worst-case screening purposes; tier 2 based on probabilistic risk assessment using species sensitivity distributions and tier 3 focusing on population modelling for specific species. The latter tier is, because of its specific characteristics, not elaborated in detail. It is proposed to use a food-chain accumulation model to translate species sensitivity thresholds on the basis of CBR into external threshold concentrations, those external thresholds could then be used to either derive an ecosystem PNEC (tier I) or Species Sensitivity Distribution (tier II). This would provide a pragmatic approach to risk assessment of bioaccumulative substances in the context of the EIF modelling framework. Finally, an outline is provided for a research project in which the a risk assessment model for bioaccumulative substances is developed. This model will then be applied to two cases for purposes of demonstration and evaluation. An indication of workload and planning is provided.

In 2008 is een beperkt Nader Onderzoek uitgevoerd m.b.t. de waterbodem van het Haringvliet met als doel een beslissing te kunnen ondersteunen of de waterbodem gesaneerd moet worden. Onderdeel van dit onderzoek is het inschatten van de ecologische risico’s aan de hand van bioaccumulatie van stoffen in organismen die in contact staan met de waterbodem, in dit geval Corbicula’s en Quagga’s. IMARES is verzocht dit deelonderzoek uit te voeren. Dit rapport beschrijft de gemeten gehalten aan microcontaminanten in Corbicula’s en Quagga’s afkomstig van verschillende locaties in het Haringvliet en de toetsing daarvan aan de op dit moment beschikbare biotanormen die afgeleid zijn voor de Kaderrichtlijn Water.

The use of a wide range of chemicals to destroy pests and weeds is an important aspect of agricultural practice in Ghana, contributing to increased crop yield and reduced post-harvest losses. Notwithstanding the beneficial effects of pesticides, their adverse effects on environmental quality and human health constitute a major issue that gives rise to concerns at local, regional and national scales. The situation is particularly worrying in view of the lack of reliable data on the long-term consequences of exposure to pesticides. Ntow’s thesis reports on current knowledge on pesticides use in vegetable farming in Ghana and establishes the fate of pesticides in situ in tropical vegetable-based agroecosystems, as well as their environmental and public health impacts on selected population groups. Thus, water, waterbed sediment and vegetable crops (viz. tomato, cabbage, pepper, onion and eggplant) were checked for residues of the pesticides monitored on the farmers’ fields. Data on persistent pesticide residues in farmers’ breast milk and blood serum indicated the presence of DDTs, dieldrin, HCB, and HCHs; this especially raises concerns for children’s health. The thesis concludes that successful actions to reduce negative impacts of pesticides require sustained, low cost, and well-targeted training interventions.

In 2008 is een beperkt Nader Onderzoek uitgevoerd m.b.t. de waterbodem van het Haringvliet met als doel een beslissing te kunnen ondersteunen of de waterbodem gesaneerd moet worden. Onderdeel van dit onderzoek is het inschatten van de ecologische risico’s aan de hand van bioaccumulatie van stoffen in organismen die in contact staan met de waterbodem, in dit geval Corbicula’s en Quagga’s. IMARES is verzocht dit deelonderzoek uit te voeren. Dit rapport beschrijft de gemeten gehalten aan microcontaminanten in Corbicula’s en Quagga’s afkomstig van verschillende locaties in het Haringvliet en de toetsing daarvan aan de op dit moment beschikbare biotanormen die afgeleid zijn voor de Kaderrichtlijn Water.

Chloorparaffines (polychlooralkanen, PCA’s) zijn sterk accumulerend (vergelijkbaar en zelfs sterker dan de PCB’s, afhankelijk van de ketenlengte) in biota. Gehalten in vis in historische buitenlandse studies (gegevens uit artikelen vanaf 1980 tot 2001) variëren van 82 (vis uit Atlantische Oceaan) tot 3700 (tarbotlever) μg/kg op vetbasis. Herhaalde blootstelling aan deze stoffen leidt bij proefdieren tot lever-, nier- en schildkliertoxiciteit waarbij de toxiciteit het grootst is bij de kortketenige, hoog gechloreerde verbindingen. Bij langdurige blootstelling resulteert dit in lever- en schildkliertumoren, maar de stoffen zijn niet genotoxisch. Door de WHO is daarom een TDI voor chronische blootstelling vastgesteld van 11 μg/kg lg/dag. Een beperkte inventariserende survey m.b.t. PCA’s (C10-C13, korte keten) is in 2008 uitgevoerd met een door IMARES recent ontwikkelde methode. De uit deze survey verkregen resultaten van diverse onderzochte Nederlandse visserijproducten, variëren voor PCA’s (C10-C13, korte keten) van

The use of a wide range of chemicals to destroy pests and weeds is an important aspect of agricultural practice in Ghana, contributing to increased crop yield and reduced post-harvest losses. Notwithstanding the beneficial effects of pesticides, their adverse effects on environmental quality and human health constitute a major issue that gives rise to concerns at local, regional and national scales. The situation is particularly worrying in view of the lack of reliable data on the long-term consequences of exposure to pesticides. Ntow’s thesis reports on current knowledge on pesticides use in vegetable farming in Ghana and establishes the fate of pesticides in situ in tropical vegetable-based agroecosystems, as well as their environmental and public health impacts on selected population groups. Thus, water, waterbed sediment and vegetable crops (viz. tomato, cabbage, pepper, onion and eggplant) were checked for residues of the pesticides monitored on the farmers’ fields. Data on persistent pesticide residues in farmers’ breast milk and blood serum indicated the presence of DDTs, dieldrin, HCB, and HCHs; this especially raises concerns for children’s health. The thesis concludes that successful actions to reduce negative impacts of pesticides require sustained, low cost, and well-targeted training interventions.

This study was performed for Concawe to obtain information on the development of an approach for assessing biodegradation of petrochemical effluents and the impact on assessing the toxicity and potential to bioaccumulate of the constituents. Whole Effluent Assessments (WEA) are being investigated as a potential tool for controlling aqueous discharges and minimizing environmental impact. The key parameter in such assessments relates to the toxicity of the effluent to aquatic organisms. Increasingly concern over long-term toxicity and the potential for toxicity to persist after discharge requires investigation.

One of the main objectives of the “Koploper” project “Identificatie van mogelijke probleemstoffen in voedselketens en toppredatoren” is to identify possible causes of the increasing number of harbour porpoises that are stranded on the Dutch coast. In order to find out whether chemical contamination could cause the increased stranding, Deltares has contracted IMARES to analyse main organohalogenated contaminants in the harbour porpoises found stranded during year 2006.

Heavy metal hyperaccumulation in plants is a poorly understood phenomenon. Transmembrane metal transporters are assumed to play a key role in this process. In the research described in this thesis, genes encoding Zn transporters of Thlaspicaerulescens, a heavy metal hyperaccumulator plant,are studied and compared to their orthologues in Arabidopsis thaliana, a non-hyperaccumulator plant.The TcZNT1 and TcZNT2 genes of T. caerulescens are members of the Zrt, Irt ( ZIP) -like gene family and show 89% and 87% similarity with the AtZIP4 and AtIRT3 genes of A. thaliana,respectively. AtZIP4 and AtIRT3 genes are induced exclusively by Zn-deficiency in Arabidopsis. In limiting Zn conditions both Arabidopsis and Thlaspi show characteristic symptoms of Zn deficiency manifested both in vegetative and reproductive tissues. However, in T. caerulescens , TcZNT1 and TcZNT2 are constitutively and highly expressed in roots, irrespective of the Zn concentration in the medium. This observation suggested a role forthesegenes in Zn uptake and possibly in explaining the Zn hyperaccumulation trait in Thlaspi . The proteins are localized in the plasma membrane, conferring zinc uptake into the cytoplasm. TcZTP1, another Zn transporter gene shows 85% sequence similarity in its coding region with the AtZAT/ MTP1 ofA. thaliana and is assumed to be localized in the vacuolar membrane. This gene belongs to the Cation Diffusion Facilitator (CDF) family.The responses of the over-expression lines of TcZNT1,TcZNT2 and TcZTP1 in A. thalianawereinvestigated with respect to deficiency and toxicity of Zn, Fe and Cd.Over-expression of TcZNT1showed higher Zn accumulation in A. thaliana , whereas this effect was small and not significant for TcZNT2.TcZNT1 over-expression lines also showed increased Cd accumulation.In addition, the TcZNT1, TcZNT2 and TcZNT1/TcZNT2 silenced T. caerulescens showedreduced Zn content in roots. These results, together with the plasma membrane localisation of TcZNT1 and TcZNT2 in cowpea protoplast, suggest a role in metal uptake of these two proteins in the plant. Over-expression of the TcZTP1 confers Zn and Cd tolerance and accumulation in A. thaliana. The regulation of expression of these genes was studied in comparison to the orthologous genes in A. thaliana by the study of the TcZNT1 and AtZIP4 promoter. The TcZNT1 promoter was isolated by PCR using forward primers designed on the A. thaliana gene upstream of AtZIP4 and a reverse primer on the T.caerulescensTcZNT1 cDNA). The promoters of ZIP4 orthologues were isolated by a similar method from Arabidopsis halleri, Arabidopsis lyrata and Cochleria pyrenaica. The sequence analysis performed on the ZIP4 promoters shows the presence of two conserved palindromic sequences in all five species, suggesting that these are essential promoter elements for both the hyperaccumulators and non-accumulators. Using (deleted) promoter: GUS fusions transformed to A. thaliana , the cis elements of AtZIP4 were identified between-263 bp and -115 bp from the start codon andfor TcZNT1between -223 bp and -98bp by 5' deletion study of the promoters. These regions also contain the two palindromic sequences in both promoters, indicating the importance of these conserved palindromes in the hyperaccumulators and non-accumulators. The AtZIP4pro-GUS transformed A. thaliana plants showed high expression in Zn-deficient roots, shoots, flowers and seeds. Similar expression pattern was observed in TcZNT1pro-GUS transformed A. thaliana plants. This suggests both the cis elements in the AtZIP4 and TcZNT1 promoters are conserved. To explain the high expression of TcZNT1 in T. caerulescens,the mode of cis/trans interaction and/or the expression profiles of thetransgenes in both species need to be studied. Most likely, theexpression profile of the transcription factors and consequently many other genes functioning in metal uptake, transport and sequestration have been changed, in the hyperaccumulator plants as an adaptation strategy to survive in the highly contaminated soil. It is expected that the knowledge obtained can be used to design strategies to generate genetically engineered plants that can be used for phytoremediation and/or that have an improved nutritional quality.

The main research questions of this research were (1) what is the extent and nature of bioavailability of sediment-bound polychlorobiphenyls (PCBs) and polyaromatic hydrocarbons (PAHs) and (2) what are the effects of lake ecosystem structure on fate and bioaccumulation of PCBs and PAHs. Fast-desorbing fractions in the sediment of floodplain lakes were estimated by the 6-h Tenax-extractable fractions with a correction factor. These fractions varied between 1 and 40% and did not show a clear trend with log KOW. This means that contaminants in these sediments were available, but to a smaller extent than total concentrations would suggest. The 6-h Tenax extractable concentration often correlated better with bioaccumulation than the total extractable concentration in sediment. Despite the reduced availability, benthivorous fish and invertebrates in floodplain lakes still rapidly accumulated substantial amounts of PCBs. PAHs were accumulated relatively less because PAHs were relatively less available than PCBs due to their stronger sorption to carbonaceous materials, also referred to as soot or black carbon. For fish, metabolic transformation caused even lower PAH concentrations. Contaminants that have been present in the sediment for longer periods of time (years to decades), were less available for Tenax extractions as well as for uptake by biota in different parts of the food web than contaminants that were recently added. Thus, aging may translate directly into reduced uptake at higher trophic levels. Nutrient additions in enclosures with benthivorous fish had a positive effect on PCB accumulation by these fish. Measured bioaccumulated concentrations of PCBs and PAHs in invertebrates in flood plain lakes were not influenced greatly by seasonal effects or ecological structure. Although effects were statistically significant, their magnitude in terms of accumulation factors was small, which may have been caused by the similar sediment composition and bioavailability of contaminants in our systems. Differences between compounds were much larger than differences due to ecosystem structure, seasons, or species composition. As for total masses of PCBs and PAHs in certain compartments however, lake ecosystem structure appeared to have a large influence on the biomass of biota and therefore also on the mass distribution of PCBs and PAHs in biotic compartments. Thus, changes in ecosystem structure strongly influenced PCB and PAH dynamics, although concentrations within the biotic compartments were not significantly influenced by biotic biomass. As for bioaccumulation modelling, when aquatic exposure concentrations were quantified accounting for sorption to carbonaceous materials, model results improved substantially. Including metabolic transformation and sediment uptake in the model accounted for a further improvement of the model fit. Implications are discussed for food chain bioaccumulation modeling, bioavailability assessment, sediment policy making and floodplain lake management.

One of the main objectives of the “Koploper” project “Identificatie van mogelijke probleemstoffen in voedselketens en toppredatoren” is to identify possible causes of the increasing number of harbour porpoises that are stranded on the Dutch coast. In order to find out whether chemical contamination could cause the increased stranding, Deltares has contracted IMARES to analyse main organohalogenated contaminants in the harbour porpoises found stranded during year 2006.

Two sampling rounds of Sardinella aurita were conducted in the waters off the coast of Mauritania to evaluate levels of contamination prior to the commencement of oil production and following the start of produced formation water discharge.

In het jaar 2006 zijn op 14 locaties in watersystemen van de Nederlandse rijkswateren monsters rode aal verzameld. In de filets zijn analyses uitgevoerd van kwik, PCB’s en een aantal andere prioritaire organochloorverbindingen . Voor de betreffende locaties is een trendanalyse voor de diverse microcontaminanten uitgevoerd en een risicoanalyse gedaan voor doorvergiftiging van visetende hogere organismen

Two sampling rounds of Sardinella aurita were conducted in the waters off the coast of Mauritania to evaluate levels of contamination prior to the commencement of oil production and following the start of produced formation water discharge.

The main research questions of this research were (1) what is the extent and nature of bioavailability of sediment-bound polychlorobiphenyls (PCBs) and polyaromatic hydrocarbons (PAHs) and (2) what are the effects of lake ecosystem structure on fate and bioaccumulation of PCBs and PAHs. Fast-desorbing fractions in the sediment of floodplain lakes were estimated by the 6-h Tenax-extractable fractions with a correction factor. These fractions varied between 1 and 40% and did not show a clear trend with log KOW. This means that contaminants in these sediments were available, but to a smaller extent than total concentrations would suggest. The 6-h Tenax extractable concentration often correlated better with bioaccumulation than the total extractable concentration in sediment. Despite the reduced availability, benthivorous fish and invertebrates in floodplain lakes still rapidly accumulated substantial amounts of PCBs. PAHs were accumulated relatively less because PAHs were relatively less available than PCBs due to their stronger sorption to carbonaceous materials, also referred to as soot or black carbon. For fish, metabolic transformation caused even lower PAH concentrations. Contaminants that have been present in the sediment for longer periods of time (years to decades), were less available for Tenax extractions as well as for uptake by biota in different parts of the food web than contaminants that were recently added. Thus, aging may translate directly into reduced uptake at higher trophic levels. Nutrient additions in enclosures with benthivorous fish had a positive effect on PCB accumulation by these fish. Measured bioaccumulated concentrations of PCBs and PAHs in invertebrates in flood plain lakes were not influenced greatly by seasonal effects or ecological structure. Although effects were statistically significant, their magnitude in terms of accumulation factors was small, which may have been caused by the similar sediment composition and bioavailability of contaminants in our systems. Differences between compounds were much larger than differences due to ecosystem structure, seasons, or species composition. As for total masses of PCBs and PAHs in certain compartments however, lake ecosystem structure appeared to have a large influence on the biomass of biota and therefore also on the mass distribution of PCBs and PAHs in biotic compartments. Thus, changes in ecosystem structure strongly influenced PCB and PAH dynamics, although concentrations within the biotic compartments were not significantly influenced by biotic biomass. As for bioaccumulation modelling, when aquatic exposure concentrations were quantified accounting for sorption to carbonaceous materials, model results improved substantially. Including metabolic transformation and sediment uptake in the model accounted for a further improvement of the model fit. Implications are discussed for food chain bioaccumulation modeling, bioavailability assessment, sediment policy making and floodplain lake management.

Heavy metal hyperaccumulation in plants is a poorly understood phenomenon. Transmembrane metal transporters are assumed to play a key role in this process. In the research described in this thesis, genes encoding Zn transporters of Thlaspicaerulescens, a heavy metal hyperaccumulator plant,are studied and compared to their orthologues in Arabidopsis thaliana, a non-hyperaccumulator plant.The TcZNT1 and TcZNT2 genes of T. caerulescens are members of the Zrt, Irt ( ZIP) -like gene family and show 89% and 87% similarity with the AtZIP4 and AtIRT3 genes of A. thaliana,respectively. AtZIP4 and AtIRT3 genes are induced exclusively by Zn-deficiency in Arabidopsis. In limiting Zn conditions both Arabidopsis and Thlaspi show characteristic symptoms of Zn deficiency manifested both in vegetative and reproductive tissues. However, in T. caerulescens , TcZNT1 and TcZNT2 are constitutively and highly expressed in roots, irrespective of the Zn concentration in the medium. This observation suggested a role forthesegenes in Zn uptake and possibly in explaining the Zn hyperaccumulation trait in Thlaspi . The proteins are localized in the plasma membrane, conferring zinc uptake into the cytoplasm. TcZTP1, another Zn transporter gene shows 85% sequence similarity in its coding region with the AtZAT/ MTP1 ofA. thaliana and is assumed to be localized in the vacuolar membrane. This gene belongs to the Cation Diffusion Facilitator (CDF) family.The responses of the over-expression lines of TcZNT1,TcZNT2 and TcZTP1 in A. thalianawereinvestigated with respect to deficiency and toxicity of Zn, Fe and Cd.Over-expression of TcZNT1showed higher Zn accumulation in A. thaliana , whereas this effect was small and not significant for TcZNT2.TcZNT1 over-expression lines also showed increased Cd accumulation.In addition, the TcZNT1, TcZNT2 and TcZNT1/TcZNT2 silenced T. caerulescens showedreduced Zn content in roots. These results, together with the plasma membrane localisation of TcZNT1 and TcZNT2 in cowpea protoplast, suggest a role in metal uptake of these two proteins in the plant. Over-expression of the TcZTP1 confers Zn and Cd tolerance and accumulation in A. thaliana. The regulation of expression of these genes was studied in comparison to the orthologous genes in A. thaliana by the study of the TcZNT1 and AtZIP4 promoter. The TcZNT1 promoter was isolated by PCR using forward primers designed on the A. thaliana gene upstream of AtZIP4 and a reverse primer on the T.caerulescensTcZNT1 cDNA). The promoters of ZIP4 orthologues were isolated by a similar method from Arabidopsis halleri, Arabidopsis lyrata and Cochleria pyrenaica. The sequence analysis performed on the ZIP4 promoters shows the presence of two conserved palindromic sequences in all five species, suggesting that these are essential promoter elements for both the hyperaccumulators and non-accumulators. Using (deleted) promoter: GUS fusions transformed to A. thaliana , the cis elements of AtZIP4 were identified between-263 bp and -115 bp from the start codon andfor TcZNT1between -223 bp and -98bp by 5' deletion study of the promoters. These regions also contain the two palindromic sequences in both promoters, indicating the importance of these conserved palindromes in the hyperaccumulators and non-accumulators. The AtZIP4pro-GUS transformed A. thaliana plants showed high expression in Zn-deficient roots, shoots, flowers and seeds. Similar expression pattern was observed in TcZNT1pro-GUS transformed A. thaliana plants. This suggests both the cis elements in the AtZIP4 and TcZNT1 promoters are conserved. To explain the high expression of TcZNT1 in T. caerulescens,the mode of cis/trans interaction and/or the expression profiles of thetransgenes in both species need to be studied. Most likely, theexpression profile of the transcription factors and consequently many other genes functioning in metal uptake, transport and sequestration have been changed, in the hyperaccumulator plants as an adaptation strategy to survive in the highly contaminated soil. It is expected that the knowledge obtained can be used to design strategies to generate genetically engineered plants that can be used for phytoremediation and/or that have an improved nutritional quality.