Afvalwater en suppletie van gietwater voor het glastuinbouwproject Kanaalzone Terneuzen

Vanuit Zeeland Seaports is de vraagstelling gekomen een berekening te maken van de hoeveelheid en samenstelling van het afvalwater uit de geprojecteerde glastuinbouwvestiging in de kanaalzone bij Terneuzen. Deze gegevens zijn nodig voor een haalbaarheidsstudie naar de afvalwaterverwerking van het tuinbouwcluster door Heros Sluiskil B.V., met daarbij de mogelijkheid voor teruglevering van het gezuiverde afvalwater aan het cluster. Daarnaast is er ter aanvulling op de in het cluster geprojecteerde hemelwateropvang, behoefte aan suppletiewater. Dit zou eventueel geleverd kunnen worden door het waterbedrijf Evides (industriewater afkomstig uit de Maas, opslag Biesbosch. Een andere mogelijkheid is levering van suppletiewater door Heros B.V. Bij teruglevering van het afvalwater aan de tuinbouw is in ieder geval een zuiveringsstap noodzakelijk is waarbij het afvalwater ontdaan wordt van overtollige zouten. Een RO (omgekeerde osmose) installatie is hiervoor de meest bruikbare optie. Door inzet van een hogere capaciteit is ook levering van suppletiewater van goede kwaliteit een mogelijkheid

Characterization of aggregates of surface modified fullerenes by asymmetrical flow field-flow fractionation with multi-angle light scattering detection

Fullerenes are carbon nanoparticles with widespread biomedical, commercial and industrial applications. Attributes such as their tendency to aggregate and aggregate size and shape impact their ability to be transported into and through the environment and living tissues. Knowledge of these properties is therefore valuable for their human and environmental risk assessment as well as to control their synthesis and manufacture. In this work, asymmetrical flow-field flow fractionation (AF4) coupled to multi-angle light scattering (MALS) was used for the first time to study the size distribution of surface modified fullerenes with both polyhydroxyl and carboxyl functional groups in aqueous solutions having different pH (6.5-11) and ionic strength values (0-200 mM) of environmental relevance. Fractionation key parameters such as flow rates, flow programming, and membrane material were optimized for the selected fullerenes. The aggregation of the compounds studied appeared to be indifferent to changes in solution pH, but was affected by changes in the ionic strength. Polyhydroxy-fullerenes were found to be present mostly as 4 nm aggregates in water without added salt, but showed more aggregation at high ionic strength, with an up to 10-fold increase in their mean hydrodynamic radii (200 mM), due to a decrease in the electrostatic repulsion between the nanoparticles. Carboxy-fullerenes showed a much stronger aggregation degree in water (50 100 nm). Their average size and recoveries decreased with the increase in the salt concentration. This behavior can be due to enhanced adsorption of the large particles to the membrane at high ionic strength, because of their higher hydrophobicity and much larger particle sizes compared to polyhydroxy-fullerenes. The method performance was evaluated by calculating the run-to-run precision of the retention time (hydrodynamic radii), and the obtained RSD values were lower than 1 %. MALS measurements showed aggregate sizes that were in good agreement with the AF4 data. A comparison of the scattering radii from the MALS with the hydrodynamic radii obtained from the retention times in AF4 indicated that the aggregate shapes are far from spherical. TEM images of the fullerenes in the dry state also showed branched and irregular clusters

Impact of water quality and irrigation management on organic greenhouse horticulture

Water quality and water supply are essential for organic greenhouse grown crops to prevent soil contaminationby undesirable chemicals and microorganisms, while providing a sufficient amount of water for plant growth.The absence of natural precipitation combined with higher evapotranspiration due to higher temperatureand longer cropping period requires an adequate supply of water. Water quality is commonly defined by itschemical, physical, and biological attributes. It is closely linked to the soil/rock native components, surroundingenvironment and land use. The runoff from urban, industrial, farming, mining, and forestry activities alsosignificantly affects the quality of water available for greenhouse horticulture. High water quality is particularlyimportant in organic greenhouse production in order to prevent soil salinization and ensure optimal soil biologicalactivity. Indeed, unbalanced organic fertilizer inputs may contribute to soil salinity, while soil microbial activitiesresponsible for nutrient mineralization, soil suppressiveness and plant health, are affected by soil pH, ions, andcontaminants. Poor water quality can also result in drip and micro irrigation clogging, plant toxicity, and productcontamination by human pathogen or illicit compounds.To achieve sustainable water management, good knowledge of crops' water requirements is essential as isknowledge of the soil water characteristics that determine the irrigation scheduling. Moreover, the adequacyof the irrigation distribution system determines the accuracy of the water supplied. Crop water needs areoften determined on the basis of daily evapotranspiration and solar radiation levels. Different irrigation controltools such as soil moisture sensors, plant sensors, lysimeters and models contribute to the optimization of theirrigation management of organic greenhouse crops. In addition to determining crop productivity, water qualityand water management also impact on product quality.In this booklet we first illustrate the water flows through different organic greenhouse growing systems. Westate the importance of water quality for organic greenhouse horticulture and give some guidelines regardingthe required water quality attributes in terms of inorganic, organic and microbial loads as well as hazardousmicroorganisms and compounds. We also define advantages and disadvantages of different water resourcesand describe the important drivers for crop and soil water demand. We then report the effects of salinity on soilmineralisation and crop development in organic greenhouse production systems. The main irrigation technologyused for organic greenhouse horticulture is described along with the most important management aspects forirrigation. Because quality attributes of greenhouse products drive consumer demand for organic products, wedefine the impact of water quality and irrigation management on product quality. Organic farming should usecultural practices that maintain land resources and ecological balance, in addition to promoting biodiversity,biological cycles, and soil biological activity. We therefore state the importance of water resources and their usefor organic greenhouse system sustainability. We then conclude by summarizing main aspects of water qualityand irrigation management, and by identifying knowledge gaps.Better prediction of the temporal dynamics of plant and soil microbial water needs in relation to sustainableproductivity and high water use efficiency is needed for greenhouse horticultural crops. It is also importantin terms of reduced attractiveness to pests and susceptibility to diseases. A reduction in spatial and temporalcrop heterogeneity should result from improved growing systems and better water and crop management.Nevertheless, advances in irrigation management for conventional greenhouse crops and development of newcontrol tools can be adapted for use in organic greenhouse horticulture. Similarly, some water treatmentsof drained or collected waters such as thermal, UV, ozone and biological treatments can be used by growersaccording to their organic regulation. Consequently, research is needed in different areas of organic greenhousehorticulture: (i) water quality in terms of relevant thresholds for contaminants and potential risks related toplant and human pathogens; (ii) efficient measures to prevent clogging of the irrigation systems; (iii) alternativewater treatments and system cleaning products; (iv) better knowledge and guidelines for non-leaching systems;(v) affordable and highly efficient control tools to assist growers; and (vi) knowledge about the environmentalimpact of different water management and water sources used for organic greenhouse horticulture to helpgrowers fulfilling the organic principles and improve their sustainability

Thyroid hormone metabolism and environmental chemical exposure

<p>Abstract</p> <p>Background</p> <p>Polychlorinated dioxins and –furans (PCDD/Fs) and polychlorinated-biphenyls (PCBs) are environmental toxicants that have been proven to influence thyroid metabolism both in animal studies and in human beings. In recent years polybrominated diphenyl ethers (PBDEs) also have been found to have a negative influence on thyroid hormone metabolism. The lower brominated flame retardants are now banned in the EU, however higher brominated decabromo-diphenyl ether (DBDE) and the brominated flame retardant hexabromocyclododecane (HBCD) are not yet banned. They too can negatively influence thyroid hormone metabolism. An additional brominated flame retardant that is still in use is tetrabromobisphenol-A (TBBPA), which has also been shown to influence thyroid hormone metabolism.</p> <p>Influences of brominated flame retardants, PCDD/F’s and dioxin like-PCBs (dl-PCB’s) on thyroid hormone metabolism in adolescence in the Netherlands will be presented in this study and determined if there are reasons for concern to human health for these toxins. In the period 1987-1991, a cohort of mother-baby pairs was formed in order to detect abnormalities in relation to dioxin levels in the perinatal period. The study demonstrated that PCDD/Fs were found around the time of birth, suggesting a modulation of the setpoint of thyroid hormone metabolism with a higher 3,3’, 5,5’tetrathyroxine (T4) levels and an increased thyroid stimulating hormone (TSH). While the same serum thyroid hormone tests (- TSH and T4) were again normal by 2 years of age and were still normal at 8-12 years, adolescence is a period with extra stress on thyroid hormone metabolism. Therefore we measured serum levels of TSH, T4, 3,3’,5- triiodothyronine (T3), free T4 (FT4), antibodies and thyroxine-binding globulin (TBG) in our adolescent cohort.</p> <p>Methods</p> <p>Vena puncture was performed to obtain samples for the measurement of thyroid hormone metabolism related parameters and the current serum dioxin (PCDD/Fs), PCB and PBDE levels.</p> <p>Results</p> <p>The current levels of T3 were positively correlated to BDE-99. A positive trend with FT4 and BDE-99 was also seen, while a positive correlation with T3 and dl-PCB was also seen. No correlation with TBG was seen for any of the contaminants. Neither the prenatal nor the current PCDD/F levels showed a relationship with the thyroid parameters in this relatively small group.</p> <p>Conclusion</p> <p>Once again the thyroid hormone metabolism (an increase in T3) seems to have been influenced by current background levels of common environmental contaminants: dl-PCBs and BDE-99. T3 is a product of target organs and abnormalities might indicate effects on hormone transporters and could cause pathology. While the influence on T3 levels may have been compensated, because the adolescents functioned normal at the time of the study period, it is questionable if this compensation is enough for all organs depending on thyroid hormones.</p

Inactive lifestyle in adults with bilateral spastic cerebral palsy

Objective: To quantify the level of everyday physical activity in adults with bilateral spastic cerebral palsy, and to study associations with personal and cerebral palsy-related characteristics. Participants and methods: Fifty-six adults with bilateral spastic cerebral palsy (mean age 36.4 (standard deviation (SD) 5.8) years, 62% male) participated in the study. Approximately 75% had high gross motor functioning. Level of everyday physical activity was measured with an accelerometry-based Activity Monitor and was characterized by: (i) duration of dynamic activities (composite measure, percentage of 24 h); (ii) intensity of activity (motility, in gravitational acceleration (g)); and (iii) number of periods of continuous dynamic activity. Outcomes in adults with cerebral palsy were compared with those for able-bodied age-mates. Results: Duration of dynamic activities was 8.1 (SD 3.7) % (116 min per day), and intensity of activity was 0.020 (SD 0.007) g; both outcomes were significantly lower compared with able-bodied age-mates. Of adults with cerebral palsy, 39% had at least one period of continuous dynamic activities lasting longer than 10 min per day. Gross motor functioning was significantly associated with level of everyday physical activity (Rs -0.34 to -0.48; p≤0.01). Conclusion: Adults with bilateral spastic cerebral palsy, especially those with low-level gross motor functioning, are at risk for an inactive lifestyle

Verkenning Borium bij vruchtgroenten : Evaluatie van het verloop van de B-concentraties in gift en drain bij een aantal teelten en experimenten met vruchtgroenten in steenwol met hergebruik van drainwater

The dynamics of Boron (B) in supply, drain and uptake are derived from 14 data sets of finished experiments.There is a clear relationship between the concentration in the drip solution and the drain, B-accumulation always occurs, with targets only being reached later in cultivation. There are large differences between individual crops and growers seem to have their own targets for B in the drain. The calculated exposure is related to the concentration in the drain. The B-values found in practice are sometimes extreme, up to the levels where there is a high risk of toxicity symptoms

Complexvorming van spoorelementen in substraten en hydroponics : Een samenvatting van resultaten uit onderzoek en literatuur

Chelates are applied in horticulture to complex (micro-)nutrients in order to improve the availability for the uptake by plant roots. In this report an overview is given of relevant literature about their functions and of the factors that affect the action of complexing agents. The effects on the availability and uptake by application in soils and growing media are being treated. Both natural- and synthetic chelating compounds are given attention in this report

Effecten van Na ophoping in de drain bij paprika : vaststellen van de schadedrempel voor Na in het wortelmilieu bij paprika met recirculatie

The effect of Na-accumulation on the growth and production of sweet-pepper was tested in a trial in stone wool with full recirculation. Four concentrations from 0 to 10 mmol/l at two K/Ca ratios were tested. No significant effects on production or quality were established. The uptake of Na was very low; only a few tenths mmol/l. On the basis of the results of this test, the limit value for discharge may be increased to 8 á 10 mmol/l. However, since the intake of Na is very low, the requirement of high quality water for sweet pepper remains unaffected