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Verification of moisture content in test soils
Get PDFIn the scientific evaluation of experimental studies on the degradation of substances in soil, the moisture content of the soil is very important. A soil that is too dry or too wet can negatively influence the activity of the microbial population. Soil moisture content is thus an important parameter, but is often not reported. In those cases, it can be estimated by means of a number of basic parameters from the study and external moisture characteristics for a given soil type. This report presents a method to perform this verification. The basis for the calculations are two collections of moisture characteristics, determined on a large number of Dutch and other European soils. In the presented methodology, a moisture characteristic from one of the two collections is selected on the basis of the texture classification of the test soil. Different verification methods for moisture content are offered, depending on the available information. The outcome of the calculations can be used in the validity assessment of the experiment. The calculations presented in the report can be performed with two spreadsheets that can be downloaded from the RIVM website Risicos van stoffen (http://www.rivm.nl/rvs/).RIVM-SO
Het onderwateroppervlak van pleziervaartuigen
No full textThe wetted surface area of recreational craft is often treated with special paint that prevents growth of algae and other organisms. The active substances in this paint (antifouling) are also emitted into the water. The extent of this emission is among others determined by the treated surface area. The RIVM has developed a method to calculate the wetted surface area of recreational craft based on boat length. This is essential to assess the environmental effects associated with these emissions. The final result of this study is a weighted average value for the wetted surface area of recreational craft in Dutch marinas, including separate values for salt water, transitional waters, and fresh surface water. Paints sold with this purpose are known as biocides. The safety of biocides for both humans and the environment is assessed during the authorisation phase of biocidal products. The active substance in antifouling paint may also be toxic to organisms other than those on the ship's hull.Het onderwateroppervlak van pleziervaartuigen wordt vaak met speciale verf behandeld die voorkomt dat er algen en andere organismen op gaan groeien. De werkzame stoffen in deze verf (antifouling) komen in het water terecht. Hoeveel dat is wordt mede bepaald door de grootte van het behandelde oppervlak. Het RIVM heeft een methode ontwikkeld om het onderwateroppervlak van recreatievaartuigen te berekenen op basis van de bootlengte. Een goede schatting van de grootte van dit oppervlak is essentieel voor de milieubeoordeling. Het eindresultaat is een gewogen gemiddelde voor het onderwateroppervlak van recreatievaartuigen in Nederlandse jachthavens en een uitsplitsing daarvan naar zeewater, binnenwateren en overgangswateren. Verven die verkocht worden met dit doel zijn biociden. Bij de toelating van biociden wordt de veiligheid van het product voor mens en milieu beoordeeld. De werkzame stof in de aangroeiwerende verf is mogelijk niet alleen giftig voor organismen die onder water aangroeien op de boot, maar ook voor de overige organismen in het water.Ministerie van Infrastructuur en Waterstaa
Aanvulling milieurisicogrenzen water voor negen sporenelementen. Afleiding volgens kaderrichtlijn water-methodiek
No full textVROM-SA
Handleiding voor de afleiding van milieurisicogrenzen binnen het raamwerk '(Inter)nationale Normen Stoffen' (INS) - Revisie 2007
No full textDit rapport is de handleiding voor het afleiden van milieurisicogrenzen die worden gebruikt in het Nederlandse milieubeleid. Het rapport is een herziening van de INS-handleiding uit 2001. Nederland onderscheidt vier milieurisicogrenzen: het verwaarloosbaar risiconiveau (VR), het maximaal toelaatbaar risiconiveau (MTR), het ernstig risiconiveau (ER) en de maximaal toelaatbare concentratie voor ecosystemen (MACeco). Welke basisgegevens zijn nodig voor het afleiden van een milieurisicogrens? De handleiding geeft dit overzicht en beschrijft hoe deze literatuurgegevens moeten worden geevalueerd op juistheid en bruikbaarheid. Vervolgens wordt de methodiek voor het afleiden van milieurisicogrenzen beschreven, inclusief de benodigde berekeningen. Voor water en sediment is deze gelijk aan de methodiek zoals voorgeschreven voor de Europese Kaderrichtlijn Water. Voor bodem is direct aangesloten op de technical guidance documenten (TGD) voor EU risicobeoordelingen van nieuwe en bestaande stoffen en biociden. De overige milieurisicogrenzen, bijvoorbeeld het VR en het ER, zijn onderdeel van het Nederlandse milieubeleid en voor de afleiding van deze risicogrenzen worden aparte procedures beschreven.This report forms the guidance document for the derivation of environmental risk limits used in environmental policy in the Netherlands. The report is a revision of the INS-guidance from 2001. The following four environmental risk limits are distinguished in the Netherlands: negligible concentration (NC), maximum permissible concentration (MPC), serious risk concentration (SRC) and the maximum acceptable concentration for ecosystems (MACeco). The guidance document answers the question on what data are needed for the derivation of an environmental risk limit by overviewing and describing how data from the literature should be evaluated for reliability and usefulness. The method of derivation, including the necessary calculations, is described. For water and sediment, the methodology is the same as that prescribed to meet requirements in the European Water Framework Directive. For soil, the methodology for the European risk assessment for new and existing substances and biocides is followed. The remaining risk limits (e.g. NC and SRC) which are required to comply with Dutch environmental policy, are subject to separate derivation procedures. These too are presented here.Directorate-General for Environmental ProtectionDirectorate for ChemicalsWaste and Radiatio
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Toxische effecten van verontreinigingen op de methaanproduktie van riviersediment
No full textThe effects of five compounds on the endogenous methane production of sediment samples of the river Rhine were examined. The concentrations of a toxicant that inhibited the methane production for 10% and 50% are called EC10 and EC50. Benzene, 1,2- dichloroethane, pentachlorophenol and chloroform had EC10 values of >10000, 860, 140 and 5.5 mg/kg dry sediment, respectively. These values are well above the actual field concentrations, so the methane production is not inhibited. In one experiment, added zinc was toxic at concentrations far below the present background concentration in the sediment (800 mg Zn/kg) with an EC10 of 48 mg Zn.kg. In a second experiment with another sediment, however, the EC10 value was 1780 mg/kg. The difference in sensitivity is probably due to a different availability of zinc in the two experiments. Factors that govern the speciation of zinc in the sediment (e.g. the concentration of sulfide) are thus important when considering possible effects of zinc on microbial activity. Insight in these mechanisms, which also apply for other heavy metals, is needed as it was shown that zinc can be toxic at very low concentrations.DGM/DWL /Kroes H
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Risico concentraties van verontreinigingen voor micro-organismen in rivier sediment
No full textThe toxic effects of 5 toxicants on 5 anaerobic microbial processes in fresh water sediments were measured. Four 14-C labelled substrates were mineralized to 14-CO2 at concentrations from 1-4 mug/l in fresh sediment microcosms. The half-lives of the substrates acetate, benzoate and 4-monochlorophenol were 12-30, 24, and 84 min. respectively. The chloroform mineralization was much slower with a half-life of 4.5 - 12 days. The natural methane production in the sediment was also used to measure the toxic effects. A dangerous Concentration 5% (DC5) can be calculated from the toxicity data using methods previously adapted for single animal species toxicity tests. Above this toxicant concentration more than 5% of the possible mineralization reactions can be partly inhibited. The HC5 concentrations for benzene, pentachlorophenol, 1,2-dichloroethane, chloroform and zinc are 1, 0.39, 0.0004, 0.0001 and 270 mg/kg sediment dry weight respectively. The chlorinated alkanes are much more toxic for anaerobic micro-organisms than for aerobic fish.DGM/HDM-DWL /Kroes H
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