32 results on '"Wouterse, M."'
Search Results
2. Heteroaggregation and sedimentation rates for nanomaterials in natural waters
- Author
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Quik, J.T.K., Velzeboer, I., Wouterse, M., Koelmans, A.A., and van de Meent, D.
- Published
- 2014
- Full Text
- View/download PDF
3. A rationale for the appropriate amount of inoculum in ready biodegradability tests
- Author
-
Struijs, J., Stoltenkamp-Wouterse, M. J., and Dekkers, A. L. M.
- Published
- 1995
- Full Text
- View/download PDF
4. Decomposition of mixtures of cover crop residues increases microbial functional diversity
- Author
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Drost, S.M., Rutgers, M., Wouterse, M., De Boer, Wietse, Bodelier, Paul, Drost, S.M., Rutgers, M., Wouterse, M., De Boer, Wietse, and Bodelier, Paul
- Published
- 2020
5. Humic substances alleviate the aquatic toxicity of polivinylpyrrolidonecoated silver nanoparticles to organisms of different trophic levels
- Author
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Whang, Z., Quik, J.T.K., Song, L., Brandhof, E.J. van den, Wouterse, M., and Peijenburg, W.J.G.M.
- Abstract
The present study investigated how humic substances (HS) modify the aquatic toxicity of silver nanoparticles (AgNPs) as these particles agglomerate in water and interact with HS. An alga species (Raphidocelis subcapitata), a cladoceran species (Chydorus sphaericus), and a freshwater fish larva (Danio rerio), representing organisms of different trophic levels, were exposed to colloids of the polyvinylpyrrolidone-coated AgNPs in the presence and absence of HS. Results show that the presence of HS alleviated the aquatic toxicity of the AgNP colloids to all the organisms in a dose-dependent manner. The particle size distribution of the AgNPs' colloidal particles shifted to lower values due to the presence of HS, implying that the decrease in the toxicity of the AgNP colloids cannot be explained by the variation of agglomeration size. The surface charge of the AgNPs was found to be more negative in the presence of high concentrations of HS, suggesting an electrostatic barrier by which HS might limit interactions between particles and algae cells; indeed, this effect reduced the algae toxicity. Observations on silver ions (Agþ) release show that HS inhibit AgNP dissolution, depending on the concentrations of HS. When toxic effects were expressed as a function of each Ag-species, toxicity of the free Agþ was found to be much higher than that of the agglomerated particles
- Published
- 2015
6. Control Towers in supply chains
- Author
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Havekes, B, Wouterse, M., and Academy for Built Environment & Logistics
- Published
- 2015
7. Monitoring soil bacteria with community-level physiological profiles using Biolog (TM) ECO-plates in the Netherlands and Europe
- Author
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Rutgers, M., Wouterse, M., Drost, S.M., Breure, A.M., Mulder, C., Stone, D., Creamer, R.E., Winding, A., Bloem, J., Rutgers, M., Wouterse, M., Drost, S.M., Breure, A.M., Mulder, C., Stone, D., Creamer, R.E., Winding, A., and Bloem, J.
- Abstract
Contains fulltext : 157089pub.pdf (publisher's version ) (Closed access)
- Published
- 2016
8. Control Towers & 4C
- Author
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Havekes, B, Wouterse, M., and Academy for Built Environment & Logistics
- Published
- 2014
9. Sustainable logistics through Cross-Chain Control Towers coordinating the collaboration between logistics partners
- Author
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Havekes, B, Wouterse, M., and Academy for Built Environment & Logistics
- Published
- 2014
10. Effects of sulfamethoxazole on soil microbial communities after adding substrate
- Author
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Demoling, L.A., Baath, E., Greve, G.D., Wouterse, M., Schmitt, H., Strategic Infection Biology, and Dep IRAS
- Subjects
bacterial infections and mycoses ,urologic and male genital diseases ,complex mixtures ,female genital diseases and pregnancy complications - Abstract
The effect of the antibiotic sulfamethoxazole (SMX) on soil bacteria was studied using two methods (leucine incorporation and Biolog plates) of estimating pollution-induced community tolerance (PICT). SMX was added to an agricultural soil in a microcosm setup. The addition of different substrates (manure and alfalfa), and a non-amended soil, were also studied over 5 weeks. PICT measurements were validated by comparison with other measurements. Community structure was assessed using phospholipid fatty acid (PLFA) analysis and community-level physiological profiling (CLPP), and bacterial growth was estimated using leucine incorporation. Increased PICT was found at SMX concentrations of 20 and 500 mg SMX kg(-1) soil in samples containing manure and alfalfa, and at 500 mg SMX kg(-1) soil in non-amended soil (only concentration tested) using leucine incorporation. No effect was seen at 1 mg SMX kg(-1) soil. It was not necessary to add any substrate to increase the microbial activity in order to detect the effects of a bacteriostatic toxicant such as SMX when using measures based on bacterial growth. Direct inhibition of bacterial growth 2 days after SMX addition was correlated to PICT. No major changes in PICT due to SMX addition were found when using Biolog plates. However, there was a tendency towards increased PICT at the higher SMX concentrations in the manure-amended soil. Thus, different methods of detecting PICT have different sensitivities in detecting the toxic effects of SMX The effects of substrate amendment were reflected by changes in the microbial community, estimated using both PLEA and CLPP SMX was found to have a clear effect at the two highest levels of SMX in the manure- and alfalfa-amended soils, with an increase in fungal and a decrease in bacterial PLFAs. Little difference in the PLFA composition was found in the non-amended soil. CLPP was only affected at the highest SMX concentration. Although different variables showed different sensitivities to the effects of SMX, the results were consistent with an initial decrease in bacterial growth rates of sensitive species, which eventually transformed into more tolerant species, altering the community composition. (C) 2009 Elsevier Ltd. All rights reserved.
- Published
- 2009
11. Locatiespecifieke ecologische risicobeoordeling - praktijkonderzoek met de TRIADE-benadering deel 2
- Author
-
Schouten AJ, Bogte JJ, Dirven-van Breemen EM, Rutgers M, Baerselman R, Beelen P van, Bloem J, Keidel H, Wouterse M, and LER
- Subjects
triade ,locations ,assessment ,veldonderzoek ,ecosystemen ,locaties ,bioassay ,bodembiologische indicator ,risico's ,pollution ,field research ,verontreiniging ,ecosystems ,risks ,toetsing - Abstract
This report describes the results of a research programme on the application of the so-called TRIAD approach for site specific ecological risk assessment of soil pollution. The method means to optimise the estimation of actual ecological effects in a specific area or ecosystem, by gathering multiple evidence along various ways. The TRIAD includes three pillars consisting of chemical, toxicological and ecological measurements. Each pillar of the TRIAD can be extended over three tiers, representing low, middle and high levels of sophistication in research methods. In the second phase of the field research, three locations were investigated with emphasis on the selection of a local reference site and ecological measurements. The chemical, toxicological and ecological measurements were integrated into an effect estimation per TRIAD-unit and one overall assessment. Effects were scaled from 0 to 1 and divided into 3 colour-categories to obtain a better overview. Although most bioassays and ecological indicators were able to characterise the samples, they showed much lower effects than predicted from the measured concentrations of pollutants. The (chemical) Toxic Pressure method, based on Species Sensitivity Distributions, seems to give an overestimation of ecological effects. It is also less discriminating in situations of multiple substance pollution exceeding Serious Risk Levels.
- Published
- 2007
12. Locatiespecifieke ecologische risicobeoordeling. Praktijkonderzoek met de TRIADE-benadering: deel 3
- Author
-
Schouten AJ, Dirven van Breemen EM, Bogte JJ, Rutgers M, Baerselman R, Bloem J, Didden WAM, Dimmers W, Groot A de, Keidel H, Mulder Ch, Peijnenburg W, Siepel H, Wouterse M, Dirven-van Breemen EM, LER, Alterra, WUR/Bodemkwaliteit, and Bedrijfslaboratorium voor Grond en Gewasonderzoek (Blgg)
- Subjects
soil pollution ,locations ,chemie ,bodemverontreiniging ,assessment ,veldonderzoek ,toxicologie ,chemistry ,locaties ,pict ,bodembiologische indicator ,risico's ,ecologie ,field research ,ecology ,verontreiniging ,risks ,toetsing ,toxicology - Abstract
The TRIAD approach was tested for its applicability in assessing actual ecological risks on five sites around the zinc factory near the city of Budel, in The Netherlands. The TRIAD method offers the possibility of a tiered approach to actual risks for the local ecosystem. Risk assessment is derived on the basis of three elements, i.e. chemistry, toxicology and ecology. It is meant as an improvement for the present remediation urgency systematics. Three of the five sites were contaminated with zinc and cadmium at different levels, that did not exceed the Dutch 'intervention values'. Besides total soil contents, mobile soil metal fractions and pore-water concentrations were measured during the chemical assessment. Several variants of the toxic pressure calculations were compared. In the toxicological assessment several bioassays were performed, which showed different sensitivities to heavy metals and influence of soil-pH and nutrients. There are still very few tests that can be used for acid sandy field soil. Many soil biological analyses (microbial and soil fauna groups) and a vegetation inventory were used for the ecological assessment. In this field study they showed a larger deviation from the reference site than the chemical and toxicological indicators. From the overall TRIAD assessment it can be concluded, among others, that selection of a non-contaminated reference site is both crucial as well as difficult. Polluted sites generally differ in more aspects from a local reference site than just in the concentration of contaminants. Although the TRIAD approach is relatively time consuming, uniformity and the scientific basis of the actual ecological assessment have improved considerably. Therefore the TRIAD approach is recommended for the future as a standard tool to assess actual ecological risks of contaminated soil.
- Published
- 2007
13. Hoofdstuk VI, 'Fiscale aspecten van de SE'
- Author
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Bellingwout, J. W., Wino van Veen, Blécourt-Wouterse, M. A., Bongard, M. P., Liem, E. T. H., Rijthoven, G. J., Tax Law, Dutch Private Law, and Research Programmes - Law
- Published
- 2004
14. Locatiespecifieke ecologische risicobeoordeling; praktijkonderzoek met de TRIADE-benadering: deel 3
- Author
-
Baerselman, R., Bloem, J., Bogte, J.J., Didden, W.A.M., Dimmers, W.J., Dirven-van Breemen, E.M., de Groot, A.C., Keidel, H., Mulder, C., Peijnenburg, W.J.G.M., Rutgers, M., Schouten, A.J., Siepel, H., and Wouterse, M.
- Subjects
Centre for Ecosystem Studies ,Soil Science Centre ,Life Science ,Alterra - Centrum Bodem ,Wageningen Environmental Research ,Sub-department of Soil Quality ,Centrum Ecosystemen ,Sectie Bodemkwaliteit - Published
- 2003
15. Natural colloids are the dominant factor in the sedimentation of nanoparticles
- Author
-
Quik, J.T.K., Stuart, M.C., Wouterse, M., Peijnenburg, W., Hendriks, A.J., Meent, D. van de, Quik, J.T.K., Stuart, M.C., Wouterse, M., Peijnenburg, W., Hendriks, A.J., and Meent, D. van de
- Abstract
Contains fulltext : 93980.pdf (publisher's version ) (Open Access)
- Published
- 2012
16. Effects of sulfamethoxazole on soil microbial communities after adding substrate.
- Author
-
Strategic Infection Biology, Dep IRAS, Demoling, L.A., Baath, E., Greve, G.D., Wouterse, M., Schmitt, H., Strategic Infection Biology, Dep IRAS, Demoling, L.A., Baath, E., Greve, G.D., Wouterse, M., and Schmitt, H.
- Published
- 2009
17. Is the amount of pesticides in Dutch regional surface waters correlated with toxic effects?
- Author
-
MEV, van Beelen P, Wouterse M, Bogte JJ, de Zwart D, van Dijk B, de Groot AC, Maas JL, Espeldoorn A, MEV, van Beelen P, Wouterse M, Bogte JJ, de Zwart D, van Dijk B, de Groot AC, Maas JL, and Espeldoorn A
- Abstract
RIVM rapport:In de zomer van 2002 werden Nederlandse regionale oppervlaktewateren bemonsterd voor de analyse van 53 bestrijdingsmiddelen en voor toxiciteitsexperimenten. De hydrofobe chemicalien (inclusief de meeste bestrijdingsmiddelen) werden geconcentreerd door sorptie aan kunsthars voorafgaand aan de toxiciteitsexperimenten. De concentraten werden getest met behulp van de PAM test met de groenalg Selenastrum capricornutum, de MicroTox test met de bacterie Vibrio fisheri, the IQ test met de watervlo Daphnia magna, een test met de kreeftachtige Thamnocephalus platyurus en een test met de rotifeer Brachionus calyciflorus. Om 50% inhibitie te veroorzaken moesten de monsters meer dan 100 keer geconcentreerd worden voor de rotifeer test en meer dan 10 keer voor de andere testen. In 44 van de 45 monsters was de concentratie van de gemeten bestrijdingsmiddelen te laag om de toxiciteit te verklaren. Dit impliceert dat de bijdrage van deze bestrijdingsmiddelen aan de totale toxiciteit vermoedelijk erg laag is in de meeste monsters, met uitzondering van een monster dat 3,1 4g parathion /liter bevatte. Dit is dichtbij de parathion concentratie die, volgens de wetenschappelijke literatuur, de mobiliteit van Daphnia magna met 50% verminderd. In onze toxiciteitsexperimenten moest het monster wel 20 keer geconcentreerd worden om 50% van Daphnia magna te remmen. Op dit moment hebben we nog geen goede verklaring voor deze discrepantie. De standaard Daphnia magna test zou kunnen verschillen van de hier gebruikte Daphnia IQ test. Verder onderzoek is nodig om te bepalen of bestrijdingsmiddelen werkelijk een acuut risico vormen voor aquatische ecosystemen in Nederlandse regionale oppervlaktewateren., In the summer of 2002, Dutch regional surface waters were sampled for analysis of 53 different pesticides and for toxicity measurements. The hydrophobic chemicals, including many pesticides, were concentrated by sorption to synthetic resins before the toxicity measurements. The concentrates were tested with the PAM test using the green algae Selenastrum capricornutum, the Microtox test using the bacterium Vibrio fisheri, the IQ test using the water flea Daphnia magna, a crustacean test using Thamnocephalus platyurus and a rotifer test using Brachionus calyciflorus. In order to obtain 50% inhibition, the samples had to be concentrated over 100 times for the rotifer test and over 10 times for the other tests. In 44 out of 45 samples the observed toxicity was too high to be explained by the low concentrations of the measured pesticides. This implies that the contribution of these pesticides to the total toxicity is probably very low in most samples, except for one sample that contained 3.1 ug/liter of parathion. This is close to the parathion concentration that, according to the scientific literature, can reduce the mobility of Daphnia magna for 50%. In our toxicity tests however, this sample had to be concentrated 20 times in order to inhibit 50% of the Daphnia magna. At the moment, we do not have a good explanation for this discrepancy. The standard Daphnia magna test might differ from the rapid Daphnia IQ test performed here. Further research is needed to determine whether pesticides can really pose an acute threat for aquatic ecosystems in Dutch regional surface waters.
- Published
- 2004
18. Locatiespecifieke ecologische risicobeoordeling. Praktijkonderzoek met de TRIADE-benadering: deel 3
- Author
-
LER, Alterra, WUR/Bodemkwaliteit, Bedrijfslaboratorium voor Grond en Gewasonderzoek (Blgg), Schouten AJ, Dirven-van Breemen EM, Bogte JJ, Rutgers M, Baerselman R, Bloem J, Didden WAM, Dimmers W, de Groot A, Keidel H, Mulder C, Peijnenburg W, Siepel H, Wouterse M, LER, Alterra, WUR/Bodemkwaliteit, Bedrijfslaboratorium voor Grond en Gewasonderzoek (Blgg), Schouten AJ, Dirven-van Breemen EM, Bogte JJ, Rutgers M, Baerselman R, Bloem J, Didden WAM, Dimmers W, de Groot A, Keidel H, Mulder C, Peijnenburg W, Siepel H, and Wouterse M
- Abstract
RIVM rapport:Het doel van het onderzoek was de beproeving van de TRIADE methodiek voor de inschatting van locatiespecifieke ecologische risico's in een praktijksituatie. De TRIADE geeft de mogelijkheid om trapsgewijs effecten van verontreinigingen te bepalen voor de aspecten chemie, toxicologie en ecologie. Deze methodiek moet een verbetering opleveren ten opzichte van de ecologische risicoschatting in de huidige saneringsurgentie-systematiek. Het onderzoek werd uitgevoerd op vijf locaties rond de zinkfabriek te Budel. Twee van deze locaties lagen op grotere afstand en werden als (lokale) referentie gebruikt. Drie locaties in de nabijheid van de zinkfabiek hadden verhoogde gehaltes aan zink en cadmium. Interventiewaarden werden niet overschreden. Het chemische onderzoek richtte zich op totaal-gehaltes, extraheerbare fracties en poriewaterconcentraties van zware metalen. Op basis daarvan werd de toxische druk berekend. Het ecotoxicologisch onderzoek bestond uit bioassays met algen, springstaarten en radijsplanten. De gebruikte testorganismen vertoonden verschillende gevoeligheden voor zware metalen, mede als gevolg van bodemeigenschappen als zuurgraad en voedingsstoffenbeschikbaarheid. Het TRIADE-onderdeel "ecologie" werd ingevuld met indicatoren uit de Bodembiologische Indicator (BoBI) en met een vegetatie-inventarisatie. Verontreinigde locaties verschillen bijna altijd in meer eigenschappen van de referentie dan alleen de concentratie van de contaminanten. Het vaststellen van een simpele oorzaak-gevolg relatie voor ecologische effecten zal daarom meestal niet mogelijk zijn. Uit het TRIADE-onderzoek kan worden geconcludeerd, dat de keuze van de locale referentie aanzienlijke invloed heeft op het berekende ecologisch risico. De TRIADE-systematiek geeft de ecologische risicoschatting desondanks een aanzienlijk bredere basis dan de huidige urgentiesystematiek. De methodiek is gebaseerd op het 'multiple weight of evidence' principe en biedt een kwantitatieve maat voor ecologische ri, The TRIAD approach was tested for its applicability in assessing actual ecological risks on five sites around the zinc factory near the city of Budel, in The Netherlands. The TRIAD method offers the possibility of a tiered approach to actual risks for the local ecosystem. Risk assessment is derived on the basis of three elements, i.e. chemistry, toxicology and ecology. It is meant as an improvement for the present remediation urgency systematics. Three of the five sites were contaminated with zinc and cadmium at different levels, that did not exceed the Dutch 'intervention values'. Besides total soil contents, mobile soil metal fractions and pore-water concentrations were measured during the chemical assessment. Several variants of the toxic pressure calculations were compared. In the toxicological assessment several bioassays were performed, which showed different sensitivities to heavy metals and influence of soil-pH and nutrients. There are still very few tests that can be used for acid sandy field soil. Many soil biological analyses (microbial and soil fauna groups) and a vegetation inventory were used for the ecological assessment. In this field study they showed a larger deviation from the reference site than the chemical and toxicological indicators. From the overall TRIAD assessment it can be concluded, among others, that selection of a non-contaminated reference site is both crucial as well as difficult. Polluted sites generally differ in more aspects from a local reference site than just in the concentration of contaminants. Although the TRIAD approach is relatively time consuming, uniformity and the scientific basis of the actual ecological assessment have improved considerably. Therefore the TRIAD approach is recommended for the future as a standard tool to assess actual ecological risks of contaminated soil.
- Published
- 2004
19. Locatiespecifieke ecologische risicobeoordeling. Praktijkonderzoek met de TRIADE-benadering: deel 3
- Author
-
Schouten AJ, Dirven-van Breemen EM, Bogte JJ, Rutgers M, LER, Alterra, WUR/Bodemkwaliteit, Bedrijfslaboratorium voor Grond en Gewasonderzoek (Blgg), Dirven van Breemen EM, Baerselman R, Bloem J, Didden WAM, Dimmers W, Groot A de, Keidel H, Mulder Ch, Peijnenburg W, Siepel H, Wouterse M, Schouten AJ, Dirven-van Breemen EM, Bogte JJ, Rutgers M, LER, Alterra, WUR/Bodemkwaliteit, Bedrijfslaboratorium voor Grond en Gewasonderzoek (Blgg), Dirven van Breemen EM, Baerselman R, Bloem J, Didden WAM, Dimmers W, Groot A de, Keidel H, Mulder Ch, Peijnenburg W, Siepel H, and Wouterse M
- Abstract
RIVM rapport:The TRIAD approach was tested for its applicability in assessing actual ecological risks on five sites around the zinc factory near the city of Budel, in The Netherlands. The TRIAD method offers the possibility of a tiered approach to actual risks for the local ecosystem. Risk assessment is derived on the basis of three elements, i.e. chemistry, toxicology and ecology. It is meant as an improvement for the present remediation urgency systematics. Three of the five sites were contaminated with zinc and cadmium at different levels, that did not exceed the Dutch 'intervention values'. Besides total soil contents, mobile soil metal fractions and pore-water concentrations were measured during the chemical assessment. Several variants of the toxic pressure calculations were compared. In the toxicological assessment several bioassays were performed, which showed different sensitivities to heavy metals and influence of soil-pH and nutrients. There are still very few tests that can be used for acid sandy field soil. Many soil biological analyses (microbial and soil fauna groups) and a vegetation inventory were used for the ecological assessment. In this field study they showed a larger deviation from the reference site than the chemical and toxicological indicators. From the overall TRIAD assessment it can be concluded, among others, that selection of a non-contaminated reference site is both crucial as well as difficult. Polluted sites generally differ in more aspects from a local reference site than just in the concentration of contaminants. Although the TRIAD approach is relatively time consuming, uniformity and the scientific basis of the actual ecological assessment have improved considerably. Therefore the TRIAD approach is recommended for the future as a standard tool to assess actual ecological risks of contaminated soil., Het doel van het onderzoek was de beproeving van de TRIADE methodiek voor de inschatting van locatiespecifieke ecologische risico's in een praktijksituatie. De TRIADE geeft de mogelijkheid om trapsgewijs effecten van verontreinigingen te bepalen voor de aspecten chemie, toxicologie en ecologie. Deze methodiek moet een verbetering opleveren ten opzichte van de ecologische risicoschatting in de huidige saneringsurgentie-systematiek. Het onderzoek werd uitgevoerd op vijf locaties rond de zinkfabriek te Budel. Twee van deze locaties lagen op grotere afstand en werden als (lokale) referentie gebruikt. Drie locaties in de nabijheid van de zinkfabiek hadden verhoogde gehaltes aan zink en cadmium. Interventiewaarden werden niet overschreden. Het chemische onderzoek richtte zich op totaal-gehaltes, extraheerbare fracties en poriewaterconcentraties van zware metalen. Op basis daarvan werd de toxische druk berekend. Het ecotoxicologisch onderzoek bestond uit bioassays met algen, springstaarten en radijsplanten. De gebruikte testorganismen vertoonden verschillende gevoeligheden voor zware metalen, mede als gevolg van bodemeigenschappen als zuurgraad en voedingsstoffenbeschikbaarheid. Het TRIADE-onderdeel "ecologie" werd ingevuld met indicatoren uit de Bodembiologische Indicator (BoBI) en met een vegetatie-inventarisatie. Verontreinigde locaties verschillen bijna altijd in meer eigenschappen van de referentie dan alleen de concentratie van de contaminanten. Het vaststellen van een simpele oorzaak-gevolg relatie voor ecologische effecten zal daarom meestal niet mogelijk zijn. Uit het TRIADE-onderzoek kan worden geconcludeerd, dat de keuze van de locale referentie aanzienlijke invloed heeft op het berekende ecologisch risico. De TRIADE-systematiek geeft de ecologische risicoschatting desondanks een aanzienlijk bredere basis dan de huidige urgentiesystematiek. De methodiek is gebaseerd op het 'multiple weight of evidence' principe en biedt een kwantitatieve maat voor ecologische ri
- Published
- 2004
20. Is the amount of pesticides in Dutch regional surface waters correlated with toxic effects?
- Author
-
Rijksinsituut voor Integraal Zoetwaterbeheer en Afvalwaterbehandeling RIZA, MEV, Beelen P van, Wouterse M, Bogte JJ, Zwart D de, Dijk B van, Groot AC de, Maas JL, Espeldoorn A, Rijksinsituut voor Integraal Zoetwaterbeheer en Afvalwaterbehandeling RIZA, MEV, Beelen P van, Wouterse M, Bogte JJ, Zwart D de, Dijk B van, Groot AC de, Maas JL, and Espeldoorn A
- Abstract
RIVM rapport:In the summer of 2002, Dutch regional surface waters were sampled for analysis of 53 different pesticides and for toxicity measurements. The hydrophobic chemicals, including many pesticides, were concentrated by sorption to synthetic resins before the toxicity measurements. The concentrates were tested with the PAM test using the green algae Selenastrum capricornutum, the Microtox test using the bacterium Vibrio fisheri, the IQ test using the water flea Daphnia magna, a crustacean test using Thamnocephalus platyurus and a rotifer test using Brachionus calyciflorus. In order to obtain 50% inhibition, the samples had to be concentrated over 100 times for the rotifer test and over 10 times for the other tests. In 44 out of 45 samples the observed toxicity was too high to be explained by the low concentrations of the measured pesticides. This implies that the contribution of these pesticides to the total toxicity is probably very low in most samples, except for one sample that contained 3.1 ug/liter of parathion. This is close to the parathion concentration that, according to the scientific literature, can reduce the mobility of Daphnia magna for 50%. In our toxicity tests however, this sample had to be concentrated 20 times in order to inhibit 50% of the Daphnia magna. At the moment, we do not have a good explanation for this discrepancy. The standard Daphnia magna test might differ from the rapid Daphnia IQ test performed here. Further research is needed to determine whether pesticides can really pose an acute threat for aquatic ecosystems in Dutch regional surface waters., In de zomer van 2002 werden Nederlandse regionale oppervlaktewateren bemonsterd voor de analyse van 53 bestrijdingsmiddelen en voor toxiciteitsexperimenten. De hydrofobe chemicalien (inclusief de meeste bestrijdingsmiddelen) werden geconcentreerd door sorptie aan kunsthars voorafgaand aan de toxiciteitsexperimenten. De concentraten werden getest met behulp van de PAM test met de groenalg Selenastrum capricornutum, de MicroTox test met de bacterie Vibrio fisheri, the IQ test met de watervlo Daphnia magna, een test met de kreeftachtige Thamnocephalus platyurus en een test met de rotifeer Brachionus calyciflorus. Om 50% inhibitie te veroorzaken moesten de monsters meer dan 100 keer geconcentreerd worden voor de rotifeer test en meer dan 10 keer voor de andere testen. In 44 van de 45 monsters was de concentratie van de gemeten bestrijdingsmiddelen te laag om de toxiciteit te verklaren. Dit impliceert dat de bijdrage van deze bestrijdingsmiddelen aan de totale toxiciteit vermoedelijk erg laag is in de meeste monsters, met uitzondering van een monster dat 3,1 4g parathion /liter bevatte. Dit is dichtbij de parathion concentratie die, volgens de wetenschappelijke literatuur, de mobiliteit van Daphnia magna met 50% verminderd. In onze toxiciteitsexperimenten moest het monster wel 20 keer geconcentreerd worden om 50% van Daphnia magna te remmen. Op dit moment hebben we nog geen goede verklaring voor deze discrepantie. De standaard Daphnia magna test zou kunnen verschillen van de hier gebruikte Daphnia IQ test. Verder onderzoek is nodig om te bepalen of bestrijdingsmiddelen werkelijk een acuut risico vormen voor aquatische ecosystemen in Nederlandse regionale oppervlaktewateren.
- Published
- 2004
21. Locatiespecifieke ecologische risicobeoordeling. Praktijkonderzoek met de TRIADE-benadering: deel 3
- Author
-
Schouten, AJ, Dirven-van Breemen, EM, Bogte, JJ, Rutgers, M, LER, Alterra, WUR/Bodemkwaliteit, Bedrijfslaboratorium voor Grond en Gewasonderzoek (BLGG), Oosterbeek, Baerselman, R, Bloem, J, Didden, WAM, Dimmers, W, de Groot, A, Keidel, H, Mulder, C, Peijnenburg, W, Siepel, H, Wouterse, M, Schouten, AJ, Dirven-van Breemen, EM, Bogte, JJ, Rutgers, M, LER, Alterra, WUR/Bodemkwaliteit, Bedrijfslaboratorium voor Grond en Gewasonderzoek (BLGG), Oosterbeek, Baerselman, R, Bloem, J, Didden, WAM, Dimmers, W, de Groot, A, Keidel, H, Mulder, C, Peijnenburg, W, Siepel, H, and Wouterse, M
- Abstract
RIVM rapport:Het doel van het onderzoek was de beproeving van de TRIADE methodiek voor de inschatting van locatiespecifieke ecologische risico's in een praktijksituatie. De TRIADE geeft de mogelijkheid om trapsgewijs effecten van verontreinigingen te bepalen voor de aspecten chemie, toxicologie en ecologie. Deze methodiek moet een verbetering opleveren ten opzichte van de ecologische risicoschatting in de huidige saneringsurgentie-systematiek. Het onderzoek werd uitgevoerd op vijf locaties rond de zinkfabriek te Budel. Twee van deze locaties lagen op grotere afstand en werden als (lokale) referentie gebruikt. Drie locaties in de nabijheid van de zinkfabiek hadden verhoogde gehaltes aan zink en cadmium. Interventiewaarden werden niet overschreden. Het chemische onderzoek richtte zich op totaal-gehaltes, extraheerbare fracties en poriewaterconcentraties van zware metalen. Op basis daarvan werd de toxische druk berekend. Het ecotoxicologisch onderzoek bestond uit bioassays met algen, springstaarten en radijsplanten. De gebruikte testorganismen vertoonden verschillende gevoeligheden voor zware metalen, mede als gevolg van bodemeigenschappen als zuurgraad en voedingsstoffenbeschikbaarheid. Het TRIADE-onderdeel "ecologie" werd ingevuld met indicatoren uit de Bodembiologische Indicator (BoBI) en met een vegetatie-inventarisatie. Verontreinigde locaties verschillen bijna altijd in meer eigenschappen van de referentie dan alleen de concentratie van de contaminanten. Het vaststellen van een simpele oorzaak-gevolg relatie voor ecologische effecten zal daarom meestal niet mogelijk zijn. Uit het TRIADE-onderzoek kan worden geconcludeerd, dat de keuze van de locale referentie aanzienlijke invloed heeft op het berekende ecologisch risico. De TRIADE-systematiek geeft de ecologische risicoschatting desondanks een aanzienlijk bredere basis dan de huidige urgentiesystematiek. De methodiek is gebaseerd op het 'multiple weight of evidence' principe en biedt een kwantitatieve maat voor ecologische ri, The TRIAD approach was tested for its applicability in assessing actual ecological risks on five sites around the zinc factory near the city of Budel, in The Netherlands. The TRIAD method offers the possibility of a tiered approach to actual risks for the local ecosystem. Risk assessment is derived on the basis of three elements, i.e. chemistry, toxicology and ecology. It is meant as an improvement for the present remediation urgency systematics. Three of the five sites were contaminated with zinc and cadmium at different levels, that did not exceed the Dutch 'intervention values'. Besides total soil contents, mobile soil metal fractions and pore-water concentrations were measured during the chemical assessment. Several variants of the toxic pressure calculations were compared. In the toxicological assessment several bioassays were performed, which showed different sensitivities to heavy metals and influence of soil-pH and nutrients. There are still very few tests that can be used for acid sandy field soil. Many soil biological analyses (microbial and soil fauna groups) and a vegetation inventory were used for the ecological assessment. In this field study they showed a larger deviation from the reference site than the chemical and toxicological indicators. From the overall TRIAD assessment it can be concluded, among others, that selection of a non-contaminated reference site is both crucial as well as difficult. Polluted sites generally differ in more aspects from a local reference site than just in the concentration of contaminants. Although the TRIAD approach is relatively time consuming, uniformity and the scientific basis of the actual ecological assessment have improved considerably. Therefore the TRIAD approach is recommended for the future as a standard tool to assess actual ecological risks of contaminated soil.
- Published
- 2004
22. Locatiespecifieke ecologische risicobeoordeling - praktijkonderzoek met de TRIADE-benadering deel 2
- Author
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LER, Schouten AJ, Bogte JJ, Dirven-van Breemen EM, Rutgers M, Baerselman R, van Beelen P, Bloem J, Keidel H, Wouterse M, LER, Schouten AJ, Bogte JJ, Dirven-van Breemen EM, Rutgers M, Baerselman R, van Beelen P, Bloem J, Keidel H, and Wouterse M
- Abstract
RIVM rapport:Dit rapport beschrijft de tweede fase in het praktijkonderzoek naar de bruikbaarheid van de TRIADE-benadering voor locatiespecifieke ecologische risicobeoordeling. In deze tweede fase werd gekozen voor een uitbreiding van de ecologische veldwaarnemingen en werd gestreefd naar een betere locale referenties voor verontreinigde percelen. Het is een volgende stap in de ontwikkeling van een beslissingsondersteunende methodiek, die op termijn de huidige urgentie-systematiek voor bodemverontreiniging zou kunnen aanvullen of vervangen. De verontreinigingsgraad was op twee van de drie locaties (te) hoog door de aanwezigheid van een cocktail aan stoffen. De monsters van de vloeivelden Tilburg voldeden het best aan de doelstelling om een uitgebreide TRIADE-beoordeling uit te voeren langs een gradient van matig verontreinigde gronden. De methodiek gaf ook hier een gradatie in effecten weer. Er zijn een groot aantal bodemecologische metingen uitgeprobeerd. De meeste gaven onderscheid tussen de monsters. De waargenomen effecten waren kleiner dan op grond van het TRIADE-onderdeel chemie verwacht zou worden. De keuze van een goede referentie blijkt een belangrijk en kritisch aspect in de beoordelingsmethodiek., This report describes the results of a research programme on the application of the so-called TRIAD approach for site specific ecological risk assessment of soil pollution. The method means to optimise the estimation of actual ecological effects in a specific area or ecosystem, by gathering multiple evidence along various ways. The TRIAD includes three pillars consisting of chemical, toxicological and ecological measurements. Each pillar of the TRIAD can be extended over three tiers, representing low, middle and high levels of sophistication in research methods. In the second phase of the field research, three locations were investigated with emphasis on the selection of a local reference site and ecological measurements. The chemical, toxicological and ecological measurements were integrated into an effect estimation per TRIAD-unit and one overall assessment. Effects were scaled from 0 to 1 and divided into 3 colour-categories to obtain a better overview. Although most bioassays and ecological indicators were able to characterise the samples, they showed much lower effects than predicted from the measured concentrations of pollutants. The (chemical) Toxic Pressure method, based on Species Sensitivity Distributions, seems to give an overestimation of ecological effects. It is also less discriminating in situations of multiple substance pollution exceeding Serious Risk Levels.
- Published
- 2003
23. Locatiespecifieke ecologische risicobeoordeling - praktijkonderzoek met de TRIADE-benadering deel 2
- Author
-
Schouten, AJ, Bogte, JJ, Dirven-van Breemen, EM, Rutgers, M, LER, Baerselman, R, van Beelen, P, Bloem, J, Keidel, H, Wouterse, M, Schouten, AJ, Bogte, JJ, Dirven-van Breemen, EM, Rutgers, M, LER, Baerselman, R, van Beelen, P, Bloem, J, Keidel, H, and Wouterse, M
- Abstract
RIVM rapport:This report describes the results of a research programme on the application of the so-called TRIAD approach for site specific ecological risk assessment of soil pollution. The method means to optimise the estimation of actual ecological effects in a specific area or ecosystem, by gathering multiple evidence along various ways. The TRIAD includes three pillars consisting of chemical, toxicological and ecological measurements. Each pillar of the TRIAD can be extended over three tiers, representing low, middle and high levels of sophistication in research methods. In the second phase of the field research, three locations were investigated with emphasis on the selection of a local reference site and ecological measurements. The chemical, toxicological and ecological measurements were integrated into an effect estimation per TRIAD-unit and one overall assessment. Effects were scaled from 0 to 1 and divided into 3 colour-categories to obtain a better overview. Although most bioassays and ecological indicators were able to characterise the samples, they showed much lower effects than predicted from the measured concentrations of pollutants. The (chemical) Toxic Pressure method, based on Species Sensitivity Distributions, seems to give an overestimation of ecological effects. It is also less discriminating in situations of multiple substance pollution exceeding Serious Risk Levels., Dit rapport beschrijft de tweede fase in het praktijkonderzoek naar de bruikbaarheid van de TRIADE-benadering voor locatiespecifieke ecologische risicobeoordeling. In deze tweede fase werd gekozen voor een uitbreiding van de ecologische veldwaarnemingen en werd gestreefd naar een betere locale referenties voor verontreinigde percelen. Het is een volgende stap in de ontwikkeling van een beslissingsondersteunende methodiek, die op termijn de huidige urgentie-systematiek voor bodemverontreiniging zou kunnen aanvullen of vervangen. De verontreinigingsgraad was op twee van de drie locaties (te) hoog door de aanwezigheid van een cocktail aan stoffen. De monsters van de vloeivelden Tilburg voldeden het best aan de doelstelling om een uitgebreide TRIADE-beoordeling uit te voeren langs een gradient van matig verontreinigde gronden. De methodiek gaf ook hier een gradatie in effecten weer. Er zijn een groot aantal bodemecologische metingen uitgeprobeerd. De meeste gaven onderscheid tussen de monsters. De waargenomen effecten waren kleiner dan op grond van het TRIADE-onderdeel chemie verwacht zou worden. De keuze van een goede referentie blijkt een belangrijk en kritisch aspect in de beoordelingsmethodiek.
- Published
- 2003
24. A rationale for the appropriate amount of inoculum in ready biodegradability tests
- Author
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Strujs, J., Dekkers, A. L. M., and Stoltenkamp-Wouterse, M. J.
- Published
- 1995
25. Dissipative particle dynamic simulation and experimental assessment of the impacts of humic substances on aqueous aggregation and dispersion of engineered nanoparticles.
- Author
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Wang Z, Quik JTK, Song L, Wouterse M, and Peijnenburg WJGM
- Subjects
- Hydrogen-Ion Concentration, Hydrophobic and Hydrophilic Interactions, Particle Size, Static Electricity, Computer Simulation, Humic Substances analysis, Nanoparticles chemistry, Nanotechnology, Water chemistry
- Abstract
Comprehensive experimental quantification and mapping of the aggregation and dispersion state of engineered nanoparticles (NPs) in the presence of humic substances is a great challenge. Dissipative particle dynamic (DPD) simulation was adopted to investigate the aggregation and dispersion mechanisms of NPs in the presence of a humic substance analog. Twelve different types of NPs including 2 metal-based NPs, 7 metal oxide-based NPs, and 3 carbon-based NPs in pure water (pH 3.0) and algae medium (pH 8.0) in the presence of a humic substance analogy were selected for experimental verification of the DPD simulation results. In agreement with results obtained with dynamic light scattering and phase analysis light scattering techniques, the simulations demonstrated that the presence of humic substances reduced the aggregation extent of the NPs. The DPD simulations showed that the stability and dispersity of the NPs increased first, and then decreased with increasing concentrations of humic substances. Moreover, there existed a concentration of humic substances where the NPs became more stable and more dispersed, which was experimentally verified in the case of all the NPs in the pure water and in the algae medium. Furthermore, theory and simulation indicate that both hydrophobic and hydrogen interaction play an important role in controlling the formation of NP aggregates in the presence of humic substances. Electrostatic interaction and steric repulsion are the main mechanisms underlying the effects of humic substances on the aqueous dispersion stability of NPs. Environ Toxicol Chem 2018;37:1024-1031. © 2017 SETAC., (© 2017 SETAC.)
- Published
- 2018
- Full Text
- View/download PDF
26. Importance of exposure dynamics of metal-based nano-ZnO, -Cu and -Pb governing the metabolic potential of soil bacterial communities.
- Author
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Zhai Y, Hunting ER, Wouterse M, Peijnenburg WJGM, and Vijver MG
- Subjects
- Calcium Compounds chemistry, Carbon metabolism, Copper toxicity, Ions, Lead toxicity, Microbial Consortia drug effects, Nanoparticles toxicity, Netherlands, Oxides chemistry, Particle Size, Soil chemistry, Soil Pollutants toxicity, Titanium chemistry, Zinc Oxide toxicity, Copper analysis, Lead analysis, Nanoparticles analysis, Soil Microbiology, Soil Pollutants analysis, Zinc Oxide analysis
- Abstract
Metal-based engineered nanomaterials (ENMs) are known to affect bacterial processes and metabolic activities. While testing their negative effects on biological components, studies traditionally rely on initial exposure concentrations and thereby do not take into consideration the dynamic behavior of ENMs that ultimately determines exposure and toxicity (e.g. ion release). Moreover, functional responses of soil microbial communities to ENMs exposure can be caused by both the particulate forms and the ionic forms, yet their relative contributions remain poorly understood. Therefore, we investigated the dynamic changes of exposure concentrations of three different types of ENMs (nano-ZnO, -Cu and -Pb) and submicron particles (SMPs) in relation to their impact on the capacity of soil bacterial communities to utilize carbon substrates. The different ENMs were chosen to differ in dissolution potential. The dynamic exposures of ENMs were considered using a time weighted average (TWA) approach. The joint toxicity of the particulate forms and the ionic forms of ENMs was evaluated using a response addition model. Our results showed that the effect concentrations of spherical nano-ZnO, -Cu and SMPs, and Pb-based perovskites expressed as TWA were lower than expressed as initial concentrations. Both particulate forms and ionic forms of spherical 18nm, 43nm nano-ZnO and 50nm, 100nm nano-Cu contribute to the overall response at the EC
50 levels. The particulate forms for 150nm, 200nm and 900nm ZnO SMPs and rod-shaped 78nm nano-Cu mainly affected the soil microbial metabolic potential, while the Cu ions released from spherical 25nm nano-Cu, 500nm Cu SMPs and Pb ions released from perovskites mainly described the effects to bacterial communities. Our results indicate that the dynamic exposure of ENMs and relative contributions of particles and ions require consideration in order to pursue a naturally realistic assessment of environmental risks of metal-based ENMs., (Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.)- Published
- 2017
- Full Text
- View/download PDF
27. Humic substances alleviate the aquatic toxicity of polyvinylpyrrolidone-coated silver nanoparticles to organisms of different trophic levels.
- Author
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Wang Z, Quik JT, Song L, Van Den Brandhof EJ, Wouterse M, and Peijnenburg WJ
- Subjects
- Animals, Colloids, Dose-Response Relationship, Drug, Particle Size, Silver metabolism, Chlorophyta physiology, Cladocera physiology, Humic Substances, Metal Nanoparticles toxicity, Povidone toxicity, Silver toxicity, Water Pollutants, Chemical toxicity, Zebrafish physiology
- Abstract
The present study investigated how humic substances (HS) modify the aquatic toxicity of silver nanoparticles (AgNPs) as these particles agglomerate in water and interact with HS. An alga species (Raphidocelis subcapitata), a cladoceran species (Chydorus sphaericus), and a freshwater fish larva (Danio rerio), representing organisms of different trophic levels, were exposed to colloids of the polyvinylpyrrolidone-coated AgNPs in the presence and absence of HS. Results show that the presence of HS alleviated the aquatic toxicity of the AgNP colloids to all the organisms in a dose-dependent manner. The particle size distribution of the AgNPs' colloidal particles shifted to lower values due to the presence of HS, implying that the decrease in the toxicity of the AgNP colloids cannot be explained by the variation of agglomeration size. The surface charge of the AgNPs was found to be more negative in the presence of high concentrations of HS, suggesting an electrostatic barrier by which HS might limit interactions between particles and algae cells; indeed, this effect reduced the algae toxicity. Observations on silver ions (Ag(+)) release show that HS inhibit AgNP dissolution, depending on the concentrations of HS. When toxic effects were expressed as a function of each Ag-species, toxicity of the free Ag(+) was found to be much higher than that of the agglomerated particles., (© 2015 SETAC.)
- Published
- 2015
- Full Text
- View/download PDF
28. Natural colloids are the dominant factor in the sedimentation of nanoparticles.
- Author
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Quik JT, Stuart MC, Wouterse M, Peijnenburg W, Hendriks AJ, and van de Meent D
- Subjects
- Chemical Phenomena, Kinetics, Nanostructures chemistry, Netherlands, Suspensions chemistry, Water Pollutants, Chemical chemistry, Colloids chemistry, Models, Chemical, Nanoparticles chemistry, Rivers chemistry
- Abstract
Estimating the environmental exposure to manufactured nanomaterials is part of risk assessment. Because nanoparticles aggregate with each other (homoaggregation) and with other particles (heteroaggregation), the main route of the removal of most nanoparticles from water is aggregation, followed by sedimentation. The authors used water samples from two rivers in Europe, the Rhine and the Meuse. To distinguish between small (mainly natural organic matter [NOM]) particles and the remainder of the natural colloids present, both filtered and unfiltered river water was used to prepare the particle suspensions. The results show that the removal of nanoparticles from natural river water follows first-order kinetics toward a residual concentration. This was measured in river water with less than 1 mg L(-1) CeO(2) nanoparticles. The authors inferred that the heteroaggregation with or deposition onto the solid fraction of natural colloids was the main mechanism causing sedimentation in relation to homoaggregation. In contrast, the NOM fraction in filtered river water stabilized the residual nanoparticles against further sedimentation for up to 12 d. In 10 mg L(-1) and 100 mg L(-1) CeO(2) nanoparticle suspensions, homoaggregation is likely the main mechanism leading to sedimentation. The proposed model could form the basis for improved exposure assessment for nanomaterials., (Copyright © 2012 SETAC.)
- Published
- 2012
- Full Text
- View/download PDF
29. Toxicity of polyfluorinated and perfluorinated compounds to lettuce (Lactuca sativa) and green algae (Pseudokirchneriella subcapitata).
- Author
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Ding G, Wouterse M, Baerselman R, and Peijnenburg WJ
- Subjects
- Chlorophyta metabolism, Fluorocarbons chemistry, Lactuca growth & development, Photosynthesis drug effects, Plant Roots drug effects, Plant Roots growth & development, Quantitative Structure-Activity Relationship, Toxicity Tests, Acute, Water Pollutants, Chemical chemistry, Chlorophyta drug effects, Fluorocarbons toxicity, Lactuca drug effects, Water Pollutants, Chemical toxicity
- Abstract
Recently, polyfluorinated and perfluorinated compounds (PFCs) have been detected in most surface waters around the world. Because some PFCs are persistent and tend to accumulate in surface waters, their potential adverse effects to aquatic organisms have received increasing attention. Nevertheless, currently available toxicity information is limited. The aim of this study was to evaluate the toxicity effects of seven PFCs on root elongation of lettuce (Lactuca sativa) and photosynthesis of green algae (Pseudokirchneriella subcapitata). It was found that the toxicity profiles of both species tested were similar and had good relations with the fluorinated carbon-chain length of the PFCs investigated. One of the compounds tested, perfluorobutanoic acid, was found to be more toxic than expected in the algae test, which may be related with acidification of the test solution. It was concluded that because short-chained PFCs are becoming the predominant PFC pollutants in surface waters, their long-term toxicity and mixture toxicity with other PFCs should be studied in greater detail.
- Published
- 2012
- Full Text
- View/download PDF
30. Transgenic maize containing the Cry1Ab protein ephemerally enhances soil microbial communities.
- Author
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Mulder C, Wouterse M, Rutgers M, and Posthuma L
- Subjects
- Bacillus thuringiensis Toxins, Bacterial Proteins physiology, Carbon metabolism, Ecosystem, Endotoxins physiology, Hemolysin Proteins physiology, Plants, Genetically Modified, Zea mays physiology, Bacterial Proteins genetics, Bacterial Toxins genetics, Endotoxins genetics, Hemolysin Proteins genetics, Soil Microbiology, Zea mays genetics
- Published
- 2007
- Full Text
- View/download PDF
31. Can transgenic maize affect soil microbial communities?
- Author
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Mulder C, Wouterse M, Raubuch M, Roelofs W, and Rutgers M
- Subjects
- Carbon metabolism, Plants, Genetically Modified, Soil Microbiology, Zea mays genetics, Zea mays physiology
- Abstract
The aim of the experiment was to determine if temporal variations of belowground activity reflect the influence of the Cry1Ab protein from transgenic maize on soil bacteria and, hence, on a regulatory change of the microbial community (ability to metabolize sources belonging to different chemical guilds) and/or a change in numerical abundance of their cells. Litter placement is known for its strong influence on the soil decomposer communities. The effects of the addition of crop residues on respiration and catabolic activities of the bacterial community were examined in microcosm experiments. Four cultivars of Zea mays L. of two different isolines (each one including the conventional crop and its Bacillus thuringiensis cultivar) and one control of bulk soil were included in the experimental design. The growth models suggest a dichotomy between soils amended with either conventional or transgenic maize residues. The Cry1Ab protein appeared to influence the composition of the microbial community. The highly enhanced soil respiration observed during the first 72 h after the addition of Bt-maize residues can be interpreted as being related to the presence of the transgenic crop residues. This result was confirmed by agar plate counting, as the averages of the colony-forming units of soils in conventional treatments were about one-third of those treated with transgenic straw. Furthermore, the addition of Bt-maize appeared to induce increased microbial consumption of carbohydrates in BIOLOG EcoPlates. Three weeks after the addition of maize residues to the soils, no differences between the consumption rate of specific chemical guilds by bacteria in soils amended with transgenic maize and bacteria in soils amended with conventional maize were detectable. Reaped crop residues, comparable to post-harvest maize straw (a common practice in current agriculture), rapidly influence the soil bacterial cells at a functional level. Overall, these data support the existence of short Bt-induced ecological shifts in the microbial communities of croplands' soils.
- Published
- 2006
- Full Text
- View/download PDF
32. Location-specific ecotoxicological risk assessment of metal-polluted soils.
- Author
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Van Beelen P, Wouterse M, Posthuma L, and Rutgers M
- Subjects
- Chromogenic Compounds, Netherlands, Reproducibility of Results, Risk Assessment methods, Toxicity Tests methods, Metals, Heavy toxicity, Soil Microbiology, Soil Pollutants toxicity
- Abstract
When chemical analysis indicates metal pollution, a second-tier method is needed to evaluate whether toxic effects occur at the polluted sites. A method based on pollution-induced community tolerance (PICT) was developed using samples taken from locations polluted with sewage more than 20 years ago. Microorganisms extracted from soil samples were exposed to a concentration range of zinc, nickel, copper, chromium (III), or chromium (VI) salts in a buffer suspension. The remaining activity of the intoxicated microorganisms was determined by color formation with 31 different organic substrates in microtiter plates. Microorganisms from moderately Zn-polluted sites (>45 mg/kg) showed an increased tolerance for zinc. Nickel tolerance was observed at 51 mg Ni/kg soil, chromium (VI) tolerance at 923 mg Cr/kg. In most cases, tolerance also was observed at higher concentrations. High concentrations of 1,494 mg Cu/kg or 3,935 mg Cr/kg did not show PICT, indicating a limited bioavailability of Cu and Cr at these sites. The benefits of our method are its greater sensitivity compared to other tests used at these sites, and its specificity for those metals that exceed allowable levels.
- Published
- 2004
- Full Text
- View/download PDF
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