The 2nd French Total Diet Study demonstrated that 0.6% of adults and 14.9% of children exceeded t... more The 2nd French Total Diet Study demonstrated that 0.6% of adults and 14.9% of children exceeded the tolerable weekly intake set by EFSA. The overexposure of several consumers (adults and children) can be partially due to the high consumption of bread and dried bread products, of bivalve mollusks and of potatoes. Except for mollusks, these foods are the main contributors identified for the general population. On this basis, the French agency for food, environmental and occupational health and safety (ANSES) assessed whether a decrease of the European maximum limits in foodstuffs could significantly reduce the level of exposure of French consumers. Applying ML set at P90 of the main contributors would neither significantly reduce exposure levels to cadmium for the general population, nor the percentage of subjects exceeding the TWI. To reduce background consumer exposure to cadmium, actions to be taken include efforts on sources that are at the origin of the soil contamination and the efficacy of consumption recommendations.
Environmental Pollution Series A, Ecological and Biological, 1984
ABSTRACT The toxicity of the dithiocarbamate fungicide thiram was studied on KB3 cells (by ATP co... more ABSTRACT The toxicity of the dithiocarbamate fungicide thiram was studied on KB3 cells (by ATP content) on two strains of vacuole-forming and four strains of non-vacuole-forming mutants of Tetrahymena (by growth rates) and on 33 strains of amoebae (by growth test). The sensitivity range is 0·1 mg litre−1 for mammalian cells, 0.5–1 mg litre−1 for T. thermophila and 2–16 mg litre−1 for amoebae, which are the most resistant organisms. The results suggest that protozoa are probably affected by thiram in soil and when accidental water contamination occurs. The results obtained with vacuoleless mutants of T. thermophila also suggest that the cell membrane is the essential site of uptake of the toxicant.
Soil samples from a former cokery site polluted with polycyclic aromatic hydrocarbons (PAHs) were... more Soil samples from a former cokery site polluted with polycyclic aromatic hydrocarbons (PAHs) were assessed for their toxicity to terrestrial and aquatic organisms and for their mutagenicity. The total concentration of the 16 PAHs listed as priority pollutants by the US Environmental Protection Agency (US-EPA) was 2634±241mg/kgdw in soil samples. The toxicity of water-extractable pollutants from the contaminated soil samples
Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis, 1997
The mouse lymphoma assay is widely used for determining the potential for chemicals to cause muta... more The mouse lymphoma assay is widely used for determining the potential for chemicals to cause mutational damage. The assay often figures mto drug and chemical safety testing strategies and into required submissions to regulatory agencies. Substantial research has been conducted to understand the capabilities (and limitations) of the assay, the proper conduct of the assay and the interpretation of the test data. This presentation aims to stimulate discussion at a rather critical time in the important issues surrounding the use ofthis (and other) mutation assay(s) . Issues to be tackled include a discussion of (t) the available mechanistic information that describes the capabilities of the assay, (2) comparison of the traditional soft agar clon ing technique with the microwell technique, (3) requirement for and utility of colony sizing, (4) poor quality of much of the published data due to inadequate attention to recovery and detection of small colony mutants, (5) possibility that the mouse lymphoma assay could replace in vitro chromosome aberration tests and proper interpretation of assay data. (This abstract of a proposed presentation does not necessarily represent US EPA policy.) Keyword(s): Mouse Lymphoma Assay
Environmental Pollution Series B, Chemical and Physical, 1980
ABSTRACT The effect of thiram (a dithiocarbamate) on the production of ATP by human KB3 cells in ... more ABSTRACT The effect of thiram (a dithiocarbamate) on the production of ATP by human KB3 cells in vitro was studied. Cells were exposed to different concentrations of thiram for various periods of time.After two hours, 0·5–10 ppm thiram caused complete inhibition of ATP production. After 40 min, 0·5 and 1 ppm thiram caused a significant decrease in ATP concentrations—possibly as a result of an impairment of mitochondrial activity. 0·1 ppm thiram may be the sensitivity threshold for KB3 cells.Effects of thiram on the nucleus and cytoplasm of KB3 cells were also observed.
Besides microgravity, inactivity is likely to play a role in the cardiovascular deconditioning af... more Besides microgravity, inactivity is likely to play a role in the cardiovascular deconditioning after space flights and weightlessness simulations. The aim of the study was to compare the effects of a 4-day head-down bed rest (HDBR) (-6 degrees) and a 4-day confinement (C) on cardiovascular responses to orthostatic stress. Eight male subjects underwent head-up tilt (HUT) (+60 degrees) and lower-body negative pressure (LBNP) (-20, -30, -40 and -50 mmHg) before (D-1) and at the end (R1) of each situation. Blood pressure, heart rate variability (HRV) and spontaneous baroreflex slope (SBS) were determined. The HDBR reduced orthostatic tolerance, as five subjects presented orthostatic hypotension during the HUT at R1, compared with two subjects at D-1. These same two subjects presented orthostatic hypotension after confinement. The main findings, after HDBR, included reductions in RR interval and total spectral power and a decrease in the parasympathetic indicator (PNS) in favour of a dec...
Decision-making for remediation of industrial wastelands are still based on the concentrations of... more Decision-making for remediation of industrial wastelands are still based on the concentrations of pollutants of concern measured in soils. In this work, two soils polluted by polycyclic aromatic hydrocarbons (PAHs) and metals were investigated for their toxicity on earthworms (Eisenia fetida), collembolae (Folsomia candida), and higher plants (Brassica chinensis, Lactucca sativa and Avena sativa) in order to study the relationships between chemical contamination and biological effects. Although the level of contamination by PAHs was elevated and commensurate in the two soils, their toxicity profile was quite different. Soil A affected survival and reproduction of invertebrates and growth of higher plants. Surprisingly, soil B, heavily contaminated by metals in addition to PAHs, was devoid of toxicity. Our results indicate that toxicity cannot simply be extrapolated from pollutant concentrations in a complex matrix in which bioavailability of pollutants may be reduced by ageing. Moreover, the use of toxicity data obtained from spiked soils characterized by readily bioavailable pollutants can also be called into question for such extrapolations. Predicting biological effects therefore requires biological tools to avoid any erroneous conclusions that can be drawn from sole extrapolation of analytical results. # 2008 Wiley Periodicals, Inc. Environ Toxicol 23: 652-656, 2008.
ABSTRACT Largement utilisés comme solvants depuis les années, 1970, les éthers de glycol sont pré... more ABSTRACT Largement utilisés comme solvants depuis les années, 1970, les éthers de glycol sont présents dans de multiples usages industriels et dans une large gamme de produits couramment employés par le consommateur (peinture, vernis, produits de nettoyage...). Dans les années 1990, des études ,: ont montré la toxicité de certains éthers de glycol et des réglementations en ont interdit l'usage en France dans les produits domestiques, cosmétique et les médicaments. Plusieurs éthers de glycol ont fait l'objet d'évaluation de dangers et d'évaluation de risques au niveau européen ou international. Les mesures réglementaires; récentes imposent que les effets toxiques (génotoxicité effet sur la reproduction et le développement) soient recherchés systématiquement par les producteurs avant la mise sur le marché de nouvelles substances. C'est dans le cadre du plan d'action gouvernemental que l'Afsset a sollicité fInserm pour une actualisation des données toxicologiques et épidémiologiques de l'expertise collective " Ethers de glycol, quels risques pour la santé ? " publiée en 1999. Le groupe d'experts réunis sous l'égide de l'Inserm a effectué le bilan des travaux menés dans ces domaines par le secteur académique et privé depuis 1999 sur les anciens et nouveaux produits. Ce bilan a permis de présenter les avancées des connaissances dans les mécanismes de toxicité et de souligner les lacunes justifiant le maintien d'une vigilance à propos de nouveaux éthers de glycol.
... detecting ecotoxic hazards which threaten aquatic ecosystems (Danielson, 1979; Lloyd, 1980; C... more ... detecting ecotoxic hazards which threaten aquatic ecosystems (Danielson, 1979; Lloyd, 1980; Cairns, 1983; Chapman and Long, 1983; Blaise et al., 1985). In selecting biotests a number of factors must be taken into account. First of all, it is impossible for a small laboratory staff ...
ABSTRACT Toxic effects of Cd++, Cu++, and Zn++ on Selenastrum capricornutum were evaluated in var... more ABSTRACT Toxic effects of Cd++, Cu++, and Zn++ on Selenastrum capricornutum were evaluated in various experimental conditions in order to determine the influence of the composition of the test medium and of the concentration of the algal biomass on the toxicity of metals to algae. Four media recommended in different standard methods (International Standards Organisation, U.S. Environmental Protection Agency, Organisation for Economic Cooperation and Development, AFNOR) were compared. Results of algal bioassays showed that the sensitivity of algae during the exponential growth phase was not influenced by the concentration of macronutrients in the medium.On the contrary, the numeration of the algal suspensions tested appeared determinant as the toxicity decreased when the quantity of algal inoculum was increased: with inocula of nearly 3 × 104, 2.5 × 105, 6 × 105, and 3 × 106 cells/mL at t = 0, the corresponding EC50 were 46, 80, 110, and up to 300 μg/L for cadmium, 10, 65, 105, and 280 μg/L for copper, and 90, 163, 225, and 365 μg/L for zinc. Modifications in the speciation forms of the metal induced by a rapid increase of the pH could be responsible for part of this decreased toxicity.
Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis, 1997
We found that numerical aberrations were induced in Chinese hamster cell lines, V79-MZ and V79, t... more We found that numerical aberrations were induced in Chinese hamster cell lines, V79-MZ and V79, treated through 2 cell cycles with benzo[a]pyrene (BP) and 7,12.dimethylbenz [a]anthracene (DMBA) in the absence of a metabolic activation system. V79 ·MZ. supplied by Glatt (German Institute of Human Nutrition, Germany), and V79 (supplied from Japan Cell Resources Bank, JCRB0603) cells were treated with chemicals (±5bromodeoxyuridine) for 24 h and harvested immed iately. Chromosome number was counted for 100 metaphases on the Giemsa stained chromosome preparations . The number of second metaphase (M2) cells and sister chromatid exchanges were scored. BP decreased the frequency of cells show ing the modal chromosome number from 75% (solvent control) to 27% at 2.5 lJ.g/m1 and to 10% at 5 ug/ml in V79-MZ cells . The distribution of chromosome number spread broadly from diploid up to tetraploid range at 2.5-10 lJ.g/ml. We concluded that BP induced aneuploidy in V79-MZ cells. No remarkable changes, however, was observed in chromosome numbers in V79 cells. DMBA induced tetraploids at 3.125-0.25 Itg/ml in V79-MZ cells and 6.25-12.5 ug/ml in V79 cells. V79-MZ responded to a spindle poison, colch icine up to 0.1 lJ.g/ml,more sensitively than V79 . The numerical aberrations mentioned above coincided with decrease in the frequency of M2 cells. V79·MZ cells may be useful to detect polyploid/aneuploid inducers.
Mutation Research-fundamental and Molecular Mechanisms of Mutagenesis, 1996
While the accumulation of genetic changes in a somatic cell is considered essential for the genes... more While the accumulation of genetic changes in a somatic cell is considered essential for the genesis of a cancer, it has become clear that not all carcinogens are genotoxic, suggesting that some carcinogens indirectly participate in the generation of genetic changes during carcinogenesis. A European project funded by the European Community was thus conceived to study mechanisms of nongenotoxic aspects
ABSTRACT Binary mixtures of atrazine (herbicide) and copper were studied in three microorganisms:... more ABSTRACT Binary mixtures of atrazine (herbicide) and copper were studied in three microorganisms: a bacterium, a protozoan and a microalga. Factorial experiments were carried out to detect interactive effects and toxicity results were interpreted with multiple regression analysis. The levels of concentrations tested on algae were close to those found in aquatic environments.This study confirms the specific toxicity of atrazine to photosynthetic cells and the broad activity spectrum of copper which is toxic to the three species tested. No significant interactions were found between atrazine (up to 100μg/1) and copper (up to 25 μg/l Cu2+) on algae. No interactive effects were registered on protozoans either. A synergistic effect does occur on bacteria but at such concentrations (10mg/1) that this effect is not considered ecologically meaningful.
We present a way to determine which pollutants should be reduced first in the presence of interac... more We present a way to determine which pollutants should be reduced first in the presence of interactions, given an initial contamination situation, and a specified goal of pollution reduction. An index of environmental toxicity is expressed as a polynomial function of the concentrations of different chemicals. The coefficients of the function are estimated by multiple regression analysis. Minimization of the cost of achieving a given level of toxicity reduction is obtained by uniform sampling and cost determination on the same polynomial. This method can be applied to any combination of pollutants and any toxicity test. As an example, the joint toxicity of chromium, copper, and zinc measured by a bacterial test, the Microtox R test, is modeled. In this simplified context, the three metals are found to interact. We show that it would be inefficient to diminish simultaneously their concentrations; instead, zinc and chromium should be removed first. The extent of removal depends on the initial concentrations and on the degree of toxicity reduction desired.
The 2nd French Total Diet Study demonstrated that 0.6% of adults and 14.9% of children exceeded t... more The 2nd French Total Diet Study demonstrated that 0.6% of adults and 14.9% of children exceeded the tolerable weekly intake set by EFSA. The overexposure of several consumers (adults and children) can be partially due to the high consumption of bread and dried bread products, of bivalve mollusks and of potatoes. Except for mollusks, these foods are the main contributors identified for the general population. On this basis, the French agency for food, environmental and occupational health and safety (ANSES) assessed whether a decrease of the European maximum limits in foodstuffs could significantly reduce the level of exposure of French consumers. Applying ML set at P90 of the main contributors would neither significantly reduce exposure levels to cadmium for the general population, nor the percentage of subjects exceeding the TWI. To reduce background consumer exposure to cadmium, actions to be taken include efforts on sources that are at the origin of the soil contamination and the efficacy of consumption recommendations.
Environmental Pollution Series A, Ecological and Biological, 1984
ABSTRACT The toxicity of the dithiocarbamate fungicide thiram was studied on KB3 cells (by ATP co... more ABSTRACT The toxicity of the dithiocarbamate fungicide thiram was studied on KB3 cells (by ATP content) on two strains of vacuole-forming and four strains of non-vacuole-forming mutants of Tetrahymena (by growth rates) and on 33 strains of amoebae (by growth test). The sensitivity range is 0·1 mg litre−1 for mammalian cells, 0.5–1 mg litre−1 for T. thermophila and 2–16 mg litre−1 for amoebae, which are the most resistant organisms. The results suggest that protozoa are probably affected by thiram in soil and when accidental water contamination occurs. The results obtained with vacuoleless mutants of T. thermophila also suggest that the cell membrane is the essential site of uptake of the toxicant.
Soil samples from a former cokery site polluted with polycyclic aromatic hydrocarbons (PAHs) were... more Soil samples from a former cokery site polluted with polycyclic aromatic hydrocarbons (PAHs) were assessed for their toxicity to terrestrial and aquatic organisms and for their mutagenicity. The total concentration of the 16 PAHs listed as priority pollutants by the US Environmental Protection Agency (US-EPA) was 2634±241mg/kgdw in soil samples. The toxicity of water-extractable pollutants from the contaminated soil samples
Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis, 1997
The mouse lymphoma assay is widely used for determining the potential for chemicals to cause muta... more The mouse lymphoma assay is widely used for determining the potential for chemicals to cause mutational damage. The assay often figures mto drug and chemical safety testing strategies and into required submissions to regulatory agencies. Substantial research has been conducted to understand the capabilities (and limitations) of the assay, the proper conduct of the assay and the interpretation of the test data. This presentation aims to stimulate discussion at a rather critical time in the important issues surrounding the use ofthis (and other) mutation assay(s) . Issues to be tackled include a discussion of (t) the available mechanistic information that describes the capabilities of the assay, (2) comparison of the traditional soft agar clon ing technique with the microwell technique, (3) requirement for and utility of colony sizing, (4) poor quality of much of the published data due to inadequate attention to recovery and detection of small colony mutants, (5) possibility that the mouse lymphoma assay could replace in vitro chromosome aberration tests and proper interpretation of assay data. (This abstract of a proposed presentation does not necessarily represent US EPA policy.) Keyword(s): Mouse Lymphoma Assay
Environmental Pollution Series B, Chemical and Physical, 1980
ABSTRACT The effect of thiram (a dithiocarbamate) on the production of ATP by human KB3 cells in ... more ABSTRACT The effect of thiram (a dithiocarbamate) on the production of ATP by human KB3 cells in vitro was studied. Cells were exposed to different concentrations of thiram for various periods of time.After two hours, 0·5–10 ppm thiram caused complete inhibition of ATP production. After 40 min, 0·5 and 1 ppm thiram caused a significant decrease in ATP concentrations—possibly as a result of an impairment of mitochondrial activity. 0·1 ppm thiram may be the sensitivity threshold for KB3 cells.Effects of thiram on the nucleus and cytoplasm of KB3 cells were also observed.
Besides microgravity, inactivity is likely to play a role in the cardiovascular deconditioning af... more Besides microgravity, inactivity is likely to play a role in the cardiovascular deconditioning after space flights and weightlessness simulations. The aim of the study was to compare the effects of a 4-day head-down bed rest (HDBR) (-6 degrees) and a 4-day confinement (C) on cardiovascular responses to orthostatic stress. Eight male subjects underwent head-up tilt (HUT) (+60 degrees) and lower-body negative pressure (LBNP) (-20, -30, -40 and -50 mmHg) before (D-1) and at the end (R1) of each situation. Blood pressure, heart rate variability (HRV) and spontaneous baroreflex slope (SBS) were determined. The HDBR reduced orthostatic tolerance, as five subjects presented orthostatic hypotension during the HUT at R1, compared with two subjects at D-1. These same two subjects presented orthostatic hypotension after confinement. The main findings, after HDBR, included reductions in RR interval and total spectral power and a decrease in the parasympathetic indicator (PNS) in favour of a dec...
Decision-making for remediation of industrial wastelands are still based on the concentrations of... more Decision-making for remediation of industrial wastelands are still based on the concentrations of pollutants of concern measured in soils. In this work, two soils polluted by polycyclic aromatic hydrocarbons (PAHs) and metals were investigated for their toxicity on earthworms (Eisenia fetida), collembolae (Folsomia candida), and higher plants (Brassica chinensis, Lactucca sativa and Avena sativa) in order to study the relationships between chemical contamination and biological effects. Although the level of contamination by PAHs was elevated and commensurate in the two soils, their toxicity profile was quite different. Soil A affected survival and reproduction of invertebrates and growth of higher plants. Surprisingly, soil B, heavily contaminated by metals in addition to PAHs, was devoid of toxicity. Our results indicate that toxicity cannot simply be extrapolated from pollutant concentrations in a complex matrix in which bioavailability of pollutants may be reduced by ageing. Moreover, the use of toxicity data obtained from spiked soils characterized by readily bioavailable pollutants can also be called into question for such extrapolations. Predicting biological effects therefore requires biological tools to avoid any erroneous conclusions that can be drawn from sole extrapolation of analytical results. # 2008 Wiley Periodicals, Inc. Environ Toxicol 23: 652-656, 2008.
ABSTRACT Largement utilisés comme solvants depuis les années, 1970, les éthers de glycol sont pré... more ABSTRACT Largement utilisés comme solvants depuis les années, 1970, les éthers de glycol sont présents dans de multiples usages industriels et dans une large gamme de produits couramment employés par le consommateur (peinture, vernis, produits de nettoyage...). Dans les années 1990, des études ,: ont montré la toxicité de certains éthers de glycol et des réglementations en ont interdit l'usage en France dans les produits domestiques, cosmétique et les médicaments. Plusieurs éthers de glycol ont fait l'objet d'évaluation de dangers et d'évaluation de risques au niveau européen ou international. Les mesures réglementaires; récentes imposent que les effets toxiques (génotoxicité effet sur la reproduction et le développement) soient recherchés systématiquement par les producteurs avant la mise sur le marché de nouvelles substances. C'est dans le cadre du plan d'action gouvernemental que l'Afsset a sollicité fInserm pour une actualisation des données toxicologiques et épidémiologiques de l'expertise collective " Ethers de glycol, quels risques pour la santé ? " publiée en 1999. Le groupe d'experts réunis sous l'égide de l'Inserm a effectué le bilan des travaux menés dans ces domaines par le secteur académique et privé depuis 1999 sur les anciens et nouveaux produits. Ce bilan a permis de présenter les avancées des connaissances dans les mécanismes de toxicité et de souligner les lacunes justifiant le maintien d'une vigilance à propos de nouveaux éthers de glycol.
... detecting ecotoxic hazards which threaten aquatic ecosystems (Danielson, 1979; Lloyd, 1980; C... more ... detecting ecotoxic hazards which threaten aquatic ecosystems (Danielson, 1979; Lloyd, 1980; Cairns, 1983; Chapman and Long, 1983; Blaise et al., 1985). In selecting biotests a number of factors must be taken into account. First of all, it is impossible for a small laboratory staff ...
ABSTRACT Toxic effects of Cd++, Cu++, and Zn++ on Selenastrum capricornutum were evaluated in var... more ABSTRACT Toxic effects of Cd++, Cu++, and Zn++ on Selenastrum capricornutum were evaluated in various experimental conditions in order to determine the influence of the composition of the test medium and of the concentration of the algal biomass on the toxicity of metals to algae. Four media recommended in different standard methods (International Standards Organisation, U.S. Environmental Protection Agency, Organisation for Economic Cooperation and Development, AFNOR) were compared. Results of algal bioassays showed that the sensitivity of algae during the exponential growth phase was not influenced by the concentration of macronutrients in the medium.On the contrary, the numeration of the algal suspensions tested appeared determinant as the toxicity decreased when the quantity of algal inoculum was increased: with inocula of nearly 3 × 104, 2.5 × 105, 6 × 105, and 3 × 106 cells/mL at t = 0, the corresponding EC50 were 46, 80, 110, and up to 300 μg/L for cadmium, 10, 65, 105, and 280 μg/L for copper, and 90, 163, 225, and 365 μg/L for zinc. Modifications in the speciation forms of the metal induced by a rapid increase of the pH could be responsible for part of this decreased toxicity.
Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis, 1997
We found that numerical aberrations were induced in Chinese hamster cell lines, V79-MZ and V79, t... more We found that numerical aberrations were induced in Chinese hamster cell lines, V79-MZ and V79, treated through 2 cell cycles with benzo[a]pyrene (BP) and 7,12.dimethylbenz [a]anthracene (DMBA) in the absence of a metabolic activation system. V79 ·MZ. supplied by Glatt (German Institute of Human Nutrition, Germany), and V79 (supplied from Japan Cell Resources Bank, JCRB0603) cells were treated with chemicals (±5bromodeoxyuridine) for 24 h and harvested immed iately. Chromosome number was counted for 100 metaphases on the Giemsa stained chromosome preparations . The number of second metaphase (M2) cells and sister chromatid exchanges were scored. BP decreased the frequency of cells show ing the modal chromosome number from 75% (solvent control) to 27% at 2.5 lJ.g/m1 and to 10% at 5 ug/ml in V79-MZ cells . The distribution of chromosome number spread broadly from diploid up to tetraploid range at 2.5-10 lJ.g/ml. We concluded that BP induced aneuploidy in V79-MZ cells. No remarkable changes, however, was observed in chromosome numbers in V79 cells. DMBA induced tetraploids at 3.125-0.25 Itg/ml in V79-MZ cells and 6.25-12.5 ug/ml in V79 cells. V79-MZ responded to a spindle poison, colch icine up to 0.1 lJ.g/ml,more sensitively than V79 . The numerical aberrations mentioned above coincided with decrease in the frequency of M2 cells. V79·MZ cells may be useful to detect polyploid/aneuploid inducers.
Mutation Research-fundamental and Molecular Mechanisms of Mutagenesis, 1996
While the accumulation of genetic changes in a somatic cell is considered essential for the genes... more While the accumulation of genetic changes in a somatic cell is considered essential for the genesis of a cancer, it has become clear that not all carcinogens are genotoxic, suggesting that some carcinogens indirectly participate in the generation of genetic changes during carcinogenesis. A European project funded by the European Community was thus conceived to study mechanisms of nongenotoxic aspects
ABSTRACT Binary mixtures of atrazine (herbicide) and copper were studied in three microorganisms:... more ABSTRACT Binary mixtures of atrazine (herbicide) and copper were studied in three microorganisms: a bacterium, a protozoan and a microalga. Factorial experiments were carried out to detect interactive effects and toxicity results were interpreted with multiple regression analysis. The levels of concentrations tested on algae were close to those found in aquatic environments.This study confirms the specific toxicity of atrazine to photosynthetic cells and the broad activity spectrum of copper which is toxic to the three species tested. No significant interactions were found between atrazine (up to 100μg/1) and copper (up to 25 μg/l Cu2+) on algae. No interactive effects were registered on protozoans either. A synergistic effect does occur on bacteria but at such concentrations (10mg/1) that this effect is not considered ecologically meaningful.
We present a way to determine which pollutants should be reduced first in the presence of interac... more We present a way to determine which pollutants should be reduced first in the presence of interactions, given an initial contamination situation, and a specified goal of pollution reduction. An index of environmental toxicity is expressed as a polynomial function of the concentrations of different chemicals. The coefficients of the function are estimated by multiple regression analysis. Minimization of the cost of achieving a given level of toxicity reduction is obtained by uniform sampling and cost determination on the same polynomial. This method can be applied to any combination of pollutants and any toxicity test. As an example, the joint toxicity of chromium, copper, and zinc measured by a bacterial test, the Microtox R test, is modeled. In this simplified context, the three metals are found to interact. We show that it would be inefficient to diminish simultaneously their concentrations; instead, zinc and chromium should be removed first. The extent of removal depends on the initial concentrations and on the degree of toxicity reduction desired.
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Papers by Paule Vasseur