Répartition de la végétation dans la savane pré-forestière

The vegetation of the Lamto area has been studied along transects linking the gallery forest to the savanna plateau. The counting strips, 20 metres wide and 200 to 460 metres long, were subdivided into a succession of quadrats 20x20 m. In each of these quadrats trees and shrubs were counted and the grass layer sampled. Results are shown on folding pages 1 to 5. Within the study area four different types of savanna are found, grass savanna, shrub savanna, tree savanna and savanna woodland. The shrub savanna in predominant. The relationships between these vegetation types, topography and soils are discussed.Duviard Dominique, Dugerdil Marc, Bonvallot Jacques. Répartition de la végétation dans la savane pré-forestière . In: La Terre et La Vie, Revue d'Histoire naturelle, tome 24, n°1, 1970. pp. 3-21

Elaboration of a toxicological reference value (TRV) for the reprotoxic effects of nonylphenols

International audienc

Determination of glyphosate and AMPA in indoor settled dust by hydrophilic interaction liquid chromatography with tandem mass spectrometry and implications for human exposure

In Press, Journal Pre-proofInternational audienceThe widespread application of glyphosate leads to significant contamination of outdoor environmental compartments, notably air and soil, which can contaminate indoor air and dust. This study assessed the contamination of indoor household dust for the first time in France and potential exposure to glyphosate through the inadvertent ingestion of dust. A specific and new analytical method was developed using HILIC MS/MS (hydrophilic interaction liquid chromatography with tandem mass spectrometry) to measure polar pesticides, such as glyphosate, aminomethylphosphonic acid, and glufosinate, in indoor dust, with a low quantification limit (25 ng/g). The dust from vacuum cleaner bags of 60 rural and urban households (Brittany, France) was analyzed. All samples contained glyphosate (median 1,675 ng/g for rural dwellings (n = 29), 457 ng/g for urban dwellings (n = 31)), more than 90% contained aminomethylphosphonic acid, and none contained glufosinate. Concentrations were influenced by the rural or urban setting, the proximity of crops, and the use of weed killers on driveways or lawns. Glyphosate exposure via indoor dust ingestion was < 1% of both acceptable daily intake and dietary intake. However, the high quantification limit of the glyphosate concentration in the food analysis method probably leads to overestimation of the dose from food

The French approach for deriving toxicity references values: the example with reprotoxic effects

International audienceFollowing the French health and environment action plan, the French Agency for Environmental and Occupational Health and Safety set up a workgroup to standardise a method of deriving toxicity reference values (TRVs). Over the last few decades, there has been increasing concern about the effect of exposure to chemicals on reproductive function, leading the group to take an interest in reprotoxic effects. This article presents the recommendations of the workgroup regarding specific reprotoxic effects. Abnormal development of foetuses and infants, together with impairment of reproduction were considered to be critical effects. Where critical windows of exposure were concerned, quantitative analysis suggested the need for several types of toxicity reference value, as a function of exposure duration: reprotoxic effects may result from acute or chronic exposure at any time of life, whilst developmental effects may occur after exposure during the pregnancy or during the lactation period. The choice of a critical study is based on epidemiological or toxicological quality criteria. The working group recommends the use of the benchmark dose approach in estimating the critical dose. Finally, the working group considered the application of uncertainty factors typically used to take into account the variability between animal and human, between different individuals, and the availability of the data

Évaluation du risque chimique en santé-travail et en santé-environnement : objectifs et méthodes

International audienceChemical risk assessment is a tool used in decision-making processes concerning situations of scientific uncertainty. Approaches to risk assessment in occupational and environmental health share the same objective of risk prevention. Nevertheless, the methods for both differ depending on whether the goal is to enforce regulations or conduct expert assessments and studies. These differences are stronger in occupational health, for which regulations require risk assessments at the work station, to classify and prioritize exposure situations to implement occupational risk prevention strategies. Risk assessment thus has somewhat different meanings in occupational and environmental health. This article attempts to clarify the different terms used in the different contexts and to describe the similarities and differences of the two approaches.L’évaluation des risques liés aux substances chimiques est un outil d’aide à la décision utilisé en situation d’incertitude scientifique. Les démarches d’évaluation des risques sanitaires en santé au travail et en santé environnementale répondent à un objectif commun de prévention des risques. Les méthodes mises en œuvre sont différentes en fonction des contextes : application de la réglementation ou expertises et études. C’est en particulier le cas de l’évaluation du risque au poste de travail, imposée par le code du travail, qui est avant tout définie comme un moyen de classer et hiérarchiser des situations d’exposition pour mettre en œuvre des moyens d’action proportionnés. Ainsi, « évaluer les risques » renvoie à une représentation souvent différente d’un domaine à l’autre. Cet article propose de clarifier les termes employés en les replaçant dans leur contexte et décrit les similarités et les différences existant entre les approches en santé-travail et santé-environnement