La santé mentale et l’exposition aux solvants organiques en milieu de travail

Grâce à leurs propriétés chimiques, les solvants organiques ont une affinité particulière avec le système nerveux, de sorte qu'ils peuvent interférer avec le fonctionnement d'un élément ou d'un ensemble d'éléments de ce système. Des études de cas et des études épidémiologiques ont démontré une association entre l'exposition à long terme à certains solvants et le risque de neuropathies, d'encéphalopathies et de troubles psychiatriques. Mais entre l'état de bien-être et la maladie, il existe un continuum de détérioration de la santé mentale. Le présent article vise à poser le problème de la détérioration du bien-être chez des personnes exposées à des agents neurotoxiques, à partir d'une étude menée auprès de 71 traavilleurs exposés professionnellement à l'éther éthylique ou l'éthanol dans une usine d'explosifs et de 74 travailleurs non exposés. Il s'agit d'une étude de nature exploratoire, portant sur la prévalence de symptômes qui pourraient résulter de l'expositon professionnelle à ces agents neurotoxiques. Les résultats montrent que les personnes exposées, comparées aux personnes non exposées, manifestent davantage de symptômes prénarcotiques durant le travail, tels que des sensations d'ivresse, des difficultés à articuler les mots... Ces personnes rapportent également une fréquence plus élevée de symptômes généraux reflétant l'instabilité de l'humeur, des problèmes de fatigue, de sommeil, de mémoire et de concentration. Le nombre rapporté de symptômes prénarcotiques et de symptômes généraux augmente avec le degré d'exposition. La discussion porte sur la signification de ces résultats pour la santé mentale des personnes impliquées.Organic solvents, due to their chemical properties have a particular affinity with the nervous system, giving them the power to interfere with the functioning of an element. Case histories and epidemiological studies have shown a relationship between a long term exposure to certain solvents and the danger of neuropathies, encephalopathies and psychiatric troubles. This article's aim is to expose the problem of the deterioration of the well being of persons exposed to neurotoxic agents. A study was made in an explosives factory with workers who were exposed to ethylic ether or ethanol and a control of 74 workers who were not exposed. This is an exploratory study which mostly looks into the prevalence of symptoms that could result from a professional contact with theses neurotoxic agents. The results show that the exposed workers, compared to those who were not exposed, are afflicted with more prenarcotic symptoms at work : such as feelings of drunkeness and difficulties in articulating words. The workers also show more frequently general symptoms such as changes of mood, problems of fatigue, sleep, memory and concentration. The reported numbers of prenarcotic symptoms increase with the degree of exposure. The significance of these results on the mental health of the persons involved is studied

Inside view IV.6.1. Research and training beyond the university wals

Peer Reviewe

Mercury cycling and human health concerns in remote ecosystems in the Americas

Fish constitutes a praised—and sometimes irreplaceable—component of the daily diet for numerous communities throughout the Americas. These populations can be exposed to mercury (Hg)—ubiquitous in fish flesh—to levels potentially harmful to their health. Mercury is subjected to various chemical transformations once released to the environment. From diffuse loading on land and waters to accumulation in the aquatic food web, this paper draws a general picture of the main processes influencing the Hg cycle in different ecozones. Contrarily to other pollutants, the amount of Hg found in fish tissues is not clearly related to the extent of Hg loading in a given ecosystem. In the Arctic, the sudden stripping of gaseous elemental Hg from the atmosphere—known as the Hg depletion events—and its subsequent transformation into methylmercury (MeHg) seems to be one of the driving force behind Hg accumulation in freshwater aquatic organisms and marine mammals. In boreal environments, numerous watershed-based processes influence the transport and methylation of Hg deposited from atmospheric source and selectively control the amount of MeHg transferred from source to fish. In the tropics, small-scale gold mining operations have induced the release of considerable amount of Hg to the environment. However, the extensive deforestation of the tropical forest and the subsequent erosion and lixiviation of land-deposited Hg down to tropical rivers appears to have a greater impact on the observed wide-scale fish Hg contamination. Mercury accumulation in remote ecosystems do represent a significant and complex environmental issue, considering: (a) the high levels of Hg monitored in fish and marine mammals flesh; (b) the large-scale occurrence of such worrying Hg bioaccumulation patterns; (c) the extensive use of aquatic resources by numerous remote communities; (d) the fact that this issue shall persist at least on the mid-term, even if strong measures are taken to lessen Hg anthropogenic loadings to the global atmosphere. Although there are no simple answers to the potential threats to human health caused by Hg accumulation, several political actions to lessen human exposure to Hg are possible and are discussed here

Mercury cycling and human health concerns in remote ecosystems in the Americas

Fish constitutes a praised—and sometimes irreplaceable—component of the daily diet for numerous communities throughout the Americas. These populations can be exposed to mercury (Hg)—ubiquitous in fish flesh—to levels potentially harmful to their health. Mercury is subjected to various chemical transformations once released to the environment. From diffuse loading on land and waters to accumulation in the aquatic food web, this paper draws a general picture of the main processes influencing the Hg cycle in different ecozones. Contrarily to other pollutants, the amount of Hg found in fish tissues is not clearly related to the extent of Hg loading in a given ecosystem. In the Arctic, the sudden stripping of gaseous elemental Hg from the atmosphere—known as the Hg depletion events—and its subsequent transformation into methylmercury (MeHg) seems to be one of the driving force behind Hg accumulation in freshwater aquatic organisms and marine mammals. In boreal environments, numerous watershed-based processes influence the transport and methylation of Hg deposited from atmospheric source and selectively control the amount of MeHg transferred from source to fish. In the tropics, small-scale gold mining operations have induced the release of considerable amount of Hg to the environment. However, the extensive deforestation of the tropical forest and the subsequent erosion and lixiviation of land-deposited Hg down to tropical rivers appears to have a greater impact on the observed wide-scale fish Hg contamination. Mercury accumulation in remote ecosystems do represent a significant and complex environmental issue, considering: (a) the high levels of Hg monitored in fish and marine mammals flesh; (b) the large-scale occurrence of such worrying Hg bioaccumulation patterns; (c) the extensive use of aquatic resources by numerous remote communities; (d) the fact that this issue shall persist at least on the mid-term, even if strong measures are taken to lessen Hg anthropogenic loadings to the global atmosphere. Although there are no simple answers to the potential threats to human health caused by Hg accumulation, several political actions to lessen human exposure to Hg are possible and are discussed here

Thyroid Hormones in Pregnancy in Relation to Environmental Exposure to Organochlorine Compounds and Mercury

Polychlorinated biphenyls (PCBs), chlorinated pesticides, and mercury are global environmental contaminants that can disrupt the endocrine system in animals and humans. However, there is little evidence that they can interfere with endocrine status in pregnant women and neonates at low levels of exposure. The aim of this study was to examine thyroid hormone levels during pregnancy and in cord blood in relation to blood concentrations of organochlorine compounds (OCs) and Hg in healthy women recruited during pregnancy. We found a significant negative correlation between maternal total triiodothyronine levels and three non-coplanar congeners (PCB-138, PCB-153, and PCB-180), three pesticides (p,p′-DDE, cis-nanochlor, and hexachlorobenzene), and inorganic Hg independently, without any other changes in thyroid status. No significant relationships were observed between OCs and cord serum thyroid hormones. Cord serum free thyroxin was negatively correlated with inorganic Hg. These results suggest that at even low levels of exposure, persistent environmental contaminants can interfere with thyroid status during pregnancy

New Evidence on Variations of Human Body Burden of Methylmercury from Fish Consumption

Epidemiologic studies commonly use mercury (Hg) level in hair as a valid proxy to estimate human exposure to methylmercury (MeHg) through fish consumption. This study presents the results yielded by a complete data set on fish consumption habits, Hg levels in edible fish resources, and corresponding Hg accumulation in hair, gathered in three distinct communities of eastern Canada. For one of these communities, the average hair Hg concentration was 14 times less than the expected value based on calculated daily oral exposure and current knowledge of MeHg metabolism. This finding could be explained by differences in specific genetic characteristics and/or interactive effects of other dietary components

Occupational exposures and airways disease : a study to develop and evaluate a questionnaire for eliciting occupational exposure history for community based studies

The role of occupational exposures in the genesis of airways disease may be underestimated in workforce studies because of the "healthy" worker effect, due either to those with more resistant airways entering a workplace or those with work related airways disease changing or quitting their job. Both effects are minimised in population-based studies which have the disadvantage that occupational exposures are of necessity self-reported. The overall goal of this research was to develop and validate an instrument to measure occupational exposures in epidemiologic research in general population studies of airways disease.The study hypothesis was that self-reported exposure information pertinent to airway disease was as accurate a reflexion of exposure as information derived from industrial hygiene expertise. To examine the study hypothesis, use was made of occupational questionnaires completed by 338 adults participating in a Montreal community based study. A list of 927 reported jobs was submitted for coding of exposures to 2 industrial hygienists working independently to code exposures.Intra-subject reproducibility of questionnaire information, assessed using a test-retest approach in 33 subjects showed good overall concordance for most components of the work history. Inter-rater reliability (between hygienists) was also good for some categories of exposures.Validity analysis of self-reported exposure, using as a reference criterion the exposure coding by either hygienist lead to poor values for sensitivity and phi-coefficients but not for specificity. Slight improvement in sensitivities and phi-coefficients was found for latest job.While smoking, a family history and atopy were determinants of asthma in multivariate models, significant exposure response relationships were obtained only with self reported exposure, not with exposures coded by either hygienist. Nevertheless the coefficients and confidence intervals for self-reported exposures were, for most part, in the same direction and range as those for exposure coded by the 2 hygienists.These results are consistent with the study hypothesis that self reported exposures perform comparably, possibly even better than exposures based on industrial hygiene expertise in characterising exposure response relationships for airway disease in community based studies

Inside view IV.6.1. Research and training beyond the university wals

Peer Reviewe

Santé territoriale, indicateurs de santé animale et vision holistique : La sélection des prises et les choix alimentaires chez les Atikamekw de Manawan et d’Obedjiwan

Dans le cadre d'un programme de recherche interdisciplinaire sur l'alimentation traditionnelle et les contaminants, des groupes de discussion ont été réalisés à l'été 2008 auprès des communautés atikamekw d'Obed jiwan et de Manawan (Québec) afin de documenter les changements qu'elles ont observés chez les animaux chassés et pêchés et d'obtenir une meilleure compréhension de leur processus de sélection des prises propres à la consommation. Les Atikamekw utilisent une multitude d'indicateurs afin d'évaluer l'état de santé des animaux qu'ils consomment. Les changements observés sont interprétés de façon holistique au sein d'une vision de la santé qui accorde une place prépondérante au territoire. La sélection des prises s'insère de plus dans un ensemble de facteurs qui influencent les choix alimentaires des Atikamekw. La documentation de ce savoir est essentielle à l'élaboration de recomman dations alimentaires culturellement pertinentes.As part of a multidisciplinary research project on traditional food and contaminants, focus groups were conducted in the summer of 2008 at the Atikamekw communities of Opitciwan and Manawan (Québec). The objective was to address the changes Atikamekw people have noticed in the game and fish and to seek a better understanding of the way they select a catch that is fit for consumption. The Atikamekw seem to use many indicators to assess the state of health of the animals they consume. These indicators are based on a holistic vision of health integrated in the concept of health of the land. The decision regarding the edibility of a catch is only one of many aspects that play a role in the process of food choices for the Atikamekw. It is essential to take these aspects into account in the development of food recommendations that are culturally relevant.En el marco de un programa de investigación interdisciplinario sobre la alimentación tradicional y los contaminantes en el verano de 2008 se realizaron grupos de discusión cerca de las comunidades atikamekw de Obedjiwan y de Manawan (Québec) con el fin de documentar los cambios que ellas han observado en los animales cazados y pescados y de obtener una mejor comprensión de los procesos de selección de capturas para el consumo. Los Atikamekw utilizan una gran variedad de indicadores con el fin de evaluar el estado de salud de los animales que ellos consumen. Los cambios observados son interpretados de manera holística en el seno de una visión de la salud que otorga un lugar preponderante en el territorio. La selección de las capturas se apoya cada vez más en un conjunto de factores que influencian las elecciones alimentarias de los Atikamekw. La documentación de este conocimiento es esencial en la elaboración de recomendaciones alimentarias culturalmente pertinentes