Blood dynamics of mercury and selenium in northern elephant seals during the lactation period

The effects of reproduction and maternal investment (i.e., milk transfer) on trace element levels remain poorly understood in marine mammals. We examined the blood dynamics of mercury (Hg) and selenium (Se) during lactation in the northern elephant seal (Mirounga angustirostris), a top predator from the North Pacific Ocean. Total Hg and Se levels were measured in whole blood and milk of 10 mother-pup pairs on days 5 and 22 of lactation. Both Hg and Se were transferred to offspring through the milk. Results suggested that the maternal transfer of Se was prominent during lactation, whereas the Hg transfer was larger during gestation. The lactation period affected Hg and Se levels in the blood of elephant seal mothers and pups. Physiological processes and their relationship to body condition should be considered carefully when interpreting trace element levels in the framework of biomonitoring.Peer reviewe

Trace elements and stable isotopes during lactation and post-weaning fast in phocids

Haul-out periods in most phocids are particularly intense from a physiological point of view since they involve extended fasting periods associated with behaviours or processes resulting in considerable energy expenditure (e.g., combat, mating, lactation, moulting). The substantial tissue reorganization during these key periods can entail the mobilization of potentially associated contaminants, such as trace elements and persistent organic pollutants. The main objectives of this study were firstly to investigate the effects of fasting, lactational, and developmental phases on trace element concentrations (Cd, Cr, Cu, Fe, Hg, Ni, Pb, Se, V, and Zn) in the northern elephant seal (Mirounga angustirostris) and the grey seal (Halichoerus grypus), and on the other hand, to assess the maternal transfer of trace elements to the offspring. Changes in the diet indicators – the carbon and nitrogen stable isotopes (δ13C and δ15N) – were also investigated throughout lactation and post-weaning fast, and their implications were developed. Different tissue samples (blood, blubber, hair, and milk) were collected repeatedly in mother-pup pairs and weaned pups in northern elephant seals and grey seals during three longitudinal fieldworks in the breeding season. Related to the remobilization of resources during lactation and pup development, short-term variations in blood concentrations of trace elements were highlighted in this study. The results imply a careful consideration of the physiological status of marine mammals when using blood in the framework of biomonitoring of trace element contamination. Although the total body burdens of trace elements decreased over lactation in adult females, circulating concentrations of some metals, like Hg, increased significantly, drawing attention to the potential adverse effects on the immune, endocrine or nervous systems in adults. Northern elephant seals and grey seals are exposed to trace elements from the first stages of development through the placenta and through the milk. Indeed, concentrations in pup hair of both species revealed a large accumulation of all assayed trace elements during the foetal development. The maternal transfer of trace elements adds to lactational transfer of others chemicals such PCBs, PBDEs, and OCPs reported in recent studies. Immunotoxic and endocrine risks related to chemical mixtures remain unclear until now and may therefore affect phocids at a crucial period of their immune development

Systèmes d’information de surveillance en santé-environnement

An environmental health tracking information system (currently known as an Environmental Public Health Tracking (EPHT)) is a study or surveillance tool to provide useful data for prioritizing prevention actions. Various approaches have been developed at the international level, with varying levels of maturity, to provide programs in which data production is consistent with the tracking objectives and ensure they are operational within a management framework. This synthesis proposes to explore integrated surveillance systems through the description of international experience. Access to information and justice in environmental matters as well as public participation in decision-making coincide with increased attention to the scientific and democratic debate on environmental justice and on joint social and environmental policies. The first EPHTs appeared in this context in the 2000s and now provide access to and integration of data or databases at different administrative levels, promote interoperability of systems, and improve the quality of the data produced and the integration of environmental aspects in all policies. Other interactive online tools provide users with easy navigation to explore various dimensions of exposure at the local level. However, the use of spatial data to characterize environmental exposures did not initially meet the objectives of the studies, which led to use biases. To partially overcome these problems, different techniques are introduced to specifically address the different environmental, behavioral, or population databases. With the emergence of the concept of the "exposome", the territorialization of the concept for management purposes requires the development of new dynamic, multidimensional, longitudinal approaches, information systems that use cross-disciplinary methods for data analysis, and stakeholder coordination at all administrative levels.Un système d’information de surveillance en santé-environnement (SISSE) peut être soit un dispositif à visée d’étude pour fournir des données utiles à la priorisation d’actions de prévention, soit un dispositif d’alerte. Différentes démarches ont été développées au niveau international, avec des niveaux de maturité variables, pour fournir des systèmes d’information nécessitant une mise en cohérence de la production de données par rapport aux objectifs de surveillance et permettre ainsi leur opérationnalité dans un cadre de gestion. Cette synthèse propose d’explorer les systèmes intégrés de surveillance à travers la description d’expériences internationales. L’accès à l’information et la participation du public au processus décisionnel en matière d’environnement coïncident avec le début de la prise en compte du débat scientifique et démocratique sur la justice environnementale et sur l’articulation entre politiques sociales et politiques environnementales. Les premiers SISSE apparaissent dans ce contexte dans les années 2000 aux États-Unis et permettent l’accès et la capacité d’intégrer des données ou bases de données aux différents niveaux administratifs, de promouvoir l’interopérabilité des systèmes, d’améliorer la qualité des données produites et une meilleure intégration de la dimension environnementale dans l’ensemble des politiques. D’autres outils interactifs en ligne permettent aux utilisateurs une information facilitée pour explorer diverses dimensions de l’exposition au niveau local. Toutefois, les données spatiales utilisées à des fins de caractérisation des expositions environnementales n’ont pas toujours été initialement collationnées pour répondre à ces objectifs, ce qui entraîne des biais d’utilisation. Pour contourner partiellement ces problèmes, différentes techniques sont adoptées pour traiter spécifiquement les différentes bases de données environnementales, comportementales ou de population. Dans le contexte de l’émergence de la notion d’exposome, la territorialisation du concept à des fins de gestion nécessite le développement de nouvelles approches dynamiques, multidimensionnelles, longitudinales et la mise en place de systèmes d’information, obligeant l’adoption de méthodes transdisciplinaires pour l’analyse des données et la coordination des acteurs sur l’ensemble des niveaux administratifs

Maternal transfer of trace metals to offspring in grey seals

Marine mammals may display high heavy metal levels in their tissues, which raises the question of the importance of toxic metal transfer from mother to offspring. Some lactating female phocids fast during the suckling period. This fasting period involves not only an important mobilization of energy reserves, but also mobilization of potentially associated contaminants. We studied maternal transfer of trace metals to offspring in the grey seal (Halichoerus grypus). Trace metal concentrations were measured in whole blood, milk and hair of mother-pup pairs in early and late lactation. Metal levels in blood decreased according to the following pattern: Fe > Zn > Se > Cu > Hg > Pb > Cr > V in mothers and pups. Cd and Ni were not detected and V, Cr and Pb levels were very low in maternal and pup blood. However, Ni and Pb levels were detected in the milk showing a transmammary transfer of these metals. Hg levels in blood and milk were higher than levels of previous metals and levels varied significantly throughout lactation. The increasing maternal levels over lactation were likely due to the remobilization of energy reserves during fasting and milk production in mothers causing a Hg release in blood. All metals were detected in hair and lanugo according to the following pattern: Fe > Zn > Hg > Cu > Se > Ni > V > Pb > Cd > Cr in mothers and Zn > Fe > Hg > Se > Cu > Pb > Ni > V > Cr > Cd in pups. Pb levels were relatively high in comparison with other phocid species. Only Hg showed a significant relationship between hair/lanugo and blood levels. This study highlights (i) a transplacental and transmammary transfer of metals in grey seals, and shows that (ii) physiological processes such as lactation and/or fasting can modify trace metal levels in the blood of mothers and pups