Mercury speciation in marine birds tissus

This email address is being protected from spambots. You need JavaScript enabled to view it.

Mercury is a global contaminant which readily bioaccumulates in aquatic organisms and biomagnifies in marine food webs mainly as neurotoxic methylmercury (MeHg). Its volatile character is responsible for its ubiquity in all the natural compartments around the world whichever the geographical origin of the pollution source. In this context, we investigate the fate of mercury ingested by high predators such as the Giant Petrel sea birds, and evidenced by transmission electron microscopy (TEM) the formation of HgSe nanocristals as a mechanism to detoxify its contaminated food.

Keywords : Pollutant, mercury, transmission electron microsopy (TEM), EDX spectroscopy, crystallography

Mercury speciation in the environment

This email address is being protected from spambots. You need JavaScript enabled to view it.

Mercury, from natural or industrial origin, is one of the most toxic inorganic contaminant for living organisms, despite its relatively low concentration in soils and aquatic environments. Its methylated form is extremely neurotoxic as a result of its bioaccumulation in the food chain. However, the high thiophilicity of divalent mercury (Hg(II)) reduces methylation rates via the formation of strong complexes with thiol groups in organic matter of the soil and precipitation of mercury sulfide minerals (HgS) in anoxic conditions. In this context, we participate to the study of the mercury speciation in the contaminated soils, and evidenced by transmission electron microscopy (TEM) the formation of HgS nanocristals in contaminated soils, including in the oxic upper horizon.

Keywords : Pollutant, mercury, transmission electron microsopy (TEM), EDX spectroscopy, crystallography

Crystalstructure of natural materials

This email address is being protected from spambots. You need JavaScript enabled to view it.

An important part of the soil properties, such as pollutant sorption, is related to the fine mineral fraction less than 2 µm, corresponding to the clay minerals. To understand the behavior of such clay minerals in the environment, it is necessary to determine their structure at the atomic level. X-ray powder diffraction and the new transmission electron microscopy (TEM) techniques are used to explore the variability of the crystalline structure of the natural minerals at the nano or sub-nano scale.
Several minerals are studied: birnessite, illite, smectite, kaolinite and palygorskyte.

Keywords: Layered materials, transmission electron microscopy, crystallography

Crystalchemistry and environment