ABSTRACT
Mercury is a global pollutant of public environmental health concern due to its long-range atmospheric distribution, environmental distribution, and neurotoxic effects. Following biological methylation, methylmercury (MeHg) can be un-evenly bioaccumulated within aquatic food chains. Fish consumption can be a significant route of human exposure to MeHg. MeHg exposure in the prenatal stage, at relatively low levels, has recently been established as harmful during neurological development, potentially leading to intellectual disability. The Minamata Convention on Mercury is a global agreement, currently under ratification, to protect human health and the environment from anthropogenic emissions and releases of mercury and mercury compounds. The resolution regarding the role of the World Health Organization and ministries of health in the implementation of the Convention includes protection of human health from critical exposures to MeHg. Riverside populations living in areas with artisanal small-scale gold mining, and relying heavily on fish consumption, have been identified as the most vulnerable population in terms of MeHg exposure and developmental neurotoxicity. This article focuses on the proper design and dissemination of fish advisories within the context of implementation of the Convention.
El mercurio es un contaminante global motivo de preocupación en materia de salud pública ambiental como consecuencia de su amplia distribución atmosférica, su distribución ambiental y sus efectos neurotóxicos. Tras su metilación biológica, el metilmercurio (MeHg) se puede bioacumular de manera desigual en las cadenas alimentarias acuáticas. El consumo de pescado puede ser una ruta significativa de exposición humana al MeHg. Recientemente, se ha establecido que la exposición a niveles relativamente bajos de MeHg en la etapa prenatal es perjudicial para el neurodesarrollo, pudiendo ocasionar discapacidad intelectual. El Convenio de Minamata sobre el Mercurio es un acuerdo a escala mundial, actualmente en fase de ratificación, cuyo objeto es proteger la salud humana y el medio ambiente de las emisiones antropogénicas y los vertidos de mercurio y sus compuestos. La resolución referente a la función de la Organización Mundial de la Salud y los ministerios de salud en la aplicación del Convenio incluye la protección de la salud humana de exposiciones importantes al MeHg. Se ha establecido que las poblaciones ribereñas que residen en zonas de extracción artesanal de oro a pequeña escala, y que dependen en gran medida del consumo de pescado, son las más vulnerables en términos de exposición al MeHg y neurotoxicidad durante el desarrollo. Este artículo se centra en el diseño y la difusión adecuados de las recomendaciones relativas al consumo de pescado en el contexto de la aplicación del Convenio.
Subject(s)
Prenatal Diagnosis , Nerve Agents/toxicity , Methylmercury Compounds/toxicityABSTRACT
Presence of mercury and other heavy metals above permissible levels in water bodies across the globe is posing a serious threat to aquatic biota and public health. Occurrence of mercury above the permissible limits in the aquatic ecosystem of Hyderabad city is well established. In this context, we carried out static- renewal bioassays on the zebra fish, Danio rerio exposed to different concentrations of mercuric chloride, and the 96-h median lethal concentration (LC50) was found to be 0.077 mgl-1. Behavioral manifestations like loss of scales, hyper secretion of mucus, surfacing and darting movements, loss of balance, irregular swimming patterns were noticed in the fish exposed to 0.077 mgl-1. The present study also examined the toxic effects of mercuric chloride on vital biochemical constituent’s total glycogen and total protein. Significant decrease (p<0.001) in glycogen and protein content of fish exposed to 0.077 mgl-1
ABSTRACT
Mercury is known to interact with different parts of living systems causing serious biochemical and physiological disorder. In order to know the effect of mercury (Hg2+) ion on chloroplasts, the cell free organelle are incubated in an isotonic buffer medium in presence of mercury ion. The metal ion is found to induce membrane lipid peroxidation, loss of photosynthetic pigments and degradation of proteins. Such degradation brings about a drastic modification of lipid-protein organization of chloroplasts as reflected from a blue shift of absorption peaks and lowering of chlorophyll-a fluorescence intensity. The detrimental effect of Hg2+ ion has been explained in terms of direct binding with lipid-protein complex of photosynthetic membrane. Such a binding of metal ion exposes the lipid-protein complex for an easier entry and attack of reactive oxygen species (ROS) generated during incubation of chloroplasts in light and dark, thereby resulting in higher disorganization, which is evident from cation- induced changes in absorption and emission characteristics of the organelle.
Subject(s)
Absorption , Chloroplasts/drug effects , Chloroplasts/metabolism , Darkness , Lipid Metabolism/drug effects , Lipid Peroxidation/drug effects , Malondialdehyde/metabolism , Mercury/pharmacology , Photosynthesis/drug effects , Pigments, Biological/metabolism , Plant Proteins/chemistry , Plant Proteins/metabolism , Protein Stability/drug effects , Thylakoids/drug effects , Thylakoids/metabolism , Triticum/cytology , Triticum/drug effects , Triticum/metabolismABSTRACT
The present study was carried out to evaluate the protective role of lycopene on cytotoxicity induced by mercury in albino mice. The animals were randomly divided into seven groups. Group I (control) were treated with tap water, Group II (positive control) were treated with 20 mg kg-1 d-1 lycopene, Group III were treated with 10 mg kg-1 body weight mercury, Group IV were treated with 10 mg kg-1 body weight mercury + 5 mg kg-1 d-1 lycopene, Group V were treated with 10 mg kg-1 body weight mercury + 10 mg kg-1 d-1 lycopene, Group VI were treated with 10 mg kg-1 body weight mercury + 15 mg kg-1 d-1 lycopene, Group VII were treated with 10 mg kg-1 body weight mercury + 20 mg kg-1 d-1 lycopene once a day for 20 consecutive days by oral gavage. The initial and final weights of all mice were measured by sensitive balance in order to investigate the effect of mercury and lycopene on the body weight of mice. Then, MN slides were prepared using the standard MN assay technique with Giemsa staining from erythrocyte cells of each mouse and were scored using binocular light microscope (Japan, Olympus BX 51). The results indicated that, all lycopene-supplemented lymphocytes showed a lower MN frequency than lymphocytes in only mercury-treated group. It was seen that lycopene had protective effect on MN particularly at 20 mg kg-1 d-1 dose when compared with the other doses. Besides, weight gain increased depending on dose of applied lycopene when compared with only mercury-treated group. In histopathological examinations, although it has been observed severe changes such as hemorrhage, hepatocyte degeneration and tubular degeneration of kidney in only mercury-treated group, there was an observable regression on the severity and account of these lesions in tissues of mice supplemented with different doses of lycopene. In vivo results showed that the lycopene supplementation decreases cytotoxicity induced by mercury and its protective role is dose-dependent.
ABSTRACT
We measured visual performance in achromatic and chromatic spatial tasks of mercury-exposed subjects and compared the results with norms obtained from healthy individuals of similar age. Data were obtained for a group of 28 mercury-exposed subjects, comprising 20 Amazonian gold miners, 2 inhabitants of Amazonian riverside communities, and 6 laboratory technicians, who asked for medical care. Statistical norms were generated by testing healthy control subjects divided into three age groups. The performance of a substantial proportion of the mercury-exposed subjects was below the norms in all of these tasks. Eleven of 20 subjects (55 percent) performed below the norms in the achromatic contrast sensitivity task. The mercury-exposed subjects also had lower red-green contrast sensitivity deficits at all tested spatial frequencies (9/11 subjects; 81 percent). Three gold miners and 1 riverine (4/19 subjects, 21 percent) performed worse than normal subjects making more mistakes in the color arrangement test. Five of 10 subjects tested (50 percent), comprising 2 gold miners, 2 technicians, and 1 riverine, performed worse than normal in the color discrimination test, having areas of one or more MacAdam ellipse larger than normal subjects and high color discrimination thresholds at least in one color locus. These data indicate that psychophysical assessment can be used to quantify the degree of visual impairment of mercury-exposed subjects. They also suggest that some spatial tests such as the measurement of red-green chromatic contrast are sufficiently sensitive to detect visual dysfunction caused by mercury toxicity.