Arsenic in the environment: effects on human health and possible prevention.

Arsenic is a major environmental pollutant and exposure occurs through environmental, occupational and medicinal sources. The contaminated drinking water is the main source of exposure and affected countries are India (West Bengal), Bangladesh, China, Taiwan, Thailand, Chile, Argentina and Romania. Concentrations of arsenic in affected areas are several times higher than the maximum contamination level (MCL) (10 microg/l). Arsenic exposure to human results in degenerative, inflammatory and neoplastic changes of skin, respiratory system, blood, lymphatic system, nervous system and reproductive system. There is no particular remedial action for chronic arsenic poisoning. Low socioeconomic status and malnutrition may increase the risk of chronic toxicity. Early intervention and prevention can give the relief to the affected population.

Metabolism of inorganic arsenic and non-cancerous health hazards associated with chronic exposure in humans.

Humans can be exposed to arsenic from a variety of environmental, occupational and medicinal sources. Exposure from drinking water is the most common source nowadays. Inorganic arsenic is metabolized by two main biochemical reactions: reduction and oxidative methylation. Recent studies have confirmed a reactivation of the toxic effects of arsenic associated with such methylation process, because the methylated metabolites, especially the trivalent forms, are more toxic than the inorganic arsenicals. Chronic exposure to arsenic can cause a variety of cancerous and noncancerous health hazards in humans. The main non-cancerous health hazards include cardiovascular disease, skin lesions, neurological problems, diabetes mellitus and hypertension.

Biological effects of heavy metals: an overview.

Heavy metals constitute a very heterogeneous group of elements widely varied in their chemical properties and biological functions. Heavy metals are kept under environmental pollutant category due to their toxic effects on plants, animals and human being. Heavy metal contamination of soil results from anthropogenic as well as natural activities. Anthropogenic activities such as mining, smelting operation and agriculture have locally increased the levels of heavy metals such as Cd, Co, Cr, Pb, As and Ni in soil up to dangerous levels. Heavy metals are persistent in nature, therefore get accumulated in soils and plants. Heavy metals interfere with physiological activities of plants such as photosynthesis, gaseous exchange and nutrient absorption, and cause reductions in plant growth, dry matter accumulation and yield. Heavy metals also interfere with the levels of antioxidants in plants, and reduce the nutritive value of the produce. Dietary intake of many heavy metals through consumption of plants has long term detrimental effects on human health.

PCB contamination in surface sediments in the coastal waters of Costa Rica

This paper describes the initial investigation of PCB concentrations in four geographical regions (three on the Pacific and one in the Caribbean) of coastal Costa Rica: Bahia Culebra, Golfo Dulce, Golfo de Nicoya, and Limón. Overall total concentrations of PCB were low in all areas except around the port of Golfito (Golfo Dulce). Overall average concentration is 2.80 ng/g dw, with a standard deviation of 2.75. The low concentration could be due to lack of contamination or the subsequent degradation in the warm climate, or the low sorptive capacity of the sediment. Further investigation is ongoing

Este articulo describe una investigación sobre las concentraciones de bifenilos policlorados (PCB) en cuatro regiones geográficas (tres en el Pacífico y una en el Caribe) costeras de Costa Rica.: Bahía Culebra, Golfo Dulce, Golfo de Nicoya, y Limón. Las concentraciones totales de PCB fueron bajas en todas las regiones excepto en el puerto de Golfito (Golfo Dulce). Las concentraciones promedio fueron de 2.80 ng /g dw, con una desviación estándar de 2.75. Las bajas concentraciones pueden estar asociadas a: la ausencia de contaminación por PCB, la degradación posterior en éste clima cálido, o la poca capacidad de absorción de los sedimentos

PCB concentrations in sediments from the Gulf of Nicoya estuary, Pacific coast of Costa Rica

Thirty-one sediment samples collected from 1996-2003 from the Gulf of Nicoya estuary on the north- western coast of Costa Rica, have been obtained for PCB analyses. This is part of the first study to evaluate the PCB contamination in coastal Costa Rica.Overall, the concentrations are low, especially when compared to sediments from more temperate climates and/or sediments from more heavily industrialized areas. Values average less than 3 ng/g dw sediment, however, a few samples contained up to 7 ng/g dw sediment. Sediments with the highest concentrations were located in the Punta Morales area, where muds were sampled from among mangrove roots. The Puntarenas samples had surprisingly low PCB concentrations, likely due to their sandy lithology. The congener distribution within the majority of the samples showed signs of either recent sources or lack of degradation. However, a few sites, specifically some of the inter-gulf islands and more remote samples had congener distributions indicative of airborne contaminants and/or degradation. Considering the presence of air-borne PCBs in the Gulf of Papagayo to the north, the lack of airborne PCBs and more varied congener distribution in the Gulf of Nicoya estuary was surprising

Se analizó los bifenilos policlorados (PCB) en 31 muestras de sedimentos colectadas entre 1996 -2003 en el estuario del Golfo de Nicoya, costa noroeste de Costa Rica. Esto es parte de un primer estudio para evaluar la contaminación por PCB en aguas costeras de Costa Rica. En general, las concentraciones fueron bajas especialmente cuando se les compara con sedimentos de climas templados y / o sedimentos de areas altamente industrializadas. Los valores promedio son inferiores a 3 ng / dw (peso seco) de sedimento. Sin embargo, unas pocas muestras contienen hasta 7 ng/ g dw de sedimento. Los sedimentos con las concentraciones más altas están localizados en el area de Punta Morales, en cienos de entre raíces de mangle. Las concentraciones de PCB en Puntarenas fueron sorprendentemente bajas, posiblemente por el tipo arenoso del sustrato. La distribución de congéneres dentro de la mayoría de las muestras muestran señal de una reciente contaminación o carencia de degradación . Sin embargo, en unos pocos sitios, específicamente en las islas internas del Golfo y otras areas más remotas tienen distribuciones de congéneres que indican contaminación por vía aerea y /o degradación. Cuando se considera la presencia de PCB transportados por via aerea en el Golfo de Papagayo al Norte, es sorprendente la ausencia en el Golfo de Nicoya de estos PCB y una distribución más variada de congéneres

PCB contamination in marine sediments from Golfo Dulce, Pacific coast of Costa Rica

Twenty-nine marine sediment samples collected from 1996 through 2002 from the Golfo Dulce embayment of Costa Rica were analyzed for PCB concentrations. The Esquinas River and Rincon Bay in the northern and western part of the gulf had relatively low overall concentrations of PCBs, with no samples having greater than 2.1 µg/g dw sediment. The Port of Golfito had the highest overall concentrations, ranging up to 15.7 µg/g dw sediment. These samples were also dominated by higher chlorinated congeners. Samples from the deeper (>100m) waters in the northern part of the gulf, as well as within the sediment plume from the Rio Coto Colorado had intermediate values. Within the Rio Coto Colorado sediment plume the concentrations did decrease with increasing depth and the congeners showed a shift towards less chlorinated congeners with depth. However, the deep northern basin had some of the highest PCB concentrations and the shift towards less chlorinated congeners was not apparent or significant. Whether the anoxic conditions that exist in the deep waters are capable of initiating dechlorination is still unknown. Overall, the data from Golfo Dulce show moderate PCB contamination, despite the pristine nature of the gulf and surrounding lands

Un total de 29 muestras de sedimentos recolectadas de 1996 a 2002 en el Golfo Dulce, Costa Rica fueron analizadas determinar las concentraciones de bifenilos policlorinados (PCBs). La Bahía de Rincón y el Río Esquinas en la parte noroeste del Golfo tienen concentraciones relativamente bajas de PCBs, con ninguna muestras superando los 2.1 ug/ dw (peso seco) de sedimento. El puerto de Golfito tuvo las mayores concentraciones hasta un máximo de 15.7 ug/g dw de sedimento. Estas muestras también estuvieron dominadas por los congéneres más clorinados. Las muestras de los sedimentos profundos (>100 m ) de las aguas de la parte norte del Golfo, así como las de la estela del Río Coto Colorado, tienen concentraciones intermedias. Dentro de la estela de sedimentos del Río Colorado las concentraciones aumentaron con la profundidad y los congéneres variaron con la profundidad hacia los menos clorinados. Sin embargo, la región profunda tuvo una de las más altas concentraciones de PCBs, pero la tendencia hacia los menos clorinados no fue aparente o significativa. No se conoce si las condiciones anóxicas en las aguas profundas son capaces de iniciar la declorización. En general, las muestras analizadas muestran concentraciones moderadas de PCBs, no obstante las condiciones pristinas del Golfo y su cuenca