PHOTO: PhD Student Laura Erban, leader and author of the study of arsenic in terrestrial water in Vietnam, like the example of the Mekong River Delta. (Courtesy Laura Erban/Stanford)
The river rises on the Tibet plateau, tours the Chinese province of Yunnan and then continues through Burma, Thailand, Laos, Cambodia and Vietnam
– The Epoch Times
Mie, 21 Ago 2013
There are many ways of poisoning and perhaps the most dangerous is that which is little suspected., and that comes from the waters that are drunk every day.
A study of theStanford University revealed thatNatural water in South Asia is contaminated with arsenic and gradually some 100 Millions of people are exposed to diseases every day, including cancer, by accumulating this toxic.
Arsenic was found in 900 deep wells along the Mekong River Delta in Vietnam, that cover some 1.000 square kilometers. A total of 42.000 records in the southern tip.
According to scientists, the toxic comes from clayey sediments that surround water wells..
The Mekong River rises on the plateau ofTibet, tours the Chinese province of Yunnan and then continues through Burma, Thailand, Laos, Cambodia and Vietnam.
To avoid drinking water with arsenic in Vietnam, many began to drill deeper wells, thinking that this would avoid this problem, but the study published last 9 August proved the opposite, since when pumping the arsenic is dragged to the lower waters.
In some cases, contamination occurred inadvertently when water pumps transported the toxic substance from the surface., along with other substances, towards the deepest part.
In the Mekong Delta, Another problem was also seen. The researchers saw that as large amounts of water are pumped, there is a subsidence of the land, including clay soil with arsenic.
By analyzing satellite radar observations of the area, Scientists found that “the compaction of clay-rich sediments, which included arsenic, “It caused land subsidence of up to three centimeters per year.”
"Esta es la primera vez que las mediciones por satélite se han utilizado para apoyar la existencia de contaminación del agua subterránea profunda", communicatedSteven Gorelick, professor of environmental Earth system science at Stanford.
Study joined ground-based data, satellite images and groundwater simulation models to support the hypothesis that compaction of clays towards depth is the likely cause of the contamination.
"Este trabajo es un hermoso ejemplo de la aplicación de los datos físicos y razonamientos físicos para explicar un fenómeno aparentemente geoquímico", the teacher pointed out Charles Harvey, from the Massachusetts Institute of Technology (WITH), specialist in the study of arsenic contamination of groundwater, who reviewed the Stanford manuscript.
"Se debe cambiar la forma en que pensamos acerca de los efectos del bombeo en la calidad del agua subterránea, and arsenic, in particular, en una variedad de sistemas de sedimentación", the teacher recommended, according to the Stanford report.
Scientists believe that if the depth of arsenic in groundwater is quantified, pumping and treatment of extracted groundwater may be limited to meet health standards. The team that published the study, including Professors Howard Zebker, geophysical, y Scott Fendorf, of the environmental system, suggest that in this way the impact can be reduced.
Arsenic in Latin American waters
TheWorld Health Organization (OMS) warned to countries likeChile, Argentina, Mexico and the United States for him high level of arsenic in drinking water and food, from some areas.
Andstudy led by Professor Manuel Santander from the University of Chile and other universities in the country, revealed high levels of arsenic in the hair of children of 6 a 7 years in Antofagasta in the north of the country.The reported cause is the mining activity in the region..
Arsenic levels in Chuquicamata reached 9,35 ppm, being the maximum in the bibliography of 3,71, and the tolerable limit of 1 ppm.
Poisoning
The immediate symptoms of arsenic poisoning arevomiting, abdominal pain and diarrhea, followed by paralysis and tremors in the extremities, cramps and in extreme cases, death”, warns WHO, and among the diseases it causes, there is thecancer and skin diseases.
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