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The sample is mixed with arsenic-free zinc and sulphuric acid, any arsenic present causing the production of arsine gas and hydrogen. The gas then is led through a tube where it is heated, decomposing into hydrogen and arsenic vapor. When the arsenic vapor impinges on a cold surface, a mirror-like deposit of arsenic forms.
The Marsh test treats the sample with sulfuric acid and arsenic-free zinc. Even if there are minute amounts of arsenic present, the zinc reduces the trivalent arsenic (As 3+). Here are the two half-reactions: Oxidation: Zn → Zn 2+ + 2 e − Reduction: As 2 O 3 + 12 e − + 6 H + → 2 As 3− + 3 H 2 O. Overall, we have this reaction:
A 2007 study found that over 137 million people in more than 70 countries are probably affected by arsenic poisoning of drinking water. The problem became a serious health concern after mass poisoning of water in Bangladesh. [1] Arsenic contamination of ground water is found in many countries throughout the world, including the US. [2]
Arsenic is also found in food, water, soil, and air. [132] Arsenic is absorbed by all plants, but is more concentrated in leafy vegetables, rice, apple and grape juice, and seafood. [ 133 ] An additional route of exposure is inhalation of atmospheric gases and dusts. [ 134 ]
In fact, when ingested, arsenic — a natural element found in the earth's crust — can affect several organs and systems, including the nervous, respiratory, cardiovascular, immune and endocrine ...
In humans, arsenic can cause cancer in the bladder, skin, lungs and liver. One of the major sources of arsenic exposure in humans is contaminated water, which is a problem in more than 30 countries in the world. [22] Humans tend to encounter arsenic by "natural means, industrial source, or from unintended sources."
"Arsenic in Drinking Water", Some Drinking-water Disinfectants and Contaminants, including Arsenic (PDF), IARC Monographs on the Evaluation of Carcinogenic Risks to Humans 84, Lyon, France: International Agency for Research on Cancer, 2004, pp. 39– 267, ISBN 92-832-1284-3
The federal government initially only agreed to repay costs to bring PFAS levels down to 70 ppt, though a state law introduced in 2019 by former State Rep. Todd Stephens found a way to remit the ...