ARSENIC

Presentation by

Hari sharma

(M-Tech environmental engineering)

[Ar] 3d10 4s2 4p3

• Arsenic is a chemical element with symbol As and atomic number 33. Arsenic is a metalloid widely distributed in the earth’s crust and present at an average concentration of 2 mg/kg.

• Exist in many different chemical forms in combination with other elements…. inorganic, which do not contain carbon and others are organic, which always contain carbon.

• The two forms of inorganic arsenic, reduced (trivalent As (III)) and oxidized (pentavalent As(V))

• Organic: plants ,soil, water etc . Ultratrace elements are defined in the scientific literature as essential elements that are required in the daily human diet at a rate of less than 1 ppm, typically less than 50 micrograms per day (ug/day)

Where is Arsenic Found?

• Everywhere.

• Arsenic makes up about 1.5 ppm (0.00015%) of the Earth's crust, making it the 53rd most abundant element.

• Soil contains 1–10 ppm of arsenic. Seawater has only 1.6 ppb arsenic.

• In nature arsenic is usually found in sedimentary or igneous rock joined to or mixed with other elements, such as oxygen.

Applications

• Agricultural

• Medical use

• Alloys

• Military

Do we Need Arsenic for Health?

• Ultratrace elements are defined in the scientific literature as essential elements that are required in the daily human diet at a rate of less than 1 ppm, typically less than 50 micrograms per day (ug/day).

• There are trace amounts of arsenic in almost all food and water, air and soil, so it is difficult to find humans who are isolated from all sources of arsenic.

Can Arsenic Cause Cancer?

• "the right dose differentiates a poison from a remedy.“

• Arsenic's paradoxical behavior make it both cause and treatment for cancer .

• arsenic is one of a handful of chemicals that is well established as a human carcinogen based on direct evidence in human populations. On the other hand, arsenic has been shown to be effective as a cancer chemotherapy drug and can be used to induce complete cures in certain forms of cancer.

What are the Symptoms of Arsenic Poisoning?

Arsenic has been the poison of choice since antiquity because it is difficult to detect in food and water and because the symptoms of poisoning by arsenic can be mistakenly attributed to many other ailments.

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• At a very high, single dose arsenic can cause severe shock, general paralysis, delirium and then death within a few hours.

• At a somewhat lower dose the primary symptoms are nausea, headache, intense gastrointestinal pain, vomiting and diarrhea.

• change in pigmentation of the skin similar to freckling; hyperkeratosis, an extensive thickening of the skin, especially the palms of the hands and soles of the feet; damage to heart and blood vessels; a decrease in both red and white blood cell production; and severe inflammation of the liver.

damage to blood vessels

condition called blackfoot disease.

How can I tell if I've been Exposed?

• Medical tests can detect arsenic in the human body, but these tests are not part of a routine physical.

• The body routinely excretes arsenic in urine, so a urine test may show whether a person is taking in harmful amounts of arsenic.

• Because of arsenic's affinity for sulfur, it binds tightly to proteins in the human body that contain sulfur atoms.

• keratin - a stable protein that contain sulfur (Hair, fingernails and toenails).

How can I tell if there is Arsenic in my Drinking Water?

• Arsenic dissolved in drinking water cannot be detected by sight, smell or taste, so the only way to tell if arsenic is present is to have the water tested by a laboratory.

• Public water suppliers are required by law to test for arsenic

Can Arsenic be Removed from Drinking Water?

• Water treatment devices are currently available .

• Another option is to use bottled water for drinking and cooking.

• Public water supply, or to construct a new well

Arsenic Pollution world

INDIA

Arsenic Pollution in India and Bangledesh

• In the Ganges Delta, the affected wells are typically more than 20 meters and less than 100 meters deep. Groundwater closer to the surface typically has spent a shorter time in the ground.

• Arsenic contamination of the groundwater in Bangladesh is a serious problem.

Another report

• The shocking data released by the Ministry of Drinking water and Sanitation reveals that around 46 million people in India are forced to drink contaminated water. These people are mostly from the rural parts of the country.

• Globally, an estimated 1.8 billion people are drinking contaminated water.

Others finding

• Punjab’s Ever Growing Contaminated Food Chain A Big Worry

• Green Revolution , was it really green?

• Arsenic is actually added to livestock feed to produce higher weight animals and to fight disease.

Mar 27 2015 1:13AM

High arsenic levels found in 12 Punjab, Haryana districts

• Central Ground Water Board (CGWB) found habitations of six districts each in the two states affected with arsenic in groundwater beyond the permissible limit of 0.05 milligram per litre.

• These include Gandiwind (Amritsar district), Patti (Tarn Taran), Jhunir (Mansa), Dhilwan(Kapurthala), Ropar and Fazilka.

Comparsion

• In West Bengal, India, water is mostly supplied from rivers. Groundwater comes from deep tubewells, which are few in number. Because of the low quantity of deep tubewells, the risk of arsenic poisoning in West Bengal is comparatively less.

• The acceptable level as defined by WHO for maximum concentrations of arsenic in safe drinking water is 0.01 mg/L. The Bangladesh government's standard is at a slightly higher rate, at 0.05 mg/L being considered safe.

Little solution

• using surface water and instituting effective withdrawal regulation. West Bengal and Bangladesh are flooded with surface water.

• regulate proper watershed management. Treat and use available surface water, rain-water, and others.

Tech

• Coagulation/filtration (also known as flocculation) removes arsenic by coprecipitation and adsorption using iron coagulants.

• Coagulation/filtration using alum is already used by some utilities to remove suspended solids and may be adjusted to remove arsenic.

• Iron oxide adsorption filters the water through a granular medium containing ferric oxide. Ferric oxide has a high affinity for adsorbing dissolved metals such as arsenic.

• Activated alumina is an adsorbent that effectively removes arsenic

• Ion Exchange , Reverse osmosis and electrodialysis.

• Subterranean Arsenic Removal (SAR) Technology

• In subterranean arsenic removal (SAR), aerated groundwater is recharged back into the aquifer to create an oxidation zone which can trap iron and arsenic on the soil particles through adsorption process.

Fact sheet

• Despite its toxicity, arsenic has a long history of being used for medicinal purposes, including as a skin bleaching agent, a cancer treatment, and an early syphilis cure.

• In 2000, the FDA approved arsenic as a treatment for some forms of leukemia.

Fun fact

• In the Victorian era, arsenic was mixed with vinegar and chalk and eaten by women to improve the complexion of their faces, making their skin paler to show they did not work in the fields.

• Arsenic is taseless.

• when it reacts with oxygen it creates fumes that smell like garlic.

• Napoleon died of Arsenic poisoning."Napoleon's wallpaper"