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Introduction
Discovering the Problem
Arsenic in Nature
Source of Contamination
Arsenicosis: Toxic Effects
Feature of Arsenicosis
Confirmation of Diagnosis
Treatment
Arsenic Detection
De-arsination
Control Measures
WHO Recommendations
Contact us
© Copyright:
MIG 1998
 

Arsenic Contamination of Drinking Water
Bangladesh is the
World's Most Vulnerable Country


Arsenic in Nature

  • In nature, there is plenty of arsenic.
  • Arsenic is present in air, soil and water
  • Rock contains 1.5-2.0 milligram of arsenic per kilogram. But, in contaminated soil, concentration of arsenic may be up to 500 mg/kg.
  • Industrial wastes may emit arsenic to the atmosphere causing higher arsenic level in the near by air than usual level (0.04030 ng/cubic meter).
  • Arsenic content of natural water may be up to 1-2 microgram/L.
  • Most fruits, vegetables, meats and fishes contain arsenic; but arsenic levels in sea water and sea fishes are higher. Sea fish may contain 5 mg of arsenic per kg weight.
  • Living with nature means human beings take a little amount of arsenic every day through breaths, food or drinks. But, as they are negligible in quantity and organic in nature, they do no harm.
  • An intake of 150 microgram of arsenic per day should not cause any harmful effect to human being, but very sensitive person often becomes sick with as low as 20 microgram of arsenic a day.
  • Table-2 shows the chemical nature of arsenic.

Table-2. Chemical Nature of Arsenic at a Glance

Formula

As

Atomic Number

33

Atomic weight

74.9216

Position in Periodic Table

VA

Density at 32 degree Fahrenheit

5.73

Melting point

1139 degree Fahrenheit

Boiling Point

1497.2 degree Fahrenheit

Types of Arsenic compounds
  • Inorganic (trivalent, e.g. arsenites, and pentavalent, e.g. arsenates); Inorganic arsenic are more toxic. In Bangladesh both tri and pentavalent compounds have been found in water.
  • Organic (mono and di-methyl arsonic acid, Na-cacodylate, atoxyl, stoversol, etc.)