DIATOM TEST

DIATOM TEST

Subject : Science & tech

Context : Recently, the Maharashtra Anti-Terrorist Squad (ATS) has relied on a forensic test known as diatom tests for leads in the alleged murder case of Mansukh Hiran.

Concept :

• A number of tests have been developed to confirm the cause of such deaths (death by drowning) with the diatom test emerging as one of the most important tests.
• The test entails findings if there are diatoms in the body being tested.

What are Diatoms?

• Diatoms are photosynthesizing algae which are found in almost every aquatic environment including fresh and marine waters, soils and almost anywhere that is moist.
• They are unicellular, photosynthetic, autotrophic organisms that have a characteristic structure frustules, comprising two thecas i.e. silica cell walls.
• The diatoms are subdivided into two major orders i.e. Centrales and Pennales depending on the shape of the frustule.
• The Centrales are radially symmetric and the Pennales have bilateral symmetry.

Science behind Diatom Test

• A body recovered from a water body does not necessarily imply that the death was due to drowning.
• If the person is alive when he enters the water, the diatoms will enter the lungs when the person inhales water while drowning.
• These diatoms then get carried to various parts of the body, including the brain, kidneys, lungs and bone marrow by blood circulation.
• If a person is dead when is thrown in the water, then there is no circulation and there is no transport of diatom cells to various organs.
• The Diatom analysis is considered positive only when the number of diatoms recovered from the body is more than a minimal established limit.
• The result of a diatom test will be different if a person is thrown in the water after he is dead.

Reliability of Diatom Test

• It is reliable unless and until the deceased person has been drinking water from the same source of water before his death.
• The diatom test need not be done if classical signs of drowning like froth at mouth and nostrils, cadaveric spasm, presence of water from drowning medium is seen in stomach and oedema of lungs are present.