Date Added
OCT 2002

There are few external symptoms of drowning, the main one being the fine white foam created by the mixture of air, water and mucus, which appears at the nostrils and mouth. Other signs will be wrinkling of the skin on the palms of hands and soles of feet if the victim has been in the water for any length of time.


In cases of suspected drowning, the pathologist will look for the presence of objects such as stones and water weeds which have been grabbed during the pre-death struggle and become locked in the clenched hand by cadaveric spasm  - a sure indication of death by drowning.


Autopsy will reveal the lungs pale and distended so that when the thoracic cavity is opened they will tend to balloon out. Lungs will be wet and heavy so that pressure from a finger will leave a clear indentation. Trachea and bronchi will be found to contain foam, and so will the lungs when sectioned.


Water is usually present in the stomach and oesophagus, and may contain debris from its source - weeds, algae, etc.


In most true cases of drowning conspicuous haemorrhaging will be found in the middle ear caused, it is thought, by barometric pressure. The same effect can not be found in cases of, for example, submersion resulting from reflex cardiac arrest.


Tests will be made to ascertain the presence of any factors which may have contributed to the drowning - not only disease and illness, but the presence of alcohol and drugs. One authority puts apparent domestic drowning in a bath which in reality resulted from drug overdoses as high as fifty percent.


Although all injuries on the body must be carefully recorded and closely examined, their presence does not necessarily prove homicide. A body in water is prey to all manner of hazards - striking submerged rocks, being struck by boats, chewed by fish and so on. Furthermore, the appearance of wounds can be misleading because of changes in the blood caused by water, making it difficult to ascertain with confidence whether the injuries were received before or after death.


Finally it must be borne in mind that many of the signs described above will be destroyed or masked as the body becomes putrefied.

When death is caused by drowning in a 'natural' water such as lakes and rivers, the water entering the body will contain microscopic organisms called diatoms; while the blood is still circulating these diatoms will be distributed around the body, finding their way into the organs and even bone marrow. Thus if a body is already dead when it enters the water diatoms will not be found (with the exception of a few which may gravitate into the lungs). In order to isolate the diatoms, parts of the organs removed at autopsy are dissolved with strong mineral acid leaving the acid-resistant silica shells of the diatoms observable with a microscope.

The diatom phenomenon is of use in investigations where a body was found in a different location to where it was drowned. It has been recognised that diatoms can be identified with their area of origin with considerable accuracy due to the fact that any combination of the more than 15,000 species is likely to be unique.

Specific gravity tests will be made of the heart blood to confirm whether drowning occurred in fresh or salt water. Fresh water (rivers, canals, ponds, etc) is termed hypotonic to plasma, and will enter the heart through the pulmonary capillaries and dilute the blood. As much as two litres can be absorbed this way, at the same time reducing the concentration of chloride. Salt water is hypertonic and will have the effect of extracting water from the blood and increasing the chloride concentration. Blood tests should be carried out within twenty four hours of death, before putrefaction begins to alter the chemistry of the blood.

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