Why Does Drinking Sea Water Kill You?

The old adage "water, water, everywhere and not a drop to drink" reflects the knowledge of seamen who knew drinking sea water could be deadly.

Salt

Seawater contains three times as much salt as the human body. The system can't metabolize the excess salt, so it pulls stored fluid out of the body's tissues and sends it into the urinary system to flush the excess salt from the blood stream, causing dehydration. A loss of 15 percent of stored water causes organs to shut down, eventually resulting in death.

Bacteria

Bacteria and micro-organisms in seawater can be fatal. Just a swallow or two can contain enough bacteria to cause infection in the blood stream or intestinal system, and result in death.

Contaminants

Seawater contains contaminants like crude oil, fuel and industrial waste that could be toxic to the human body if ingested.

References

• Seashell and Such: Can I Drink Seawater
• National Oceanic and Atmospheric Administration: Can Humans Drink Seawater
• Earthsky: Why Shouldn't We Drink Seawater?