Why Drinking Sea Water is Harmful

“Water, water, everywhere,

And all the boards did shrink,

Water, water, everywhere,

Nor any drop to drink.”

These sage words are from the Rime of the Ancient Mariner by Samuel Taylor Coleridge. Following this little limerick at sea could save a person’s life. The ocean may seem like a big body of water, but there’s more than just water in the sea; it also contains millions of compounds other than H0. One of these is the ion Sodium Chloride, NaCl, more commonly known as salt. This ion adds grave danger to what seems like harmless water.

One of the major dangers of drinking sea water is, ironically, dehydration. While humans need incredible amounts of fluids to sustain us, we only need salt as long as it is kept in a careful balance at around .9% of our blood content. According to the Woods Hole Oceanographic Institute, the oceans are on average 3.5% salt. This large difference causes the salt levels in the blood to rise. This means that the kidneys must compensate by excreting salt faster by inducing more sodium to be excreted in urine. This means a person who drinks sea water must urinate often to excrete the salt, losing not only the sea water but spare body fluids as well. Thus the person becomes dehydrated from drinking.

Drinking sea water also strains a person’s kidneys. The kidneys can only concentrate so much sodium into urine. The sodium levels of water exceed this. The kidneys can’t keep up, and sodium levels in the blood begin rising. This leads to sodium toxicity. Sodium is a necessary element in sending nerve impulses, but overdosing on sodium send this impulse system haywire. Symptoms of sodium toxicity include swelling of the limbs, mouth ulcers, seizures and arrhythmia. Coupled with the crippling dehydration this toxicity is fatal if not treated immediately. Some myths exist around consumption of sea water. The most widespread myth is that drinking sea water will cause you to go insane; however there is no scientific evidence for this.  The “insanity” could just be confusion brought on from severe dehydration.

Some people have claimed to be able to drink sea water. Alain Bombard, a French physician, claimed that in 1952 he was able to survive a year at sea subsisting only on seawater and sustenance from the ocean. However, his experience was denounced by German physician Hannes Lindemann, who said that when he attempted to recreate Bombard’s experiment he became severely dehydrated. Many others have claimed to be able to drink seawater in a 3:2 seawater-freshwater ratio; however these claims have not been scientifically evaluated and therefore should not be tried at home.

Though its deadliness has been disputed over the years, the fact remains that seawater can cause some serious issues in the body. It can cause dehydration and death. Therefore if you consume seawater, be smart and do it near a hospital. Or, even smarter, don’t do it at all.