## CONSUMING SEA WATER

"Water, water, every where, n or any drop to drink."

--Samuel Taylor Coleridge, The Rime of the Ancient Mariner, part II, stanza 9

What would happen to you if you drank seawater?

"Let's say you're alone on a raft in the middle of the South Pacific, with no fresh water to speak of. What are the health implications of drinking salt water--will it make you vomit, will it make you delirious, will it dehydrate you further, etc.?"

— Jesse Sussell

We need water to live, and we need salt to live, so what's the big deal about sailors not being able to drink saltwater?

The answer is that we only need a small amount of salt to live. According to the Salt Institute (a non-profit association of salt
producers, founded in 1914), the recommended daily dose is around 500 mg/day--around a quarter of a teaspoonful. The optimal amount of salt varies based on the person's lifestyle, genetic makeup and geographic location (basically, all factors that affect how often and how much you sweat). Most Americans consume much more than they need, around 3500
mg/day.

But when we're talking about seawater, we're not just talking about common salt. Other compounds and elements and minerals called salts are found in ocean water, such as epsom salts, potassium salts, iodine salts, and so forth. Some of these taste bitter or sour, although they may be of value to the human diet, such as magnesium chloride and potassium chloride.

On this scale, the ocean is classified as "highly saline" (over 1.0% dissolved salts.) In fact, seawater is around 3.5% dissolved salts by weight. That's about three times as salty as human blood. That's way more salt than we can safely metabolize.

Which gets us at last to your question--what happens if you drink seawater? Bill Bryson puts it vividly:

Take a lot of salt into your body and your metabolism very quickly goes into crisis. From every cell, water molecules rush off like so many voluntary firemen to try to dilute and carry off the sudden intake of salt. This leaves the cells dangerously short of the water they need to carry out their normal functions. They become, in a word, dehydrated. In extreme situations, dehydration will lead to seizures, unconsciousness, and brain damage. Meanwhile, the overworked blood cells carry the salt to the kidneys, which eventually become overwhelmed and shut down. Without functioning kidneys you die. That is why we don't drink seawater.

In conclusion, if you drink too much salt water, you need to urinate more water than you drank to get rid of the excess salt, and dehydration sets in. Drinking even a little seawater starts you down a dangerous road: The more you drink, the thirstier you get.