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Is it possible to drink ocean water?


The ocean covers over 70% of the Earth’s surface and contains around 1.35 billion cubic kilometers of water. With such a massive amount of water in the oceans, it is natural to wonder whether ocean water is suitable for drinking. At first glance, with water covering the majority of the planet, it would seem that the answer is yes. However, drinking ocean water directly can actually be very dangerous for humans. In this article, we will explore whether it is possible to drink ocean water, looking at the risks and dangers as well as any potential ways to make ocean water potable.

Is Ocean Water Safe to Drink?

The simple answer is no – ocean water is not safe to drink in its raw form. Here are some key reasons why drinking ocean water is dangerous:

  • Salt content – Ocean water contains high concentrations of salts, especially sodium chloride. The average salinity of ocean water globally is around 3.5%. At this salinity level, ocean water is hypertonic, meaning it has a higher salt content than the cells in the human body. Drinking high volumes of saline water results in dehydration as the salts cause fluids to be pulled from the body’s cells.
  • Toxins – Ocean water contains numerous toxins and heavy metals including mercury, lead, copper and cadmium. Exposure to high levels of these metals can lead to organ damage over time.
  • Pathogens – Raw ocean water may contain bacteria, viruses, protozoa and fungi that can cause serious gastrointestinal illness if ingested. Pathogens such as Vibrio vulnificus or Cryptosporidium can be life-threatening if the person drinking the ocean water has a compromised immune system.
  • Marine life – Microscopic marine organisms like algae, plankton, and brine shrimp are found in ocean water and can cause nausea and vomiting if consumed in large amounts.

So in summary, the high salt content, toxins, pathogens and marine life make raw ocean water potentially deadly to drink. Dehydration, electrolyte imbalance, metal poisoning, infection and nausea are just some of the possible consequences. Only a small amount of ocean water is needed to make someone violently ill.

When is it Safe to Drink Ocean Water?

Ocean water should never be consumed without treatment. However, there are some situations where drinking ocean water may be necessary for survival:

  • Emergency rations – After purifying ocean water, small sips can be used as an emergency source of hydration if no other clean water source is available. This is an absolute last resort if stranded at sea or in an ocean survival situation.
  • Desalination – Ocean water that has been desalinated and disinfected through advanced technological processes can be made safe for drinking. Desalination is used to provide potable water in many arid coastal regions around the world.
  • Boiling – In a life or death emergency, boiling ocean water for 1 minute can help make it safer to drink by killing pathogens, but it does not remove salt, heavy metals or toxins.

Outside of emergency situations, there are no circumstances where untreated ocean water is safe to drink. Consuming it should only be considered when facing imminent death from dehydration and no other water sources can be found. Even then, drinking amounts should be strictly rationed.

Dangers of Drinking Ocean Water

Let’s look in more detail at why drinking ocean water can be so hazardous:

Dehydration

The average salt concentration of seawater is over 3%. For comparison, the salt content of the human body is only about 0.9%. Because of this discrepancy, consuming ocean water leads to dehydration as water is drawn out of body cells to dilute the salt.

The more ocean water someone drinks, the worse the dehydration becomes. Even small amounts can make people nauseous as the body struggles to deal with the excess salt intake. Severe dehydration from drinking seawater leads to organ failure and eventual death if untreated.

Electrolyte Imbalance

Apart from sodium and chloride, ocean water contains other dissolved electrolytes like magnesium, calcium and potassium. Drinking ocean water drastically upsets the balance of electrolytes in the body.

This electrolyte imbalance can cause neurological symptoms like headaches, confusion, muscle twitching and seizures. In the long term, it may lead to coma and death.

Heavy Metal Poisoning

Toxic heavy metals including mercury, lead, cadmium and arsenic are found in varying concentrations in the ocean. Over time, consuming ocean water leads to the accumulation of these metals in the body resulting in poisoning.

Children are especially vulnerable to heavy metal toxicity which can impair brain development. In adults, high exposure can damage the kidneys, liver and neurological function.

Infection

Drinking untreated ocean water risks many types of infection:

  • Bacterial infections – Pathogenic bacteria like Vibrio vulnificus live in warm ocean water and can cause vomiting, diarrhea, abdominal pain and even septic shock from wound infections.
  • Viral infections – Contaminated ocean water may contain hepatitis A virus, noroviruses and other viruses that typically cause gastrointestinal symptoms like nausea, cramps and diarrhea.
  • Parasitic infections – Ocean water harbors protozoan parasites like Giardia and Cryptosporidium which cause prolonged diarrheal illness if ingested.
  • Fungal infections – Candida fungi are present in ocean water and may lead to oral thrush or yeast infections if swallowed.

Those with a weakened immune system are at highest risk of these potentially deadly ocean water-related infections. But even in healthy people, the high microbial load can overwhelm defenses and cause vomiting, diarrhea and severe dehydration.

Nausea and Vomiting

Drinking more than a couple of mouthfuls of ocean water generally induces vomiting and nausea. This is the body’s defense mechanism to expel the excess salt, toxins and microbes consumed in the ocean water.

While vomiting provides temporary relief of symptoms, it worsens dehydration and electrolyte imbalance. It can also lead to dangerous aspiration into the lungs in those who are already weak.

Can Ocean Water Ever be Made Potable?

While drinking untreated ocean water is extremely hazardous, with modern technologies, seawater can be treated to make it safe and potable for human consumption.

Some ways ocean water can be purified include:

Desalination

Desalination is the process of removing dissolved salts and minerals from saline water to produce freshwater suitable for drinking. Two main desalination methods exist:

  • Thermal desalination – Seawater is heated to produce water vapor that is condensed and collected as fresh water. The leftover concentrated brine is returned to the ocean.
  • Reverse osmosis – Ocean water is forced against membranes through which filtered water can pass while salt molecules are left behind. Israel and Saudi Arabia lead the world in using reverse osmosis desalination.

Over 300 million people globally rely on desalinated ocean water for their daily drinking needs. Modern desalination plants can remove up to 99% of salt and impurities.

Disinfection

After desalination, the water is disinfected to kill any remaining bacteria, viruses or parasites. This is done through:

  • Chlorination – Adding chlorine compounds like sodium hypochlorite.
  • Ultraviolet radiation – exposing water to UV light kills pathogens.
  • Ozonation – Ozone gas bubbled through water acts as a disinfectant.

A combination of these processes produces water that meets drinking quality standards.

Supplementation

Desalinated ocean water has very low mineral content. Additional treatment may be needed to add back beneficial minerals like calcium and magnesium. Fluoride may also be added to promote dental health. Seawater that is purified using these advanced technologies can be made entirely safe and potable.

Can Ocean Water Hydrate You?

Given its hypertonic salt content, ocean water leads to dehydration instead of hydration. The body uses more water to dilute the absorbed ocean water salts than is gained by drinking it.

However, in an extreme survival situation with no other water source, rationing tiny sips of ocean water may temporarily prolong life. But this only delays the inevitable dehydration and organ failure.

For real hydration, seawater must be desalinated or rainwater collected. Without access to clean water for rehydration, drinking ocean water hastens death instead of preventing it. It should only ever be considered as an absolute last resort.

What Amount of Ocean Water is Deadly?

Surprisingly little ocean water needs to be drunk for it to be potentially lethal:

  • 1 liter – Causes acute electrolyte imbalance and dehydration requiring medical treatment.
  • 500 ml – Leads to vomiting, diarrhea, headaches and dizziness.
  • 250 ml – Causes nausea, thirst, and short-term kidney dysfunction.
  • 100 ml – Results in vomiting in over 90% of cases.

So drinking even a standard cupful of ocean water is enough to make most people violently ill. Consuming up to a liter could be fatal without rapid intervention with intravenous fluids. Over 3 liters ingested in a short period is likely to cause death in previously healthy adults.

Children, the elderly and those with medical conditions have a much lower tolerance to the effects of drinking ocean water. The smaller the amount consumed, the greater someone’s chances of survival – but severe illness is inevitable.

Tips for Ocean Survival

Here are some tips if you ever find yourself adrift and lacking fresh water:

  • Ration ocean water intake – Take the smallest sips needed to prolong life. Limit it to 100-200ml per 24 hours.
  • Collect rainwater – Use any containers to gather rainwater for drinking instead of ocean water.
  • Eat fish/marine life – Provides hydration and delays thirst.
  • Protect yourself from sun exposure – Reduces sweating and urination which worsens dehydration.
  • Stay calm and conserve energy – Lowers metabolic demands for water.
  • Desalinate water – Make basic solar stills to distill freshwater.
  • Get medical help – Seek urgent medical care after rescue to correct electrolyte imbalances.

Following these tips gives the best chance of survival until clean water or rescue arrives. But drinking ocean water should only ever be a life-or-death last resort when all other options have been exhausted.

Frequently Asked Questions

Why can’t humans drink saltwater?

The salt content of ocean water is around 3.5% which is hypertonic compared to the cells in the human body. Consuming saltwater draws fluid out from body cells due to osmosis, leading to dangerous dehydration and electrolyte imbalances. Humans do not possess the physiological adaptations to safely excrete excess salt gained from drinking seawater.

Can you boil ocean water to make it drinkable?

Boiling ocean water kills pathogens making it safer to drink by reducing the risk of gastrointestinal illness. However, it does not remove salt, heavy metals, toxins or other contaminants. While boiling may be helpful as an emergency short-term measure, it does not make ocean water fully potable.

Do any animals drink ocean water?

Some marine animals and birds have adapted to tolerate or process the salt in ocean water for hydration and survival. Examples include fish, sea turtles, penguins and pelicans. Their kidneys are specially adapted to excrete excess salt. Humans lack this biological capacity to safely metabolize salt from drinking ocean water.

Has anyone survived drinking ocean water?

There are rare reports of individuals surviving a few weeks lost at sea drinking limited rationed amounts of ocean water. However, they all required intensive medical treatment after rescue to correct severe dehydration, electrolyte abnormalities and organ impairment from salt poisoning. Drinking ocean water reduces survival time rather than prolonging it in most cases.

Can you use ocean water in a neti pot?

No – seawater should never be used for nasal irrigation or neti pots. The high salinity causes painful irritation and damage to the sensitive nasal passages and sinuses. Pathogens present in ocean water can also lead to dangerous nasal and brain infections like Naegleria fowleri. Only specially prepared sterile saline should be used.

Conclusion

In summary, drinking untreated ocean water is extremely hazardous and potentially deadly due to the risks of dehydration, salt poisoning, heavy metal toxicity and infection. No amount of seawater can be considered safe to drink in its raw form. While emergency survival rationing may temporarily prolong life, medical treatment is invariably required afterwards to correct electrolyte abnormalities and organ damage. Ocean water needs extensive desalination and disinfection to be made potable. If you find yourself adrift at sea without fresh water, consuming ocean water should only be considered as an absolute last resort.