Externet Posted June 13, 2014 Share Posted June 13, 2014 If seawater is ingested, read somewhere it works as a poison. Well, the poisonous effects have to manifest at a certain volume (that I do not know) ingested. Let's assume drinking a litre in 24 hours is really bad for the body. Perhaps lethal. If only the sodium chloride is removed from seawater, leaving all other natural elements present in seawater; will drinking a litre in 24 hours still be poisonous ? (Assume no bio-microorganisms presence in any case) Link to comment Share on other sites More sharing options...
barfbag Posted June 13, 2014 Share Posted June 13, 2014 Seawater contains three times as much salt as the human body, and your body will not metabolize it. Your body will then take stored fluid and send it to the urinary system to help wash the excess salt away. This can cause dehydration and if your body loses 15% of its stored fluid you will die. It will also flush out any water or nutrients already ingested. If you drank salt water a lot of it would come out like Diarrhea like used in flush diets. The salt would also leave you thirstier than when you started, which is bad if your only drink is more salt water. It is not a chemical type poison. The salt will dehydrate you, and you are mostly a sack of 70% water. Link to comment Share on other sites More sharing options...
CharonY Posted June 13, 2014 Share Posted June 13, 2014 You have to understand that literally everything is poison. The reason is that our body (and cells) only operate within certain physicochemical parameters. Too much or too little of certain things will cause injury and eventually death. As such the distinction between toxic or not is really just a matter of dose and not a property of the chemical itself. Distilled water can upset your osmotic balance too and cause death under certain conditions (due to electrolyte loss, for example). Link to comment Share on other sites More sharing options...
Moontanman Posted June 13, 2014 Share Posted June 13, 2014 If seawater is ingested, read somewhere it works as a poison. Well, the poisonous effects have to manifest at a certain volume (that I do not know) ingested. Let's assume drinking a litre in 24 hours is really bad for the body. Perhaps lethal. If only the sodium chloride is removed from seawater, leaving all other natural elements present in seawater; will drinking a litre in 24 hours still be poisonous ? (Assume no bio-microorganisms presence in any case) You could easily drink a liter of sea water not be affected. Remove the Sodium chloride and all you have is hard water, completely drinkable.. Link to comment Share on other sites More sharing options...
barfbag Posted June 13, 2014 Share Posted June 13, 2014 @ moontanman, Drinking a litre of saltwater would flush out your system for starters and the water would mostly come out in the form of Diarrhea. Your body would also send some of its water reserves to help flush the digestive tracts free from salt. The above may be harmless, but usually this question is in regards to ocean survival, and drinking any salt water will lessen your lifespan in that situation. Link to comment Share on other sites More sharing options...
CharonY Posted June 13, 2014 Share Posted June 13, 2014 Actually the question was about toxicity of seawater which can be characterized using standard tox parameters. Sea water is obviously a mixture but taking specifically sodium chloride the reported LD50 (concentration where 50% of test animals die) is at 3g/kg. About 4% of seawater is salt (let us assume all NaCl for simplicity), so in 1kg of water you got about 40g of salt. Assuming a body weight of say, 70kg the LD50 is estimated to be 210 g. So ingesting that amount has less then a 50% chance of killing someone. For more accurate assessment one would need to look at actual dose-response curves. To put that into relation, sucrose is at about 29 g/kg, ethanol about 7g/kg and caffeine 0.2 g/kg. Link to comment Share on other sites More sharing options...
Moontanman Posted June 13, 2014 Share Posted June 13, 2014 @ moontanman, Drinking a litre of saltwater would flush out your system for starters and the water would mostly come out in the form of Diarrhea. Your body would also send some of its water reserves to help flush the digestive tracts free from salt. The above may be harmless, but usually this question is in regards to ocean survival, and drinking any salt water will lessen your lifespan in that situation. No one said anything about a survival situation, a liter of seawater is not much, I would imagine in a day of scuba diving I drink or ingest a liter of sea water easy. Just playing in the ocean all day, surfing and other things result in ingesting sea water. A liter is not enough to harm you... Link to comment Share on other sites More sharing options...
John Cuthber Posted June 14, 2014 Share Posted June 14, 2014 Some of the replies seem to have missed the point of the OP. It says "Let's assume drinking a litre in 24 hours is really bad for the body. Perhaps lethal. If only the sodium chloride is removed from seawater, leaving all other natural elements present in seawater; will drinking a litre in 24 hours still be poisonous ?" OK, the assumption is invalid (at least for a healthy 70Kg adult) Drinking a litre of sea water carrying about 40 grams of salt is unlikely to be fatal. But it's something like a fifth of the mean fatal dose so it is likely to be observably toxic. Let's look at the other point "If only the sodium chloride is removed from seawater, leaving all other natural elements present in seawater; will drinking a litre in 24 hours still be poisonous ?"" It has roughly 0.05 moles of Mg per litre: about 1.2 grams. That's probably marginal for upsetting your stomach a bit. Spread over 24 hrs along with a normal diet the answer is that it's not going to do any real harm (as moontanman said). But it's probably still rather high for drinking as your "normal" water supply every day. It's never going to matter: there's no practical way of stripping just the NaCl from sea water Link to comment Share on other sites More sharing options...
sciencehealth Posted June 17, 2014 Share Posted June 17, 2014 There are desalination tools available, which remove the salt (NaCl) but keep most other elements in the water. Many travelers across the sea have used them so far and probably drunk several liters of desalinated seawater per day and have been fine. So, obviously, other minerals or substances ingested with seawater in reasonable amounts are not (very) toxic. Usgs.gov Drinking seawater at the river mouth could be hazardous, though (less salt but more industrial toxins). Drinking seawater dehydrates you. This is because human kidneys have a limited capability to concentrate urine, which means for every gram of salt they excrete they also have to excrete a certain amount of water, which is greater than the amount of water in seawater you've drunk. In summary, for every liter of seawater you drink your kidneys will excrete at least 1.5 liters of urine, so your water balance will be minus 0.5 liters. Drinking seawater is never a god idea to overcome dehydration, because every little amount of seawater you drink will result in a negative water balance. This is explained a bit more here. Dehydration is lethal when you lose more than about 10% of water from your body, which is 7 liters for a 70 kg man. Drinking 1 liter of seawater would result in "only" 0.5 liters of your body water, which is far from lethal (assuming you were well hydrated on the beginning). Link to comment Share on other sites More sharing options...
John Cuthber Posted June 22, 2014 Share Posted June 22, 2014 "There are desalination tools available, which remove the salt (NaCl) but keep most other elements in the water." How? 1 Link to comment Share on other sites More sharing options...
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