Drinking seawater or river water can have various effects on the human body, and these effects can differ based on several factors, including the individual's overall health, the amount consumed, and the water's salinity and contaminants. Here are the main effects:


1. Dehydration: Unlike quenching thirst, drinking sea or highly contaminated river water can lead to increased dehydration. The high salt content in seawater can draw moisture out of your cells and into your digestive system, making you even thirstier.


2. Electrolyte Imbalance: Sea water contains high levels of sodium and chloride ions. Consuming it can disrupt your body's electrolyte balance, potentially leading to muscle cramps, weakness, and, in severe cases, cardiac issues.


3. Kidney Strain: The kidneys must work harder to filter out the excess salt and impurities in seawater or heavily polluted river water. Over time, this can put a strain on your kidneys and may lead to kidney problems.


4. Digestive Distress: Drinking untreated river water can expose you to contaminants like bacteria, parasites, and chemicals. This can result in gastrointestinal issues such as diarrhea, vomiting, and stomach cramps.


5. Salt Poisoning (Hypernatremia): Consuming large quantities of seawater can lead to salt poisoning, which can cause symptoms like nausea, confusion, seizures, and in severe cases, coma or death.

6. Bacterial Infections: Drinking untreated river water can introduce harmful bacteria and parasites into your body, potentially leading to waterborne illnesses like cholera, dysentery, or giardiasis.

7. Chemical Contaminants: River water may contain industrial pollutants, heavy metals, and chemicals that can have long-term health effects if consumed regularly. These contaminants can accumulate in your body over time and lead to chronic health issues.


8. Parasitic Infections: River water may also carry parasitic organisms like schistosomiasis-causing parasites, leading to chronic health problems if left untreated.


9. Reduced Cognitive Function: Dehydration from drinking sea water or contaminated river water can impair cognitive function, affecting decision-making, concentration, and overall mental alertness.


10. Long-Term Health Consequences: Consistently drinking untreated river water or seawater can have cumulative health effects, potentially leading to chronic kidney disease, high blood pressure, and other severe health conditions over time.


To avoid these harmful effects, drinking clean, safe water is crucial. In situations where clean water is not readily available, it's best to use proper water purification methods like boiling, water filters, or chemical treatment to make the water safe for consumption. Drinking water from natural sources like rivers or the sea without treatment or filtration should be avoided whenever possible, especially in emergencies.