Which method is known to indicate the presence of saltwater drowning?

The presence of Cl- ions in the blood is a crucial indicator of saltwater drowning because when a person is submerged in saltwater, the high concentration of sodium chloride in the water is absorbed into the bloodstream. This condition leads to an increase in chloride ions as well as sodium ions, both of which are associated with saltwater exposure.

This increase in chloride levels can be detected even after a person has been rescued and resuscitated, allowing forensic pathologists to distinguish between drowning in freshwater and saltwater. In contrast, while increased blood sodium levels can also occur, the specific presence of chloride ions serves as a more direct marker for the type of drowning.

Rise in potassium levels and decrease in blood pH can occur as general responses to various forms of drowning and other stressors on the body but are not specific indicators of saltwater drowning.