What are the effects on a human body that consumes brackish water of different NaCl concentrations ranging from 1,500ppm to 30,000ppm? My understanding is 500ppm or higher is considered unsafe, blood and IV fluids are around 9,000ppm, recommended daily sodium allowance is around 2,300mg or 2.3L of water at 1,000ppm, and around 30,000-35,000ppm (sea water) the kidneys can no longer remove salt from the body. It seems that in premodern times, humans often did not have a choice in their water sources and many resorted to drinking brackish water. What's even more interesting is entire settlements were created that relied on brackish water with concentrations around 1,000-2,000ppm, and many domesticated animals still rely on these water sources. What types of health effects would these people have experienced in both the short term and long term, and would the prevalence of these effects increase linearly with the salinity of the water or do issues become compounding?