The Indo-Gangetic basin accounts for roughly a quarter of the global extraction of groundwater, and is the key source of freshwater for over 700 million people in India, Pakistan, Bangladesh and Nepal. The researchers’ analysis of the quality of groundwater up to a depth of 200 meters (650 feet) found that about 23 percent of the water is too salty, while nearly 37 percent contains arsenic at concentrations toxic to humans. Photo: Nature Geoscience 
 
 “Elevated arsenic is primarily a concern for drinking water, while salinity affects irrigation and also the acceptability of groundwater for drinking,” the researchers wrote in the study. Although a certain level of salinity in groundwater is natural, the concentration is pushed beyond acceptable levels through inefficient farmland irrigation and poor drainage. Similarly, groundwater arsenic concentration is also raised beyond its natural levels by the indiscriminate use of phosphate fertilizers and mining. Photo: NASA 
 
 Arsenic poisoning through consumption of contaminated groundwater has long been a serious public health issue in South Asia. The findings of the new study indicate that contamination is a much bigger threat to groundwater in South Asia than depletion, as the water table across the Indo-Gangetic Basin remained largely stable — and even rose — in 70 percent of the aquifer between 2000 and 2012.
– A river basin in southern Asia is so enormous that 750 million people rely on it for their groundwater. Now, a new study in Nature Geoscience presents an equally staggering stat: 60% of that water is unfit for drinking or farming because it's contaminated by salt or arsenic, reports the Guardian. About 23% of the groundwater in the Indo-Gangetic Basin to a depth of 650 feet is too salty—an issue perhaps caused by poor farmland irrigation or drainage—and another 37% is tainted by toxic levels of arsenic, researchers say. Like salt, arsenic is present naturally, but levels can spike with mining and the use of fertilizers. The basin, so named because it's near the Indus and Ganges rivers, serves people in Pakistan, India, Nepal, and Bangladesh, and it accounts for one-quarter of the world's groundwater. "Elevated arsenic is primarily a concern for drinking water, while salinity affects irrigation and also the acceptability of groundwater for drinking," the researchers say, per International Business Times. However, researchers say that "deep tube wells" could penetrate deeper into the basin to pull out non-contaminated water, per Nature World News. Perhaps the only good news from the report is that the amount of water in the basin remained relatively stable, in contrast to other groundwater sources around the world. (Testing has found issues with 2,000 US water systems.)