The researchers studied the groundwater in the Fenhe River basin to understand its chemistry and origins. They found that the groundwater is of good quality, with most samples falling into the safe category. The water is slightly alkaline and contains mainly bicarbonate and calcium ions. The isotopes in the groundwater suggest it comes from precipitation in the summer months. Rock weathering is the main source of ions in the water, with equal contributions from silicate, evaporate, and carbonate rocks. This information can help manage and use groundwater resources in the Fenhe River basin sustainably.