Carbon Filter
"It's a mixture of mercury and sulfur. My guess is that the ancient river became the deep ravine it is today because of a volcanic eruption a long time ago. There are also clues that there are alkaline hot springs underground. This is the source of the faint sulfur smell in the water. Beside that, there is a large amount of natural cinnabar too under the ground. The mercury pollution on the ground and water also comes from this natural cinnabar." Xu Xiang said while looking at the data on the screen of the poison detector.
A Lu Da looked at her and thought in his heart: 'It's strange. I can understand her, but why can't I understand what she is talking about?'
Seeing his puzzled face, Xu Xiang said, "Anyway, I can help you solve water problems and poisoning problems."