How much nitrogen from fertiliser has accumulated in the groundwater of rivers around the world?

Scientists noted that nitrogen has stopped accumulating in these two rivers due to legislative initiatives in the field of agricultural activities, and the situation will soon return to normal. In the case of the Zhujiang and Yangtze, where 2.2 million and 18 million tonnes of nitrogen have accumulated respectively, the situation is much worse, as the process of nitrogen accumulation in them does not stop, and it may take at least 35 years to clean up groundwater from it.