Spatial and Temporal Variations of Water Quality in Songhua River from 2006 to 2015: Implication for Regional Ecological Health and Food Safety

The Songhua River is the largest river in northeastern China; the river's water quality is one of the most important factors that influence regional ecological health and food safety in northeastern China and even the downstream of the Heilong River in Russia. In recent years, the Chinese government implemented several water resource protection policies to improve the river's water quality. In order to evaluate the influence of the new policies on the water quality in the Songhua River, water quality data from 2006 to 2015 were collected monthly from the nine sites along the mainstream of the Songhua River. Results show that the water quality in the Songhua River could be divided into two groups during the last 10 years. Before 2010, water quality in the Songhua River was primarily influenced by regional human activities. Industries were the major pollutant sources in the upstream of the Songhua River. After several new policies were implemented by the local government in 2010, water quality in the Songhua River improved. As a result, the biodiversity of fish and ecological health in the Songhua River improved.