Assessment of eutrophication types of lakes and ecological risk of heavy metals in Riparian soils in lower reaches of the Yellow River, China

Compared with the eutrophic criteria of lakes in china and using individual grading and comprehensive grading methods, we evaluated the nutritional type of those lakes in lower reaches of the yellow river. At the same time, we take the soil background values of heavy metals in The Lower Yellow River as the assessment standards and use the potential ecological risk index method to evaluate the pollution level and the ecological risk of heavy metals in riparian soil. The results shows: most of lakes water has been suffering from varying degrees of pollution, water quality is deteriorating and nutritional types of water have reached the eutrophical level. The assessment result indicate that heavy metal pollution in riparian soil is generally at a light level and posed low ecological risk, in which Cd and Hg make the main contribution to the ecological risk with the average ratio 46.8% and 33.6%, respectively.