Abstract: Based on catastrophe theory, this paper established an index system and catastrophe progression model for the integrated assessment of eco-risk in coastal waters, including three risk types of “eutrophication-heavy metal pollution-organic pollution” and three dimensions of “water-sediment-organism”. According to the related quality standards, a four-level evaluation standard of eco-risk (zero, low, medium, and high) was proposed, and by using the monitoring data of 2007 and 2009, an integrated assessment of the eco-risk in Luoyuan Bay was conducted. In 2007-2009, the spatial variation of the eco-risk in Luoyuan Bay had a downward trend from bayhead to baymouth, and the risk level in 2009 was overall lower than that in 2007.The key factor of the eco-risk in the Bay was eutrophication.The approach established in this paper could identify the spatiotemporal variation characteristics of eco-risk in coastal waters, and better reflect the key eco-risk factor, providing a basic approach for effective forecasting and early warning of eco-risk in coastal waters.

Key words: catastrophe theory, coastal water, eco-risk, Luoyuan Bay