A port statistics-based generic ballast water estimation and risk assessment approach and its application to Chinese ports

The Ballast Water Management Convention now enters the experience-building stage, but developing countries have no adequate ballast water information yet. Against this background, considering the richness and generality of common port statistics, we develop a new generic approach to estimate discharge volumes and assess asso-ciated risks. This is one of the few efficient and feasible ways for port authorities to manage real discharged ballast water. Discharge volumes during 2017-2020 and risks in 2017 are analyzed for bulker and tanker. Results show that: (1) Ports in Yangtze River Delta and Bohai Rim received most ballast water, especially Ningbo-Zhoushan port as high-risk region receiving about 65 million tons per year; (2) With a higher ratio of discharge volumes to cargo throughputs, the tanker tends to release more ballast water than the bulker; (3) Chinese ports suffer more than 0.9 of the probability of non-indigenous species introduction. All these findings help implement convention globally.