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 associated 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.