Ballast Water Discharges and Safety Aspects of Using Active Substances for Ballast Water Treatment

This chapter gives an overview of the safety aspects of discharging ballast water into the environment due to the disinfection of the ballast water by the ship’s ballast water management systems (BWMS) using active substances (AS). Such a system is required to undergo a testing process according to the International Maritime Organization (IMO) BWMS Code and Procedure (G9). The BWMS Code describes to which level the discharge of ballast water may contain harmful aquatic organisms and pathogens (standard D-2), which is not dealt with in the current chapter. Procedure (G9) describes the procedure for approval of BWMS that make use of AS, which is the topic of this chapter. The consequences of the application of AS to the BWMS may be the formation of disinfection by-products (DBPs). Therefore, a technical working group has been established to ensure that the discharge of AS and DBPs remains below predefined acceptable limits to protect the environment, the crew and the ship against any side effects of the treatment by the BWMS. A risk assessment (RA) methodology has been developed by the Ballast Water Working Group of the UN Joint Group of Experts on the Scientific Aspects of Marine Environment Protection (GESAMP-BWWG). The methodology is based on internationally accepted RA procedures. The RA deals with the potential risks for the environment due to the direct discharge and for human health due to potential direct exposure of the crew of the ship or port State control officers when conducting their regular activities onboard, or due to the indirect exposure of the general public by swimming or by eating contaminated seafood. In case the treatment of the ballast water may cause a risk to the environment, the workers onboard, or the general public, such BWMS may not receive an approval recommendation by GESAMP-BWWG. The final decision about the acceptability of BWMS, and therefore, the allowance to market BWMS, is taken by the Marine Environmental Protection Committee of IMO based on the recommendation of GESAMP-BWWG. This chapter presents GESAMP-BWWG RA methodology with the theoretical background and the insights after >10 years of its application and improvements.