Ballast Water Working Group

Lead agency: International Maritime Organization

The International Convention for the Control and Management of Ships’ Ballast Water and Sediments, (BWM Convention) was adopted at IMO on 13 February 2004, in response to the increasing concern of the international community with regard to the transfer of invasive species in ships’ ballast water. The Convention has yet to enter into force.

The GESAMP – “Ballast Water Working Group on Active Substances”, GESAMP – BWWG, or WG 34, was established in November 2005 to review any proposals submitted to IMO in preparation for the BWM Convention for approval of Ballast Water Management systems (further referred to as treatment systems) that make use of ‘Active Substances’. WG 34 reports to IMO on whether such proposals present unreasonable risk to the environment, human health, property or resources in accordance with the criteria specified in the Procedure for approval of ballast water management systems that make use of Active Substances (G9) adopted by IMO under resolution MEPC.126(53). WG 34 does not evaluate the operation or design of the systems, or their effectiveness, only their potential for environmental and human health risks. In contrast with the hazard-based approach applied by WG 1, the evaluation by WG34 followed a risk-based approach.

Active Substances

‘Active substances’ are defined by the Convention as “substances or organisms, including a virus or a fungus, that have a general or specific action on or against harmful aquatic organisms and pathogens” and the approval of systems using such substances is described in resolution MEPC.126(53) adopted in 2005.

It is increasingly believed that use of active substances will become a condition to comply with the provisions of the Convention, as other methods appear less effective. However, the use of active substances risks that the ballast water is still toxic at the time of discharge into the environment and that organisms in the receiving water may suffer unacceptable harm. A cautious approach therefore needs to be taken by developers of such ballast water management systems and thorough toxicity testing is needed to determine if an active substance can be used and under which conditions the potential of harming the receiving environment or human health is acceptably low.

The Procedure for approval of ballast water management systems that make use of active substances (G9) is aimed at ensuring proper application of the BWM Convention and provides a safeguard for the sustainable use of active substances.

The approval of systems that make use of active substances consists of two-tiers – Basic and Final Approval, and involves the evaluation of the physical and chemical hazards to ensure that a ballast water management system does not pose unreasonable risks for environment, human health, property or resources, as follows:

  • aquatic toxicology (acute as well as chronic toxicity);
  • accumulation and degradation in water, sediments and organisms;
  • bioconcentration and persistence within the living environment and the food web;
  • mammalian toxicology (short-term as well as long-term hazards);
  • methods in analytical chemistry;
  • physical data and physical effects on the ship and the environment;
  • risks of potential residues in seafood; and
  • risks for ship and personnel safety on board.

The complex interaction between manufacturer, administration submitting the proposal, WG 34, the MEPC Ballast water review group and the MEPC itself is set out in Guideline G9. To assist manufacturers, WG34 developed a comprehensive Methodology for information gathering and its conduct of work, which clarifies the responsibilities of the Administrations in providing data to IMO and the procedures used for evaluating the proposals. The MEPC agreed that the WG34 Methodology is a living document, which may be further refined taking into account the best practices and lessons learned during the evaluation process. There are currently three different revisions of the Methodology that are all applicable as outlined below:

BWM.2/Circ.13/Rev.1 of April 2012: Has been applied to all submissions for Basic Approval to MEPC 65 and onwards and will be applied to subsequent submissions for Final Approval of those systems.

BWM.2/Circ.13/Rev.2 of April 2014: Should be applied to all submissions for Basic Approval to MEPC 69 and onwards and subsequent submissions for Final Approval of those systems.

BWM.2/Circ.13/Rev.3 of May 2015: Should be applied to all submissions for Basic Approval to MEPC 71 and onwards and subsequent submissions for Final Approval of those systems.

The MEPC has encouraged proponents to make use of the most recent revision of the Methodology at their earliest opportunity.

More information about IMO's work on Ballast Water Management can be found on the IMO Website.