Water Safety Plan on cruise ships: a promising tool to prevent waterborne diseases

Legionella spp. and other waterborne pathogens have been isolated from various water systems on land based premises as well as on ships and cases of Legionnaires' disease have been associated with both sites. Peculiarities of cruise ships water systems make the risk management a challenging process. The World Health Organization suggests a Water Safety Plan (WSP) as the best approach to mitigate risks and hazards such as Legionella spp. and others.

To develop WSP on a cruise ship and discuss challenges, perspectives and key issues to success.

Hazards and hazardous events were identified and risk assessment was conducted of the ship water system. Ship company management, policies and procedures were reviewed, site visits were conducted, findings and observations were recorded and discussed with engineers and key crew members were interviewed.

A total of 53 hazards and hazardous events were taken into consideration for the risk assessment and additional essential barriers were established when needed. Most of them concerned control measures for biofilm development and Legionella spp. contamination. A total of 29 operational limits were defined. Supplementary verification and supportive programs were established.

Application of the WSP to ship water systems, including potable water, recreational water facilities and decorative water features and fountains, is expected to improve water management on ships. The success of a WSP depends on support from senior management, commitment of the Captain and crew members, correct execution of all steps of a risk assessment and practicality and applicability in routine operation. The WSP provides to shipping industry a new approach and a move toward evidence based water safety policy.