Introduction:
The Territorial Unit of Porto Torres, USMAF-SASN Campania Sardinia, Italian Ministry of Health Office (UTPT) has monitored water intended for human consumption (WIHC) onboard ships docking at North Sardinian ports since 2006. Our aim is to analyze water quality emerging from the ship’s distribution system in compliance with Italian Dl2023/18¹ and European DEU2020/2184². Legionella, monitored by specific national guidelines^3-6, is a parameter for risk management of internal distribution systems in Dl2023/18.

Methods:
Non-compliances with Dl2023/18 and DEU2020/2184, from ordinances/prescriptions related to water samples collected by UTPT inspectors, were reported in an Excel table (ship’s name, sampling dates and locations, type of non-compliances, prescriptions/notes) and analyzed with Excel®software.

Results:
In 2013-2017, the 13.4% of the 521 Legionella samples are non-compliant (mean value 65974 UFC/l; parametric Italian/European value <1000 UFC/l^1-5). The UTPT ordinances/prescriptions always include risk analysis on water distribution system and measures to decrease the microbiological load, according to the Italian guidelines^3-5. In the same period, 11.6% of the 112 WIHC samples has a trihalomethanes-total (THMs) non-compliance when considered the Italian parametric value 30 µg/l^1,6, 0% if considered European 100 µg/l^2,7. One non-compliant sample has Coliform bacteria (0.9%).

Conclusions:
As THMs concentration in ships depends also on extra-chlorination by internal automatic disinfection system of bunkered disinfected water, Italian ships are forced, since 2001^1,6, to find the balance between low THMs concentration (30 µg/l^1,6 ) (and accurate control of extra-chlorination) and the need of water microbial growth control. The Italian proactive approach to waterborne risks, since 2005⁴, helps shipowners and Institutions (UTPT) to reach the balance, providing more instruments to work with. DEU2020/2184 encourages Member States to strive for THMs concentration lower than 100 µg/l^2,7 although the risk assessment of supply/domestic distribution systems shall be compulsorily only by 2029. It could be easier/advisable to reach these goals together.