Qualitative and quantitative aspects of drinking water supply in Sardinia, Italy. A descriptive analysis of the ordinances and public notices issued during the years 2010-2015

Background. The aim of the study is to analyze the regional district ordinances and the warnings regarding qualitative and quantitavive drinking water abnormalities discovered by the Sardinian Municipalities and the Water Managing Authority between 2010 and 2015 in order to describe and identify the causes leading to an interruption or a limitation of the drinking water supply. Methods. We carefully reviewed all ordinances and warnings of non-potable water and service interruption published between 2010 and 2015 by the websites of 377 Sardinian Municipalities and by the main regional newspapers, the Water Managing Authority and the Regional Health Trusts. Results. From 2010 to 2015, 738 warnings/ordinances regarding drinking water supply limitation or interruption were issued. The warnings involved more than half (n. 191, 50.7%) of the 377 Sardinian Municipalities. Considering that these Municipalities included the main Sardinian cities we estimated that 80.3% of the population was affected by the issue. During the 6 years we observed a progressive increase of Municipalities involved beginning with 25 and reaching up 110 in 2014. The initial 29 warnings rose to 256 in 2014 along with an increased number of abnormal values, parameters and standards of the drinking water. Regarding the ordinances issued by the 191 Mayors we noticed that the legal limits were exceeded in 23 cases. Among those, we underline the abnormal levels of chlorites and trihalomethanes (22% of cases), the turbidity, the abnormal concentration of total chemical substances and the abnormal level of coliforms, Escherichia coli, manganese, aluminum, nitrites and iron. Conclusions. According to our observations, the Sardinian drinking water supply system is affected by a major inconvenience and the data suggest that qualitative abnormalities are mainly due to water purification treatments used in addition to the poor water supply network in existence. Considering these results, a cooperation between all Authorities involved would be desirable in order to analyze official data and provide a careful evaluation of population exposure and real risks related to the level of every parameter considered