Water samples collected from public
drinking water supplies in Sicily were analysed
for electric conductivity and for their chloride,
sulphate and nitrate contents. The samples were
collected as uniformly as possible from throughout the Sicilian territory, with an average sampling density of about one sample for every 7,600
inhabitants. Chloride contents that ranged from
5.53 to 1,302 mg/l were correlated strongly with
electric conductivity, a parameter used as a proxy
for water salinity. The highest values are attributable to seawater contamination along the coasts
of the island. High chloride and sulphate values
attributable to evaporitic rock dissolution were
found in the central part of Sicily. The nitrate
concentrations ranged from 0.05 to 296 mg/l, with
31 samples (4.7% of the total) exceeding the
maximum admissible concentration of 50 mg/l.
Anomalous samples always came from areas of
intensive agricultural usage, indicating a clear anthropogenic origin. The same parameters were
also measured in bottled water sold in Sicily, and
they all were within the ranges for public drinking
water supplies. The calculated mean nitrate intake
from consuming public water supplies (16.1 mg/l)
did not differ significantly from that of bottled
water (15.2 mg/l). Although the quality of public
water supplies needs to be improved by eliminating those that do not comply with the current
drinking water limits, at present it does not justify
the high consumption of bottled water (at least for
nitrate contents)