Quality control of drinking water in Brasov municipality using first draw and full flush sampling procedures

Abstract

The present study investigates the influence of in-house installation systems to the tap water quality in Brasov Municipality in order to get an overview of the current contamination levels of drinking water at the consumer’s tap. In a sampling campaign organized in March 2013, the samples were collected from customer’s cold line pipe with first draw (1st liter taken in the morning from kitchen without previous flush of the tap) and fully flushed sampling (after flushing five minutes same tap) procedures. In the monitoring program were included samples from Tarlung Water Plant, drinking water samples from storage tanks situated in different Brasov areas, 34 samples from customer’s tap and 12 samples from branch pipes. The investigated parameters (metals, organic compounds and microbiological parameters) were those included in Romania Legislation in accordance with European Drinking Water Directive 98/83/EC. The metallic element Al, As, Cd, Cu, Cr, Fe, Mn, Ni, Pb, Se, Sb and Zn were analyzed in tap water samples using inductively coupled plasma atomic emission spectroscopy technique. The monitoring data show an influence of the material used in the internal distribution system within the customer buildings to the tap waters quality. Around 18% of first draw samples indicated a pollution of drinking water with Ni (two samples) and Pb (two samples). The metal concentrations recorded in tap waters collected with tap flushing procedure and also the samples collected from branch pipe were situated in the limit values in all studied cases.It was notice a decrease of free chlorine concentration in stagnated water (in most samples, below the limit of detection for the test method) compared with branch pipe and fully flushed samples. This permits the development of microorganisms, the stagnated water being unprotected from the bacteriological point of view. The present study demonstrate that materials used in water supply domestic installations have a major contribution in deterioration of water quality provided by the local distribution network, due to the processes of water stagnation and lack of maintenance of the internal distribution materials.