ABSTRACT
An extraordinary bloom of Planktothrix rubescens, which can produce microcystins (MCs), was observed in early 2009 in the Occhito basin, used even as a source of drinking water in Southern Italy. Several activities, coordinated by a task force, were implemented to assess and manage the risk associated to drinking water contaminated by cyanobacteria. Main actions were: evaluation of analytical protocols for screening and confirmatory purpose, monitoring the drinking water supply chain, training of operators, a dedicated web site for risk communication. ELISA assay was considered suitable for health authorities as screening method for MCs and to optimize frequency of sampling according to alert levels, and as internal control for the water supplier. A liquid chromatography-tandem mass spectrometric method able to quantify 9 MCs was optimized with the aim of supporting health authorities in a comprehensive risk evaluation based on the relative toxicity of different congeners. Short, medium, and long-term corrective actions were implemented to mitigate the health risk. Preoxidation with chlorine dioxide followed by flocculation and settling have been shown to be effective in removing MCs in the water treatment plant. Over two years, despite the high levels of cyanobacteria (up to 160 × 10(6) cells/L) and MCs (28.4 µg/L) initially reached in surface waters, the drinking water distribution was never limited.
Subject(s)
Bacterial Toxins/analysis , Cyanobacteria/isolation & purification , Drinking Water/analysis , Water Pollutants/isolation & purification , Alkaloids , Chlorine Compounds/chemistry , Cyanobacteria Toxins , Disinfection/methods , Drinking Water/microbiology , Environmental Monitoring , Eutrophication , Flocculation , Italy , Microcystins/analysis , Oxides/chemistry , Risk Assessment , Tropanes/analysis , Uracil/analogs & derivatives , Uracil/analysis , Water Purification/methods , Water Supply/analysisABSTRACT
This report presents a case study of a comprehensive sanitary survey on ca. 160 community drinking water supplies after a severe (post-Tsunami) flooding event in Sri Lanka. Sanitary inspection and microbiological and chemical water quality analyses were performed according to specifically-designed procedures established on the World Health Organization (WHO) guidelines. Significant hazards and critical points were identified in almost all the investigated water supplies. The overall results showed a significant level of microbiological and chemical risk associated with drinking water consumption within the investigated areas. The criteria and methods practised in this study are proposed as a model to assure an effective and reliable monitoring in post-emergencies involving possible deterioration of water quality and to identify health priorities related to water consumption.
Subject(s)
Sanitation , Tsunamis , Water Supply/standards , Data Collection , Safety , Sri Lanka , Water Microbiology , World Health OrganizationABSTRACT
A simple and sensitive liquid chromatographic-tandem mass spectrometric (LC/MS/MS) method has been developed and validated to confirm and quantify acrylamide monomer (AA) in drinking water using [13C3] acrylamide as internal standard (IS). After a preconcentration by solid-phase extraction with spherical activated carbon, analytes were chromatographed on IonPac ICE-AS1 column (9 x 250 mm) under isocratic conditions using acetonitrile-water-0.1 M formic acid (43 + 52 + 5, v/v/v) as the mobile phase. Analysis was achieved using a triple-quadrupole mass analyzer equipped with a turbo ion spray interface. For confirmation and quantification of the analytes, MS data acquisition was performed in the multireaction monitoring mode, selecting 2 precursor ion to product ion transitions for both AA and IS. The method was validated for linearity, sensitivity, accuracy, precision, extraction efficiency, and matrix effect. Linearity in tap water was observed over the concentration range 0.1-2.0 microg/L. Limits of detection and quantification were 0.02 and 0.1 microg/L, respectively. Interday and intraday assays were performed across 3 validation levels (0.1, 0.5, and 1.5 microg/L). Accuracy (as mean recovery) ranged from 89.3 to 96.2% with relative standard deviation <7.98%. Performance characteristics of this LC/MS/MS method make it suitable for regulatory confirmatory analysis of AA in drinking water in compliance with European Union and U.S. Environmental Protection Agency standards.
Subject(s)
Acrylamides/analysis , Acrylamides/toxicity , Water Supply/analysis , Carbon Isotopes/analysis , Chromatography, Gas/methods , Chromatography, Liquid/methods , Europe , European Union , Solvents , Spectrum Analysis/methods , United States , United States Environmental Protection Agency/standards , Water Supply/standardsABSTRACT
Contaminated water are recognized as a potential source of Cryptosporidium oocysts. In Italy studies on the environmental spread of the parasite are still scarce even if a high frequency of serological responses could suggest high rates of endemic Cryptosporidium infections. In this investigation the occurrence of the parasite in water samples from a municipal wastewater treatment plant was monitored with the aim to evaluate possible correlation between oocysts and bacterial indicators, pathogens and physico-chemical parameters using a multivariate analysis. Data collected showed high numbers of oocysts, with a high percentage of positive samples and a significant correlation with pH, redox potential and total organic carbon. No correlation was found between Cryptosporidium concentration and that of the other microrganisms. The results, through a probing statistical analysis, show that none of the selected microrganisms was a reliable predictor of the presence of the parasite.
