Levels of Trihalomethanes in Stored Water from High and Fundamental Schools:Comparison between Two Temporal Data Sets

Epidemiological studies have been investigating the relationship between chlorination byproducts exposure and cancer. Studies showed the incidence of colon, rectum and bladder cancer in laboratory animals when halogenated byproducts were administered to them, such as trihalomethanes. Based on this fact, in this work, two data sets of water quality parameters were analyzed with focus on total trihalomethanes (THMt). These two data sets are from two different time periods (one in 2014 and other in 2017). All the samples were collected in the same months, in both data sets. The samples were taken from its same corresponding sampling points in both periods of time. Trihalomethanes (THMs) are undesired byproducts of chlorination and its formation occurs when the chlorine used in water treatment reacts with natural organic matter, which is present in natural waters, during the disinfection process. The aim of this research was to investigate the THMs levels in storage water from the chlorination performed by the Water Treatment Station (WTS) of the Maringá-Parana-Brazil;also, to compare the results obtained with the maximum allowable values (MAVs) established by the Consolidation Resolution n.05/2017, current law of water quality in Brazil. Water samples were collected in eight high and fundamental schools of Maringá-Paraná-Brazil and analyzed through the gas chromatography method by the use of mass spectrometry detector with purge-and-trap concentrator (GC-MS) for THM. Furthermore, parameters such as pH and residual chlorine were analyzed following the methodology proposed by the Standard Methods for the Examination of Water and Wastewater. The study results to THMt show that the maximum value of 21.5 μg/L obtained is within the MAV of 100 μg/L. Chloroform was the compound with higher concentrations in all samples in THMt analysis. Results of residual chlorine and pH also are within the MAVs. Studies like this are important to continuous monitoring of the water quality distributed to population.

Analysis of Haloacetic Acids(HAA5)in Waters of Public Schools and Residencies in Maringa-Brazil

For water to become suitable for human consumption in most water treatment plants this occurs by making use of the chlorination process where the organic matter is destroyed by the action of chlorine. Chlorine is a disinfectant that at low concentrations meets requirements such as not being toxic to humans and inactivating microorganisms. The reaction of chlorine with organic compounds results in chlorination byproducts, many potentially harmful to human health, such as trihalomethanes, haloacetic acids, among others. The present work aimed to collect and analyze samples of treated water from reservoirs from public schools in the city of Maringá, Brazil. Analyses of haloacetic acids (HAA5: monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, bromoacetic acid and dibromoacetic acid), natural organic compounds and free residual chlorine were performed (the latter analysis, in loco). The water collection points were chosen in order to maximize the concentration of haloacetic acids that characterize network distant points from treatment station and also samples near the water treatment plant. With the results, the formation of haloacetic acids between the entrance water of the school and the water of the reservoir of the collection points were compared, where higher values were obtained in the reservoirs. Furthermore, the haloacetic acid levels of water supplied to the population close to the treatment station and distant points of the treatment station were compared, resulting in larger values at the distant points. The value of 0.170 mg/L in haloacetic acid (the maximum value allowed by the legislation is 0.080 mg/L) was obtained at a point distant in the network from the treatment plant. The Consolidation Ordinance n.5/2017, current legislation for treated water in Brazil, was used in relation to the maximum allowable values for free residual chlorine and haloacetic acids.