Evaluation of the concentration of trihalomethanes compounds in drinking water distributed in David City, Panamá, and its risks to human health

Abstract

The disinfection of water for human consumption gives rise to the formation of by-products highly harmful to health, called Trihalomethanes (THMs). The objective of this study is to determine the presence and concentration of trihalomethanes compounds in the drinking water supplied by the Algarrobos water treatment plant, in the City of David, Province of Chiriquí, Panama, and to evaluate whether these concentrations represent a risk to the human health of consumers of this vital liquid. The determination of trihalomethanes in the water samples was carried out with a gas chromatograph equipped with a DB-624 capillary column (30m x 0.32mm x 1.8µm) coupled to a microelectron capture detector (µ-ECD) high temperature, Ni53. Water samples were collected at 9 strategic points of the distribution network of the Los Algarrobos plant on July 18, 2017, and analyzed in duplicate using the solid phase microextraction technique (HS-SPME) using silica fiber from 1cm long covered with Polydimenthylsiloxane/divinylbenzene (PDMS/DVB) 65μm thick. The concentration range of total trihalomethanes was between 0.01 and 4.15µg/L, with chloroform being the predominant compound with 52.1%, bromodichloromethane with 18.6%, and chlorodibromomethane with 16.4%. and finally, bromoform with 12.9%. The average concentration of trihalomethanes in surface waters was 2.35µg/L. The values of trihalomethanes found are lower than the maximum allowable concentration (80µg/L) established by the EPA for these compounds, so they do not represent a risk with adverse health effects.