الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Clean water is essential for good public health. Humans cannot survive without water; our bodies are made up of 67 percent water. Thus water must be purified for domestic public use. Chlorination is the most efficient method of disinfecting tap water, and it has resulted in a decrease in death and morbidity from many recognized waterborne illnesses.Chlorination is a useful remedy in the event of a water disaster since it can quickly remove an excess of germs. An emergency water situation might be anything from a membrane failure to a mix of filtered and untreated water.The four major THM chemicals as byproducts of water disinfection with chlorine are chloroform (CF), bromodichloromethane (BDCM), dibromochloromethane (DBCM), and bromoform (BF). As Class B carcinogens, these chemicals have been linked to liver and kidney abnormalities, central rjervous system issues, and an elevated risk of carcinogenicity and mutagenicity. Many cancer risk evaluations have been done on DBPs, however the majority of them expressed the risk as an increased cancer incidence with time. Human commonly exposes by oral consumption, inhalation through breathing, and dermal contact through skin during everyday indoor activities including washing, bathing, and cooking. Therefore, the purpose of this study is to assess the exposure and determine the current level of TF1M in drinking tap water of different Alexandria districts and to estimate the THM exposure, lifetime CR caused by different routes of entry to human due to the use of tap water in different Alexandria districts.The THMs species are dibromochloromethane, bromoform, chloroform, and bromodichloromethane.
Water samples were collected from seven water treatment plants and its distribution systems, Water samples locations were Abu Qir, SidiBeshr, Kafr Abdu, Roshdy, Camp-shizar, Bahary and Albitash. Samples were collected from residential buildings with a total of 7 samples during the period from August to October, 2020. The mean ambient temperature during these 3 months ranged from33°C to25°C. To examine seasonal variations, samples were collected another time during the period from January to March 2021. The mean ambient temperature during these 3 months ranged from 10°Cto 18°C. Samples were made by mixing 10 ml of water with 2 ml of pentane for 2 minutes in a 25 ml separating funnel. The upper phase was collected into 2 ml vials with screw covers and PTFE (Teflon septum) septa after 3 minutes of phase separation.A gas chromatograph with a mass detector (GC-ECD, Varian, and Model CP-3800) was used to measure THM levels. A capillary column DB-5 (J&W Scientific Inc/Agilent Technologies, 30 m0.25 mm 0.25 m) was used for chromatographic separation.The temperature schedule for the GC oven was as follows: 40°C for 2 minutes, then 10°C each minute until 150°C. Each experiment utilised a carrier gas (N2) at a flow rate of 0.8 ml min-1 and a split ratio of 1:10. In the capillary column, 2 1 of each sample was injected.Samples wereanalyzed in Alexandria Water Company at Alnozha airport, at Almahmoudiacanal Street.
In this study, two approved risk assessment models were adopted:-the World Health Organization (WHO) index for additive toxicity and the USEPA-approved risk assessment model.