Risk Assessment of Municipal Tap Water Supply for Trihalomethanes, the Chlorination Byproducts: Comparison of Different Boiling Methods

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Pinyapat kongngen
Kannikar Chatsantiprapa

Abstract

Introduction: This study was aimed at monitoring and assessing human health risk of
trihalomethanes (THMs) in drinking water. Municipal tap water samples were collected in Ban Samran
district, Khon Kaen Province, 2 times in November 2014. Methods: The water samples were analyzed
for baseline THMs and then heated in an open and a closed boiler simultaneously until boiled for 5
min, and re-heated again at 10 and 24 hours. At each boiling interval, water samples were analyzed
for THMs by Purge and Trap method with a gas chromatography- electron capture detector. The
water samples were also tested for cytotoxicity using MTT assay with Chang liver cells. Health risk of
THMs via ingestion model was also estimated. Results: The occurrence of THMs levels prior to
boiling was chloroform (CF)> bromodichlomethane (BDCM)> chlorodibromomethane (CDBM)> bromoform
(BF). The rank of lifetime additional cancer risk was BDCM>CF>CDBM>BF. With
increasing boiling time the concentration of THMs were reduced effectively. The test of cell toxicity via
MTT assay revealed that boiling of the water samples did not affect the Chang liver cell viability.
Conclusion: Since the total lifetime additional cancer risk from all THMs in water was marginally
acceptable and BDCM presented the highest cancer risk of all THMs studied, compounds providing
bromide ions should be avoided in use to reduce the cancer risk for water environment.

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References

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