title: Removal of trihalomethane from chlorinated seawater using gamma radiation.
abstract: Chlorine addition as a biocide in seawater results in the formation of chlorination by-products such as trihalomethanes (THMs). Removal of THMs is of importance as they are potential mutagenic and carcinogenic agents. In this context, a study was conducted that used ionizing radiation to remove THMs from chlorinated (1, 3, and 5 mg/L) seawater by applying various dosages (0.4-5.0 kGy) of gamma radiation. Bromoform (BF) showed a faster rate of degradation as compared to other halocarbons such as bromodichloromethane (BDCM) and dibromochloromethane (DBCM). In chlorine-dosed seawater, total irradiation dose of 0.4 to 5 kGy caused percentage reduction in the range of 6.9 to 76.7%, 2.3 to 99.6%, and 45.7 to 98.3% for BDCM, DBCM, and BF, respectively. During the irradiation process, pH of the chlorinated seawater decreased with increase in the absorbed dose; however, no change in total organic carbon (TOC) was observed. The results show that gamma dose of 2.5 kGy was adequate for maximum degradation of THM; but for complete mineralization, higher dose would be required.
authors.affiliation: Water and Steam Chemistry Division, Bhabha Atomic Research Centre, Kalpakkam, 603102, Tamil Nadu, India.
authors.forename: R
authors.initials: R
authors.lastname: Rajamohan
authors.affiliation: Centre for Research, Anna University, Chennai, 600025, Tamil Nadu, India. u_natesan@yahoo.com.
authors.forename: Usha
authors.initials: U
authors.lastname: Natesan
authors.affiliation: Water and Steam Chemistry Division, Bhabha Atomic Research Centre, Kalpakkam, 603102, Tamil Nadu, India.
authors.forename: V P
authors.initials: VP
authors.lastname: Venugopalan
authors.affiliation: Water and Steam Chemistry Division, Bhabha Atomic Research Centre, Kalpakkam, 603102, Tamil Nadu, India.
authors.forename: Puspalata
authors.initials: P
authors.lastname: Rajesh
authors.affiliation: Water and Steam Chemistry Division, Bhabha Atomic Research Centre, Kalpakkam, 603102, Tamil Nadu, India.
authors.forename: S
authors.initials: S
authors.lastname: Rangarajan
mesh_terms: D002713:Chlorine; D005720:Gamma Rays; D006846:Hydrocarbons, Halogenated; D012623:Seawater / Q000737:chemistry*; D022882:Trihalomethanes / Q000737:chemistry / Q000378:metabolism*; D014874:Water Pollutants, Chemical
chemical_list: D006846:Hydrocarbons, Halogenated; D022882:Trihalomethanes; D014874:Water Pollutants, Chemical; C032707:chlorodibromomethane; D002713:Chlorine; C025191:bromodichloromethane; C015044:bromoform
keywords: Chlorination; Gamma irradiation; Seawater; Total organic carbon; Trihalomethane