• Environmental Analysis Health and Toxicology
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• v.12 no.3_4
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• pp.1-13
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• 1997

First- and second-order kinetic oxidation rates of trichlorobenzenes (TCBs) were obtained and compared by a chemical activation system (CAS) which mimics mixed functional oxidase activity. The system consists of EDTA, ferrous sulfate, ascorbic acid, and $H_2O_2$ in potassium phosphdte buffer (monobasic at pH 7.4). The rate of transformation in CAS was enhanced in the presence and absence of catalase in the sequence 1, 2, 3-TCB < 1, 2, 4-TCB < 1, 3, 5-TCB. In general, the rates of degradation were greater in the test media with catalase. The effect of photolysis on the degradation of the TCBs with the CAS were examined. Sensitized photolysis with nitrite, Fenton's reagent, TiO$_2$ and triethylamine (TEA) studied in concert with the CAS demonstrated significant enhancement of the degradation rate of TCBs. Disappearance rates of TCBs in CAS with prior photolysis or prior photosensitization were at least 10-fold higher than the sum of the rate for each single experiment. This study proves that the combination of the CAS and photolysis can be used as a suitable technique for enhancing degradation of TCBs in aqueous systems.

• Environmental Analysis Health and Toxicology
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• v.10 no.3_4
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• pp.21-28
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• 1995

The photodegradation of TCBs in humic acid solutions at pH 7 was evaluated under laboratory sunlight simulated irradiation for 8 and 42 days. The irradiation to TCBs in solution in the presence of humic acid produced trichlorophenols, dichlorophenols in addition to the minor photodegraded products such as dichlorobutadiene, dichlorobenzaldehyde and pentachlorobiphenyls. The formation of photodegradation products indicate that the excited singlet oxygen and solvated electrons play a major contributors to the photodegradation process.

• Environmental Analysis Health and Toxicology
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• v.11 no.3_4
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• pp.33-44
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• 1996

Photolysis of TCBs in aqueous solutions of sodium nitrite and triethylamine (TEA) at neutral pH has been investigated. TCBs yielded trichloronitrobenzenes(TCNBs) as primary photoproducts, and their corresponding trichlorophenols (TCPs) via two types of reaction, one, nitration, and the other, by direct hydroxylation with OH radical. Isomerized products and TCBs were also identified. Photosensitization with TEA resulted in the formation of small yields of dichlorobenzenes(DCBs) by reductive dechlorination of TCBs.

• Fisheries and Aquatic Sciences
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• v.4 no.2
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• pp.58-64
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• 2001

Eight chlorobenzenes (out of a total of 12 in the congener series) were measured in the sediments from 21 stations in the southeastern coastal areas of Korea. The levels of total chlorobenzene isomers varied between 2.08 and 12.45 ng/g dry weight. The highest contents of total chlorobenzenes (CBs) were found in the sediments from Pohang coast. Trichloro­benzenes (the sum of 1,3,5-, 1,2,4- and 1,2,3-trichlorobenzene) were dominant classes among four congeners, whereas tetrachlorobenzenes (the sum of 1,2,3,5-, 1,2,4,5- and 1,2,3,4-tetra­chlorobenzene) and pentachlorobenzene were low levels. The contributions of total CBs showed similar patterns for all stations with positive significant correlation within CBs species. It means that CBs contamination in the southeastern coasts of Korea came from the similar source.