Photolysis of pentachlorophenol-treated wood. Chlorinated dibenzo-p-dioxin formation

Abstract

single-time assays of trihalomethanes in drinking water. Furthermore, there is sufficient variation in even a large system so that a simple harmonic model cannot allow prediction of trihalomethane concentrations from one day to the next. If a maximum contaminant level for these compounds in drinking water is to be monitored, recognition of the 24-h variation is essential, but in addition the larger contribution of as yet undefined sources of day-to-day variability must be taken into account. The observed day-to-day variability may be of a systematic nature, i.e., possibly reflecting certain weekly cycles in water usage or in operations of the water treatment plant. Or, it may be simply a part of the broad scale irregular fluctuations known to be typical for the day-to-day behavior of river flow, ambient air and water temperatures, influencing the amount of humic material available for reaction with chlorine and the rate of trihalomethane formation. This question, although it cannot be answered with certainty given the available data, is, however, important, since it has a bearing on the potential predictability of trihalomethane concentrations in drinking water. An investigation is contemplated to address this matter. Literature Cited(1) Fed. Re gist., 43 (No. 28) (Feb 9, 1978).(2) Keith, "Identification and Analysis of Organic Pollutants in Water", Ann Arbor Science Publishers, Ann Arbor, Mich., 1976, p 105. (3) "Standard Methods for Examination of Water and Wastewater", 12th ed.,

Phototransformation of polychlorinated dibenzo-p-dioxins from photolysis of pentachlorophenol on soils surface

“…It also has been proved that the irradiation of several PCPcontaining aqueous solutions indicated the formation of higher chlorinated PCDD/Fs (Vollmuth et al, 1994). Laboratory studies have been conducted to determine the effect of sunlight on the concentrations of PCP and PCDDs in wood treated with PCP (Lamparski and Stehl, 1980). However, few studies on the phototransformation of PCDDs via photolysis of PCP on soils surface have been reported.…”

Environmental photochemistry of polychlorinated dibenzofurans (PCDFs) and dibenzo‐p‐dioxins (PCDDs): A review

“…70ppm for the two artificial sunlight exposures. 18 Moreover, in the case of Dow pentachlorophenol (16), the equilibrium concentration of H 7 CDDs were 35 and 35ppm, while those of H 6 CDDs were 10.5 and llppm for both artificial and natural sunlight, respectively. 18 It is noteworthy that methylene chloride was used as carrier solvent for Reaction 10.…”

“…18 Moreover, in the case of Dow pentachlorophenol (16), the equilibrium concentration of H 7 CDDs were 35 and 35ppm, while those of H 6 CDDs were 10.5 and llppm for both artificial and natural sunlight, respectively. 18 It is noteworthy that methylene chloride was used as carrier solvent for Reaction 10. According to Lamparski and his associates, 18 most of the hexa-and heptachloroisomers of PCDDs were generated through photodegradation of O 8 CDD (17) rather than by condensation of tetrachlorophenols and 16.…”

Photochemistry of halogenated benzene derivatives. Part VIII. Photoformation of 2-methyl-4,5,6,7-tetrachlorobenzoxazole from pentachlorophenol in water–acetonitrile

“…Several authors have reported solution phase as well as solid phase environmental photochemistry of P5CP (1) (12)(13)(14)(15)(16)(17)(18)(19)(20)(21). Recently, we (22) have reported our investigations on the environmental photochemistry of several PCPs, namely tetra-and pentachlorophenols in H20-CH3CN (2:3 v/v) at A r 290 nm concluding that the process of reductive 'For Part VII, see ref.…”