Photochemischer Abbau von 2,3,7,8-Tetrachlordibenzo-p-dioxin (TCDD) unter simulierten Umweltbedingungen

Airborne dioxins and dibenzofurans: sources and fates

“…First, we find the same PCDD and PCDF congener profiles in sediments and in air particulates; this indicates no degradation has taken place in the water column. Second, photolysis of TCDD on silica gel has been shown to be rapid (22). Third, Townsend (23) found a decrease in the ratio of H7CDD to OCDD on particulates collected at increasing distances from a combustion facility.…”

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

“…Figure 2 indicates that the photodecomposition of CAP 21 in the adsorbed phase is faster when radiations of A>230nm (quartz filter) are used compared to the photolysis with radiations of A>290nm (borosilicate filter). According to these authors, 31 in sunlight, photodecomposition of T 4 CDD 21 present in soils is likely to occur even in the absence of hydrogen donors (organic solvents). Likewise, Crosby and Wong 32 have exposed herbicide formulations (Agent Orange) containing known amounts of 2,3,7,8-T 4 CDD (21) dispersed on surfaces of soils or leaves of a rubber plant (Hevea brasiliensis) to sunlight (Figure 3).…”

“…Gebefugi and his associates 31 have investigated the photodegradation of 2,3,7,8-T 4 CDD (21) adsorbed on silica gel 60 (0.063-0.2 mm) ( Figure 2). The dioxin 21 (240 ng) was coated on 500 g silica gel; whereby a monolayer was obtained.…”