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Within the study of the formation of chlorinated dioxins and dibenzofurans and their precursors the thermolysis of hexachloroethane over the aluminum melt was investigated. «De novo» synthesis of precursors of PCDD/F was studied in the model system AlCl 3 /elemental carbon. Totally chlorinated heterocyclic compounds have been detected parallel with the formation of organochlorine compounds. The possibility of inserting oxygen to aluminum organyls was presented. In order to gain more detailed knowledge of the catalytic behaviour of fly ash the chemistry of thermolysis of phenoxy- and chlorophenoxy aluminum compounds at 300 o C with the presence and absence of Al 2 O 3 was investigated. Reagent compounds and products of thermolysis were followed by mass spectrometry

Thermal decomposition of trichloroethylene was investigated by means of passing air containing trichloroethylene vapor through a quartz tube heated at 300 to 800°C in order to establish an effective decomposition method for waste trichloroethylene. Main pyrolysis products were carbon tetrachloride, tetrachloroethylene, hexachloroethane, hexachlorobutadiene, and hexachlorobenzene. More than 99% trichloroethylene was decomposed by heating over 500°C.

We describe the primary aerobic biodegradation of a B20 fuel (20% soybean fatty acid methyl esters, 80% petroleum diesel) by unacclimated inocula from a rainwater detention pond. Biodegradation was rapid and essentially complete, with an overall median 'half-life', at approximately 100 ppm B20, of 6.8 days (n=34). Using purge-and-trap and extraction methodologies, both coupled to GC/MS, and hexachloroethane and hexachlorobenzene as conserved internal markers in the B20, we followed the biodegradation of total detectable material, 76 individual analytes and eight undifferentiated groups of isomers, and calculated their half-lives under these conditions. The fatty acid methyl esters, n-alkanes and iso-alkanes, and simple and alkylated aromatic compounds were the most readily degraded compounds, followed by the naphthenes. The last (identified) compounds to be degraded were ethylalkanes, trisubstituted cyclohexanes and decalins, but even these disappeared with an apparent 'half-life' of

Artemisia lerchiana is a wormwood species of the Central Asian steppe regions, where it completely cover whole areas. For the first time it was possible to show through field experiments that C1/C2 halocarbons (VCHCs), such as chloroform (CHL), tetrachloroethene (PER) and hexachloroethane (HEX), can be taken up by test plants of the species A. lerchiana via the soil/root pathway and metabolised inter alia into trichloroacetic acid (TCA) under semi-aride conditions. At the same time, chlorophyll a fluorescence measurements carried out on the test plants revealed a phytotoxic influence on plant vitality (max. decline in vitality of 52% with application of CHL) and less efficient energy flows in the photosynthesis mechanism of the A. lerchiana test plants. The authors examine possible links between the simultaneous appearance of VCHCs and additional drought stress in the acceleration of desertification processes.

The EPA Mobile Incinerator has demonstrated its ability to successfully destroy dioxin. A trial burn conducted in 1987 demonstrated the incinerator's ability to destroy a wide variety of compounds. The destruction and removal efficiency (DRE) of carbon tetrachloride, hexachloroethane, and trichlorobenzene was greater than the required 99.99%, and the DRE for PCBs was greater than the required 99.9999%. The field demonstration of the mobile incinerator that began in 1985 is scheduled for completion in 1989 after incinerating 4,530,000 kg of waste material.

The U.S. Air Force is currently evaluating a mobile, full-scale incinerator for restoration of sites contaminated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The field trial has been divided into three phases: (1) verification trial burn using TCDD contaminated soils, (2) TCDD surrogate trial burn employing clean soil spiked with the surrogates hexachloroethane (HCE) and 1,2,4-trichlorobenzene (TCB), and (3) a long-term operational test of 150 days to evaluate the reliability, maintainability and cost associated with the rotary-kiln incinerator. The subject of this paper, the surrogate trial burn, was conducted in May, 1987 to demonstrate the ability of the incinerator to destroy at least 99.9999 percent of the two TCDD surrogates. The surrogate trial burn shows that the ENSCO rotary-kiln incinerator is capable of removing TCDD and other related chemicals from a soil matrix in a manner protective of the environment. Future tests of this unit will include the thermal processing of 11,000 cubic yards of TCDD contaminated soil during a heavily documented field trial.