Abstract
The approximately annually produced 3,000 million tons of crude oil contain about 40 million t C6‐C8‐aromatics, and about 30 million t naphthalenes. In refineries some higher quantities are additionally produced by disproportionating, cracking or by other processes. Minor shares are isolated, and used in the chemical industry. Most of these valuable amounts are however burnt, some parts are transformed during combustion, or are lost. It is estimated that about 13 million t C6‐C8‐aromatics, and about 3 million t naphthalene and higher alkylated volatile aromatic hydrocarbons enter annually the environment, mostly from the oil industry and from automobile exhaust. About 15% is introduced into the sea. The bigger share is first introduced into the atmosphere, toluene and xylenes also in considerable amounts from solvent losses. Some naphthalene and chlorinated benzenes enter the environment as insecticides. Global cycles are discussed. It seems that C6‐C8‐aromatics evaporate or stay rather in the atmosphere, and are transformed or degraded there, whereas naphthalenes accumulate rather in the sea, particularly in fish, other aquatic animals or sediments. Of course the local concentrations may vary widely. Also, one should not forget, that it takes some weeks to mix thoroughly the atmosphere of one hemisphere, 1 to 2 years between the hemispheres, 1,000 years to mix thoroughly oceans, and even longer soils, according to their local composition.1 Air contains for instance about 0,001–0,003 mg benzene/m3 in remote rural areas. But in urban streets or in specific industrial sites the concentration may be several hundred times higher. Transport behaviour of volatile aromatic hydrocarbons, their degradation and overall environmental fate are also discussed, to make clear, where emphasis for further studies is relevant.

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