Organochlorine compounds and their reactions in the atmosphere

To estimate the influence of the chlorinated hydrocarbons on the quality of the environment, primarily chemico-ecological and toxico-ecological data are required. In addition to their level of production, range of application, and distribution tendency, a knowledge of their transformation under environmental conditions is desirable. On one hand, the change of a substance under biotic and abiotic environmental conditions provides an indication of whether an enrichment of the environment with the relevant chemical may be anticipated in the long term on the other hand, these investigations allow possible persistent transformation products to be characterized. In contrast to the biological degradation pathways and transformation processes of environmental chemicals, whose course is accompanied by only very small amounts of energy, energy sources with an inexhaustible capacity and constant intensity are available for abiotic conversions. Temperature and uv radiation become the most important manifestations of the largest energy source of our environment, the sun, whose direct or indirect effect is especially important during an ecological assessment of chlorinated hydrocarbons. It is also important to know in which ecological systems these chemicals occur, because both dynamic and catalytic effects can be traced back primarily to the respective state of the molecule and the interaction with the surroundings. In this connection the task posed is an investigation of the reactions of chlorinated hydrocarbons under simulated atmospheric conditions. Such simulations are made more difficult by virtue of the complexity of these reactions. The atmosphere may be portrayed as a large chemical reactor in which complicated reactions take place under the action of the sun's uv radiation and are catalyzed by trace substances and whereby large amounts of substances are reacted. Numerous equilibria are established under the influence of chemical, photochemical, and physical factors. To study individual reaction mechanisms, it is necessary to create conditions which correspond to those in the atmosphere, or a partial simulation to enable the experimental results to be interpreted with some degree of probability.