PERSISTENT, ECOTOXIC, AND BIOACCUMULATIVE COMPOUNDS AND THEIR POSSIBLE ENVIRONMENTAL-EFFECTS

The relationship between physico-chemical properties, environmental di stribution and effects of organochlorine compounds as a major class of persistent organic pollutants (POPs) are discussed. The environmental fate of a compound includes its transport and dispersion in the envir onment as well as its accumulation and transformation in defined envir onmental compartments. Accumulation and transformation as the result o f environmental distribution may have long-term consequences; this is indicated by the ultimate accumulation and long-term bioactivity of se veral widely spread organochlorines, and is clearly evident in the dec omposition of chlorofluorocarbons in the stratosphere. Depending on th e order of trophic levels biomagnifiaction factors of 10 000 up to 100 000 are encountered for persistent semivolatile organochlorines like 4,4'-DDE, PCB congeners or some Toxaphene constituents. Mammals show i ntra-species pollutant transfer during the lactation period. While the mother animal is partly depleting its body burden the calve accumulat es in a critical period of its life via the milk a concentrated input of persistent organochlorines. A similar depletion phenomenon is also found for fish and crustacean which enrich in the eggs a substantial p art of the accumulated body burden of the female.The air skimming of s emivolatiles by plant surfaces leads to surprisingly high levels of po llutants in the upper soil layers of forests that otherwise would be c onsidered pristine in terms of human activities.