Large dams as purification systems for toxic PCDD/PCDF and dl-PCB congeners

摘要

Large dams are considered as constructions with negative effects on river ecosystems' structure and functioning. According to Miller (1995), the main negative impacts of large dams on the environment are expressed as: degradation of river continuity, which influences the hydrological regime below the dam, enormous losses of water through evaporation, destruction of forestlands and croplands caused by flood and collapse, displacement of people, loss of nutrient-rich silts in downstream croplands and estuaries, and disrupted migration and spawning of some fish.