EFFECT OF NITRIFICATION IN ORTA LAKE

摘要: Summary Lake Orta (Northern Italy) is subjected from 1927 to discharges of industrial wastewaters rich in ammonia, copper and other metals, mainly a rayon factory. From previous investigations it known that two years after the start ammonia pelagic benthic biocoenoses were completely destroyed, but some time lake was recolonized by few phytoplanktonic zooplanktonic species. The most interesting features are connected nitrification processes. waters have nowadays mean inorganic nitrogen content 11 mg N 1−1. hypolimnion all through year show pH values near 4; epilimnion low during winter followed increasing up 9 spring autumn. ionic composition gradually changed very soft bicarbonate unique sulphate-nitrate-ammonia type whose fluctuations governed excess one oxidation forms. hypolimnic capacity more or less stable ten largely exceeded inputs. processes slow due temperatures. presence denitrification indicated mass balances compounds.