On the Distribution of Mineral Nitrogen Forms in Polluted River Reaches in Urban Territories

Abstract

Statistical analysis of data collected in field observations of river water quality in an urban area was used to recognize characteristic features of the distribution and relationships between concentrations of mineral nitrogen forms in polluted surface waters. The distribution of the relative mole fraction of nitrites in water is always unimodal, while other N forms can have bimodal distributions. Significant correlations between the concentrations of nitrites, nitrates, ammonium, and the total mineral nitrogen were found to exist in waters heavily polluted with nitrogen compounds. These correlations are interpreted based on a simple kinetic model of nitrification and denitrification processes. Denitrification processes are shown to play an important role in nitrogen balance in polluted waters. An estimate is proposed for the admissible level of river water pollution by nitrogencontaining compounds.

The Acceptor Side of Photosystem II Is the Initial Target of Nitrite Stress in Synechocystis sp. Strain PCC 6803

“…However, there have been reports of high nitrite concentrations occurring in both terrestrial and aquatic ecosystems (5)(6)(7). Imbalances in nitrification and denitrification, resulting from the inhibition or disruption of steps in these processes, can cause nitrite accumulation in aquatic systems (3,8). Anthropogenic inputs of nitrite to the ecosystem arise from agricultural effluents, industrial discharges, and the release of wastes and sewage (9,10).…”