[Evaluation of pollutants drift by river flow from non-point sources]
2005
Kolmakova, E.G.(Belarus State Pedagogical Univ., Minsk (Belarus))
The evaluation has been made for the case study of Neman drainage basin, where water and chemical flow is formed without participation of transit water. The dynamics of chlorides, sulphates, nitrites, phosphates, oil products flow during 1965-2001 has been considered. The change of the amount of diffuse input pollutants downstream the river Neman has been analyzed as well. The evaluation of pollutants input from non-point sources is carried out using the method which is based on the equation of the material mass balance in the watercourse. In accordance with the method, pollutants emission from diffuse sources is calculated as the difference between overall chemical flow and natural flow plus pollutants flow from point sources. The data of natural background period was used to calculate flow from natural sources. Urban areas are considered to be the main point sources of pollution. It has been determined that in the conditions of human impact on the Neman catchment the diffuse emission of the main pollutants (except phosphates) will increase. At present, according to the data of lower stream of the Neman river, more than 2/3 anthropogenic ion flow (including 3/4 chlorides, 4/5 sulphates), l/4 phosphates, about 3/4 nitrites, 2/3 oil products come into the river water just from non-point sources. The diffuse input part in overall pollutants flow can increase in the upstream of main rivers and small watercourses, where there are no large industrial centers
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