Iranian Association of Environmental Health (IAEH)
Abstract
Tajan River is among significant rivers of Caspian Sea water basin.
Pollution sources that threaten the quality of water in Tajan River may
be classified in to two categories namely point and non-point sources.
Major pollutants of latter category are Mazandaran wood and pulp,
Paksar dairy products and Sari Antibiotic production factories, as well
as 600-dastgah residential area. On the other hand, non-point sources
whose waste is considered as a distributed load consist of Sari
municipal wastewater and agriculture-related pollutants that are
drained towards the river. In order to model the quality of river flow,
Qual2E model is taken in to consideration. Considering TDS, the river
quality is completely acceptable in cold seasons. However, in spring
and summer the value of this parameter is increased and this causes
some restrictions in the use of this water for irrigation of specific
sensitive crops. Agricultural activities and consequent irrigated
waters are the major causes of higher reported TDS values in warm
seasons. Current status of DO is completely acceptable and this is
highly related to the relative high value of width on depth ratio along
the river. BOD and COD locate in a fairly poor condition. Quality
deterioration is more noticeable in cold seasons. Higher rate of
precipitation and consequent greater runoff generation towards the
river basin justify the relative increase of mentioned parameters in
fall and winter. Generally, non-point pollution sources are more
contributed in deterioration of Tajan River water quality
