Document Type : ORIGINAL RESEARCH ARTICLE

Authors

1 Department of Environmental Health Engineering, Tabriz University of Medical Sciences, Tabriz, Iran

2 Center for Solid waste Research, Institute for Environmental Research, Tehran University of Medical Sciences, Tehran, Iran

3 Health and Environment Research Center, Institute for Health Management, Tabriz University of Medical Sciences, Tabriz, Iran

4 East Azerbaijan Regional Water Authority, Tabriz, Iran

5 Agricultural Biotechnology Research Institute of Iran, Tabriz, Iran

6 Medical Geography, Ministry of Health, Tehran, Iran

Abstract

Eutrophication is considered as a serious problem in water reservoirs. Awareness about the eutrophic status of each reservoir could help in providing a better understanding of the problem in a global scale. The present study was conducted to assess temporal and spatial eutrophication index in a water reservoir (Sahand dam) in the northwest of Iran. Physico-chemical parametres that are effective on eutrphic condition occurrence  were analyzed, and trophic state index was calculated on a scale of 0-100 by measuring Secchi disk depth, chlorophyll a, total phosphorus, total nitrogen, total suspended solids, and phosphorus P/N ratio. Moreover, using the overlapping, the reservoir was mapped based on the mentioned index. Seasonal variation of dissolved solids in the reservoir was recorded due to precipitation and subsequent dilution and evaporation. Thermal stratification was observed during the summer months. The total trophic state index value was calculated as 55.5- 58.07, with minimum value belonging to P/N and maximum value belonging to suspended solids for individual parameters. There were some spatial and temporal differences for trophic state index in the reservoir. It was found that the whole area of the reservoir was in almost moderately upper-mesotrophic condition and in some target stations it was very close to eutrophic condition. The worst condition was observed in Qaranqu River as the main input to the reservoir. Due to the significant impact of suspended particles resulting from erosion of the surrounding lands on TSI value, there is an urgent need for mitigation measures to intercept eutrophication.

Graphical Abstract

Assessment of temporal and spatial eutrophication index in a water dam reservoir

Highlights

  • A compilation method was used to study eutrophication based on TSI calculation and GIS zoning
  • Thermal stratification was observed in summer and mixed condition was observed in March and November
  • The total TSI value was between 55.5 and 58.07, with the maximum value belonging to Qaranqu river
  • The entire reservoir was upper meso-trophic in terms of nutritional class
  • Increased TSS due to precipitation and erosion in spring had an important effect on the TSI value.

Keywords

Main Subjects

Letters to Editor

GJESM Journal welcomes letters to the editor for the post-publication discussions and corrections which allows debate post publication on its site, through the Letters to Editor. Letters pertaining to manuscript published in GJESM should be sent to the editorial office of GJESM within three months of either online publication or before printed publication, except for critiques of original research. Following points are to be considering before sending the letters (comments) to the editor.

[1] Letters that include statements of statistics, facts, research, or theories should include appropriate references, although more than three are discouraged.
[2] Letters that are personal attacks on an author rather than thoughtful criticism of the author’s ideas will not be considered for publication.
[3] Letters can be no more than 300 words in length.
[4] Letter writers should include a statement at the beginning of the letter stating that it is being submitted either for publication or not.
[5] Anonymous letters will not be considered.
[6] Letter writers must include their city and state of residence or work.
[7] Letters will be edited for clarity and length.

CAPTCHA Image