The use of diatom indices for the assessment of Shatt al-Arab River water quality

الملخص EN

Indices are the result of attempts to describe physico-chemical changes in water quality (pH, salinity, ammonium, nitrate, phosphate, organic materials,...etc.), there are various indices that used diatoms as bioindicators such as diatomic index, diversity index, diatom assemblage index, generic diatom index, and trophic diatom index.

In the present study, samples of water and Planktonic diatoms were collected together in two seasons (Winter 2009 / Summer 2010) from four station (Sindibad, Ashar, Abu Al-Khaseeb and Fao) along Shatt AL-Arab river, a total of 53 species belonging to 26 genera were registered, and the statistical analysis stated that salinity, nitrate, and N:P ratio have an important role in the determination of diatom communities in which there is a negative significant correlation between salinity and the percentage of eutrophic species, and a positive significant correlation between nitrate and the percentage of eutrophic species, also there is a positive strong significant correlation between the study stations were unpolluted except at Abu Al-Khaseeb station in Summer whose water was moderately polluted, but both diatomic index and trophic diatom index values showed that all water stations were polluted, diatomic index values indicated that water stations ranged from slight to moderately polluted, and trophic diatom index values indicated that station waters were either oligo-mesotrophic or mesotrophic state, except at Abu Al-Khaseeb station in which values indicated eutrophic state at both seasons, and the statistical analysis showed significant correlation between diatomic index and both silicate, and percentage of eutrophic species, thus indicated that diatomic index is an a properite index to evaluate the degree of the present study area pollution.