Abstract:

Four major anions (nitrate, phosphate, sulfate and chloride)  are measured in Tigris river at Mosul in six locations since Sept.2005 to June 2006.  The same 4 anions are measured previously by researches or thesis, so their results are added to the former one for comparison. The variation of flow is also reported for the whole period in order to study the concentration-flow relationship. The nitrate and phosphate concentrations are increasing with the river flow increase and decreasing with its decrease for most periods, (reaching up to1.05mg/l at June for nitrate and 0.482mg/l at April for phosphate) .The lowest concentrations are observed (as low as 0.285 mg/l at Dec. for nitrate and 0.07mg/l at Jan for phosphate). Sulfate and chloride concentration are varying oppositely to the river flow for most periods, both showing their peaks at Jan. and their lowest at June (reaching up to 170 mg/l for sulfate, and 33.4 mg/l for chloride) while the minimum values are 68mg/l for sulfate, and 15.6 mg/l for chloride. The data of the previous years are not complete and data for only 8 years are available. It indicates that the anions concentrations variation corresponding to the river flow is similar to that of  the studied years. However the data with equal flow rate only are used for comparison purposes to achieve correct results. All of the studied anions are increasing since 1982-2006 in different percentages except the phosphate. The 4 major anions are lower than the standards and MCL for the recent and previous studies.

Keywords: