srjalsSRJALSSRJALS2788-9386https://doi.org/10.47310/srjals.2024.v04i01.002Study the Monthly Changes in the Chemical Properties of Tigris River and the Effect on Water Quality in Some Areas of Wasit ProvinceMahdi WasmeySeheib AlaidiDepartment of Soil and Water Recourses, College of Agriculture, Wasit University, IraqTo study the monthly changes in some chemical properties of Tigris river water and the effect on water quality in some areas of Wasit Province, the study was applied for the period January 2023 to November 2023. Five sites between sites were 10 km and a total distance was 50 km. Samples were collected on (January, March, May, July, September, November). The study of numerical measurements of the chemical properties of water including (pH, electrical conductivity Ec, total dissolved solids, TDS, total suspended solids TSS, dissolved oxygen DO, biological requirement for oxygen BOD, chlorides CL, total hardness TH. The results showed that the highest value of pH recorded during the cold months (January) reached 8.67, while the lowest values during the hot months (July) reached 7.48, with an average of 8.03. The highest value of electrical conductivity was recorded during the hot months (July) and it reached 1.22 des m⁻1, while the lowest value was recorded at the cold months (November) which reached 0.56 des m⁻1 and the total average was 0.83 des.m-1. The results showed that the total dissolved solids TDS was the lowest value during (November) and reached 355.60 mg L⁻1, while the highest value was during the July (769.40 mg L⁻1) and the total average was 529.93 mg L⁻1. The study explained that the highest value of TSS total solid salts was achieved (77.20 mg L⁻1) and the lowest value was (44.40 mg L⁻1) and the total average was 63.07 mg L⁻1. The results showed that the value of CL chlorides increased in the cold months, compared to the hot months, they were 147.59 and 94.96 mg L⁻1, respectively. The results were record of the lowest value of dissolved oxygen in the city of July was 5.38 mg L⁻1, while the highest value was recorded in November, which was 11.88 mg L⁻1. However, the value of BOD did not reach the highest value during the hot month (July) when it reached 4.31 mg L⁻1, compared to the month of January, which reached the lowest value, which was 0.63 mg L⁻1.