Evaluating Water Quality of the Tigris River in the Qayyarah District/ Nineveh/ Iraq Through the Concentrations of Some Heavy metals and Some Limnological Parameters

The current study aimed to evaluate the water of the Tigris River and its suitability for drinking.  The physical, chemical, and biological parameters of the Tigris River water in the Qayyarah district were studied.  The studied samples were collected for a period of six months from October 2023 to March 2024. The water was divided according to some physical, chemical, and biological factors such as tTemperature, eElectrical cConductivity (EC), tTotal dDissolved sSolids (TDS), pH, dDissolved oxygen (DO), cChemical oOxygen dDemand (COD), tTotal aAlkalinity, chloride (Cl^-), p < /ins>Phosphate (PO₄), nNitrite (NO₂), sSilica (SiO₂), hHeavy metals, and tTotal p < /ins>Plate cCount (TPC).  The results of the study showed that numerous samples conformed to Iraqi and international standards for drinking water, except for the tTotal p < /ins>Plate cCount (TPC), which was high and appeared in all samples throughout the study period between (360 and1500) cell/ ml.  The water temperature ranged between (9 & 24 ) degrees CCelsius, and the electrical conductivity ranged between (293- 395) µS/ cm, and the dDissolved oOxygen rate recorded 9.26 mg/ L.  Chemical oOxygen dDemand rate was 1.23 mg/ L.  Nitrite concentrations were low, ranging between 0.14- 0.35μg/ L. Total alkalinity ranged between 96- 128mg/ L as CaCO3, phosphate ranged between 0.002- 0.067μg/ L, silica ranged between 1.4- 2.15μg/ L, and varying values of heavy metals were recorded: 0.095- 0.887mg/ L for lead, 0.044- 0.059mg/ L for cadmium, and 0.053- 0.177mg/ L for zinc.