Assessment of Birjand flood plain water quality by physico-chemical parameters analysis in Iran

We assessed the physico-chemical status of twelve surface water samples from the Birjand flood plain (east of Iran) during fall 2010. The sampling points were selected on the basis of their importance. The physico-chemical parameters such as pH, temperature (T), electrical conductivity (EC), total dissolved solids (TDS), total hardness (TH), calcium (Ca2+), magnesium (Mg2+ ), sodium (Na+), potassium (K+), chloride (Cl-), sulphtate (SO42-), bicarbonate (HCO3–), carbonate (CO32–), nitrite (NO2–), nitrate (NO3–), dissolved oxygen (DO), biochemical oxygen demand (BOD5), and chemical oxygen demand (COD) of surface water were determined. The results showed that there were a statistical significant positive correlation between the pH and DO. pH and temperature indicated negative association with most of the parameters. Furthermore, EC showed highly significant positive association with TDS, TH, Ca2+, Na+, and Cl-. Results showed that the quality of surface water was not suitable for drinking, with references to the concentrations of EC, TDS, TH, Na+, HCO3-, and BOD5 which were more than the prescribed limits, in most sites.