Application of Nile Chemical Pollution Index to evaluate the quality of water for drinking and agricultural purposes on Bahr Yusuf Branch, River Nile, Egypt

Bahr Yusuf is one of the most important branches of the River Nile in Egypt, being the main source of drinking and irrigation waters for many cities. Nile Chemical Pollution Index (NCPI) was estimated to assess the quality of such waters. Water samples were collected from 6 locations along the canal in El-Minia and El-Fayoum Governorates. Seven chemical parameters were determined including dissolved oxygen (DO), biological oxygen demand (BOD), ammonia (NH₃), total dissolved solids (TDS), total suspended solids (TSS), nitrate (NO₃^-) and ortho-phosphorus (PO₄^-3). Results indicated that all the tested parameters were within the permissible limits of both the Egyptian and WHO standards for drinking water and FAO standards for irrigation water. The NCPI records ranged from 13-19 indicating clean (less than 15) to slightly polluted (16-20) waters. Classification of water based on electrical conductivity illustrates that the canal water belongs to medium salinity class (C2). The total hardness concentrations were belonging to medium hard to hard category except one very hard category. The SAR estimates were excellent (S1), PI were class II category, RSC were safe/good to marginal/doubtful and Na% were good (20 – 40) to permissible (40 - 60), PS were classified as “excellent to good” (<5 meq/l) to “good to injurious” category (5-10 meq/l). In addition, the balance error % were less than the allowed error, KR were < 1.0. So, all the samples are acceptable, indicating their suitability for drinking and irrigation purposes.