Nutrient Loading Dynamics and Water Quality Assessment in the Northern Al-Kabir River Estuary Using an Integrated PCA–Redfield–CCME WQI Approach

Abstract

This study was conducted during the period 2023–2024 at the estuary of the Al-Kabeer
 Al-Shamali River, located in the Al-Raml Al-Janoubi area, Latakia Governorate, Syria, to investigate the dynamics of nutrient transport and assess their impact on water quality. Principal Component Analysis (PCA), the Redfield ratio (N:P) , monthly nutrient load calculations, and the Canadian Council of Ministers of the Environment Water Quality Index (CCME WQI) were applied. One water sample was collected monthly over one year. River discharge and several physicochemical parameters were measured, including pH, temperature, total hardness, electrical conductivity, turbidity, phosphate, nitrate, nitrite, ammonium, chloride, and sulfate The PCA results indicated that the nutrient group( NO₃⁻، NO₂⁻، PO₄-³)  , represented one of the major factors controlling variations in water quality. Monthly nutrient load analysis showed that periods of high river discharge during winter transported greater quantities of nutrients to the coastal environment. The Redfield ratio was considerably higher than the reference ratio (16:1), indicating phosphorus limitation and the sensitivity of the system to any additional phosphorus input. The CCME WQI value was 46.03, classifying the water quality as "Marginal", reflecting water quality deterioration due to elevated nutrient and ionic concentrations and the exceedance of most measured parameters beyond the permissible limits specified by the Syrian Standard Specifications (2007).