Assessment of Physicochemical Properties and Water Quality of the Lom River (NW Bulgaria)

Abstract

This study presents results of physicochemical monitoring and water quality assessment of a small lowland river, located in an agricultural region. The analysis is conducted in compliance with the Bulgarian river water quality standard. It is based on output data from three water sampling points, which include information about 14 parameters, measured from 2012 until 2016. An assessment of the pollution status was carried using CCME Water Quality Index and Oregon Water Quality Index (OWQI). The overall water quality index was calculated as 58.78 which fell under the “marginal” water class (index value ranges from 0 to 100). Results showed worsening of the physicochemical properties as moving downstream the river sections. Downstream is observed a slight deterioration in the values and concentrations of some physicochemical parameters (BOD5, N-NO3, Total Nitrogen, and Total Phosphorous) due to the effects of urban sewerage, urban wastewater and agricultural wastes. Based on the used indexes, the water quality is categorized as “Good” to “Poor”. CCME WQI indicates the water in the upstream can maintain healthy river ecosystems but in the downstream the quality is frequently endangered. OWQI index showed the water in the upstream river section is suitable for daily living activities, but in the downstream quality is in the “Poor” category and it needs “Special treatment”.