Determination of Surface Water Quality Status and Identifying Potential Pollution Sources of Lake Tana: Particular Emphasis on the Lake Boundary of Bahirdar City, Amhara Region, North West Ethiopia, 2013

Abstract

Background: The water quality of Lake Tana is influenced by environmental stress and anthropogenic activities. Point and non-point sources are the major factors which affect the quality of the lake.

Objectives: To determine surface water quality status of Lake Tana and to identify the potential pollution sources bound to Bahirdar City Administration, Ethiopia.

Methodology: Laboratory based cross – sectional study was conducted in order to assess the quality and to identify the potential pollution sources of the lake. Geo referenced water samples were collected at eight sampling stations. Repeated water samples were collected and analyzed.

Result: The common water quality monitoring parameter were analysed, very low dissolved oxygen (3.5 mg/l) and high biochemical oxygen demand (23.7mg/l) were investigated in severely stressed sites. In addition to these, enriched nutrient like phosphorus and nitrate were identified to a level that influences algal growth. According to microbial analysis, total coli forms >180mg/100ml and Escherichia coli type one were isolated.

Conclusions: The Canadian Water Quality Index result categorizes the lake as poor state to aquatic life, recreation and drinking.

Keywords: Water quality, Lake, surface water, Water pollution, Point source pollution, Water Quality Index