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.
