Combined effects of municipal and industrial wastes on the quality of the new northern Calabar River, Nigeria

This study was conducted to investigate the combined effects of municipal and industrial waste discharges on the quality of the new northern Calabar River in the Niger Delta province (5.317°N, 6.467°E) of Nigeria. Water samples were collected in June 2015 from five regions along the stretch of the river. The five regions comprised three observed pollution sources (abattoir, open market, and noodle factory) and two non-pollution sources at the downstream and upstream sections of the river. Using standard analytical protocols, results showed that the current pollution loads of the river varied significantly (p < 0.05) across the three pollution sources. Over 33% of studied quality indicators of the river including total hardness (1526.19±154 mg/l), biochemical oxygen demand (10.14±4 mg/l), and chemical oxygen demand (57.62±13 mg/l) over time increased beyond their permissible limits due to the disposal of municipal and industrial wastes into the river. The present quality of the river was only fair with a Water Quality Index of 64.71. This result suggests that the water quality is usually protected but occasionally impaired by the wastes discharged into the river, leading to conditions that often depart from permissible levels.