CARACTÉRISATION DES EAUX D'UNE LAGUNE ESTUARIENNE DE LA CÔTE D’IVOIRE : LA LAGUNE ABY

Abstract

This study is conducted to determine the physical and chemical characteristics of the surface waters of Aby lagoon. Seventy two (72) water samples were collected seasonally from June 2010 to March 2011 in six (06) stations spread throughout the Aby lagoon. Parameters such as (temperature, pH, conductivity, total dissolved solids, salinity and dissolved oxygen) were measured in situ and suspended solids, ammonia, total phosphorus, Biochemical oxygenates demand (BOD) and Chemical Oxygen Demand (COD) by conventional chemical methods. The following average concentrations were obtained: dissolved oxygen (6.17 mg/L), Suspended matters MES (10.29 mg/L), total phosphorus (0.05 mg/L), ammonia (0.04 mg/L), BOD (17.59 mg/L) and COD (39.84 mg/L). The results of this study show that the biodegradable domestic effluent threatens the water quality of the Aby lagoon. The concentrations of nutrients (total phosphorus and ammonia) are under the norm. However, the areas under the influence of continental waters showed the highest concentrations of organic pollution parameters. It will be necessary to educate the riverine population about the harmful consequences of the indiscriminate use of fertilizers and the domestic effluents must be treated before discharge it into the lagoon.