Monitoring of organic load in a tropical urban river basin (Cameroon) by means of BOD and oxydability measurements

The tenor in organic matter has been assessed in an urban aquatic ecosystem the Mfoundi River Basin of Cameroon.The double technique of the Biochemical Oxygen Demand (BOD5) and the Oxydability test have been employed in this assessment. The results obtained indicate a high content of organic matter in the watershed with the highest values of BOD 297.5 mg O2 dm-3 and Oxydability 50.255 mg O2 dm-3 observed at the Akeu stream. The spearman correlation coefficient between BOD5 and Oxydability for the seasonal distribution is 0.22 which is positive but not statistically significant due to a high variability of biodegradable and non-biodegradable organic matter present in the river basin. The same value calculated between these organic tests with respect to the sampling sites is negative (-0.15) due probably to their abiotic and biotic heterogeneity. The results reveal a high tenor in organic matter in the hydro-system during the dry season, with a relative reduction during the rainy season, a situation that exposes the population of Yaoundé and its environs to acute pollution which can lead to numerous water related health hazards.