Health hazards and pollution from open drains in a Nigerian city

A study has been made of the chemical and microbiological quality of wastewaters flowing in open drains in high-, medium-, and low-density areas in the city of Ibadan in Nigeria. The wastewater from the high-density area showed high values for turbidity, suspended solids, oxidizable organic matter, BOD, ammoniacal nitrogen and fecal coliforms. In the medium-density area the values were lower and in the low-density area the values were lowest. The samples also showed considerable numbers of total coliforms, Staphylococcus aureus, Trichomonas sp, Balantidium coli, Giardia intestinalis, Entamoeba histolytica, Entamoeba coli, Ascaris sp, Ancylostoma sp, Schistosoma hematobium, and Strongyloides sp. Scattered all over the city, the open drains contributed to parasitic infections in the populations and pollution of streams and groundwater. The information presented in this report should be of considerable interest to many developing countries where open drains are common. The solution lies in the elimination of open drains by introducing underground water carriage systems or through organized open drains with covers.