A Macro and Micro Study of the Environmental Impacts of Sewage Discharges : THE MACRO AND MICRO STUDY OF THE IMPACT OF SEWAGE DISCHARGES TO AQUATIC ENVIRONMENTS CLOSE TO HUMAN HABITATS

Sanitation is the greatest medical global advance since 1840 according to a recent survey conducted by the British Medical Journal. Its impact far exceeds the phenomenal discoveries of antibiotics and any modern surgical advances. Beaches in the Isle of Man and Cambois in the Northeast of England were designated as sites for the study of the impacts of sewage discharges from marine outfalls on the aesthetics and bacteriological quality of beaches/bathing waters. Aesthetic studies showed beaches littered with sewage derived debris, (SDD) considerably worse after heavy rainfall. The presence of SDD such as faeces, sanitary wear, floating debris, unsightly surface slicks, and discoloration are the most important features associated in the public mind with sewage pollution. Liquid and floatable solid wastes discharged at any level under seawater rise to the surface and strong winds override tidal currents in determining their direction/dispersion. Fresh sewage discharged from marine outfalls returned to pollute the study beaches/bathing waters within three hours of discharge. Culture-based enumeration methods estimated total populations of bacteria in bathing/offshore seawater samples. Total coliform and E.coli densities in bathing water samples exceeded the UK EC mandatory standards. Quantitative Rhodamine-wt tracer Dye concentrations could not be used to accurately model the dispersion of sewage bacteria in the marine environment.