Pollution of the Chao Phraya River Estuary

Programmed sampling and testing of the Chao Phraya River estuary in Thailand, where the water temperature averages 30○C during periods of low flow, indicates a strong oxygen demand for nitrification and in turn a reservoir of oxygen from nitrates to prevent anaerobic conditions downstream. With tidal movement of 40 km (30 miles), net downstream travel at 7 km-10 km per day and 6+ days of detention in the estuary, the bacteria Nitrosomonas and Nitrobacter nitrify a continuous supply of ammonia to nitrates. This requires modifications in standard determinations of BOD as well as modifications of the parameters and equations defining DO concentrations for use on tropical estuaries.