A simple indicator showing ...
Published by Bruno Peeters, managing director at Model Engineering
A simple indicator showing the oxygen balance (demand supply) of a river would be dissolved oxygen (DO) at the water temperature (T). This can be measured quickly with a portable DO & T meter. Other objective indicators to characterize the oxygen demand (from organic and nitrogenous pollution) are total organic carbon (TOC) and total Kjeldahl nitrogen (TKN). However these require sampling and lab analysis by qualified staff. A less objective but simple indicator could be biochemical oxygen demand (BOD) but this takes several days (standard: 5 days at 20 °C) and the results can vary a lot depending on the skills of the analysts. Additional indicators would be total heavy metals (THMe) and total suspended solids (TSS). However TSS will largely vary with weather conditions upstream (heavy rainfalls) and with water flow velocities.