How do effluents affect rivers, streams, lakes and oceans?
Organic loading of wastewaters may cause oxygen depletion in a water system. Lack of oxygen or ‘oxygen debt’ can drive fish away from parts of the water system. Prolonged exposure to low dissolved oxygen levels also increases the susceptibility of aquatic organisms to other environmental stresses and can kill some of the biota – animal and plant life – in a water system. Lack of oxygen will also result in the breakdown of sulphur compounds and cause the water to have an unpleasant odor, affecting its aesthetic value and preventing recreational use. Nutrients such as phosphorous and nitrogen cause eutrophication – the excessive growth of algae and water plants – in a water system. The effects of a heavy loading of suspended solids include milkiness, silting up and shallowing of waterways. However, the loading of suspended solids is nowadays so low that these effects are practically nonexistent due in a large part to governmental regulations. AOX emissions from pulp mills may adversely a
