Nitrogenous wastes: often overlooked pollutants in aquatic\ud environments

[Extract] Nitrogenous wastes, including ammonia, nitrite and nitrate, in aquatic systemsoriginate [that is, systems originate] from the runoff of various anthropogenic sources, the decomposition of organic matter and leaching of geological deposits, as well as ammonia being excreted by aquatic animals as a by-product of protein catabolism. To date, most research on these pollutants have been performed from an aquaculture perspective since nitrogenous wastes are a ubiquitous concern under farming conditions. However, they are often overlooked as potential causes for altered distribution and abundance of aquatic animals in the wild, likely due to perceived relatively low levels of nitrogenous wastes in most aquatic ecosystems and the relatively high tolerance of aquatic animals to these pollutants. Nevertheless, recent research is suggesting that these can be inaccurate or biased