Origin,causes and effects of increased nitrite concentrations in aquatic environments

Literature frequently mentions increasednitrite concentrations along with itsinhibitory effect towards bacteria and aquaticlife. Nitrite accumulation has been studied fordecades, and although numerous causal factorshave already been commented on in literature,the mechanism of nitrite accumulation is notalways clear. From the broad range ofparameters and environmental factors reviewedin this paper, it is obvious that the causesand consequences of nitrite accumulation arenot yet completely understood. Among others,pH, dissolved oxygen, volatile fatty acids,phosphate and reactor operation have been foundto play a role in nitrite accumulation, whichresults from differential inhibition ordisruption of the linkage of the differentsteps in both nitrification anddenitrification. In the case of nitrification, thisdifferential inhibition could lead to thedisplacement or unlinking of the ammoniaoxidisers and nitrite oxidisers. In this paper,the idea is formulated that the nitrifierpopulation forms a role model for the totalmicrobial community. Increased nitriteconcentrations would in this aspect not onlysignal a disruption of nitrifiers, but possiblyalso of the total configuration of themicrobial community.