Nitrifying Kinetics and the Persistence of Nitrite in the Seine River, France. Issue 3 (1st May 2017)

• Record Type: Journal Article
• Authors: Raimonet, M.; Cazier, T.; Rocher, V.; Laverman, A. M.
• Is Part Of: Journal of Environmental Quality. Volume 46:Issue 3(2017)
• Page Start: 585
• Page End: 595
• Publication Date: 2017-05-01
• Subjects: Agricultural ecology -- Periodicals; Environmental engineering -- Periodicals; Pollution -- Periodicals; 630
• DOI: 10.2134/jeq2016.06.0242
• Languages: English
• ISSNs: 0047-2425

Abstract

Abstract : Although a higher oxidation rate for nitrite than for ammonia generally prevents nitrite accumulation in oxic waters, nitrite concentrations in the Seine River (1–31 μM) exceed European norms. We investigated the kinetics of in situ ammonia‐ and nitrite‐oxidizing communities in river water and wastewater treatment plant (WWTP) effluents to determine the role of pelagic nitrification in the origin and persistence of nitrite downstream of Paris. The main source of nitrite is the major Parisian WWTP, and its persistence, up to tens of kilometers downstream of the plant, is explained by low ammonia and nitrite oxidation rates and high river flow. Furthermore, similar nitrite and ammonia oxidation rates preclude a rapid consumption of both preexisting nitrite and nitrite produced by ammonia oxidation. Maximum ammonia oxidation rates are two to three times higher downstream than upstream of the WWTP, indicating the input of ammonia oxidizers and ammonia from the WWTP. In both river water and WWTP effluents, nitrite oxidizers were unable to oxidize all available nitrite. In the human‐impacted Seine River, this phenomenon might be due to mixotrophy. This study highlights the low resilience of the river to nitrite contamination as well as the importance of managing nitrite, nitrifiers, and organic matter concentrations in WWTP effluents to avoid nitrite persistence in rivers. Core Ideas: Nitrite in the Seine River mostly originates from wastewater treatment plant effluents. Nitrite persists in the river because of similar ammonia and nitrite oxidation rates. Despite high nitrite concentrations, relatively low nitrite oxidation rates occur, possibly due to mixotrophy.