A variety of factors can affect NO3 concentrations in surface waters, including atmospheric nitrogen (N) deposition, fertilizer N inputs, wastewater N contaminants, internal N cycling processes (e.g. plant uptake, mineralization, nitrification, denitrification) and hydrological flowpaths. Elevated levels of N inputs to ecosystems due to anthropogenic influences may have profound effects, includ...

A new type of biofilter packed with composite carriers was designed for tertiary denitrification of the secondary effluent with removal of both oxidized nitrogen and suspended solids (SS). At the empty bed residence time of 15 min and organic carbon to nitrate nitrogen (C/NO3-N) ratios of 2, 1.5 and 1 g/g, the removal percentage of NO3-N was 67%, 58% and 36% in the ethanol biofilter, and was 61...

Knowledge of key sources and biogeochemical processes that affect the transport of nitrate (NO(3)(-)) in streams can inform watershed management strategies for controlling downstream eutrophication. We applied dual isotope analysis of NO(3)(-) to determine the dominant sources and processes that affect NO(3)(-) concentrations in six stream/river watersheds of different land uses. Samples were c...

High-elevation red spruce [Picea rubens Sarg.]-Fraser fir [Abies fraseri (Pursh.) Poir] forests in the Southern Appalachians currently receive large nitrogen (N) inputs via atmospheric deposition (30 kg N ha(-1) year(-1)) but have limited N retention capacity due to a combination of stand age, heavy fir mortality caused by exotic insect infestations, and numerous gaps caused by windfalls and ic...

Rare examples of phosphine complexes of lead(II) are reported. The reaction of Pb(NO3)2 with Me2P(CH2)2PMe2, o-C6H4(PMe2)2 or Et2P(CH2)2PEt2 (L-L) in H2O/MeCN gave white [Pb(L-L)(NO3)2], irrespective of the ratio of reagents used. The X-ray structures of [Pb{Me2P(CH2)2PMe2}(NO3)2] and [Pb{o-C6H4(PMe2)2}(NO3)2] reveal chelating diphosphines and κ(2)-NO3(-) groups occupying one hemisphere about t...

Changes in agricultural management can minimize NO3-N leaching, but then the time needed to improve ground water quality is uncertain. A study was conducted in two first-order watersheds (30 and 34 ha) in Iowa's Loess Hills. Both were managed in continuous corn (Zea mays L.) from 1964 through 1995 with similar N fertilizer applications (average 178 kg ha(-1) yr(-1)), except one received applica...

1999) in a variety of locations and soil types. The AEM technique, however, may be more sensitive than tradiThere is not extensive research on the potential of anion exchange tional extractions to treatment differences at low soil membranes (AEMs) for determining available N in soils of turfgrass NO3–N concentrations (Pare et al., 1995; Wander et al., systems, nor on the use of reflectance mete...

A bacterial strain F-5-2, isolated from soil and identified as Klebsiella pneumoniae, removed NH4+ completely in 24 h of aerobic cultivation in a medium containing 1 mg/ml of NH4NO3. However, 70% of the NO3- originally provided remained. When 100 microM Fe2+ was added to the medium, both NH4+ and NO3- were removed simultaneously and completely from the culture within 6 h of incubation. In addit...