Luminescent pentanuclear tetra-decker Ln(III) complexes [Eu5L4(OH)2(NO3)4(H2O)2].NO3.3H2O , [Nd5L4(OH)2(NO3)5MeOH].3MeOH.2H2O and [Eu5L4(CF3SO3)4(MeO)2(H2O)4].CF3SO3.H2O are formed from Ln(NO3)3.6H2O (Ln = Eu (1), Nd (2)) and Eu(CF3SO3)3, respectively (H2L = N,N'-bis(5-bromo-3-methoxysalicylidene)phenylene-1,2-diamine).

Mobilization of natural nitrate (NO3-) deposits in the subsoil by irrigation water in arid and semiarid regions has the potential to produce large groundwater NO3-concentrations. The use of isotopes to distinguish between natural and anthropogenic NO3- sources in these settings could be complicated by the wide range in delta15N values of natural NO3-. An approximately 10 000 year record of pale...

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...

Agricultural-induced increase of nitrate (NO3) loading in groundwater is a worldwide problem. This study investigates the impacts of agricultural activities on groundwater NO3 pollution in a Yellow River irrigated region. The agricultural land use patterns are dependent on the land and water conditions. Besides wheat–maize rotation, the most popular cultivation pattern, other patterns with high...

Little is known about seepage wetlands, located within agricultural landscapes, with respect to removing nitrate (NO3 ) from agricultural catchments, mainly through gaseous emissions of nitrous oxide (N2O) and dinitrogen (N2) via denitrification. These variables were quantified using a push–pull technique where we introduced a subsurface water plume spiked with N-enriched NO3 and 2 conservative...

Riparian wetlands have been shown to be effective "sinks" for nitrate N (NO3-), minimizing the downstream export of N to streams and coastal water bodies. However, the vast majority of riparian denitrification research has been in agricultural and forested watersheds, with relatively little work on riparian wetland function in urban watersheds. We investigated the variation and magnitude of den...

Reactions of H2salen (H2L, N,N'-ethylene bis(salicylideneimine)) with Yb(CF3SO3)3, Yb(OAc)34H2O and Yb(NO3)36H2O in MeOH–EtOH under reflux gave NIR luminescent complexes [Yb6L9(H2L)2] (1), [Yb3L3(HL)(OH)2] (2) and [Yb2L2(H2L)2(NO3)(MeOH)2]NO3 (3), respectively.

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...

The concentration and amounts of NO3-N and TN transported in surface, accelerated subsurface, and subsurface runoff and stream flow draining a 20 ha pasture watershed were measured over a period of 3 yr. A slight decrease and increase of NO3-N and particulate N concentrations, respectively, were obtained with increased flow of the runoff types and stream, due to dilution and increased sediment ...

[1] In most climates on Earth, biological processes control soil N. In the Atacama Desert of Chile, aridity severely limits biology, and soils accumulate atmospheric NO3 . We examined this apparent transformation of the soil N cycle using a series of ancient Atacama Desert soils (>2 My) that vary in rainfall (21 to <2 mm yr ). With decreasing rainfall, soil organic C decreases to 0.3 kg C m 2 a...