Using Rare‐Earth Oxide Tracers for Studying Soil Erosion Dynamics

Abstract

ABSTRACTthese advantages will not be fully recognized unless the spatial and temporal predictability of process-basedSpatially averaged soil erosion data provide little information on models are validated. Thus, spatially distributed erosion soil erosion dynamics. Dynamically varied, spatially distributed erosion data are needed to better understand erosion processes and data are of great importance in advancing process-based thoroughly evaluate process-based erosion prediction models. The erosion prediction models.objectives of this study are to examine the feasibility of direct mixingVarious types of tracers have been developed and rare-earth element (REE) oxides with soil materials to trace soil used to obtain spatially distributed data. Commonly used erosion at a plot scale and to explore further the potential of using tracers include atomic bomb fallout radionuclide 137 Cs this technique to study soil erosion dynamics. Five REE oxide powders (Ritchie and McHenry, 1990; Walling and He, 1999 Pb provide little information on sediment origin. better understand soil erosion dynamics, but also for Unlike bomb-produced and cosmogenic radionuthorough validation of process-based erosion models.clides, radioactive elements can be manipulated and Spatially distributed soil erosion data are also useful deliberately introduced to study soil erosion. A major for evaluating on-site impacts such as effects of soil concern with this type of tracer is the radiological risk redistribution on crop yields and off-site impacts includto researchers and the environment. Exotic particles ing sediment origin and destination. Many processsuch as fluorescent glass or magnetic plastic beads have based erosion prediction models have been developed been used to overcome this concern, but suffer other in the past several decades to predict soil erosion at serious shortcomings. Major criticisms for exotic partivarious temporal and spatial scales (Nearing et al., 1989; cles are that (i) these particles may not bind with soil Hairsine and Rose, 1992; Borah, 1989). Since erosion particles or soil aggregates and therefore are transprocesses constantly change in time and space, processported separately; (ii) exotic particles differ in size distribased models have advantages over spatially and tempobution, particle density, shape, surface morphology, and rally lumped empirical prediction models. Element Applicationwith silt fractions. They also developed and tested a A wooden box (4 by 4 m) with adjustable slope was quick acid-leaching method for extracting REEs from used in the study. The box was arbitrarily set to a 10% soil and sediment samples for analysis by ICPMS. The slope, partially because it is close to the standard 9% quick extraction method makes it possible to take full slope used for developing the Universal Soil Loss Equaadvantage of this new technology. The advantages of tion. The sieved soil was packed into the soil box to a ICPMS as identified by Jarvis (1989) include exceptional depth of 0.2 m over a 0.5-m sand layer, wh...

87Sr/86Sr and trace element mapping of geosphere-hydrosphere-biosphere interactions: A case study in Ireland

“…In such cases, this similarity indicates that the relative abundances of the REE+Y are not markedly fractionated during weathering and aqueous transport. However, at a finer scale the REE+Y patterns of smaller streams or rivers often broadly reflect the predominant lithology in the catchments and allow these elements to be exploited as a tracer of water source and mixing (Lawrence et al, 2006a(Lawrence et al, , 2006bSadeghi et al, 2013;Zhang et al, 2003). Groundwater and river/streamwater associated with marinederived carbonate-rich catchments often exhibit LREE depleted patterns that resemble seawater (e.g.…”

Multi‐year tracking of sediment sources in a small agricultural watershed using rare earth elements

“…Rare earth elements (REEs), which are elements of atomic number 57 through 71, with similar chemical properties, have been successfully used as a multi-sediment tracer (Liu et al, 2004;Mahler et al, 1998;Matisoff et al, 2001;Wei et al, 2003;Zhang et al, 2003). REEs are nearly uniformly incorporated into Multi-year tracking of sediment sources in a small agricultural watershed using rare earth elements different sizes of soil aggregates for loess-derived silt loam soils, and direct mixing of REEs does not substantially change the physicochemical properties of soil aggregates (Zhang et al, 2001).…”

“…Polyakov (2002) pointed out that a partial flushing of tracer particles from the tagged soil probably occurred due to the inadequate binding of the REEs with soil aggregates. Laboratory experiments (Zhang et al, 2003; showed the initial flushing of poorly incorporated tracers and decrease in the tracer enrichment with cumulative rainfall. The significant relationship for the lower channel may have been the result of the initial flushing of poorly incorporated tracers during the large storms of 2001.…”

Multiple rainfall event pollution transport by sustainable drainage systems: the fate of fine sediment pollution

“…The REO tracers used for the car park, roof and road were Nd, Sm, Gd, Tb; Y, La, Ce, Pr; Dy, Ho, Er, Yb, respectively. The sediment was tagged following the detailed methodology described by Zhang et al (2001Zhang et al ( , 2003, at a tracer concentration rate of 10 g/kg of sediment (Allen et al 2015), and released evenly onto the urban surfaces only once at the beginning of the sampling period. Tagged sediment was designed to mimic naturally occurring urban sediment pollution, in both mass and particle size distribution (PSD).…”