Spatial and temporal distribution of rare earth elements in the Neuse River, North Carolina

Rare earth elements (REEs) signatures in the dissolved loads of rivers serve as excellent monitors of weathering processes within a basin. However, quantifying REE behavior spatially (along a river's profile) and temporally (seasonable variations) is rare. This investigation reports REE concentrations of dissolved river loads collected during four sampling seasons at five monitoring stations along the Neuse River, North Carolina. The areal percentage of the Neuse River's catchment lithology composition, Post Archean Australian Shale (PAAS) normalized REE patterns, inter-REE ratios, and calculated anomalous REE values (i.e. cerium anomaly, gadolinium anomaly) were determined at each site in four seasons over a year. Our results show slight differences among inter-REE relationships and anomalous REE values in the dissolved loads along the length of the river. PAAS normalized REE patterns of dissolved water loads vary slightly spatially and temporally among the five sampling stations, and experience varying values of anomalous REE values. Collected data indicates that both variations in localized REE patterns and local bedrock occur along the river profile. Significant gadolinium (Gd) anomalies varied seasonally and spatially at select sites, suggesting changes in REE behavior along a river result from both natural and anthropogenic processes.