Identifying organic matter provenance in sediments using isotopic ratios in an urban river

Abstract

To provide a better understanding of potential hazard of effluent detritus, both at the present and in the future, the dispersal and accumulation of sewage-derived materials in the receiving river should be addressed. For the goals, we determined concentrations and isotopic compositions of sedimentary organic carbon (SOC) and nitrogen (SON) and those of effluents in an urban river (Nanming River, China). In the river, the two major sources of sedimentary organic matter (SOM) are effluent detritus (δ 13 C: -25.0‰; δ 15 N: +8.5‰; C/N: 8.1) and C3 plants growing along the river bank (δ 13 C: -27.7‰; δ 15 N: -0.9‰; C/N: >28). Isotopic difference between the two end-members was observed to be 9.4‰ for nitrogen, compared with 2.7‰ for carbon, and hence nitrogen isotopic difference between end-members is large enough to be used as a tracer for source recognition of SOM. Using a mixing model, we found that at outfalls sewage-derived SON accounted for >60% of the bulk SON. At site 40 km far from outfall, fraction of sewage-derived SON was still high to 50%. But at most sites, though about 450,000 m 3 sewage effluents per day discharge into the river, effluent detritus and C3 plants contributed nearly the same to SOM, indicated that natural contribution from C3 plants should be also paid attention to.

Sources of sediment-bound organic matter infiltrating spawning gravels during the incubation and emergence life stages of salmonids

“…The isotopic ranges in Table 2 for the farm yard manure/ slurry samples reflected those typically reported for grass ( in the farm yard manure and slurries collected from the Aran, Lugg and Test catchments suggest input from livestock fed a maize diet, which may be the source of the 13 C-enriched values in the interstitial sediments sampled from the artificial redds of the Rede and Test (although local direct inputs from soils under maize cultivation cannot be ruled out). Although overlap between the bulk isotopic values measured for different sources is common (Michener and Lajtha, 2007;Xiao and Liu, 2010), isotopic datasets frequently distinguish various sources, especially when combined Table 3 The results of the KW-H test for discriminating the sources of the interstitial sediment-bound organic matter using individual fingerprint properties.…”

Spatial and Temporal Variability of Sediment Organic Matter Recycling in Two Temperate Eutrophicated Estuaries

“…In temperate estuaries and deltas, the origin of organic matter and its potential reactivity is complex and is linked to different types of organic matter: terrestrial, riverine, marine and urban waste (Cifuentes et al 1988;Barth et al 1998;Hellings et al 1999;Lansard et al 2009;Xiao and Liu 2010;Pastor et al 2011b). In estuarine environments, the composition of organic matter in the upper sediment layer that is mineralized responds seasonally to the changes in the composition of suspended particles.…”

Effects of HCl pretreatment, drying, and storage on the stable isotope ratios of soil and sediment samples

“…The stable isotope fractionation of OM is dictated by differences in the stable isotope ratios and the contribution of the end‐member, carbon (C), nitrogen (N), and sulfur (S) . The δ 13 C value is often used to determine the origin of OM in the environment . Organic materials originating from marine, terrestrial, and marsh environments generally have δ 13 C values in the range of –5 to –35‰, with marine materials in the range of –23 to –18‰, and terrestrial materials in the range –28 to –25‰ .…”

“…[4] The δ 13 C value is often used to determine the origin of OM in the environment. [10,11] Organic materials originating from marine, terrestrial, and marsh environments generally have δ 13 C values in the range of -5 to -35‰, with marine materials in the range of -23 to -18‰, and terrestrial materials in the range -28 to -25‰. [5,6] The δ 13 C values of C3 plants range from -35 to -22‰, while for C4 plants they range from -15 to -6‰.…”