Chemical and spectroscopic characterization of humic substances from sediment and riparian soil of a highly polluted urban river (Suquía River, Cordoba, Argentina)  

Chemical and spectroscopic characterization of humic substances from sediment and riparian soil of a highly polluted urban river(Suquía River,Córdoba,Argentina)

作　　者：Carolina Merlo Carolina Vázquez Ana Graciela Iriarte Carlos Matías Romero 

机构地区：[1]Instituto Multidisciplinario de Biología Vegetal(CONICET).Avenue V elez Sarsfield 1611,Córdoba,Argentina [2]Facultad de Ciencias Agropecuarias,Universidad Nacional de Córdoba.Ingeniero Agr onomo F elix Aldo Marrone 746,Córdoba,Argentina [3]INFIQC,Departament of Fisicoquímica,Facultad de Ciencias Químicas,Universidad Nacional de Córdoba.Haya de La Torre and Medina Allende,Córdoba,Argentina [4]Agriculture and Agri-Food Canada,Lethbridge Research and Development Centre,5403e1st Avenue South,Lethbridge,Alberta T1J 4B1,Canada [5]Department of Biological Sciences,University of Lethbridge,4401 University Drive,Lethbridge,Alberta,T1K 3M4,Canada

出　　处：《International Journal of Sediment Research》2020年第3期287-294,共8页国际泥沙研究（英文版）

基　　金：This work was supported by the Secretaria de Ciencia y Tecnologia-Universidad Nacional de Córdoba,Argentina(SECyT-UNC);the National Research Council of Argentina(CONICET)。

摘　　要：The Suquía River,the largest urban river in C ordoba(Argentina),has been severely polluted for decades.Actions must be taken to restore its environmental quality by managing riparian zones for increased water-self purification.The current study aimed to characterize organic matter(OM)dynamics and humic substances(HS)spectrochemical properties along the lower-middle basin of the Suquía River.Riparian soil(0e20 cm)and sediment(0e10 cm)samples were collected from a reference location(S1)and four polluted sites(S2eS5)during a low-flow period.The contents of soil and sedimentary OM and HS fractions were analyzed by wet oxidation,as well as HS Fourier transform infrared(FT-IR)and ultravioletevisible(UVeVis)spectrochemical properties.The OM and HS fractions from riparian soil were high upstream of C ordoba City(S1 and S2,50.2e50.4 g/kg OM)and within a 50 km downstream location(S5,30.9 g/kg OM)owing to a surplus of fresh plant biomass-carbon(C)inputs.Highly heterogeneous sediment samples did not show any significant differences among sites(P>0.05).The lowest values of the ratio of absorbances at 465 and 665 nm(E4/E6)(1.78)and the Δ log K(0.15)coefficient(a measure of HS maturity degree)were obtained downstream of C ordoba City,for both riparian soil and sediment,indicating that HS were enriched by more condensed aromatic structures within highly degraded portions of the river.All samples exhibited similar IR spectra,implying overlapping recalcitrant-C structures at the functional group level,but with different absorbance intensity.Data from the current study constitute a baseline for understanding the chemical nature of HS from sediment and riparian soil along the Suquía River and can be used as a reference for future studies tracking OM compositional changes over time.The Suquia River,the largest urban river in Cordoba(Argentina),has been severely polluted for decades.Actions must be taken to restore its environmental quality by managing riparian zones for increased water-self purification.The current study aimed to characterize organic matter(OM) dynamics and humic substances(HS) spectrochemical properties along the lower-middle basin of the Suquia River.Riparian soil(0-20 cm) and sediment(0-10 cm) samples were collected from a reference location(S1)and four polluted sites(S2-S5) during a low-flow period.The contents of soil and sedimentary OM and HS fractions were analyzed by wet oxidation,as well as HS Fourier transform infrared(FT-IR) and ultraviolet-visible(UV-Vis) spectrochemical properties.The OM and HS fractions from riparian soil were high upstream of Cordoba City(S1 and S2,50.2-50.4 g/kg OM) and within a 50 km downstream location(S5,30.9 g/kg OM) owing to a surplus of fresh plant biomass-carbon(C) inputs.Highly heterogeneous sediment samples did not show any significant differences among sites(P> 0.05).The lowest values of the ratio of absorbances at 465 and 665 nm(E4/E6)(1.78) and the Δ log K(0.15) coefficient(a measure of HS maturity degree) were obtained downstream of Cordoba City,for both riparian soil and sediment,indicating that HS were enriched by more condensed aromatic structures within highly degraded portions of the river.All samples exhibited similar IR spectra,implying overlapping recalcitrant-C structures at the functional group level,but with different absorbance intensity.Data from the current study constitute a baseline for understanding the chemical nature of HS from sediment and riparian soil along the Suquia River and can be used as a reference for future studies tracking OM compositional changes over time.

关 键 词：LOTIC ecosystems Organic matter HUMIC acids FT-IR SPECTROSCOPY UV-VIS SPECTROSCOPY 

分 类 号：X52[环境科学与工程—环境工程] X53