title: Off-line TMAH-GC/MS and NMR characterization of humic substances extracted from river sediments of northwestern São Paulo under different soil uses.
abstract: Humic substances (HS) vary according to the physical and chemical factors present in the environment. Thus, the characterization of HS is very important because it improves the understanding of the groups that comprise the chemical structure. Sediment HS were extracted from four locations representative of sugar cane cultivation, pasture, urban area and the impoundment of the Água Vermelha Hydroelectric Power Plant. Characterization using nuclear magnetic resonance (NMR) allowed us to infer that the HS from an area predominantly characterized by sugar cane cultivation (41.9%) and a typical rural area (35.0%) showed the highest aromaticity percentage. Using the off-line TMAH-thermochemolysis-GC-MS, we inferred that the HS of a typical rural area had a structure rich in plant waxes, plant biopolyester and a large amount of fatty acid methyl ester, which are related to the large amount of humic acid in the structure. The HS samples from the sugar cane cultivation area and the impoundment receiving all of the pollution load from the Turvo/Grande Hydrographic Basin (Bacia Hidrográfica do Turvo/Grande-BHTG) contained contributions from compounds rich in lipids and fatty acid methyl esters, highlighting the presence of the breakdown of petroleum-derived hydrocarbons in the area receiving the entire pollution load. We conclude that the HS extracted from the sediments of the Preto, Turvo and Grande rivers showed well-defined characteristics that varied depending on soil use and occupation, especially the HS extracted from sediments sampled in areas typically planted with sugar cane and rural areas, whose structures contained more aromatic groups.
authors.affiliation: Departamento de Química e Ciências Ambientais, Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista "Júlio de Mesquita Filho", R. Cristóvão Colombo 2265, 15054-000 São José do Rio Preto, SP, Brazil. Electronic address: amandatadini@hotmail.com.
authors.forename: Amanda Maria
authors.initials: AM
authors.lastname: Tadini
authors.affiliation: Departamento de Química e Ciências Ambientais, Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista "Júlio de Mesquita Filho", R. Cristóvão Colombo 2265, 15054-000 São José do Rio Preto, SP, Brazil.
authors.forename: Glaucia
authors.initials: G
authors.lastname: Pantano
authors.affiliation: Departamento de Química e Ciências Ambientais, Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista "Júlio de Mesquita Filho", R. Cristóvão Colombo 2265, 15054-000 São José do Rio Preto, SP, Brazil.
authors.forename: Ana Lúcia
authors.initials: AL
authors.lastname: de Toffoli
authors.affiliation: Centro Interdipartimentale di Ricerca sulla Risonanza Magnetica Nucleare (NMR) per L'ambiente, l'Agro-Alimentare ed i Nuovi Materiali, CERMANU, Università di Napoli Federico II, Via Università 100, 80055 Portici, Italy.
authors.forename: Barbara
authors.initials: B
authors.lastname: Fontaine
authors.affiliation: Centro Interdipartimentale di Ricerca sulla Risonanza Magnetica Nucleare (NMR) per L'ambiente, l'Agro-Alimentare ed i Nuovi Materiali, CERMANU, Università di Napoli Federico II, Via Università 100, 80055 Portici, Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Spaccini
authors.affiliation: Centro Interdipartimentale di Ricerca sulla Risonanza Magnetica Nucleare (NMR) per L'ambiente, l'Agro-Alimentare ed i Nuovi Materiali, CERMANU, Università di Napoli Federico II, Via Università 100, 80055 Portici, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Piccolo
authors.affiliation: Departamento de Química e Ciências Ambientais, Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista "Júlio de Mesquita Filho", R. Cristóvão Colombo 2265, 15054-000 São José do Rio Preto, SP, Brazil.
authors.forename: Altair Benedito
authors.initials: AB
authors.lastname: Moreira
authors.affiliation: Departamento de Química e Ciências Ambientais, Instituto de Biociências, Letras e Ciências Exatas, Universidade Estadual Paulista "Júlio de Mesquita Filho", R. Cristóvão Colombo 2265, 15054-000 São José do Rio Preto, SP, Brazil. Electronic address: bisinoti@ibilce.unesdp.br.
authors.forename: Márcia Cristina
authors.initials: MC
authors.lastname: Bisinoti
mesh_terms: D001938:Brazil; D004784:Environmental Monitoring; D008401:Gas Chromatography-Mass Spectrometry; D019015:Geologic Sediments / Q000737:chemistry*; D006812:Humic Substances / Q000032:analysis*; D009682:Magnetic Resonance Spectroscopy; D045483:Rivers / Q000737:chemistry*; D012987:Soil / Q000737:chemistry; D014873:Water Pollutants / Q000032:analysis* / Q000737:chemistry
chemical_list: D006812:Humic Substances; D012987:Soil; D014873:Water Pollutants
keywords: Humic substances; NMR; Off-line pyrolysis TMAH-GC/MS; River sediments; Soil uses