Characterization of dissolved organic carbon in rainwater of an urban/coastal site in Mediterranean area

Concentration and optical characteristics of dissolved organic matter were studied in rainwater in the urban/coastal city of Thessaloniki, Northern Greece for 2-yr sampling period (2014-2016). The concentration of DOC ranged from 0.33-24.5 mg/L with higher values measured in spring-summer period. Higher aromaticity and fluorescence intensity was observed in winter. Chromophoric organic matter represents a significant fraction of DOC that is highly correlated with fluorescence during cold period. Three factor spectral profiles of fluorescence were elucidated, with peaks at protein-like and humic-like area at different intensities. Fluorophores at shorter wavelengths are more susceptible to changes. DOC showed negative relationship with precipitation height, particularly during autumn and spring suggesting washout effect. NMR spectra showed the dominance of aliphatic protons in rainwater. Levoglucosan, sucrose and arabitol were determined in rainwater at concentrations <0.07-2.2 mu g/L, <0.03-5.1 mu g/L and <0.03-2.1 mu g/L, respectively showing impact of biomass combustion and biogenic emissions. (c) 2018 Elsevier B.V. All rights reserved.