Application of Nontarget High-Resolution Mass Spectrometry Fingerprints for Qualitative and Quantitative Source Apportionment: A Real Case Study

High-resolution mass spectrometry
(HRMS) provides extensive
chemical
data, facilitating the differentiation and quantification of contaminants
of emerging concerns (CECs) in aquatic environments. This study utilizes
liquid chromatography-HRMS for source apportionment in Chebei Stream,
an urban water stream in Guangzhou, South China. Initially, 254 features
were identified as potential CECs by the nontarget screening (NTS)
method. We then established 1689, 1317, and 15,759 source-specific
HRMS fingerprints for three distinct sources, the mainstream (C3),
the tributary (T2), and the rain runoff (R1), qualitatively assessing
the contribution from each source downstream. Subsequently, 32, 55,
and 3142 quantitative fingerprints were isolated for sites C3, T2,
and R1, respectively, employing dilution curve screening for source
attribution. The final contribution estimates downstream from sites
C3, T2, and R1 span 32–96, 12–23, and 8–23%,
respectively. Cumulative contributions from these sources accurately
mirrored actual conditions, fluctuating between 103 and 114% across
C6 to C8 sites. Yet, with further tributary integration, the overall
source contribution dipped to 52%. The findings from this research
present a pioneering instance of applying HRMS fingerprints for qualitative
and quantitative source tracking in real-world scenarios, which empowers
the development of more effective strategies for environmental protection.