Inflow rate-driven changes in the composition and dynamics of chromophoric dissolved organic matter in a large drinking water lake
Artikel i vetenskaplig tidskrift, 2016

Drinking water lakes are threatened globally and therefore in need of protection. To date, few studies have been carried out to investigate how the composition and dynamics of chromophoric dissolved organic matter (CDOM) in drinking water lakes are influenced by inflow rate. Such CDOM can lead to unpleasant taste and odor of the water and produce undesirable disinfection byproducts during drinking water treatment. We studied the drinking water Lake Qiandao, China, and found that the concentrations of suspended particulate matter (SPM) in the lake increased significantly with inflow rate (p < 0.001). Similarly, close relationships between inflow rate and the CDOM absorption coefficient at 350 nm a(350) and with terrestrial humic-like fluorescence C3 and a negative relationship between inflow rate and the first principal component (PC1) scores, which, in turn, were negatively related to the concentrations and relative molecular size of CDOM (p < 0.001), i.e. the concentration and molecular size of CDOM entering the lake increased proportionately with inflow rate. Furthermore, stable isotopes (?D and ?18O) were depleted in the upstream river mouth relative to downstream remaining lake regions, substantiating that riverine CDOM entering the lake was probably driven by inflow rate. This was further underpinned by remarkably higher mean chlorophyll-a and in situ measured terrestrial CDOM fluorescence (365/480 nm) and apparent oxygen utilization (AOU), and notably lower mean PC1 and CDOM spectral slope (S275-295) recorded in the upstream river mouth than in the downstream main lake area. Strong negative correlations between inflow rate and a(250):a(365), S275-295, and the spectral slope ratio (SR) implied that CDOM input to the lake in rainy period was dominated by larger organic molecules with a more humic-like character. Rainy period, especially rainstorm events, therefore poses a risk to drinking water safety and requires higher removal efficiency of CDOM during drinking water treatment processes.

Lake Qiandao

Drinking water

Parallel factor analysis (PARAFAC)

Inflow rate

Chromophoric dissolved organic matter (CDOM)

Författare

Yongqiang Zhou

Sino-Danish Center for Education and Research

Chinese Academy of Sciences

Nanjing Institute of Geography and Limnology Chinese Academy of Sciences

Yunlin Zhang

Nanjing Institute of Geography and Limnology Chinese Academy of Sciences

Erik Jeppesen

Aarhus Universitet

Sino-Danish Center for Education and Research

Kathleen Murphy

Chalmers, Bygg- och miljöteknik, Vatten Miljö Teknik

DRICKS Ramprogrammet för dricksvattenforskning vid Chalmers

Kun Shi

Nanjing Institute of Geography and Limnology Chinese Academy of Sciences

Mingliang Liu

Institute of Hangzhou Environmental Science

Xiaohan Liu

Nanjing Institute of Geography and Limnology Chinese Academy of Sciences

Sino-Danish Center for Education and Research

Guangwei Zhu

Nanjing Institute of Geography and Limnology Chinese Academy of Sciences

Water Research

0043-1354 (ISSN)

Vol. 100 211-221

Drivkrafter

Hållbar utveckling

Ämneskategorier

Miljövetenskap

DOI

10.1016/j.watres.2016.05.021

PubMed

27192356