Singlet Oxygen Formation in Lake Waters from Mid-Latitudes

Photochemical Characterization of Surface Waters from Lakes in the Adirondack Region of New York

“…Furthermore, the mean Φ app, 3 DOM TMP * was higher than those for whole waters from temperate lakes in northern Minnesota and Wisconsin , and mountain lakes in northwestern Italy , but was lower than those measured for Lake Greifensee , and lakes in the Terra Nova Bay area of Antarctica . Φ app, 1 O 2 were also on the same order of magnitude as values for whole waters and DOM isolates from a wide range of lakes (e.g., Lake Superior) and rivers, ,,,,,,,,− but the mean Φ app, 1 O 2 fell below those for surface waters from wetland (e.g., prairie potholes , ) and estuaries (e.g., the Florida Everglades) as well as wastewater effluent. ,,,, Φ app, 3 DOM HDO * fell on the lower end of the Φ app of high-energy 3 DOM* (i.e., measured by sorbate probes) for wastewater effluent and whole lake and river waters, ,, but compared well with values determined for Suwannee River DOM isolates under the same irradiation conditions, confirming their similarity in the formation efficiency of high-energy 3 DOM*. Lastly, Φ app, • OH were substantially lower than those for whole waters and DOM isolates from various sources, ,,,,,,,,, in part because the majority of literature Φ app, • OH were measured at shorter excitation wavelengths (e.g., <400 nm).…”

“…Similarly, the noontime surface [ 1 O 2 ] ss were predicted to vary from 3.6 × 10 –14 to 9.0 × 10 –14 M across Adirondack lakes and spanned the range of surface values predicted under summer noon sunlight or measured under natural sunlight (e.g., Spring-Fall) for various lake, river, and wetland waters from mid-latitudes. ,,,,, The ratio of [ 1 O 2 ] ss to [ 3 DOM TMP * ] ss averaged 0.89 ± 0.14 for Adirondack lake waters, which fell within ranges predicted by the O 2 -dependent quenching of 3 DOM* (i.e., 0–2), but was slightly below values measured for terrestrially- and wastewater-derived DOM isolates (1.06–1.13) , as well as whole waters from temperate lakes in northern Minnesota (2.45 ± 0.73) and Wisconsin (1.1–6.0; recalculated using k TMP, 3 DOM TMP * of 8.1 ± 2.2 × 10 8 M –1 s –1 107 ). , On the other hand, the noontime surface [ 3 DOM HDO * ] ss ranged from 1.3 × 10 –14 to 2.9 × 10 –14 M and exhibited relatively consistent ratios of 0.28–0.33 to [ 1 O 2 ] ss and [ 3 DOM TMP * ] ss and therefore, [ 3 DOM HDO * ] ss in Adirondack lake waters could in principle be approximated as ∼30% of [ 1 O 2 ] ss or [ 3 DOM TMP * ] ss . Similar to previous findings, ,,, [ 1 O 2 ] ss , [ 3 DOM TMP * ] ss , and [ 3 DOM HDO * ] ss all showed positive correlations (ρ = 0.700–0.891; p < 0.001 to p = 0.003; Figure S4) with DOM quantity measures such as [DOC], CDOM 250–450 , and FDOM, confirming the usefulness of these metrics for predicting the patterns of [ 1 O 2 ] ss and [ 3 DOM*] ss in sunlit Adirondack lake waters. Compared to [ 3 DOM*] ss and [ 1 O 2 ] ss , the noontime surface [ • OH] ss were several orders of magnitude lower, ranging from 7.2 × 10 –18 to 1.7 × 10 –16 M and overlapped with values predicted or measured for the surface layer of seawater, lakes, and wetlands at solar noon, mid-latitude light conditions. ,,,,,, …”

“…94 Similarly, the noontime surface [ 1 O 2 ] ss were predicted to vary from 3.6 × 10 −14 to 9.0 × 10 −14 M across Adirondack lakes and spanned the range of surface values predicted under summer noon sunlight or measured under natural sunlight (e.g., Spring-Fall) for various lake, river, and wetland waters from midlatitudes. 29,100,134,136,140,141 The ratio of [ 1 O 2 ] ss to [ 3 DOM TMP * ] ss averaged 0.89 ± 0.14 for Adirondack lake waters, which fell within ranges predicted by the O 2 -dependent quenching of 3 DOM* (i.e., 0−2), 24 but was slightly below values measured for terrestrially-and wastewater-derived DOM isolates (1.06− 1.13) 105,142 as well as whole waters from temperate lakes in northern Minnesota (2.45 ± 0.73) and Wisconsin (1.1−6.0; recalculated using k TMP, 3 DOM TMP * of 8.1 ± 2.2 × 10 8 M −1 s −1 107 ). 32,33 On the other hand, the noontime surface [ 3 DOM HDO * ] ss ranged from 1.3 × 10 −14 to 2.9 × 10 −14 M and exhibited relatively consistent ratios of 0.28−0.…”

Correlating the chemical and spectroscopic characteristics of natural organic matter with the photodegradation of sulfamerazine

“…The total fluorescence and Peak A fluorescence for all forms of NOM were positively correlated with [ 1 O 2 ] ss (R 2 ≥ 0.95), its formation rate (R 2 ≥ 0.95), and SMR degradation rate constant (R 2 ≥ 0.95). The relationship between fluorescence and singlet oxygen production was reported for both humic substances (Coelho et al 2011) and lake water (Shao et al 1994). Excluding SRFA, there was also a positive correlation between total fluorescence and [ 3 NOM * ] ss (R 2 = 0.98) and with their corresponding formation rates (R 2 = 0.86).…”

“…Recent studies show that correlations between parameters such as quantum yield (Cawley et al 2014) and spectroscopic characteristics can be potential predictors of NOM reactivity. Fluorescence is one predictor of 1 O 2 formation in natural waters (Shao et al 1994) and from soil humic substances (Coelho et al 2011). Fluorescence was also shown to correlate with the quantum yield of the hydroxyl radical in wastewater (Lee et al 2013) The specific ultraviolet absorbance at 254 nm (SUVA 254 ) is correlated with aromatic carbon content (Weishaar et al 2003).…”