 |
| Titel |
Sorption and transformation of the reactive tracers resazurin and resorufin in natural river sediments |
| VerfasserIn |
D. Lemke, R. González-Pinzón, Z. Liao, T. Wöhling, K. Osenbrück, R. Haggerty, O. A. Cirpka |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1027-5606
|
| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 18, no. 8 ; Nr. 18, no. 8 (2014-08-25), S.3151-3163 |
| Datensatznummer |
250120442
|
| Publikation (Nr.) |
 copernicus.org/hess-18-3151-2014.pdf |
|
|
|
|
|
| Zusammenfassung |
| Resazurin (Raz) and its reaction product resorufin (Rru) have increasingly
been used as reactive tracers to quantify metabolic activity and hyporheic
exchange in streams. Previous work has indicated that these compounds undergo
sorption in stream sediments. We present laboratory experiments on Raz and
Rru transport, sorption, and transformation, consisting of 4 column and 72
batch tests using 2 sediments with different physicochemical properties under
neutral (pH = 7) and alkaline (pH = 9) conditions. The study aimed at
identifying the key processes of reactive transport of Raz and Rru in
streambed sediments and the experimental setup best suited for their
determination. Data from column experiments were simulated by a
travel-time-based model accounting for physical transport, equilibrium and
kinetic sorption, and three first-order reactions. We derived the travel-time
distributions directly from the breakthrough curve (BTC) of the conservative
tracer, fluorescein, rather than from fitting an advective-dispersive
transport model, and inferred from those distributions the transfer functions
of Raz and Rru, which provided conclusive approximations of the measured
BTCs. The most likely reactive transport parameters and their uncertainty
were determined by a Markov chain–Monte Carlo approach. Sorption isotherms
of both compounds were obtained from batch experiments. We found that kinetic
sorption dominates sorption of both Raz and Rru, with characteristic
timescales of sorption in the order of 12 to 298 min. Linear sorption models
for both Raz and Rru appeared adequate for concentrations that are typically
applied in field tracer tests. The proposed two-site sorption model helps to
interpret transient tracer tests using the Raz–Rru system. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|