Pesticide fate on catchment scale: conceptual modelling of stream CSIA data
-
Published:2017-10-18
Issue:10
Volume:21
Page:5243-5261
-
ISSN:1607-7938
-
Container-title:Hydrology and Earth System Sciences
-
language:en
-
Short-container-title:Hydrol. Earth Syst. Sci.
Author:
Lutz Stefanie R.ORCID, Velde Ype van derORCID, Elsayed Omniea F., Imfeld Gwenaël, Lefrancq Marie, Payraudeau Sylvain, van Breukelen Boris M.
Abstract
Abstract. Compound-specific stable isotope analysis (CSIA) has proven beneficial in the characterization of contaminant degradation in groundwater, but it has never been used to assess pesticide transformation on catchment scale. This study presents concentration and carbon CSIA data of the herbicides S-metolachlor and acetochlor from three locations (plot, drain, and catchment outlets) in a 47 ha agricultural catchment (Bas-Rhin, France). Herbicide concentrations at the catchment outlet were highest (62 µg L−1) in response to an intense rainfall event following herbicide application. Increasing δ13C values of S-metolachlor and acetochlor by more than 2 ‰ during the study period indicated herbicide degradation. To assist the interpretation of these data, discharge, concentrations, and δ13C values of S-metolachlor were modelled with a conceptual mathematical model using the transport formulation by travel-time distributions. Testing of different model setups supported the assumption that degradation half-lives (DT50) increase with increasing soil depth, which can be straightforwardly implemented in conceptual models using travel-time distributions. Moreover, model calibration yielded an estimate of a field-integrated isotopic enrichment factor as opposed to laboratory-based assessments of enrichment factors in closed systems. Thirdly, the Rayleigh equation commonly applied in groundwater studies was tested by our model for its potential to quantify degradation on catchment scale. It provided conservative estimates on the extent of degradation as occurred in stream samples. However, largely exceeding the simulated degradation within the entire catchment, these estimates were not representative of overall degradation on catchment scale. The conceptual modelling approach thus enabled us to upscale sample-based CSIA information on degradation to the catchment scale. Overall, this study demonstrates the benefit of combining monitoring and conceptual modelling of concentration and CSIA data and advocates the use of travel-time distributions for assessing pesticide fate and transport on catchment scale.
Funder
Seventh Framework Programme
Publisher
Copernicus GmbH
Subject
General Earth and Planetary Sciences,General Engineering,General Environmental Science
Reference77 articles.
1. Abe, Y. and Hunkeler, D.: Does the Rayleigh equation apply to evaluate field isotope data in contaminant hydrogeology?, Environ. Sci. Technol., 40, 1588–1596, https://doi.org/10.1021/es051128p, 2006. 2. Accinelli, C., Dinelli, G., Vicari, A., and Catizone, P.: Atrazine and metolachlor degradation in subsoils, Biol. Fert. Soils, 33, 495–500, https://doi.org/10.1007/s003740100358, 2001. 3. Al-Khatib, K., Baumgartner Unland, J., Olson, B. L. S., and Graham, D. W.: Alachlor and metolachlor transformation pattern in corn and soil, Weed Sci., 50, 581–586, https://doi.org/10.1614/0043-1745(2002)050[0581:AAMTPI]2.0.CO;2, 2002. 4. Atteia, O., Franceschi, M., and Dupuy, A.: Validation of reactive model assumptions with isotope data: application to the Dover case, Environ. Sci. Technol., 42, 3289–3295, https://doi.org/10.1021/es071269m, 2008. 5. Barra Caracciolo, A., Giuliano, G., Grenni, P., Guzzella, L., Pozzoni, F., Bottoni, P., Fava, L., Crobe, A., Orrù, M., and Funari, E.: Degradation and leaching of the herbicides metolachlor and diuron: a case study in an area of Northern Italy, Environ. Pollut., 134, 525–534, https://doi.org/10.1016/j.envpol.2004.08.014, 2005.
Cited by
22 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献
|
|