Celine Duwig

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Watercress (Lepidium sativum) is consumed as a vegetable, especially by the indigenous community in New Zealand. An investigation was carried out on the accumulation of arsenic by watercress, following earlier reports of inordinate arsenic concentrations in some aquatic macrophytes collected from the Waikato River, North Island, New Zealand. The Waikato(More)
Predictions of natural attenuation of volatile organic compounds (VOCs) in the unsaturated zone rely critically on information about microbial biodegradation kinetics. This study aims at determining kinetic rate laws for the aerobic biodegradation of a mixture of 12 volatile petroleum hydrocarbons and methyl tert-butyl ether (MTBE) in unsaturated alluvial(More)
Rapid urbanization and the absence of efficient water management policies are increasingly degrading the water quality of tropical reservoirs in developing countries. The small tropical reservoir of Cointzio, located in the Trans-Mexican Volcanic Belt, is a warm monomictic water body (surface area = 6 km2 with short water residence time <1 year) that is(More)
The formation of 4-nitroso-sulfamethoxazole and 4-nitro-SMX, two transformation products (TPs) of sulfamethoxazole (SMX) was investigated under batch soil slurry experiments and in a field study. Due to their low occurrence levels (ng/L) in environmental waters, a suitable analytical method based on liquid chromatography - high resolution - mass(More)
With the increasing accessibility of image acquisition techniques, image processing has become an essential component of soil science. Here, Image Processing is specifically used to the accurate prediction of solute transport through soils. To do so, dye tracers are leeched into soil cores to visualize active flow paths in cross sections of soil. We have(More)
An increasing number of studies pointed out the ubiquitous presence of medical residues in surface and ground water as well as in soil compartments. Not only antibiotics can be found in the environment but also their transformation products about which little information is generally available. The development of bacterial resistance to antibiotics is(More)
Up till now, the diclofenac (DCF) transformation into its nitrogen-derivatives, N-nitroso-DCF (NO-DCF) and 5-nitro-DCF (NO2-DCF), has been mainly investigated in wastewater treatment plant under nitrification or denitrification processes. This work reports, for the first time, an additional DCF microbial mediated nitrosation pathway of DCF in soil under(More)
We propose to study the mechanical properties of a volcanic soil sample (monolith) using a computer model. We propose the use of CT-images to construct the Mechanical Computational Model. The image obtained from the CT-Scan give us a 3D model of the pores system of the monolith. This system relates the internal connectivity between different pores and the(More)
In the Mezquital Valley, Mexico, crops have been irrigated with untreated municipal wastewater for more than a century. Atrazine has been applied to maize and alfalfa grown in the area for weed control for 15 years. Our objectives were to analyse (i) how wastewater irrigation affects the filtering of atrazine, and (ii) if the length of irrigation has a(More)
We propose the use of the Lagrangian method Smoothed particle Hydrodynamics (SPH) to model the behaviour of fluids through a pore structure of a volcanic soil core sample. Such studies are of importance to simulate preferential flows which are essential in the leeching of organic and chemical compounds in underground aquifers. Our approach combines X-ray(More)
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