Combining experimental techniques with non-linear numerical models to assess the sorption of pesticides on soils.

The risk assessment of groundwater pollution by pesticides may be based on pesticide sorption and biodegradation kinetic parameters estimated with inverse modeling of datasets from either batch or continuous flow soil column experiments. In the present work, a chemical non-equilibrium and non-linear 2-site sorption model is incorporated into solute transport models to invert the datasets of batch and soil column experiments, and estimate the kinetic sorption parameters for two pesticides: N-phosphonomethyl glycine (glyphosate) and 2,4-dichlorophenoxy-acetic acid (2,4-D). When coupling the 2-site sorption model with the 2-region transport model, except of the kinetic sorption parameters, the soil column datasets enable us to estimate the mass-transfer coefficients associated with solute diffusion between mobile and immobile regions.

Combining steam injection with hydraulic fracturing for the in situ remediation of the unsaturated zone of a fractured soil polluted by jet fuel.

A steam injection pilot-scale experiment was performed on the unsaturated zone of a strongly heterogeneous fractured soil contaminated by jet fuel. Before the treatment, the soil was stimulated by creating sub-horizontal sand-filled hydraulic fractures at three depths. The steam was injected through one hydraulic fracture and gas/water/non-aqueous phase liquid (NAPL) was extracted from the remaining fractures by applying a vacuum to extraction wells.

Spatial distribution of jet fuel in the vadoze zone of a heterogeneous and fractured soil.

The goal of the present work is to screen and evaluate all available data before selecting and testing remediation technologies on heterogeneous soils polluted by jet fuel. The migration pathways of non-aqueous phase liquids (NAPLs) in the subsurface relate closely with soil properties. A case study is performed on the vadoze zone of a military airport of north-west Poland contaminated by jet fuel.

Soil column experiments used as a means to assess transport, sorption, and biodegradation of pesticides in groundwater.

Soil column experiments are used to investigate the fate of three pesticides of high, intermediate, and low solubility in groundwater: N- phosphonomethyl glycine (glyphosate); O,O-diethyl-S-[(ethylthio)methyl]phosphorodithioate (phorate); (2,4-dichlorophenoxy)acetic acid (2,4-D). Feed solutions are prepared by adding each pesticide (100 mg/L glyphosate, 50 micro g/L phorate, 50 mg/L 2,4-D) along with conservative tracer, KBr, in synthetic groundwater. The concentration of the pesticides in effluents is detected by ion chromatography (glyphosate, 2,4-D) and GC-FID (phorate).

Capillary electrophoretic analysis of brimonidine in aqueous humor of the eye and blood sera and relation of its levels with intraocular pressure.

The aim of this study was the development of a capillary electrophoretic method for the determination of the levels of the selective alpha(2)-adrenergic receptor agonist brimonidine in aqueous humor of the eye and blood sera and their relation to its efficacy in reducing the intraocular pressure (IOP). Analysis of brimonidine was performed by capillary zone electrophoresis using 20 mM borate, pH 9.3, as operating buffer and detection at 255 nm.