A high-resolution monitoring station for the in situ assessment of nitrate-related redox processes at an agricultural site.

Biogeochemical redox processes control the chemical behavior of many major and trace elements, making their comprehension crucial for predicting and protecting environmental health. Nitrogen (N) is especially susceptible to changes in soil redox conditions and affects the cycles of other redox-sensitive species. Elevated N concentrations, in nitrate form, in agricultural soils and associated freshwater ecosystems constitute a problem in many parts of the world. Although a wide variety of measures have been adopted, their assessment through concentration measurements in groundwater and surface water of the different monitoring networks has shortcomings. Nitrate, as a non-point pollutant, is subject to several processes (e.g., transformation and retardation) before it is detected, making it impossible to evaluate measurements' effectiveness reliably. Thus, we designed and constructed a monitoring station featuring commercially available products and self-manufactured components at an agricultural site for the in situ assessment of nitrate-related processes by high-resolution monitoring of hydraulic (soil water content, matric potential, groundwater head) and hydrogeochemical variables (oxidation-reduction potential and groundwater and pore water chemistry) within the vadose zone and the shallow aquifer. The monitoring station has proven to be a reliable tool. Changes over depth and time of measured variables have been identified, allowing the detection of the transient behavior of the redox reactive zone and the interpretation of ongoing denitrification processes and other redox nitrate-triggered phenomena, such as uranium roll-front and selenium accumulation at the redox interface. Measuring both geochemical and soil water variables allows for the calculation of in situ solute inputs into the groundwater and their reaction rates.

Egg white specific IgE levels in serum as clinical reactivity predictors in the course of egg allergy follow-up.

It is thought that the natural evolution of egg allergy has a good tolerance prognosis. However, there are few follow-up studies that determine the exact probability of tolerance. The aim of this study was to determine the likelihood that children younger than 2,5 years of age with allergy to egg would eventually have tolerance to it and to analyze if monitoring egg white-specific IgE level over time could be used as a predictor for determining when patients develop clinical tolerance. We performed a retrospective study of our last 42 patients diagnosed with egg allergy. Annual follow-up comprised prick testing, specific IgE (sIgE) and provocation testing with egg white (EW), allowing the prediction of tolerance at that timepoint with a probability of >or=95%. Median survival time was 48 months. The mean initial and final levels of EW sIgE were lower in the patients that reached tolerance (p<0.05). EW sIgE levels of 1.52, 1.35, and 2.59 KUA/l, respectively predicted clinical reactivity (PPV > 95%) at the different follow-up timepoints analyzed (25-36, 37-48 and 49-60 months. Quantification of egg white specific IgE levels is a useful test for diagnosing symptomatic allergy to egg white in the pediatric population and could eliminate the need to perform oral challenges tests in a significant number of children.