El sistema de labranza no afecta a la macrofauna en el sudeste de la provincia de Buenos Aires, Argentina

Soil degradation increased incessantly in the Pampas region of Argentina, due to the intensification of agricultural activities, when carried out with conventional tillage (CT) systems. No-tillage system was adopted as conservation practices by the farmers. The objectives of this study were: a) to determine the macrofauna taxa and their relative abundance under CT and NT in two different seasons; and b) to evaluate soil tillage and seasonal effects on the density of the main macrofauna taxa. The study was conducted from 2002 to 2004 in 46 production farms, in Balcarce, Argentina. Ten soil monoliths (25.2 cm side; 30 cm depth) ramdomly directed field at July-August; and at October-November to determine the number of individuals of macrofauna and Enchytraeidae. Soil macrofauna density did not differ between tillage systems. Oligochaeta Megadrilli density was generally not affected by the tillage system (P>0.05) except in 2004 when it was greater under CT in July-August (P=0.0002). Chilopoda density was greater in soils under NT, with significant differences in 2002 in October-November (P=0.0070). In July-August of 2003 it was higher in CT (P=0.0109). Diplopoda were more abundant only under NT in July-August 2004 (P=0.0010). In July-August a significantly (PEn la región pampeana Argentina se ha producido una degradación del suelo creciente debido a la intensificación de las actividades agrícolas llevadas a cabo con sistemas de labranza convencionales (LC). La siembra directa (SD) fue adoptada como práctica conservacionista por los agricultores. Los objetivos de este estudio fueron, a) determinar los taxa de la macrofauna y su abundancia relativa bajo LC y SD en dos estaciones diferentes y b) evaluar los efectos de los sistemas de labranza y estaciones sobre la densidad de los principales taxa de la macrofauna. El estudio fue llevado a cabo desde 2002 hasta 2004 en 46 lotes de producción en Balcarce, Argentina. En cada lote se tomaron diez muestras de suelo al azar de (25,2 cm de ancho y 30 cm de profundidad) en julio-agosto y en octubre-noviembre para determinar el número de individuos de la macrofauna y de los Enchytraeidae. La densidad de la macrofauna no difirió entre sistemas de labranza. La densidad de Oligochaeta Megadrilli no fue afectada por el sistema de labranza (P>0,05) excepto en 2004 cuando fue mayor bajo LC en julio-agosto (P=0,0002). La densidad de Chilopoda fue mayor bajo SD, aunque solo se observaron diferencias significativas en octubre-noviembre de 2002 (P=0,0070). En julio-agosto de 2002 la densidad fue mayor en LC (P=0,0109). Diplopoda fue más abundante bajo SD sólo en julio-agosto de 2004 (P=0,0010). La densidad de Enchytraeidae fue mayor en LC que en SD en el período julio-agosto (

PRESSURIZED-LIQUID EXTRACTION FOR DETERMINATION OF IMIDAZOLINONE HERBICIDES IN SOIL

A rapid and simple method has been developed for determination of imidazolinone (IMI) residues in soil. Extraction of the analytes from the soil matrix was performed with a pressurized-liquid-extraction apparatus built in this laboratory. Four different types of soil sample (clay, clay loam, sandy clay loam, and silty loam) were fortified with target compounds at levels of 10 and 50 ng g-1 by a procedure which can mimic weathered soils. The samples were then dried and packed in a 25 cm × 4.6 mm i. d. stainless steel column; this was placed inside a GC oven and extracted by passing an aqueous solution of KCl (0.1 M, 20 mL) through the column at 90°C. Quantification of the analytes in the final extract (50-μL injection) was performed by reversed-phase liquid chromatography-mass spectrometry with a TurbolonSpray interface. Recoveries of the analytes were greater than 83% and RSD less than 7%. The method detection limit was in the 1 - 2.5 ng g-1 range in analysis by time-scheduled selected-ion monitoring (SIM)

Simultaneous quantitation of free and conjugated phytoestrogens in leguminosae by High Performance Liquid Chromatography-Tandem Mass Spectrometry.

Phytoestrogens are diphenolic compounds that are present in several edible plants and are particularly abundant in soybeans. Because of their estrogenical, antriestrogenical, anticarcinogenic and antioxidant activities in animal and humans, they became of great interest. Dietary factors are considered important in determination of risks, in fact, studies have revealed beneficial or protective effects of the consumption of vegetables, in particular soy and soybean products. So that in the present paper the simultaneous determination of eight isoflavones and coumestrol in vegetables is reported. The quantitative analysis has been made by means of LC separation combined with tandem mass spectrometry. In particular, a new simple and fast extraction methodology and a clean-up, based on cold aided de-fatting, is proposed. Method performancewas evaluated by comparison with a reference procedure. The developed procedure was then used for a survey of phytoestrogens concentration in some selected vegetables

HPLC-MS/MS con sorgente a fotoionizzazione nella determinazione di benzidine e cloroaniline in effluenti industriali

Le benzidine e le cloroaniline, sono composti chimici potenzialmente presenti in numerosi processi industriali, quali ad esempio l’industria tessile dei pellami e nella produzione dei coloranti. La contaminazione ambientale da parte di tali sostanze, quindi, è un evento da tener presente, anche in considerazione delle rilevanti implicazioni tossicologiche di gran parte delle stesse (cancerogeni accertati o probabili, utilizzo della benzidina addirittura proibito dal 2002). Le tecniche analitiche reperibili in letteratura per la determinazione di queste sostanze in campioni acquosi sono quelle basate su GC ed HPLC. Tutte presentano delle limitazioni nella applicazione pratica, dovute a problemi di sensibilità e specificità dei metodi utilizzati. Tuttavia, dato che questi composti tossici devono essere determinati in matrici molto complesse (come gli effluenti industriali) ed a bassissime concentrazioni, occorre che la tecnica di rivelazione sia molto specifica e selettiva. Per questo motivo appare opportuno ricorrere alla spettrometria di massa come metodo di rivelazione e di conferma per questi analit