Classification Method fo Urban Solid Waste Disposal Sites

One of the environmental liabilities left by abandoned urban waste disposal sites, closed without the correct procedures, is the risk of exposure to their effluents, whose emissions may occur for many years. The purpose of the proposed methodology, referred to as SISTAVAFE, an assessment system of a closed landfill, is to contribute in the risk assess- ment of exposure to leachate as well as to suggest procedures for site monitoring, according to different levels of care and urgency. The method is based on four matrices that help make an initial evaluation of the risk source, potential target and the surface and underground environmental paths. This paper only addresses the contamination caused by liquid effluents.

Properties of a Lateritic Red Soil for Pollutant Containment

In many regions of Brazil, lateritic clays are the natural candidates for the construction of compacted clay liners of waste disposal sites because of their availability and appropriate geotechnical characteristics. Lateritic soils have been extensively used in recent decades in dam and road construction, but little is known about the migration of pollutants through compacted layers of such soils. This paper describes the characteristics of a lateritic clay, representing a group of soils of significant occurrence in the State of S?o Paulo, to be employed in a clay liner of a waste disposal site. Laboratory tests to assess permeability, adsorption and diffusion of six metals through the compacted soil showed that permeability criterion may be met in the field, that the soil presents a modest capacity to retain cadmium and that constituent metal oxides may be dissolved from the soil grains by acidic solutions.

Direct Electrochemical Determination of Glyphosate Herbicide Using a Screen-Printed Carbon Electrode Modified with Carbon Black and Niobium Nanoparticles

Glyphosate is a herbicide that has been widely used worldwide and is used in agricultural areas to control weeds and unwanted vegetation.Electrochemical sensors developed from different nanomaterials have high efficiency,excellent cost-benefit,and fast analysis time for detecting traces of environmental pollutants.This study aimed to produce an electrochemical sensor with disposable screen-printed electrodes based on carbon black modified with niobium nanoparticles to determine glyphosate in aqueous solutions.The morphology,structure and electrochemical performance of the sensor were characterized by scanning electron microscopy,energy-dispersive X-ray spectroscopy,X-ray diffraction and cyclic voltammetry.Differential pulse voltammetry in BR buffer solution at pH 5.0 allowed the generation of a method to quantify glyphosate concentration in a linear range of 5.90-172.30μmol/L(1.00-29.13μg/mL),with a limit of detection calculated at 3.07μmol/L(0.52μg/mL).The method efficiently quantified glyphosate in real water samples and showed no interference from K^(+),Na^(+),Ca^(2+),Mg^(2+)ions or thiamethoxam,imidacloprid and carbendazim pesticides.