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Torrijos M.C.,CONICET | Torrijos M.C.,National University of La Plata | Giaccio G.,Commission of Scientific Research of Buenos Aires Province CIC | Giaccio G.,National University of La Plata | And 2 more authors.
Materials and Structures/Materiaux et Constructions | Year: 2010

The durability of concrete constructions is strongly related with the transport of fluids through the material. The presence of pores and cracks increases the permeability of the material, enhancing the ingress of aggressive agents that contribute to the material degradation. In this sense the internal structure is decisive, mainly the characteristics of the mortar matrix and the aggregates of greater size and its interfaces. In this work the incidence of different types of cracks on the transport properties is analyzed, considering several cases of degradation: concretes damaged by exposure to low humidity conditions or to high temperatures (150 and 500°C), and a concrete affected by alkali-silica reaction (ASR). The characterization of the internal structure was made at the mesostructural level through the assessment of the density and width of cracks; as transport properties the water absorption, capillary absorption, water penetration and coefficient of water permeability were considered. As expected the width, the density and the type of fissures had a strong impact on the transport properties, however each variable will have a higher or lower incidence depending on the transport mechanism involved. In concretes damaged by drying shrinkage the permeability increased steadily with the crack density, however, the capillary absorption after reaching a maximum decreased for cracks of greater width. At the same time in concrete damaged by ASR, differences were found in the water penetration test in accordance with the crack orientations which were not verified in the values of the coefficient of permeability. © 2010 RILEM. Source

Peluso F.,National University of Central Buenos Aires | Peluso F.,Commission of Scientific Research of Buenos Aires Province CIC | Dubny S.,National University of Central Buenos Aires | Dubny S.,Commission of Scientific Research of Buenos Aires Province CIC | And 2 more authors.
Human and Ecological Risk Assessment | Year: 2014

DelAzulPestRisk is a risk-based chemical ranking model based on human and local biota toxicities that estimates the integrated risk of pesticides in water from their extensive (concentration, risk) and intensive (persistence, bioaccumulation) chemical properties. The model is built on two modules: human health risk factor (estimated based on the probabilistic cancer and non-cancer health risk by using U.S. Environmental Protection Agency models applied to a bathing exposure scenario) and biota health risk factor (quantified on the basis of the probabilistic toxicity exposure ratio -PEC/PNEC- for three local representatives of water biota multiplied by an amplification factor supported by the persistence and bioaccumulation potential). The model was applied to shallow creeks of Tres Arroyos County, Argentina, which flow across wheat and soybean agricultural lands, and in whose waters were detected many organochlorine pesticides (α, γ, y, δ-HCH, aldrin, heptachlor, γ-chlordane, endosulfan, endosulfan sulphate, dieldrin, and DDD). Dieldrin, aldrin, and heptachlor generated the worst potential effects-due mainly to the cancer and non-cancer dermal health risk-although this was not a significant environmental threat. DelAzulPestRisk is a screening assessment tool for water management purposes that become useful in countries lacking efficient water quality control systems. © 2014 Taylor & Francis Group, LLC. Source

Peluso F.,Flatlands Hydrology Institute Dr Eduardo Usunoff | Peluso F.,Commission of Scientific Research of Buenos Aires Province CIC | Othax N.,Flatlands Hydrology Institute Dr Eduardo Usunoff | Othax N.,CONICET | And 3 more authors.
Human and Ecological Risk Assessment | Year: 2014

The aim of the study is to assess the probabilistic non-cancer and cancer risks by recreational bathing in Tres Arroyos creeks (southeastern Buenos Aires Province, Argentina). In these waters, hazardous substances (heavy metals, pesticides) have been detected, possibly related to agricultural activities. To assess such risk, USEPA models in aggregated (exposure through accidental oral water intake and dermal contact simultaneously) and cumulative approaches (combined exposure to more than one substance) were applied, performed for bathers of 5, 10, 15, and 20 years old. The results show that chronic bathing in these waters is not harmful at the concentrations and the exposure scenarios considered. Arsenic was the riskiest substance for both non-cancer and cancer effects, affecting mainly the youngest age group, and the accidental water intake during bathing was the most relevant pathway of exposure. On the other hand, the study highlights the key role of the frequency and duration of the bath event. We discuss the results in light of a previous paper of our authorship concluding that the health risk assessment is a valid alternative to analyze recreational water quality, which, unfortunately, is unused by water management agencies in Argentina. © 2014 Copyright Taylor and Francis Group, LLC. Source

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