Atilio Andrés Porta

Levels of glyphosate in surface waters, sediments and soils associated with direct sowing soybean cultivation in north pampasic region of Argentina

Levels of glyphosate were determined in water, soil and sediment samples from a transgenic soybean cultivation area located near to tributaries streams of the Pergamino-Arrecifes system in the north of the Province of Buenos Aires, Argentina. Field work took into account both the pesticide application and the rains occurring after applications. The pesticide was analysed by HPLC-UV detection, previous derivatization with 9-fluorenylmethylchloroformate (FMOC-Cl). In addition, SoilFug multimedia model was used to analyse the environmental distribution of the pesticides. In the field, levels of glyphosate in waters ranged from 0.10 to 0.70 mg/L, while in sediments and soils values were between 0.5 and 5.0 mg/Kg. Temporal variation of glyphosate levels depended directly on the time of application and the rain events. The results obtained from the application of the model are in accordance with the values found in the field.

Cu(II) acute toxicity to the rotifer Brachionus calyciflorus, as affected by fulvic acids of freshwater origin.

Natural fulvic acids (FA) from the Rio Santiago, an affluent of the Rio de la Plata estuary, were isolated by adsorption on XAD-2 at pH 2, and were then characterized by IR and fluorescence spectra, acidity and complexing capacity to Cu(II). The effect of the interaction between FA and Cu(II) on the acute toxicity of this heavy metal was assayed with the rotifer Brachionus calyciflorus in standardized in-vitro tests. A CuSO(4).5H(2)O concentration of 0.080 ppm produced 89.2% mortality in the absence of FA. At FA/Cu ratios >/= 1 no mortality was observed. Based on the values of the FA-Cu binding parameters and acute toxicity inhibition, it was possible to predict the effect of dissolved organic matter on the toxicity of copper in this surface freshwater body.

Analysis of total metals in waste molding and core sands from ferrous and non-ferrous foundries

Waste molding and core sands from the foundry industry are successfully being used around the world in geotechnical and soil-related applications. Although waste foundry sands (WFSs) are generally not hazardous in nature, relevant data is currently not available in Argentina. This study aimed to quantify metals in waste molding and core sands from foundries using a variety of metal-binder combinations. Metal concentrations in WFSs were compared to those in virgin silica sands (VSSs), surface soils and soil guidance levels. A total analysis for Ag, Al, Ba, Be, Cd, Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Pb, Sb, Te, Tl, V, and Zn was conducted on 96 WFSs and 14 VSSs collected from 17 small and medium-sized foundries. The majority of WFSs analyzed, regardless of metal cast and binder type, contained metal concentrations similar to those found in VSSs and native soils. In several cases where alkyd urethane binder was used, Co and Pb concentrations were elevated in the waste sands. Elevated Cr, Mo, Ni, and Tl concentrations associated with VSSs should not be an issue since these metals are bound within the silica sand matrix. Because of the naturally low metal concentrations found in most WFSs examined in this study, they should not be considered hazardous waste, thus making them available for encapsulated and unencapsulated beneficial use applications.

Use of standardized procedures to evaluate metal leaching from waste foundry sands

As part of the casting process, foundries create sand molds and cores to hold the molten metal to specific dimensional tolerances. Although most of the waste foundry sands (WFSs) from this process are land filled, there is great interest in diverting them for use in agricultural and geotechnical applications. One potential limitation to their beneficial use is concern that the WFSs will leach high levels of trace metals. The aim of this study was to quantify Ag, Ba, Cd, Cr, Cu, Ni, Pb, and Zn in leaching extracts from 96 waste molding and core sands from ferrous and nonferrous foundries. The procedures used to assess leaching in the WFSs were the Extraction Procedure, the Toxicity Characteristic Leaching Procedure, and the American Society for Testing and Materials water extraction procedure. The metal extract concentrations were compared with those found in virgin silica sands and Argentinean and U.S. hazardous waste laws to determine if the WFSs met toxicity limits. Regardless of metal cast and sand binder type, the majority of the WFS extracts analyzed contained metal concentrations similar to those found in virgin sand extracts and were below levels considered hazardous. However, 4 of 28 sands that used alkyd urethane binder were deemed hazardous because Pb concentrations in these sands were found to exceed regulatory thresholds. Although other regulated metals, such as As, Hg, and Se, were not analyzed in the extracts, this dataset provides additional evidence that many WFSs have a low metal leaching potential.

Exposure and risk analysis to particulate matter, metals, and polycyclic aromatic hydrocarbon at different workplaces in Argentina

In order to estimate air quality at work environments from small and medium-sized enterprises (SMEs), we determined both the concentration of particulate matter (PM10 and PM2.5) and the presence of polycyclic aromatic hydrocarbons (PAHs), as the heavy metals in the composition of the particulate matter. Three SMEs located in the city of La Plata, Argentina, were selected: an electromechanical repair and car painting center (ERCP), a sewing work room (SWR), and a chemical analysis laboratory (CAL). The results evidenced high levels of PM exceeding the limits allowed by the USEPA and the presence of benzo(k)fluoranthene in all the analyzed sites and benzo(a)pyrene in the most contaminated site (ERCP). Regarding metals, the presence of Cd, Ni, Cu, Pb, and Mn, mainly in the fraction of PM2.5, in the same workplace was found. As far as risk assessment at all the workplaces surveyed is concerned, risk values for contracting cancer throughout life for exposed workers (LCR) did not comply with the parameters either of USEPA or of WHO (World Health Organization).

The effect of air pollution on children's health: a comparative study between La Plata and Bahía Blanca, Buenos Aires Province, Argentina

We present the results of a study of outdoor air quality in two comparable regions of Buenos Aires province (Argentina); La Plata and Bahia Blanca, developed jointly by researchers of the National University in both cities, and of the Hospital of Bahia Blanca, between 2009 and 2011. Both regions are characterized by a large petrochemical complex and a village with outstanding traffic. In this study, we measure levels of volatile organic compounds (VOCs), particulate matter suspended in air (PM) in air outdoor and affectation of respiratory system in children between 6 and 12 years. Also, analysis of the effect of the air pollution exposure was made through the calculation of potentially increased life time cancer risk (LCR) in children. In both regions, including three areas: urban, industrial and residential (reference area), 20 VOCs were sampled by passive monitoring (3M 3500), and determined by GC/FID, comprising n-alkanes, cycloalkanes, aromatics, chlorinated compounds,