Toxic elements in soil and rice in Ecuador

The concentration of trace toxic metals (Cr, Zn, As, Pb, Cd, Cu, and Ni) in soil and rice plants, including the stems, leaves, and grain, from the main rice-producing provinces in Ecuador, was determined. Additionally, the soils were analyzed to determine their properties, composition, total content, bioavailable fraction, and geochemical fractions of toxic elements. Approximately 30% of soil samples in the case of Cr and Cu and 10% of samples in the case of Ni exceeded the legal thresholds for Ecuador. Moreover, for Cr and Cu, approximately 4% and 13% of samples, respectively, exceeded the threshold value of 100 mg kg−1 proposed for these two elements in several international regulations. Concentrations of As, Pb, and Cd in the soils were below the threshold values established both by Ecuadorian laws and by other countries. The concentrations of metals in rice plants did not correlate linearly with the total metal concentrations in the soil, nor with their bioavailability. However, the bioconcentration factors for As, Cd, Cu, Ni, and Zn could be predicted from bioavailability by a power law with exponents ranging from −0.724 to −1.625, which is typical of accumulator plants, where trace metal homeostasis plays an important role.info:eu-repo/semantics/publishedVersio

Selectivity of sodium pyrophosphate and unbuffered chlorides (CuCl2 and LaCl3) as extractants of aluminum bound to soil organic matter in soils of the sandy coastal plain in São Paulo state

O Al em complexos com matéria orgânica do solo é comumente determinado por técnicas de dissolução seletiva. Um extrator comum para essa forma do elemento é o pirofosfato de sódio. Devido à sua falta de seletividade para algumas amostras de solos, extratores não tamponados de Al, como CuCl2 e LaCl3, têm sido recomendados. A seletividade do pirofosfato de sódio (Al p) e dos cloretos não tamponados de cobre (AlCu) e de lantânio (AlLa) como extratores de Al ligado à matéria orgânica foi avaliada em 31 perfis de solos (Espodossolos e Neossolos Quartzarênicos), representativos das áreas sob vegetação de restinga do litoral paulista. Os resultados foram comparados aos obtidos com oxalato de amônio e KCl, seguindo-se as interpretações comumente observadas na literatura quanto à capacidade extratora e seletividade dos reagentes utilizados. Pirofosfato careceu de total seletividade para amostras que apresentaram formas inorgânicas de Al. Os reagentes CuCl2 e LaCl3, por sua vez, foram mais seletivos para as formas de Al orgânico nas mesmas amostras, cuja ordem de extractabilidade foi: Al p>AlCu>AlLa . As diferentes habilidades extratoras e as relações entre os reagentes utilizados possibilitaram convergir evidências analíticas a fim de analisar e interpretar algumas determinações, como saturação por Al no húmus e estabilidade das interações Corg-metal. Horizontes espódicos Bs, Bhs e Bsm detiveram a maior estabilidade da interação Corg-metal e saturação por Al no húmus entre todos os horizontes estudados. Dos resultados encontrados, conclui-se que todos os reagentes analisados podem ser utilizados como extratores de Al associado à matéria orgânica dos solos, uma vez que permitiram estabelecer relações e interpretações contundentes quanto ao entendimento da química dos complexos Al-húmus dos solos de restinga estudados. Esses extratores, portanto, são adequados e têm potencial para os estudos e entendimento dos processos envolvidos na gênese dos Espodossolos tropicais derivados de sedimentos quartzosos costeiros.Aluminum in complexes with soil organic matter is usually determined by selective extraction techniques. A common extractant for this Al form is sodium pyrophosphate. Due to its lack of selectivity for some soil samples, unbuffered Al extractants, such as CuCl2 and LaCl3, have been recommended. The selectivity of sodium pyrophosphate (Al p) and of unbuffered Cu (AlCu) and La (AlLa) chlorides to extract aluminum bound to soil organic matter (Al-humus) was evaluated in soil samples from 31 pedons (Spodosols and Quartzipsamments) representative of the sandy coastal plains of the state of São Paulo. The results were compared with those obtained by ammonium oxalate and KCl and the extraction capacity and selectivity of the reagents interpreted as commonly used in the literature. Pyrophosphate was not totally selective for some samples containing inorganic aluminum. CuCl2 and LaCl3, in turn, were more selective for Al-humus in the same samples and their order of extractability was: Al p>AlCu>AlLa . Based on the different extraction capacities and the relations between the reagents used the analytic evidences were converged in order to analyze and interpret parameters such as Al saturation in the soil organic matter and stability of C-metal interactions. The stability of the interaction C-metal and humus Al saturation of all horizons studied was greater in the Bs, Bhs and Bsm spodic horizons. Based on the results it was concluded that all reagents studied can be used as Al extractants since they allow establishing relations and interpretations that may help understanding the complex chemistry of Al-humus on the studied Restinga soil. These extractors are therefore adequate and promising to study and understand processes involved in the genesis of tropical Spodosols derived from sandy coastal plain sediments.Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)FAPES

Temporomandibular disorders: the habitual chewing side syndrome

Background:Temporomandibular disorders are the most common cause of chronic orofacial pain, but, except where theyoccur subsequent to trauma, their cause remains unknown. This cross-sectional study assessed chewing function (habitualchewing side) and the differences of the chewing side and condylar path and lateral anterior guidance angles in participantswith chronic unilateral temporomandibular disorder. This is the preliminary report of a randomized trial that aimed to testthe effect of a new occlusal adjustment therapy.Methods:The masticatory function of 21 randomly selected completely dentate participants with chronic temporoman-dibular disorders (all but one with unilateral symptoms) was assessed by observing them eat almonds, inspecting the lateralhorizontal movement of the jaw, with kinesiography, and by means of interview. The condylar path in the sagittal plane andthe lateral anterior guidance angles with respect to the Frankfort horizontal plane in the frontal plane were measured onboth sides in each individual.Results:Sixteen of 20 participants with unilateral symptoms chewed on the affected side; the concordance (Fisher’s exacttest, P = .003) and the concordance-symmetry level (Kappa coefficientk= 0.689; 95% confidence interval [CI], 0.38 to 0.99;P = .002) were significant. The mean condylar path angle was steeper (53.47(10.88) degrees versus 46.16(7.25) degrees;P = .001), and the mean lateral anterior guidance angle was flatter (41.63(13.35) degrees versus 48.32(9.53) degrees P = .036)on the symptomatic side.Discussion:The results of this study support the use of a new term based on etiology, ‘‘habitual chewing side syndrome’’,instead of the nonspecific symptom-based ‘‘temporomandibular joint disorders’’; this denomination is characterized inadults by a steeper condylar path, flatter lateral anterior guidance, and habitual chewing on the symptomatic sideThis study was financed with a grant PI11/02507 from the Institute of Health Carlos III of the Ministry of Science and Innovation of the Government of Spain. It was completed with the equipment granted by the General Directorate of Universities and Research; Department of Education and University. Xunta de Galicia. Official Journal No. 143 Galicia, July 22, 1996. And the Department of Innovation, Industry and Commerce. Xunta de Galicia, April 30, 2004S

Smectite in mangrove soils of the State of São Paulo, Brazil

Minerais de argila esmectíticos são freqüentemente identificados em solos de manguezais, mas são escassas as informações sobre os tipos encontrados e suas origens. A despeito da importância para a agronomia e geotecnia, as esmectitas desempenham também importante papel no âmbito ambiental, atuando na adsorção de nutrientes, poluentes orgânicos e metais pesados. Esmectitas em solos de manguezais podem ser de origem detrítica, marinha ou continental, e também de neoformação. Assim, este estudo objetivou identificar os tipos de esmectitas presentes em solos de manguezais do Estado de São Paulo e relacioná-los com suas possíveis origens. Para tanto, foram amostrados solos de cinco manguezais distribuídos ao longo do litoral paulista, cuja identificação dos constituintes mineralógicos da fração argila foi realizada por difratometria de raios X (DRX) com aplicação do teste de Greene-Kelly e por espectroscopia no infravermelho com transformada de Fourier (FTIR). Destacando os picos na banda de 3.560 cm-1 e na região próxima a 798 e 820 cm-1, verificou-se o predomínio de nontronita nos solos dos manguezais do Rio Sítio Grande, Ilha de Pai Matos, Ilha do Caranguejo e Rio Itapanhaú e, possivelmente menor participação de montmorilonita férrica no manguezal do Rio Escuro. Como os sedimentos continentais destes ambientes são muito pobres em esmectitas, a origem destes minerais nos solos dos manguezais estudados está relacionada à sedimentação deixada pelas transgressões marinhas pretéritas ou aos processos de neoformação ou, ainda, com uma combinação de ambas origens.Smectitic clay minerals are frequently identified in mangrove soils, but there is little information about their types and origins. Besides their importance in the agronomical and geotechnical areas, smectites play an important environmental role by adsorbing nutrients, organic pollutants and heavy metals. Smectites found in mangrove soils can be of marine or continental detrital origin, or of neoformation origin. Thus, the objective of this study was to identify the types of smectites present in the State of São Paulo mangrove soils (Brazil), and to relate them to their possible origins. Soil samples were taken in five mangroves along the State of Sao Paulo State coast line. The mineral composition of the clay fraction was identified by X-ray Diffractometry (XRD) applying the Greene-Kelly test and by Fourier transform infrared spectroscopy (FTIR). Highlighting the peaks in the 3,560 cm-1 band and in the region near 798 and 820 cm-1, there was a predominance of nontronite in the soil at the Sítio Grande River, Pai Matos Island, Caranguejo Island and Itapanhaú River mangroves, and possibly a lower concentration of ferric montmorillonite in the Escuro River mangrove. Since the continental sediments in these environments are very poor in smectite, the origin of these minerals in the mangrove soils studied is related to sedimentation left by past marine transgressions, to neoformation processes, or yet to a combination of both origins

Valor predictivo de la candidiasis oral como marcador de evolución a SIDA

Objetivo: Determinar la validez de la candidiasis oral (CO) como marcador clinico de evolucion en los pacientes infectados por el Virus de la Inmunodeficiencia Humana. Diseno del estudio: En 1992, se efectuo una exploracion oral a un colectivo de 200 pacientes infectados por VIH, con una edad media de 36,8'}7 anos (rango 25-46 anos) para establecer el diagnostico de CO. Se registraron las variables edad, sexo, tiempo de evolucion de la enfermedad, conducta de riesgo, numero de linfocitos CD4/'ÊL, estadio clinico y tratamiento antirretroviral. De los 200 pacientes del grupo de estudio, 157 no cumplian criterios de SIDA en el momento de la exploracion basal y a estos se les efectuo un seguimiento semestral hasta que cumplieron dichos criterios, concluyendo el estudio al final de 2001. Resultados: De los 157 pacientes seleccionados, 71 (45,2%) no presentaron CO y de estos el 28,7% evoluciono a SIDA durante el periodo de seguimiento. De los 86 (54,8%) pacientes con CO, el 48,2% evoluciono a SIDA (RR=2,71). Al trasladar el origen del estudio al ano 1997 cuando se inicio la administracion de la terapia antirretroviral de alta eficacia (TAAE), no se observaron diferencias en el porcentaje de pacientes que evolucionaron a SIDA en relacion a la existencia o no de CO en la exploracion basal. El analisis multivariante demostro que la asociacion de la variable de exposicion CO con la evolucion a SIDA no alcanzo un valor predictivo. Conclusiones: El valor pronostico a largo plazo de la CO, no se ha determinado en pacientes que reciben terapia antirretroviral de alta eficacia (TAAE). La recuperacion inmunologica y la disminucion de enfermedades oportunistas observadas tras la administracion de TAAE, hacen que muchos pacientes que alcanzaron la condicion de SIDA no cumplan en la actualidad dichos criterios, lo que obliga a renovar la propia definición del síndrome para poder evaluar marcadores de pronóstico.Objective: To determine the validity of oral candidiasis (OC) as a clinical marker of progression in patients with human immunodeficiency virus infection. Study design: In 1992, an oral examination was carried out on a group of 200 HIV-infected patients with a mean age of 36.8 ± 7 years (range 25-46 years) to establish the diagnosis of OC. The following variables were recorded: age, sex, duration of the disease, risk behaviour, CD4 lymphocyte count, clinical stage and antiretroviral treatment. Of the 200 patients in the group evaluated, 157 did not fulfil the criteria for AIDS at the time of the baseline examination; these patients constitute the study group and underwent 6-monthly follow-up until they fulfilled these criteria. The study was concluded at the end of 2001. Results: Of the 157 patients selected, 71 (45.2%) did not present OC and, of these, 28.7% progressed to AIDS during the followup period. Of the 86 (54.8%) patients with OC, 48.2% progressed to AIDS (RR= 2.71). If the start date of the study was taken as 1997, when highly active antiretroviral therapy (HAART) was introduced, no differences were found in the percentage of patients who progressed to AIDS with respect to the presence or absence of OC at the baseline examination. Multivariate analysis demonstrated that the association of the presence of OC with progression to AIDS did not reach a predictive value. Conclusions: The long-term prognostic value of OC has not been established in patients receiving highly active antiretroviral therapy (HAART). The immunological recovery and the reduction in the number of opportunistic diseases observed after the administration of HAART means that many patients who developed AIDS do not currently satisfy these criteria, making a review of the definition of the syndrome itself a necessity in order to be able to evaluate prognostic markers

Fiabilidad de las pruebas de fuerza en salto vertical y velocidad de carrera en escolares de 6 a 8 años

El objetivo del presente estudio fue determinar la fiabilidad de diversas pruebas de salto vertical y de carrera rápida en escolares de 6 a 8 años. Participaron 56 sujetos de ambos sexos (30 niñas y 26 niños), de edades comprendidas entre 6 y 8 años, seleccionados aleatoriamente entre los de un mismo centro escolar, a los que se administró una batería de pruebas de fuerza de salto vertical sobre plataforma de contactos (SJ, CMJ, CMJA y 1RJ) y de carrera rápida (30 m) en dos ocasiones (T1 y T2), con una semana de intervalo entre ambas. Se estudió la reproducibilidad entre repeticiones (variabilidad intraindividual) para cada una de las dos sesiones de valoración (T1, T2) y la variabilidad temporal (entre T1 y T2), mediante el cálculo de diferentes estadísticos (coeficiente de variación, CV; coeficiente de correlación intraclase, CCI; error metódico, EM) y de su significación estadística. La reproducibilidad entre repeticiones de las pruebas de salto vertical CMJ y 1RJ se demostró elevada (CCI 0,95) en ambas sesiones. En la segunda sesión de valoración también lo fue la reproducibilidad de SJ, mientras que CMJA se mantuvo en niveles inaceptables (CCI = 0,69-0,80). La variabilidad entre sujetos se mostró bastante más elevada que en estudiantes de educación física adultos (CV = 8,3-11,8 %). La reproducibilidad temporal (día a día, entre dos sesiones separadas por una semana) de las pruebas puede considerarse cuestionable en términos generales, observándose un elevado error metódico (EM = 9,9-15,1 %) y un empeoramiento significativo de los resultados en la segunda sesión en las pruebas de salto con contramovimiento (CMJ y CMJA) y de carrera rápida de 30 m (p 0,05). En función de los resultados se proponen algunas medidas conducentes a la mejora de la fiabilidad de las pruebas

Assessment of variations in air quality in cities of Ecuador in relation to the lockdown due to the COVID-19 pandemic

This study analyzes the effect of lockdown due to COVID-19 on the spatiotemporal variability of ozone (O3), sulfur dioxide (SO2), and nitrogen dioxide (NO2) concentrations in different provinces of continental Ecuador using satellite information from Sentinel - 5P. The statistical analysis includes data from 2018 to March 2021 and was performed based on three periods defined a priori: before, during, and after lockdown due to COVID-19, focusing on the provinces with the highest concentrations of the studied gases (hotspots). The results showed a significant decrease in NO2 concentrations during the COVID-19 lockdown period in all the study areas: the Metropolitan District of Quito (DMQ) and the provinces of Guayas and Santo Domingo de los Ts & PRIME;achilas. In the period after lockdown, NO2 concentrations increased by over 20% when compared to the pre-lockdown period, which may be attributable to a shift towards private transportation due to health concerns. On the other hand, SO2 concentrations during the lockdown period showed irregular, non-significant variations; however, increases were observed in the provinces of Chimborazo, Guayas, Santa Elena, and Morona Santiago, which could be partly attributed to the eruptive activity of the Sangay volcano during 2019-2020. Conversely, O3 concentrations increased by 2-3% in the study areas; this anomalous behavior could be attributed to decreased levels of NOx, which react with ozone, reducing its concentration. Finally, satellite data validation using the corresponding data from monitoring stations in the DMQ showed correlation values of 0.9 for O3 data and 0.7 for NO2 data, while no significant correlation was found for SO2.info:eu-repo/semantics/publishedVersio

Relationship between soil, landscape and geological substrate of the sandy coastal plain of São Paulo state

Atributos morfológicos de 28 pedons, descritos e amostrados em cronossequências, e datações absolutas por luminescência (TL e LOE) e 14C foram utilizados para elucidar os principais fatores envolvidos na formação e evolução dos Espodossolos nos depósitos marinhos quaternários da planície costeira do Estado de São Paulo. Os solos estudados localizam-se nos municípios de Bertioga (Baixada Santista), Cananeia e Ilha Comprida (Litoral Sul). Essa abordagem, pouco comum nos estudos dos ambientes de planície costeira brasileiros, possibilitou as seguintes interpretações: (a) o relevo, a dinâmica hídrica e o tempo (incluindo as variações do nível relativo do mar) são os principais condicionantes da diferenciação espacial dos Espodossolos nos terraços marinhos; (b) os Espodossolos mais antigos e bem drenados, devido às condições de relevo e rebaixamento do nível do lençol freático, apresentam grande variabilidade e diversidade de seus horizontes e atributos morfológicos, diferindo daqueles mal drenados (antigos ou jovens), em que os horizontes são mais homogêneos; (c) os Espodossolos mais antigos, quando bem drenados, mostram-se em avançado estádio de degradação, enquanto os mal drenados encontram-se bem preservados, indicando que a sua gênese e permanência na paisagem estão ligadas ao relevo, que, por sua vez, controla a dinâmica hídrica; (d) os Espodossolos mais evoluídos e antigos, dotados de horizontes cimentados (orstein), podem ser considerados indicadores pedolitoestratigráficos dos depósitos marinhos pleistocênicos da Formação Cananeia; e (e) a gênese do horizonte orstein se deu em condições topográficas e hidrológicas pretéritas diferentes das atuais, indicando se tratar de solos poligenéticos ou paleossolos.This paper presents the results of morphological properties and absolute dating by luminescence and 14C of 28 pedons from Quaternary marine deposits located in three counties along the coast in São Paulo State, Brazil: Bertioga, Cananéia, and Ilha Comprida. The objective was to provide evidence to elucidate the main processes of the genesis of Spodosols. This approach, which is unusual in research concerned with Brazilian Quaternary coastal plains, resulted in the following interpretations: (a) relief, hydrologic conditions and time were the main soil formation factors responsible for the spatial differentiation of the Spodosols in marine terraces; (b) The horizon morphologic features of the most aged and well-drained Spodosols are highly variable and diverse. On the other hand, poorly drained Spodosols (old or young) are more homogeneous; (c) the oldest Spodosols, when well-drained, are in an advanced degradation stage while the poorly drained are well-preserved. This suggests that the genesis and permanence of the Spodosols on the landscape depend on the relief features controlling the hydrologic dynamics; (d) the most aged and developed Spodosols with orstein horizons can be considered lithostratigraphic indicators of marine deposits of the Pleistocene age in the Cananéia Formation; (e) the orstein horizon genesis took place under ancient topographic and hydrologic conditions that differ from the current. This indicates that such Spodosols are polygenetic or paleosols.Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)FAPES

Analysis of total arsenic content in purchased rice from Ecuador

Natural and anthropogenic sources contribute to arsenic contamination in water and human food chain in Andean countries. Human exposure to arsenic via rice consumption is of great concern in countries where this crop is the dominant staple food, and limited information is available on the arsenic contamination on rice in Ecuador. This work was to contribute to the lack of knowledge analysing total arsenic by hydride generation-atomic absorption spectrometry in the samples of white, brown and parboiled rice purchased in Ecuadorian markets and produced in the two main rice wetlands in Ecuador, Guayas and Los Ríos, were carried out. For the samples from Guayas, arsenic concentration in white, brown and parboiled rice were 0.174 ± 0.014, 0.232 ± 0.021, and 0.186 ± 0.017 mg/kg respectively, whereas samples of white rice from Los Ríos showed a total arsenic level of 0.258 ± 0.037 mg/kg. This last arsenic concentration exceeds recommended maximum permissible limit by the FAO/WHO. Obtained data have available to estimate the Ecuadorian dietary exposure revealing serious health risk for population.S