Estudio epidemiológico de arsénico en agua subterránea para consumo humano en el territorio del Cluster Lechero Regional, Argentina / Epidemiological study of arsenic in groundwater for human consumption in the territory of the Cluster Lechero Regional, Argentina

En diversas regiones del mundo se han encontrado acuíferos, destinados para el consumo humano, con niveles de arsénico que sobrepasan los límites recomendados por las agencias ambientales o fijados por la legislación, lo que representa un grave problema de salud pública. En el noroeste de la provincia de Santa Fe y sur de Santiago del Estero, área en estudio, los antecedentes indican la existencia de acuíferos con concentraciones de minerales que superan ampliamente los valores recomendados para consumo humano. Estos niveles de salinidad aumentan con la profundidad, y se detecta además, la presencia de tóxicos como el arsénico, siendo un factor condicionante para el aprovechamiento del agua subterránea. En el territorio del Cluster Lechero Regional, se estudió la composición salina del agua subterránea y, en particular, la concentración de arsénico, con el objetivo de establecer niveles de toxicidad y el potencial desarrollo de enfermedades crónicas. Los resultados muestran elevada salinidad y una concentración media de arsénico en la zona de 0,203 mg/L. Estimamos que, para una población de riesgo de 57.436 habitantes que no tienen acceso a sistemas de agua de red, expuestos teóricamente a la concentración de arsénico hallada en este estudio, se manifiesten 500 casos de cáncer atribuibles a este nivel de exposición en los próximos años. La población infantil comprendida entre 0 y 2 años de edad (3.690 niños de la región) podría desarrollar lesiones dérmicas y efectos neurológicos de distinta magnitud.

In various regions of the world, it has been found aquifers, destined for human consumption, with arsenic levels that exceed the limits recommended by the environmental agencies or required by law, so that represents a serious public health problem. In the northwest of the province of Santa Fe and the south of Santiago del Estero, defined study area, the background information indicates the existence of aquifers with concentrations of minerals that far exceeded the recommended values for human consumption. These levels of salinity increases with depth and, in addition, it was detected the presence of toxic substances such as arsenic, being a conditioning factor for the groundwater use. In the territory of the Cluster Lechero Regional, the composition of the saline groundwater was analized and, in particular, the concentration of arsenic was assessed, with the aim of setting levels of toxicity and the potential development of chronic diseases. Results showed high salinity and an average concentration of arsenic in the area of 0.203 mg/L. We believe that for a high risk population of 57,436 inhabitants, with no access to a water system network, and theoretically exposed to the concentration of arsenic found in this study, it would be expected 500 cases of cancer attributable to this level of exposure, in the next years. Children between 0 and 2 years old (3,690 children from the region) could develop skin lesions and neurological effects of different magnitude.

Chi-square analysis of the reduction of ATP levels in L-02 hepatocytes by hexavalent chromium

This study explored the reduction of adenosine triphosphate (ATP) levels in L-02 hepatocytes by hexavalent chromium (Cr(VI)) using chi-square analysis. Cells were treated with 2, 4, 8, 16, or 32 μM Cr(VI) for 12, 24, or 36 h. Methyl thiazolyl tetrazolium (MTT) experiments and measurements of intracellular ATP levels were performed by spectrophotometry or bioluminescence assays following Cr(VI) treatment. The chi-square test was used to determine the difference between cell survival rate and ATP levels. For the chi-square analysis, the results of the MTT or ATP experiments were transformed into a relative ratio with respect to the control (%). The relative ATP levels increased at 12 h, decreased at 24 h, and increased slightly again at 36 h following 4, 8, 16, 32 μM Cr(VI) treatment, corresponding to a "V-shaped" curve. Furthermore, the results of the chi-square analysis demonstrated a significant difference of the ATP level in the 32-μM Cr(VI) group (P < 0.05). The results suggest that the chi-square test can be applied to analyze the interference effects of Cr(VI) on ATP levels in L-02 hepatocytes. The decreased ATP levels at 24 h indicated disruption of mitochondrial energy metabolism and the slight increase of ATP levels at 36 h indicated partial recovery of mitochondrial function or activated glycolysis in L-02 hepatocytes.

Câncer de pulmão ocupacional / Occupational lung cancer

O câncer de pulmão é multicausal. Fatores hereditários, genéticos e ambientais interagem na sua gênese. O principal fator de risco é o tabagismo. Entretanto, o ambiente de trabalho é um local de possível exposição a agentes cancerígenos. Atualmente, a International Agency for Research on Cancer lista 19 substâncias/situações de trabalho/ocupações comprovadamente associadas ao câncer de pulmão (grupo 1). A abordagem da ocupação em pacientes portadores de câncer de pulmão é fraca, impactando negativamente na busca da causalidade e, consequentemente, no desvelamento de casos de câncer ocupacional. Os objetivos desta revisão foram elencar os agentes reconhecidamente indutores de câncer de pulmão, discutir a contribuição da ocupação no desenvolvimento da doença, citar as publicações nacionais sobre o tema e sugerir uma lista de procedimentos que são essenciais para uma adequada investigação da relação de causalidade entre câncer de pulmão e ocupação.

Lung cancer is a multifactorial disease. Hereditary, genetic, and environmental factors interact in its genesis. The principal risk factor for lung cancer is smoking. However, the workplace provides an environment in which there is a risk of exposure to carcinogens. The International Agency for Research on Cancer currently lists 19 substances/work situations/occupations that have been proven to be associated with lung cancer (group 1). Thorough occupational history taking is not widely practiced in patients with lung cancer, which has a negative impact on the investigation of causality and, consequently, on the identification of cases of occupational cancer. The objectives of this review were to list the agents that are recognized as causes of lung cancer, to discuss the contribution of occupation to the development of the disease, to cite national studies on the subject, and to propose a list of procedures that are essential to the appropriate investigation of causality between lung cancer and occupation.

Nanoparticles-A Thoracic Toxicology Perspective

A substantial literature demonstrates that the main ultrafine particles found in ambient urban air are combustion-derived nanoparticles (CDNP) which originate from a number of sources and pose a hazard to the lungs. For CDNP, three properties appear important-surface area, organics and metals. All of these can generate free radicals and so induce oxidative stress and inflammation. Inflammation is a process involved in the diseases exhibited by the individuals susceptible to the effects of PM- development and exacerbations of airways disease and cardiovascular disease. It is therefore possible to implicate CDNP in the common adverse effects of increased PM. The adverse effects of increases in PM on the cardiovascular system are well-documented in the epidemiological literature and, as argued above, these effects are likely to be driven by the combustion-derived NP. The epidemiological findings can be explained in a number of hypotheses regarding the action of NP:-1) Inflammation in the lungs caused by NP causes atheromatous plaque development and destabilization; 2) The inflammation in the lungs causes alteration in the clotting status or fibrinolytic balance favouring thrombogenesis; 3) The NP themselves or metals/organics released by the particles enter the circulation and have direct effects on the endothelium, plaques, the clotting system or the autonomic nervous system/ heart rhythm. Environmental nanoparticles are accidentally produced but they provide a toxicological model for a new class of purposely 'engineered' NP arising from the nanotechnology industry, whose effects are much less understood. Bridging our toxicological knowledge between the environmental nanoparticles and the new engineered nanoparticles is a considerable challenge.

Riesgo infantil por exposición a carcinógenos en un área de alto tránsito vehicular / Child risk exposure to carcinogens in a high traffic area

La contaminación del aire es una amenaza aguda, acumulativa y crónica para la salud y el ambiente. Las personas están expuestas a contaminantes de aire en exteriores e interiores. Las exposiciones a los mismos puede generar o agravar afecciones respiratorias, cardíacas y otras. La presente experiencia nace como la necesidad de conocer la calidad del aire en áreas de alto tránsito vehicular, con potencial riesgo para la salud de la población infantil. Experiencia que se desarrolla desde la gestión de la Dirección de Salud Ambiental, con una visión epidemiológica, con la participación de Centros de Investigación-Universidades Nacionales y recursos municipales.Sobresale en esta investigación la caracterización de escenarios de riesgo por los valores alto de benceno; con su correspondiente índice de peligro, según peso corporal del niño. También por el alto porcentaje de emisiones vehicular de material particulado. Se ha detectado la presencia en el 21 % de las muestras benzo[a]pireno, asociados con las partículas finas y se ha encontrado mayor valor de mutagenicidad (ensayo de Ames), en una de las zonas bajo estudio. Detección de tóxicos críticosque estarían presentes, durante la ventana de vulnerabilidad crítica del desarrollo del niño, llevando a intensificar las medidas correctivas y los estudios en la población vulnerable.

Mutagénesis ambiental y el uso de biomarcadores para predecir el riesgo de cáncer: [revisión] / Environmental mutagenesis and use of biomarkers in cancer risk prediction: [review]

The field of environmental mutagenesis or toxicology genetics aims to study the genetic damage that leads to mutations produced by physical, chemical and biological agents, to identify these agents and analyze their interactions and ways of action. There are enough experimental and epidemiological evidences implicating mutations in oncogenes, tumor suppressor genes and DNA repair genes as determinants in the onset and progression of the neoplastic process. A valuable tool in public and occupational health is the monitoring of populations exposed to potentially hazardous agents. The objective is to protect the health and quality of life of high risk groups on account of the nature of the agents of exposure. Monitoring of genotoxic effects in exposed populations as well as the analysis of susceptibility polymorphism are visualized as key tools in the realm of future public and occupational health in order to prevent the occurrence of environmental and specially occupational origin of tumors. This paper reviews the main concepts concerning this issue and refers to studies on the subject in Costa Rica.

Gut microflora & toxic metals: chromium as a model.

The gastrointestinal tract (GIT) is exposed to various environmental pollutants including metals, that contaminate food and water which may have toxic effects on body. GIT has large amount of microbes that live in symbiosis and help the host in different ways. The resident gut microflora have a significant role to play in detoxification and elimination of the harmful metals from the body. Chromium is a naturally occurring heavy metal found commonly in environment in trivalent (Cr III) and hexavalent (Cr VI) forms. Cr (VI) compounds have been shown to be potent occupational carcinogens. The reduction of Cr (VI) to Cr (III) results in the formation of reactive intermediates that together with oxidative stress and oxidative tissue damage, and a cascade of cellular events including modulation of apoptosis regulatory gene p53 contribute to the cytotoxicity, genotoxicity and carcinogenicity of Cr(VI)-containing compounds. The data discussed here with reference to chromium show that gut microflora have a marked capacity to cope with the increased load of ingested metals and may contribute significantly in the protection against metal toxicity.

Spermatogenic and steroidogenic impairment after chromium treatment in rats.

Feeding of hexavalent chromium at doses of 20, 40 and 60 mg/kg daily for 90 days caused cellular impairment in rat testis. Spermatogenic inhibition coupled with deminution in testicular protein, DNA and RNA was significant at the doses 40 and 60 mg kg chromium. Decline of Leydig cell population and nuclear diameter indicated the steroidogenic impairment and the effect was confirmed by the significant inhibition of 3 beta-delta 5-hydroxy steroid dehydrogenase along with low level of serum testosterone.

Mutagênese, carcinogênese e teratogênese: métodos e critérios de avaliaçäo / Mutagenesis, carcinogenesis and teratogenesis: evaluation methods and criterias

O desenvolvimento industrial tem como consequência inevitável a exposiçäo do homem a um número crescente de agentes que constituem um risco para sua saúde. E imprescindível estabelecer normas de uso desses agentes, baseadas em estudos atualizados, capazes de identificar os que tem potencialidades mutagênicas, teratogênicas ou carcinogênicas. A vulnerabilidade do material genético a agressöes impostas pelo ambiente criou uma nova área de pesquisa - a Genética Toxicológica - na qual especialistas em genética, bioquímica, biologia molecular e toxicologia trabalham para estudar as lesöes e alteraçöes induzidas por substâncias químicas. Os ensaios de genotoxidade säo acompanhados de protocolos detalhados e da análise crítica de sua aplicabilidade