Riesgo para la población rural en zonas con alto contenido de arsénico en agua / Risk for rural population in areas with high arsenic water content

El arsénico (As) es un tóxico natural presente en aguas subterráneas y superficiales. En este trabajo se estimó el riesgo por ingesta de agua subterránea con elevadas concentraciones de As para pobladores rurales bonaerenses. Además se consideró una fuente adicional de exposición a la presencia de As en tejidos blandos del pejerrey (Odontesthes bonariensis), que es la especie nativa de mayor importancia comercial. La concentración de As se determinó por espectroscopía de emisión atómica por plasma de acoplamiento inductivo (ICP-OES). En las muestras de agua subterránea las concentraciones se hallaron en el rango de < 10-170 µg/l, mientras que en músculos de peces estuvo comprendida entre 0,29-8,41 µg/g y en hígado entre 0,24-8,98 µg/g (en peso seco). El hidroarsenicismo crónico regional endémico Argentino (HACREA), enfermedad que se origina por el consumo de cantidades variables de As en un largo período de tiempo, genera diferentes afecciones de piel. El riesgo estimado por ingesta de agua subterránea en todas las localidades estudiadas superó el valor aceptado de riesgo individual máximo (10-5), según la Agencia de Protección Ambiental de los Estados Unidos (USEPA). Los niveles de As hallados en tejidos de peces, sugieren que existiría transferencia de este elemento desde el agua a los distintos órganos, que podría resultar perjudicial para el consumo humano.

Arsenic (As) is a natural toxic present in groundwater and surface water. This study estimated the risk of ingestion of high As concentrations present in groundwater for a rural population in Buenos Aires Province. The presence of As in soft tissues of silverside (Odontesthes bonariensis) was also considered as an additional source of As exposure, which is the native species of major commercial importance. Arsenic concentration was determined by inductively coupled plasma atomic emission spectroscopy (ICP-OES). In water samples As concentrations were found in the range of < 10-170 µg/l, in fish muscle the concentration range was between 0,29 to 8,41 µg/g, and in liver between 0,24 to 8,98 µg/g, of dry weight. The endemic regional chronic hydroarsenicism Argentino (ERCHA), a disease caused by consumption of varying As concentrations during a long time, generates different skin pathologies. The risk estimated for groundwater intake in this rural population at all sites studied exceeded the accepted value of maximum individual risk (10-5), according to United States Environmental Protection Agency (USEPA). As concentration in fish tissues, could be shown transference of this element to different organs, being harmful for human consumption.

Evaluación de la frecuencia de espina bífida oculta y su posible relación con el arsénico ambiental en una muestra prehispánica de la Quebrada de Camarones, norte de Chile / Spina bifida occulta associated with environmental arsenic exposure in a prehispanic sample from northern Chile

Background: The Camarones River Valley, located in the extreme north of Chile, is characterized by high environmental arsenic levels and an arid desert. It has been inhabited by humans for the past 7,000 years. Evidence exists for chronic arsenic poisoning in both prehispanic and present populations residing in the area. Chronic arsenic exposure causes multi-systemic problems and can induce congenital malformations, in particular neural tube development defects such as spina bifda. Aim: To study the prevalence of spina bifda among prehispanic mummies of the area. Material and Methods: Onehundred and twenty prehistoric adult individuals were analyzed for evidence of spina bifda occulta of the sacrum in skeletal samples from the sites of Camarones 8, Camarones 9, Azapa 140 and Lluta 54, held in repository at the Museo Universidad de Tarapacá de Arica- San Miguel de Azapa. A diagnosis was considered positive when at least S1, S2 or S3 were affected. As controls, mummies of individuals that resided in Lluta and Azapa valley, with a low arsenic exposure, were analyzed. Results: The frequency of spina bifda occulta among samples from the Camarones coast and Lluta and Azapa Valley were 13.5 and 2.4 percent respectively. Conclusions: Considering these were contemporaneous samples, and are believed to have had no other differences in diet or other factors, the differential exposures to arsenic could have produced the observed differences in spina bifda frequencies.

Optimización y validación metodológica de la cuantificación de arsénico por inyección en flujo -generación de hidruros- espectrometría de absorción atómica (IF-GH-EAA) previa derivatización con L-cisteína / Optimization and validation method for arsenic quantification by flow injection-hydride generation - atomic absorption spectrometry (FI-HG-AAS) after L-cysteine derivatization

El arsénico (As) es un contaminante natural que afecta una amplia zona de Argentina. El nivel de As en agua de consumo es utilizado para evaluar la fuente de exposición y en orina para evaluar exposición a este tóxico. El presente trabajo tuvo como objetivo la optimización y validación metodológica de una técnica para la cuantificación de As [As suma = As inorgánico (AsI) + especies metiladas: ácido monometilarsónico (MMA) y ácido dimetilarsónico (DMA)], producto del metabolismo del AsI, por inyección en flujo- generación de hidruros- espectrometría de absorción atómica (IF-GH-EAA), previa derivatización con L-cisteína. La recuperación de las especies estudiadas: AsI (AsIII y AsV), MMA y DMA fue cercana al 100% en todos los casos. Los límites de detección y cuantificación encontrados fueron para agua y orina: 2 y 3 µg/L; 5 y 8 µg/L respectivamente y el rango dinámico de trabajo establecido fue desde 5 a 75 µg/L, permitiendo cuantificar As en muestras de agua cercanos a los estándares internacionales vigentes para valores máximos de As en agua de consumo y en orina en niveles comparables con los establecidos en población laboralmente no expuesta. Esta propuesta metodológica es una alternativa para evaluar la exposición al As en muestras de agua y orina, sin necesidad de utilizar prolongados pre-tratamientos de muestra, de forma más rápida y económica.

Arsenic (As) is a natural contaminant that affects a large area of Argentina. Quantification of As in drinking water has been used to evaluate the source of exposure and As in urine to assess exposure to this toxic. This study aimed to optimize and validate a methodological technique for the quantification of As [As sum = inorganic As (AsI) + methylated species: monometilarsonic acid (MMA) and dimetilarsinic acid (DMA)], product of AsI metabolism by flow injection hydridegeneration-atomic absorption spectrometry (FI-GH-AAS), after derivatization with L-cysteine. The recovery of the studied species: AsI (AsIII and AsV), MMA and DMA was close to 100% in all cases. The limits of detection and quantitation were foundfor water and urine: 2 and 3 µg/L; 5 and 8 µg/L respectively and a linear working range from 5 to 75 µg/L, allowing quantify As in water close to international standards of maximum As values for drinking water and urine samples with levels comparables with those found in people non exposed ocupacionally . This methodology is a valid alternative for assessing exposure to As in water and urine samples without the need of prolonged pre-treatment sample, more quickly and inexpensively.

Arsenic and liver disease.

The hepatotoxic action of arsenic, when used as a therapeutic agent, has long been recognised. Data on liver involvement following chronic exposure to arsenic-contaminated water are scanty. The nature and degree of liver involvement are reported on the basis of hospital based studies in patients who consumed arsenic contaminated drinking water for one to 15 years. Two hundred forty-eight patients with evidence of chronic arsenic toxicity underwent clinical and laboratory examination including liver function tests and hepatitis B surface antigen (HBsAg) status. Liver biopsy was done in 69 cases; in 29 patients, liver arsenic content was estimated by neutron activation analysis. Hepatomegaly was present in 190 of 248 patients (76.6%). Non-cirrhotic portal fibrosis was the predominant lesion (91.3%) in liver histology. The maximum arsenic content in liver was 6 mg/kg (mean 1.46 [0.42], control value 0.16 [0.04]; p <0.001); it was undetected in 6 of 29 samples studied. The largest number of patients with liver disease due to chronic arsenicosis from drinking arsenic contaminated water are reported. Non-cirrhotic portal fibrosis is the predominant lesion in this population. Hepatic fibrosis has also been demonstrated due to long term arsenic toxicity in an animal model. Initial biochemical evidence of hepatic membrane damage, probably due to reduction of glutathione and antioxidant enzymes, may be seen by 6 months. Continued arsenic feeding resulted in fatty liver with serum aminotransferases elevated at 12 months and hepatic fibrosis at 15 months.

Hepatic manifestations in chronic arsenic toxicity.

OBJECTIVE: The hepatotoxic action of arsenic, when used as a therapeutic agent, has long been recognized. Data on liver involvement following chronic exposure to arsenic-contaminated water are scanty. We report the nature and degree of liver involvement on the basis of hospital-based and cohort follow-up studies in patients who consumed arsenic-contaminated drinking water for 1 to 15 years. METHODS: 248 patients with evidence of chronic arsenic toxicity underwent clinical and laboratory examinations including liver function tests and HBsAg status. Liver biopsy was done in 69 cases; in 29 patients, liver arsenic content was estimated by neutron activation analysis. A cohort follow up of 23 patients who took arsenic-free water for 2-12 years was also carried out. RESULTS: Hepatomegaly was present in 190 of 248 patients (76.6%). Noncirrhotic portal fibrosis (91.3%) was the predominant lesion in liver histology. The maximum arsenic content in liver was 6 mg/Kg (mean 1.46 [0.42], control value 0.16 [0.04]; p < 0.001); it was undetected in 6 of 29 samples studied. Cohort follow-up studies showed elevation of globulin in four cases and development of esophageal varices in one case. CONCLUSION: We report the largest number of patients with liver disease due to chronic arsenicosis from drinking arsenic-contaminated water. Noncirrhotic portal fibrosis is the predominant lesion in this population.