La prohibición de los perdigones de plomo es efectiva/The ban of lead-shot is effective

Radiografía de patos con perdigones en su molleja (ingeridos) y en el resto del cuerpo (disparo)/X-ray of ducks with lead shot in their gizzards (ingested) and in the rest of the body (fired) (IREC)

El perdigón de plomo fue prohibido en 2001 en los humedales españoles incluidos en la lista Ramsar, que enumera estas zonas de importancia internacional. Diez años más tarde, esta prohibición y la consecuente adopción del uso del perdigón de acero por parte de los cazadores ha empezado a dar sus frutos, según un estudio que publica la revista Environment International
“Lo más importante de nuestro trabajo es que se demuestra que el cambio de material –del perdigón de plomo al acero–, aun siendo una prohibición espacial parcial, ha reducido la intoxicación en las aves y la contaminación de la carne de caza”, declara Rafael Mateo Soria, del Instituto de Investigación en Recursos Cinegéticos (IREC), coautor del trabajo.
Los perdigones acumulados en los humedales, en muchas zonas con más de cien de estos proyectiles por metro cuadrado, permanecen en los sedimentos durante décadas. El principal daño que causan afecta a la propia salud de las aves. Al ingerir la munición, esta queda retenida en su molleja y se va deshaciendo de forma abrasiva en el estómago. El plomo liberado se absorbe y llega a los diferentes tejidos del animal.
En especies como el ánade azulón, en que un 30% de las aves cazadas a principios de los años 90 en el delta del Ebro habían ingerido perdigones de plomo, este porcentaje ha bajado hasta el 15%. La misma tendencia se observa en otras especies como el pato cuchara, la cerceta común o el porrón común.
Por el contrario, en el caso de los ánades rabudos cazados sigue siendo alarmante que más del 70% presenten perdigones en su molleja, un valor similar al observado hace tres décadas. El científico señala que para averiguar la razón del alto porcentaje de intoxicación en esta especie van comenzar el marcaje de aves con emisores. “Lo que sí sabemos es que por su tipo de dieta es una especie con alto riesgo de ingerir perdigones. No obstante, en otras que también tienen estos factores de riesgo, como el porrón europeo, su tasa sí ha disminuido al cambiarlos por los de acero”, añade.
Otro problema que origina el perdigón de plomo es la contaminación de la carne. Las trazas en los animales abatidos con este metal, incluso después de retirar los perdigones, superan los valores establecidos para la carne de consumo humano
Los investigadores quieren destacar que el cumplimiento de esta prohibición por parte de los cazadores ha sido muy alto y que han seguido cazando aves acuáticas en la misma cantidad después del cambio del plomo al acero. Sin embargo, la ley solo prohíbe el perdigón de plomo en humedales protegidos. Por este motivo, en los arrozales que los patos usan como zonas de alimentación sí están permitidos, lo que mantiene focos de contaminación para las aves y su carne.
Este estudio ha permitido valorar la efectividad de las medidas adoptadas por los países firmantes del Acuerdo para la Conservación de las Aves Acuáticas Migradoras de África-Eurasia (AEWA), un acuerdo para proteger las aves acuáticas en toda su ruta migratoria entre África y Eurasia y que han firmado una treintena de países europeos.

Ánade real o azulón/Mallard

Lead shot was forbidden in 2001 in Spanish wetlands on the Ramsar List of these areas of international importance. Ten years later, this prohibition -and the consequent use of steel shot by hunters- has started to bear fruit, according to a report in the journal ‘Environment International’.
“The most important part of our work is that it shows that, despite it’s still covering a partial area, the change of material from lead to steel shot has reduced waterfowl poisoning and the contamination of hunted meat,” says Rafael Mateo Soria of the Hunting Resources Research Institute (IREC) and co-author of the study.
Lead shot accumulating in wetlands, with over 100 per square metre in many areas, remains in the sediments for decades.Its main damage is to the health of waterfowl. When the shot is eaten it is retained in the gizzard and is worn down in the stomach, freeing lead that reaches the animal’s tissues.
In species such as the mallard, 30% caught at the start of the 1990s in the Ebro delta had ingested lead shot, a figure which has now dropped to 15%. The same trend has been seen in other species such as the northern shoveller, the Eurasian teal and the common pochard.
On the other hand, the case of the northern pintail caught continues to cause alarm since over 70% have shot in their gizzards, a rate similar to that seen three decades ago. The scientist notes that to discover the reason for the high percentage of poisoning in this species, they will start to fit birds with transmitters. "What we do know is that, because of its type of diet, this is a species with a high risk of ingesting shot. Nevertheless, in others that also have these risk factors, such as the common pochard, the rate has reduced after the change to steel shot," he added.
Another problem caused by lead shot is the contamination of meat. Even after lead shot was banned, the traces in animals caught with this metal exceed the limits set for meat for human consumption.
Researchers stress that the hunters’ compliance with this prohibition has been very high and that they have continued to hunt waterfowl in the same amount after the change from lead to steel. However, the law forbids lead shot in protected wetlands only. For this reason, lead shot is permitted in rice fields that ducks use as feeding areas, thus maintaining focuses of contamination for the birds and their meat.
This study has allowed the assessment of the effectiveness of the measures adopted by countries signing the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA), an agreement to protect waterfowl along their entire migration route between Africa and Eurasia and signed by some 30 European countries.


Tomado de/Taken from Sinc Noticias (español/inglés)

Resumen de la publicación/Abstract of the paper
Reducing Pb poisoning in birds and Pb exposure in game meat consumers: The dual benefit of effective Pb shot regulation
Mateo, R., Vallverdú-Coll, N., López-Antia, A., Taggart, M.A., Martínez-Haro, M., Guitart, R., Ortiz-Santaliestra, M.E.
Environment International 63: 163–168, 2014.
Abstract
The use of lead (Pb) ammunition in the form of shot pellets has been identified as a Pb exposure risk in wildlife and their human consumers. We explore the hypothesis that Pb shot ban enforcement reduces the risk of avian Pb poisoning as well as Pb exposure in game meat consumers. We assessed compliance with a partial ban on Pb shot commencing in 2003 by examination of 937 waterbirds harvested by hunters between 2007 and 2012 in the Ebro delta (Spain). Prevalence of Pb shot ingestion was determined, as were Pb concentrations in liver and muscle tissue to evaluate the potential for Pb exposure in game meat consumers. Hunted birds with only embedded Pb shot (no steel) declined from 26.9% in 2007–08 to < 2% over the following three hunting seasons after ban reinforcement. Pb shot ingestion in mallards decreased from a pre-ban value of 30.2% to 15.5% in the post-ban period. Liver Pb levels were predominantly defined by the presence of ingested shot, whereas muscle levels were defined by the presence of both ingested and embedded shot. Only 2.5% of mallard muscle tissue had Pb levels above European Union regulations for meat (0.1 μg/g wet weight) in the 2008–09 season, when Pb shot ingestion prevalence was also at a minimum (5.1%). Effective restrictions in Pb ammunition use have a dual benefit since this reduces Pb exposure for game meat consumers due to embedded ammunition as well as reducing Pb poisoning in waterbirds.

Nanopartículas y arcilla: una extraña mezcla/Nanoparticles and clay: a strange mix

Copyright: University of Virginia

Las nanopartículas y la arcilla se unen para dar dar lugar a un novedoso y barato sistema de purificación de agua, de interés para paises en vías de desarrollo y para zonas del primer mundo que no tienen acceso a agua tratada.
PureMadi, una organización sin ánimo de lucro de la Universidad de Virginia, ha inventado una sencilla placa cerámica para la purificación de agua. Llamada MadiDrop, la tableta - desarrollada y probada exhaustivamente en la Universidad de Virginia, está impregnada con nanopartículas de plata o de cobre. Desinfecta el agua pore seis meses simplemente poniéndola sobre un recipiente donde se vierte el agua. Está siendo desarrollada para su uso en las comunidades sudafricanas que tienen poco o ningún acceso a agua limpia
"Madi" es la palabra Tshivenda para agua. PureMadi reúne a profesores y estudiantes de la Universidad de Virginia con el fin de mejorar la calidad del agua, la salud humana, la empresa local y la calidad de vida en los países en vías de desarrollo.
Durante el pasado año, PureMadi estableció una fábrica de filtros de agua en la provincia de Limpopo, Sudáfrica, empleando trabajadores locales. La fábrica produjo varios centenares de filtros de agua en forma de maceta, Según James Smith, ingeniero civil y ambiental de la Universidad de "Con el tiempo esa fábrica será capaz de producir de 500 a 1.000 filtros por mes, y nuestro plan a 10 años vista, es la construcción de 10 a 12 fábricas en Sudáfrica y en otros países.../....Cada filtro puede servir para una familia de cinco o seis personas entre dos y cinco años, así que tenemos la intención de servir al menos a 500.000 personas al año con nuevos filtros."
La idea es crear empresas sostenibles que sirvan a sus comunidades y empleen trabajadores locales. Un pequeño porcentaje de los beneficios retornará a PureMadi y se usará para ayudar a establecer más fábricas.
Los filtros están hechos con arcilla local, serrín y agua. Los materiales se mezclan y se comprimen en un molde. El resultado es un filtro con forma de maceta, que luego se cuece en un horno, donde se quema el serrín dejando una cerámica con poros muy finos. El filtro se pinta luego con una disolución diluida de nanopartículas de plata o de cobre que sirven como desinfectante muy eficaz para los gérmenes patógenos transmitidos por el agua y causantes de diarrea, vómitos y deshidratación.
El diseño permite al usuario verter agua no tratada, como un río o un pozo, en la olla y dejar que se filtre a través suyo y caiga en un cubo de cinco galones (unos veinte litros) de capacidad. El filtro tiene una velocidad de flujo de entre uno y tres litros a la hora  lo suficiente para beber y cocinar. El agua filtrada sale a través de un grifo en el cubo.
Las pruebas han demostrado que los filtros son seguros y liberan sólo pequeñas cantidades de partículas de plata y cobre, que están dentro de los valores normales para el agua potable en el mundo desarrollado. Los filtros también podrán ser útiles en zonas rurales de países desarrollados, como Estados Unidos, donde las personas dependen de agua sin depurar
La plata se ha utilizado desde tiempos inmemoriales en varias formas plata metálica, nitrato de plata...) para el tratamiento de quemaduras, heridas e infecciones bacterianas. Su empleo decayó debido a la aparición de los antibióticos, pero muchos gérmenes se han hecho resistentes a los antibióticos, por lo que la plata ha vuelto a tomar actualidad como agente antimicrobiano. Además su uso en de nanopartículas aumenta sus capacidades antimicrobianas debido a la gran superficie de contacto de dichas partículas.

Nanopartículas de plata/Silver nanoparticles

Nanoparticlas and clay, together to give a novel and cheap system of water depuration, to be used in developped countries and in zones of the first worlfd without access to depuration facilities.
PureMadi, a nonprofit University of Virginia organization, has invented a simple ceramic water purification tablet. Called MadiDrop, the tablet -- developed and extensively tested at University of Virginia -- is impregnated with silver or copper nanoparticles. It can repeatedly disinfect water for up to six months simply by resting in a vessel where water is poured. It is being developed for use in communities in South Africa that have little or no access to clean water.
"Madi" is the Tshivenda word for water. PureMadi brings together U.Va. professors and students to improve water quality, human health, local enterprise and quality of life in the developing world.
During the past year, PureMadi has established a water filter factory in Limpopo province, South Africa, employing local workers. The factory produced several hundred flowerpot-like water filters. According to James Smith, a U.Va. civil and environmental engineer, "Eventually that factory will be capable of producing about 500 to 1,000 filters per month, and our 10-year plan is to build 10 to 12 factories in South Africa and other countries…/…"Each filter can serve a family of five or six for two to five years, so we plan to eventually serve at least 500,000 people per year with new filters."
The idea is to create sustainable businesses that serve their communities and employ local workers. A small percentage of the profits go back to PureMadi and will be used to help establish more factories.
The filters are made of local clay, sawdust and water. Those materials are mixed and pressed into a mold. The result is a flowerpot-shaped filter, which is then fired in a kiln. The firing burns off the sawdust, leaving a ceramic with very fine pores. The filter is then painted with a thin solution of silver or copper nanoparticles that serve as a highly effective disinfectant for waterborne pathogens, the type of which can cause severe diarrhea, vomiting and dehydration.
The design allows a user to pour water from an untreated source, such as a river or well, into the pot and allow it to filter through into a five-gallon bucket underneath. The pot has a flow rate of one to three liters per hour, enough for drinking and cooking. The filtered water is accessed through a spigot in the bucket.
Testing shows that the filters are safe to use and release only trace amounts of silver or copper particles, well within the safe water standards of the developed world. The filters also would be useful in rural areas of developed countries such as the United States where people rely on untreated well water.
Silver has been used since time immemorial in various forms (metallic silver, silver nitrate ...) for the treatment of burns, wounds and bacterial infections. Its use declined due to the advent of antibiotics, but as many bacteria have become resistant to antibiotics, silver presents today a potential interest as antimicrobial agent. Furthermore, its use as nanoparticles increases its antimicrobial capabilities due to the large surface area of these particles.

Tomado de/Taken from Sciencedaily

Propiedades antibacterianas de la plata/Silver antimicrobial propierties
Resumen de la publicación científica/Abstract of the paper
Silver nanoparticles as a new generation of antimicrobials
M. Rai, A. Yadav,A. Gade
Biotechnology Advances, 27(1) 76–83 (2009)
Abstract
Silver has been in use since time immemorial in the form of metallic silver, silver nitrate, silver sulfadiazine for the treatment of burns, wounds and several bacterial infections. But due to the emergence of several antibiotics the use of these silver compounds has been declined remarkably. Nanotechnology is gaining tremendous impetus in the present century due to its capability of modulating metals into their nanosize, which drastically changes the chemical, physical and optical properties of metals. Metallic silver in the form of silver nanoparticles has made a remarkable comeback as a potential antimicrobial agent. The use of silver nanoparticles is also important, as several pathogenic bacteria have developed resistance against various antibiotics. Hence, silver nanoparticles have emerged up with diverse medical applications ranging from silver based dressings, silver coated medicinal devices, such as nanogels, nanolotions, etc.

La atmósfera sobre el Mar Muerto contiene grandes concentraciones de mercurio oxidado/Air Above Dead Sea Contains Very High Levels of Oxidized Mercury

Según los investigadores, la atmósfera del Mar Muerto está cargada con mercurio oxidado. En esa zona se encuentran algunos de los mayores niveles de mercurio oxidado, aparte de las regiones polares.
Daniel Obrist y sus colegas del Desert Research Institute de Reno, Nevada (E.E.U.U.) y de la Hebrew University de Israel han encontrado y medido varios periodos con niveles extremadamente elevados de mercurio oxidado. El mercurio atmosférico puede estar en estado elemental u oxidado. Procede de fuentes naturales y antropogénicas y en la atmósfera se convierte de una forma a otra. Las especies oxidadas se depositan rápidamente después de su formación, siendo ésta la manera en que el mercurio, un potente neurotóxico, encuentra su camino en los ecosistemas globales, acumulándose en la cadena alimentaria a través de la pesca oceánica y llegando hasta el hombre.
Hasta ahora, las observaciones de concentraciones elevadas de mercurio oxidado se habían limitado a la atmósfera polar, en la que se forma mercurio oxidado durante los denominados 'eventos de disminución de mercurio atmosférico'. En ellos el mercurio elemental es convertido en mercurio oxidado que rápidamente se deposita sobre la superficie terrestre. Estos eventos pueden aumentar en cientos de toneladas cada año, la cantidad de mercurio en estos entornos árticos sensibles.

(GEM es Mercurio Elemental Gaseoso y RGM es Mercurio (oxidado) Gaseoso Reactivo)

Se pensaba hasta ahora que las temperaturas altas impedían estos procesos, pero se ha encontrado uno similar en el Mar Muerto, a temperaturas de 45ºC. Los mecanismos implicados en la conversión del mercurio en el Mar Muerto son similares a los de las regiones polares y son causados por el bromo.
Los investigadores opinan que los niveles de bromo observados sobre los océanos podrían ser lo bastante grandes como para iniciar la oxidación del mercurio. "Hemos descubierto que el bromo puede oxidar al mercurio en la atmósfera y lejos de los Polos, a latitudes medias. Esto apunta a un papel importante de la oxidación del mercurio inducida por el bromo sobre los océanos de todo el mundo"
Los resultados se publicaron on-line el 28 de noviembre en la revista 'Natural Geoscience'


Researchers have found that the atmosphere over the Dead Sea is laden with oxidized mercury. Some of the highest levels of oxidized mercury ever observed outside the Polar Regions exist there.
Daniel Obrist and colleagues at the Desert Research Institute in Reno, Nevada (USA), and at Hebrew University in Israel, measured several periods of extremely high atmospheric oxidized mercury. Mercury exists in the atmosphere in an elemental and in an oxidized state. It's emitted by various natural and human processes, and can be converted in the atmosphere between these forms. The oxidized form is deposited quickly after its formation, and that is the way in which mercury, a potent neurotoxin, finds its way into ecosystems accumulating through the food chain, via the fish caught in oceans and arriving at last to the man..
Until now, the observations of high naturally-occurring oxidized mercury levels had been limited to the polar atmosphere, where oxidized mercury is formed during 'atmospheric mercury depletion events' in which elemental mercury is converted to oxidized mercury, which is then readily deposited on earth surfaces. These events may increase mercury loads to sensitive arctic environments by hundreds of tons of mercury each year.

(GEM: Gaseous Elemental Mercury; RGM: Reactive (oxidized) Gaseous Mercury)

High temperatures were thought to impede this chemical process, but now a similar process has been found above the Dead Sea, a place where temperatures reach 45 degrees Celsius. The mechanisms involved in the conversion of mercury above the Dead Sea are similar to those in Polar Regions and are driven by bromine.
The researches also think that bromine levels observed above oceans may be high enough to initiate mercury oxidation. "We discovered that bromine can oxidize mercury in the mid-latitude atmosphere, far from the poles. That points to an important role of bromine-induced mercury oxidation in mercury deposition over the world's oceans."
The results were published online November 28th in the journal Nature Geoscience

Tomado de/Taken from Science Daily

Resumen de la publicación/Abstract of the paper
Bromine-induced oxidation of mercury in the mid-latitude atmosphere
Daniel Obrist, Eran Tas, Mordechai Peleg, Valeri Matveev, Xavier Faïn, David Asaf and Menachem Luria
Nature Geoscience 4, 22–26 (2011)
Mercury is a potent neurotoxin, which enters remote ecosystems primarily through atmospheric deposition. In the polar atmosphere, gaseous elemental mercury is oxidized to a highly reactive form of mercury, which is rapidly removed from the atmosphere by deposition. These atmospheric mercury-depletion events are caused by reactive halogens, such as bromine, which are released from sea-ice surfaces. Reactive halogens also exist at temperate and low latitudes, but their influence on mercury in the atmosphere outside polar regions has remained uncertain. Here we show that bromine can oxidize gaseous elemental mercury at mid-latitudes, using measurements of atmospheric mercury, bromine oxide and other trace gases over the Dead Sea, Israel. We observed some of the highest concentrations of reactive mercury measured in the Earth’s atmosphere. Peaks in reactive mercury concentrations coincided with the near-complete depletion of elemental mercury, suggesting that elemental mercury was the source. The production of reactive mercury generally coincided with high concentrations of bromine oxide, but was also apparent at low levels of bromine oxide, and was observed at temperatures of up to 45 °C. Using a chemical box model, we show that bromine species were the primary oxidants of elemental mercury over the Dead Sea. We suggest that bromine-induced mercury oxidation may be an important source of mercury to the world’s oceans

Información adicional/Suplementary information

Elementos traza en el Monte Everest/Trace elements on Mount Everest

Los científicos han encontrado niveles dañinos de metales pesados contaminantes en lugares remotos del monte Everest, una indicación de las grandes distancias que la contaminación atmosférica industrial puede recorrer.
Según los investigadores de la Universidad de Southern Maine en Gorham, todas las muestras de nieve recogidas entre los 5.334 y 7.772 metros metros de altitud contienen niveles de cadmio y de arsénico superiores a los valores permitidos en los E.E.U.U., mientras que las muestras de suelo contienen niveles perniciosos de cadmio.
De acuerdo al estudio, publicado en la revista Soil Survey Horizons, los niveles de las toxinas son mayores según nos acercamos a la cumbre de la montaña, lo que parece indicar que fueron transportados por vientos de gran altitud desde zonas industriales asiáticas.
Los investigadores señalan que estos resultados son preocupantes porque los escaladores y montañeros utilizan nieve derretida para obtener agua potable y porque los fuertes vientos pueden también levantar las toxinas desde el suelo.
En este caso, la cuestión no radica en la ingestión temporal de agua contaminada con elementos tóxicos. El problema es que uno de los rincones más salvajes e inaccesibles de nuestro planeta ha sido ya contaminado por la mano del hombre.

Scientists have found harmful levels of heavy metal pollutants on remote reaches of Mount Everest, an indication of the great distances industrial air pollution can travel.
Every snow sample collected at altitudes between 5,334 and 7,772 meters (17,500 to 25,498 feet) contained levels of cadmium and arsenic that exceeded U.S. safety standards, according to researchers at the University of Southern Maine in Gorham, while every soil sample contained unsafe levels of cadmium.
According to the study, published in the journal Soil Survey Horizons, toxin levels were highest toward the top of the mountain, which suggests that high-altitude winds had carried the toxins from Asian industrial sites.
Researchers called the results a reason for concern because mountaineers rely on melted snow for drinking water and high winds may also kick up toxins located in the soil.
In this case, the question is not the temporal comsuption of water polluted with toxic elements. The problem is that one of the more inaccessible and wild places of our planet is also polluted by anthropogenic causes!

Tomado de/Taken from Environment360

Abstract of the paper
Trace Element Deposition on Mount Everest
B. Yeo and S. Langley-Turnbaugh
Soil Survey Horizons
The objective of this study of the North Ridge of Everest was to examine trace element concentrations and altitudinal trends in soil and snow. Mount Everest was selected because its remote location and extreme elevation isolates it from localized pollution sources. Soil samples were collected on the Rongbuk glacier of Mount Everest (Qomolangma) from 5334 to 6553 m, and fresh surface snow samples (0–10 cm) were collected along the climbing route of the northeast ridge from 6858 m to 7752 m. The samples were analyzed for Pb, Zn, Cd, Ni, Cr, Co, Cu, As, Mn, Hg, and V using inductively coupled plasma spectroscopy. Results show that As and Cd are both above USEPA drinking water guidelines in all snow samples, and arsenic is above the USEPA soil screening guidelines in all soil samples. There was a clear trend in element variation in the soil samples, with the highest concentrations found at 5944 m. There was no clear trend detected in the snow samples, possibly due to vertical mixing of surface snow. Anthropogenic sources are suspected to have contributed to the elevated concentrations of both cadmium and arsenic.

Una planta silvestre que usa metales pesados contra bacterias/A wildflower using heavy metals against bacteria

Una planta silvestre que acumula metales pesados en sus hojas, los utiliza como una especie de blindaje contra infecciones bacterianas
Thlaspi caerulescens es una pequeña planta que medra en los suelos ricos en cinc cercanos a minas en Europa y Gran Bretaña. Se sabe que acumula cinc, níquel y cadmio en grandes cantidades, pero el por qué de este hecho era un misterio.
Ahora, científicos de la Universidad de Oxford han demostrado que cuando las plantas de Thlaspi acumulan metales en sus hojas, se vuelven resistentes frente a la bacteria Pseudomonas syringae pv. maculicola.
Los investigadores han demostrado también que las bacterias aisladas de las hojas de plantas procedentes de una antigua mina galesa de plomo y cinc, tienen una mayor tolerancia al cinc que las bacterias aisladas de suelos normales. Esto demuestra que tanto la planta como el patógeno se adaptan para sobrevivir en ambientes ricos en metales, y que los patógenos se adpatan para superar las defensas de la planta. Según Gail Preston, coautor del estudio, 'los metales pesados podrían ser parta de una 'carrera armamentista' entre las plantas y los microorganismos que intentan colonizarlas'.
Esta planta ha sido propuesta para la fitoremediación de suelos contaminados por cadmio.

An unusual wildflower that accumulates metals in its leaves has been found to use them as a kind of 'armour' against bacterial infection.
Thlaspi caerulescens is a small plant that grows on metal-rich soils scattered around Britain and Europe, such as the sites of former mine workings. The plant is known to accumulate zinc, nickel and cadmium to very high concentrations in its leaves, but why it should do this has remained a mystery.
Now scientists from Oxford University have shown that when Thlaspi plants accumulate metals in their leaves they become resistant to attack by the bacterium Pseudomonas syringae pv. maculicola.
The researchers also showed that bacteria surviving on Thlaspi plants on the site of a former lead-zinc mine in Wales had a higher tolerance for zinc than bacteria isolated from plants growing on normal soils. This indicates that both the plant and its pathogens show evidence of local adaptation to survival in metal-rich environments, and that pathogens can adapt to overcome plant defences based on metals. According to Gail Preston, co-author of the study, 'heavy metals may be part of an evolutionary 'arms race' between plants and the microorganisms that try to colonise them.'
This wildflower has been previously proposed for fitoremediation of cadmium polluted soils.

Tomado de /Taken from Science Daily

Scietific paper
Fones H, Davis CAR, Rico A, Fang F, Smith JAC, et al. (2010) Metal Hyperaccumulation Armors Plants against Disease. PLoS Pathog 6(9): e1001093.
doi:10.1371/journal.ppat.1001093

Abstract
Metal hyperaccumulation, in which plants store exceptional concentrations of metals in their shoots, is an unusual trait whose evolutionary and ecological significance has prompted extensive debate. Hyperaccumulator plants are usually found on metalliferous soils, and it has been proposed that hyperaccumulation provides a defense against herbivores and pathogens, an idea termed the ‘elemental defense’ hypothesis. We have investigated this hypothesis using the crucifer Thlaspi caerulescens, a hyperaccumulator of zinc, nickel, and cadmium, and the bacterial pathogen Pseudomonas syringae pv. maculicola (Psm). Using leaf inoculation assays, we have shown that hyperaccumulation of any of the three metals inhibits growth of Psm in planta. Metal concentrations in the bulk leaf and in the apoplast, through which the pathogen invades the leaf, were shown to be sufficient to account for the defensive effect by comparison with in vitro dose–response curves. Further, mutants of Psm with increased and decreased zinc tolerance created by transposon insertion had either enhanced or reduced ability, respectively, to grow in high-zinc plants, indicating that the metal affects the pathogen directly. Finally, we have shown that bacteria naturally colonizing T. caerulescens leaves at the site of a former lead–zinc mine have high zinc tolerance compared with bacteria isolated from non-accumulating plants, suggesting local adaptation to high metal. These results demonstrate that the disease resistance observed in metal-exposed T. caerulescens can be attributed to a direct effect of metal hyperaccumulation, which may thus be functionally analogous to the resistance conferred by antimicrobial metabolites in non-accumulating plants.

Aniversario del protocolo de Montreal/Anniversary of the Montreal Protocol

El Protocolo de Montreal es un tratado internacional diseñado para proteger la capa de ozono reduciendo la producción y el consumo de las sustancias responsables del la reducción la capa de ozono. El acuerdo estuvo a la firma a partir del 16 de septiembre de 1987 y entró en vigor el 1º de enero de 1989, habiendo sido revisado y actualizado en diferentes ocasiones. Se cree que si todos los países cumplen con los objetivos propuestos dentro del tratado, la capa de ozono podría haberse recuperado para el año 2050. Debido al alto grado de aceptación e implementación que se ha logrado, el tratado ha sido considerado como un ejemplo excepcional de cooperación internacional, habiendo sido ratificado por 196 estados.
Desde su entrada en vigor, las concentraciones atmosféricas de los clorofluorocarbonos (CFC) más importantes y los hidrocarburos clorados se han estabilizado o se ha reducido. La concentración de halones ha continuado en aumento a medida los halones que se encuentran almacenados en los extintores de incendio es liberados. Sin embargo, la tasa de aumento ha disminuido y se espera que comience a declinar su presencia hacia el 2020. La concentración de los hidroclorofluorocarburos (HCFC) que los sustituyen transitoriamente ha aumentado significativamente, en gran parte debido a los múltiples usos en los que reemplazan a los CFC (por ejemplo, como disolventes o refrigerantes). Dado que los HCFC, menos peligrosos para el ozono, parecen contribuir de forma significativa al efecto invernadero aumentando el calentamiento global, deberían también ser objeto de una similar prohibición en el futuro.
No obstante este peligro, el Protocolo de Montreal puede ser considerado el acuerdo ambiental internacional más exitoso del mundo hasta la fecha, y un ejemplo de que las tendencias medioambientales pueden invertirse aplicando politicas medioambientales activas.

The Montreal Protocol is an international treaty designed to protect the ozone layer by phasing out the production of numerous substances responsible for ozone depletion. The treaty was opened for signature on September 16, 1987, entered into force on January 1, 1989, and has been revised and actualized in several occasions. It is believed that if the international agreement is adhered to, the ozone layer is expected to recover by 2050. Due to its widespread adoption and implementation it has been hailed as an example of exceptional international co-operation. It has been ratified by 196 states.
Since the Montreal Protocol came into effect, the atmospheric concentrations of the most important chlorofluorocarbons (CFCs) and related chlorinated hydrocarbons have either leveled off or decreased. Halon concentrations have continued to increase, as the halons presently stored in fire extinguishers are released, but their rate of increase has slowed and their abundances are expected to begin to decline by about 2020. Also, the concentration of the hydrochlofluocarbons (HCFCs) increased drastically at least partly because for many uses CFCs (e.g. used as solvents or refrigerating agents) were substituted with HCFCs. These last are less dangerous than CFCs for the ozone layer, but contribute significantly to the greenhouse effect increaging the Earth's global warming, so they will be also subjected to a similar banning in the future.
The Montreal Protocol can be considered the most successful international environmental agreement to date, and an example of inversion of environmental dangerous tendences by active environmental policies.

Tomado de/Taken from Wikipedia (español)/(english)
Gracias a/Thanks to Radagast ¿Quién se acuerda del ozono?

El desastre del Golfo de Mexico/The disaster of the Gulf of Mexico

El vídeo en directo del crudo manando en el Golfo de México es a la vez trágico e hipnótico. A cada segundo que pasa, más y más galones de petróleo y de gas natural se vierten en el océano.

British Petroleum's live video stream of oil gushing into the Gulf of Mexico is simultaneously tragic and hypnotic. With each passing second, more gallons of crude oil and natural gas escape into the ocean.

Para saber más/To known more Gulf Coast Oil Leak

Los metales pesados en China/Heavy metals in China

Las autoridades chinas han prometido llevar a cabo más esfuerzos para contener la contaminación producida en la manufactura de metales pesados, a la que se culpa del número creciente de los casos de envenamiento por plomo del pais.
Los datos del primer censo nacional de febrero de 2010 sobre fuentes de contaminación, muestran que los metales pesados son los principales contaminantes del país, emitiéndose cerca de 900 toneladas al año. Se trata de plomo, mercurio y cromo que suelen originarse durante los procesos de purificación de los metales.
Debido a los numerosos casos de contaminación por metales pesados del año pasado, más de 92.000 personas han participado en una campaña nacional contra las fábricas que operan ilegalmente y emiten más metales pesados polucionantes que los permitidos por la legislación. Según las estadísticas oficiales, de un total de 9.123 compañías emisoras de metales pesados, 2.183 resultaron perniciosas para el medio ambiente, habiéndose cerrado 231 y suspendiéndose a 641 más. Se examinaron 1.296 fábricas emisoras de arsénico, de las cuales 304 operaban en la ilegalidad. Se cerraon 36 y se suspendió a 248.
En el año 2009, cundió la alarma entre la opinión pública y las autoridades debido a los frecuentes casos de contaminación por metales pesados. Según las autoridades, hubo 12 episodios que originaron que 4.035 personas tuvieran niveles sanguíneos de plomo demasiado elevados y 182 los tuvieran de cadmio.
Un estudio del Centro de Investigación de Ciencias Eco-ambientales de la Academia China de la Ciencia ha demostrado que alrededor del 20% de las tieerras de labor chinas están contaminadas por metales pesados, lo que ha originado que las cosechas disminuyan en más de 10 millones de toneladas.
Con objeto de combatir la contaminación por metales pesados, China promulgará regulaciones sobre reciclado y manejo de residuos de la industria de materiales electrónicos en 2011

China's top environmental watchdog on Friday pledged more efforts to curb pollution caused by heavy metal manufacturing, which has been blamed for a growing number of lead poisoning cases in the country.
The data released in the first national census on pollution sources in February show heavy metals have become the country's main pollutant, with nearly 900 tons emitted every year. Heavy metals mainly refer to toxic metals such as lead, mercury and chromium, which usually arise from purification of metals.
Due to the numerous heavy metal pollution cases last year, more than 92,000 people across the country participated in a nationwide campaign against factories operating illegally by emitting more heavy metal pollution than regulations allow. Of the total 9,123 companies emitting heavy metals, 2,183 of them were found to be harmful to the environment, with officials closing 231 and suspending 641, the statistics showed. About 1,296 factories causing arsenic emissions were examined and 304 were found to be operating illegally. Some 36 were shut down and 248 were suspended.
In 2009, the frequent cases of heavy metal pollution across the country have raised the alarm for the public and authorities. At a press conference in January, Zhou told the media that the ministry received 12 cases related to heavy metal pollution in 2009, causing 4,035 people to suffer excessive blood lead levels and 182 with excessive cadmium levels.
A study from the Research Center for Eco-Environmental Sciences at the Chinese Academy of Sciences shows about 20 percent of the country's farmland was polluted by heavy metals, causing the crop output to decrease by more than 10 million tons.
In order to fight heavy metal pollution, China will launch a regulation on recycling and dealing with electronic waste in 2011.

Tomado de/Taken from Sina English

Ciclos biogeoquímicos/Biogeochemical cycles

Un ciclo bigeoquímico es una representación de la circulación de un elemento o compuesto químico a través de los diferentes compartimentos medioambientales de la Tierra: litosfera (corteza terrestre), hidrosfera, atmósfera y biosfera. La circulación de los elementos es el resultado de diversas interacciones de la materia y la energía, y está propulsado por la radiación solar, energías mecánica y química y por la energía térmica terrestre.
Los metales pesados, circulan a través de todos los compartimentos con diferentes tiempos de residencia, pero los correspondientes a suelos y sedimentos varían entre cientos y millones de años, por lo que pueden considerarse como reservorios temporales, donde quedan retenidos hasta que vuelven a ser removilizados (véase fraccionamiento químico).
El ciclo que aparece en esta entrada es una adaptación del propuesto por Ward* .


A biogeochemical cycle shows the circulation of a given chemical element or substance throughout the different environmental sections of the Earth: lithosphere (earth's crust), hydrosphere, atmosphere and biosphere. The cycling is a result of various material and energy interactions, being fuelled by solar radiation, and mechanical, chemical and the erath's thermal energy.
Heavy metals move within and between the spheres with different residence times, but the corresponding to soils and sediments vary between hundred and million of years, so they behave like temporal reservoirs from which they can be released again to environment (See chemical fractionation).
The cycle depicted in this post is adapted from Ward *.

* In Environmental Analytical Chemistry. F. W. Fifield and P. J. Haines (Eds). Blackie Academic and Professional. Chapman & Hall, London 1995