Método SORAS para purificação de água contaminada pelo arsênio

Como é público e notório, e está comprovado em diversos estudos científicos, a mineração de ouro em rocha arsenopirita conduzida pela Kinross em Paracatu está contaminando o ar, os solos e as águas com arsênio inorgânico altamente tóxico e danoso para a sua saúde.

Enquanto uma solução judicial para o problema não é encontrada, é preciso tomar alguns cuidados para minimizar a exposição ao arsênio. Obviamente, a maioria das pessoas que moram em Paracatu não podem se mudar da cidade, e continuam sujeitas a respirar o veneno, dia e noite.

Algumas pessoas, como os habitantes do Vale do Ribeirão Santa Rita, encontram-se forçadas a consumir água do subsolo que já está gravemente contaminada pela atividade minerária da Kinross, conforme mostramos ano passado [1].

É possível que pessoas vivendo em outras regiões também sejam afetadas, pela influência das barragens de rejeitos da Kinross [2].

De qualquer modo, a água sob influência da mineração não está própria para consumo. 

Se você mora na região impactada pela mineração, ou se usa água de poço contaminada pelo arsênio, recomendamos que você trate a água de beber da seguinte forma (método SORAS-"Solar Oxidation and Removal of Arsenic", desenvolvido pelo suíços Stephan Hug e Martin Wegelin, do Instituto Federal Suíço para Ciência e Tecnolgia Ambiental (EAWAG) [3]:

- encha uma garrafa PET transparente com 1 litro da água contaminada pelo arsênio;

- pingue algumas gotas de ácido cítrico (você deve achar no supermercado, pois ele é usado para a preparação de refrescos e doces). Se não encontrar, use 4 a 8 gotas de suco de limão mesmo;

- deixe a garrafa PET deitada ao sol, durante o dia todo; dentro de algumas horas, a parte ultravioleta  da luz do sol, na presença do ácido cítrico e de hidróxido de ferro presente na água acelera a oxidação do arsênio (III) para arsênio (V), que se liga mais fortemente ao ferro dissolvido, formando um precipitado; 

- à noitinha, coloque a garrafa de pé e deixe-a quieta até o dia seguinte. Se o método de purificação funcionou, você verá o precipitado (uma "laminha") no fundo da garrafa. Despeje a água tratada num filtro de barro normal ou num recipiente limpo, tomando o cuidado de não agitar o precipitado. Jogue fora o precipitado contendo arsênio e ferro.

Referências:

[1] Santos MJ, Dani SU. 2016. Arsenic contamination of the environment and the human compartment by gold mining in Paracatu, MG, Brazil. Congresso da Sociedade de Análise de Risco Latino Americana, IPT, São Paulo, Brasil – 10-13 Mai, 2016.

[2] Conheça a hipótese da contaminação das águas subterrâneas de Paracatu: http://alertaparacatu.blogspot.ch/2009/12/hipotese-de-contaminacao-das-aguas-de.html.

[3] Hug SJ, Canonica L, Wegelin M, Gechter D, Von Gunten U. Solar oxidation and removal of arsenic at circumneutral pH in iron containing waters. Environ Sci Technol. 2001 May 15;35(10):2114-21.

El Salvador, Prizing Water Over Gold, Bans All Metal Mining

https://www.nytimes.com/2017/03/29/world/americas/el-salvador-prizing-water-over-gold-bans-all-metal-mining.html?_r=0

By GENE PALUMBO and ELISABETH MALKINMARCH 29, 2017
 

SAN SALVADOR — Lawmakers in El Salvador voted overwhelmingly on Wednesday to prohibit all mining for gold and other metals, making the country the first in the world to impose a nationwide ban on metal mining, environmental activists said.

Declaring that El Salvador’s fragile environment could not sustain metal mining operations, legislators across the political spectrum approved the ban, which had broad support, particularly from the influential Roman Catholic Church.

Supporters said the law was needed to protect the country’s dwindling supply of clean water.

“Today in El Salvador, water won out over gold,” Johnny Wright Sol, a legislator from the center-right Arena party, wrote on Twitter.

The vote in the Legislative Assembly turned a decade-old moratorium on mining into law, halting efforts by international companies to tap the gold belt running across the northern provinces of El Salvador.

“It’s a wonderful moment for the first country to evaluate the costs and benefits of metallic mining and say no,” said Andrés McKinley, a mining and water specialist at Central American University in San Salvador.

The law does not apply to quarrying or the mining of coal, salt and other nonmetallic substances.

Other countries are unlikely to follow El Salvador’s national ban, mining watchdog groups say. But the law sets a powerful example to communities that oppose large mining projects and bolsters the case against mining in environmentally delicate areas.

“Globally there is a growing questioning of mining as an economic development engine,” said Keith Slack, the global program director for extractive industries at Oxfam America in Washington. “I think it definitely strengthens the voice of communities that are raising the questions.”

Around the world, scattered bans on the use of cyanide to extract gold from low-grade ore, commonly used in open-pit mining, are in place, including in Montana, according to Jamie Kneen, a spokesman for Mining Watch Canada. Costa Rica has a national ban on open-pit gold mining.

Germany, the Czech Republic, Hungary, Turkey and several Argentine provinces have cyanide bans. In the Philippines, the government ordered more than half the mines to shut down or be suspended.

         

The risks of mining in El Salvador, however, are especially acute. The tiny country is densely populated and the second-most environmentally degraded country in the Americas, after Haiti, according to the United Nations.

“Mining is an industry whose primary and first victim is water,” said Mr. McKinley, who added that El Salvador faced a significant scarcity. “We are talking about an issue that is a life-or-death issue for the country.”

Mr. Wright, the legislator who worked to persuade his business-friendly party to support the law, said that climate change was already having an impact on El Salvador. “More than a theory or an uncertain science that it might have been 10 years ago, today for Salvadorans, it is a reality,” he said.

Unlike mining in neighboring Central American countries, mining in El Salvador has been limited to small-scale operations. The civil war of the 1980s deterred efforts to develop large-scale mines. International mining companies did not begin exploring until the 2000s.

Opposition to one of those companies eventually grew into a social movement against mining. The company, Pac Rim Cayman, sought a license to open a mine in the impoverished northern province of Cabañas but was rejected in 2005 because it had not met all the legal requirements.

As opposition mounted, clashes around the proposed mine led to the deaths of several anti-mining activists.

The de facto moratorium on permits that began under a government led by the Arena Party continued under the two successive governments led by the left-wing Farabundo Martí National Liberation Front.

Last October, El Salvador won an international dispute that had been filed by Pac Rim and continued by the Canadian-Australian company, OceanaGold, that acquired it. An international arbitration panel rejected OceanaGold’s claims for compensation.

Follow Elisabeth Malkin on Twitter @ElisabethMalkin.
Gene Palumbo reported from San Salvador, and Elisabeth Malkin from Mexico City

Equipe médica comprova mais um caso de intoxicação pelo arsênio em Paracatu com desfecho fatal

Desta vez a vítima, uma paciente de 19 anos, desenvolveu sintomas neurológicos, hematológicos e gastrointestinais durante a gravidez, vindo a perder o feto de 22 semanas. A equipe médica interdisciplinar do Hospital de Base de Brasília diagnosticou intoxicação crônica pelo arsênio.

A paciente vive em Paracatu, cidade contaminada pelo arsênio liberado pela maior mineração de ouro a céu aberto do Brasil, operada pela transnacional canadense Kinross Gold Corporation. 

O arsênio é absorvido através das vias respiratória e gastrointestinal e acumula-se lentamente nos ossos das pessoas. Durante a gravidez, a taxa de osteoressorção aumenta, e consequentemente a taxa de liberação do arsênio armazenado cronicamente nos ossos aumenta, podendo atingir níveis de intoxicação sub-aguda.

Este não é o primeiro caso de morte causada pela Kinross em Paracatu, nem será o último, pois o arsêno liberado pela mineradora continuará matando por décadas e séculos. Mas este é um dos casos mais bem documentados até o momento. 

Em 2009, a Fundação Acangau entrou com uma ação civil pública em Paracatu exigindo a realização de um estudo epidemiológico, clínico e laboratorial de toda a população da cidade. Passados 7 anos, o pedido ainda não foi atendido, e as pessoas continuam a ser intoxicadas e mortas pela Kinross em Paracatu, com a cumplicidade de certos políticos e a condescendência de certas autoridades do Ministério Público e da Justiça.

A vítima desta vez entrou com uma ação contra a Kinross. A depender do padrão de impotência, inação, cooptação, incompetência e corrupção por parte de ceras autoridades de Paracatu e do Brasil, a vítima corre o risco de ser culpada por ter nascido em Paracatu, e a invasora Kinross inocentada de mais um crime hediondo.

Sergio Ulhoa Dani, de St.Gallen, Suíça, em 01 de agosto de 2016

Une contamination grave, persistante et progressive de l’environnement, assortie d’une intoxication de la population par l’arsenic libéré par l’entreprise minière Kinross à Paracatu, Brésil est confirmée

Décembre 2015. 

Un rapport remis cette semaine au tribunal du Minas Gerais et aux Ministères publics de l’Etat du Minas Gerais et fédéral confirme l’intoxication chronique de dizaines de personnes par l’arsenic libéré par l’activité aurifère menée à grande échelle à Paracatu.

Les mesures des taux d’arsenic ont été réalisées par un géologue de Paracatu, Marcio Jose dos Santos, en collaboration avec un médecin exerçant en Suisse, Sergio Ulhoa Dani. Les spécialistes ont mesuré la concentration d’arsenic dans les eaux souterraines et superficielles et dans l’urine des enfants et adultes résidents en aval des barrages de rejets toxiques de la transnationale canadienne Kinross Gold Corporation (TSX:K; NYSE:KGC).

Des dizaines de personnes examinées présentaient des niveaux d’arsenic dans l’urine supérieurs à la concentration maximale tolérable, conformément aux taux fixés par l’OMS.

Ci-dessous figure un résumé du rapport remis aux autorités judiciaires de Paracatu, incluant les 10 recommandations faites par les spécialistes.

En savoir plus …
http://www.alertaparacatu.blogspot.ch/2015/12/comprovada-contaminacao-ambiental-grave.html

UN strengthens regulations on lead in infant formula and arsenic in rice

Joint FAO-WHO Codex Alimentarius Committee sets new food safety standards

http://www.fao.org/news/story/en/item/238802/icode/ 

Photo: ©FAO/Giulio Napolitano

Rice for sale at a vendor's stall in Cox's Bazar, Bangladesh.







17 July 2014, Geneva - UN food standards body the Codex Alimentarius Commission this week adopted new standards to protect consumer health worldwide, including setting out maximum acceptable levels of lead in infant formula and of arsenic in rice. 

Jointly run by the UN Food and Agriculture Organization (FAO) and the World Health Organization (WHO), the Codex Alimentarius Commission sets international food safety and quality standards to promote safer and more nutritious food for consumers worldwide. Codex standards serve in many cases as a basis for national legislation, and provide the food safety benchmarks for international food trade.

The annual meeting this week was attended by representatives from 170 countries and the European Union, as well as 30 international governmental and non-governmental organizations.

Lead in infant formula

The Codex Alimentarius Commission adopted a recommendation that no more than 0.01 mg per kg of lead should be permitted in infant formula as consumed. 

Infants and young children are particularly vulnerable to the toxic effects of lead. They can suffer profound and permanent adverse health effects, particularly affecting the development of the brain and nervous system, which can diminish their ability to learn.

Lead occurs in the environment and trace amounts can end up in the ingredients that are used in the production of infant formula.

Levels of lead in infant formula can be controlled by sourcing raw materials from areas where lead is less present.

Arsenic in rice

For the first time, Codex has adopted a maximum level for arsenic in rice of 0.2 mg/kg.

Long-term exposure to arsenic can cause cancer and skin lesions. It has also been associated with developmental effects, heart disease, diabetes, and damage the nervous system and brain.

Arsenic is naturally present at high levels in the groundwater and soil in some parts of the world. The toxic element can enter the food chain when it is absorbed by crops from water and soil. 

Rice in particular can take up more arsenic than other crops and as a staple food for millions of people can contribute significantly to arsenic exposure, which is detrimental to human health. 

Arsenic contamination in rice is of particular concern in some Asian countries where paddy fields are irrigated with groundwater containing arsenic-rich sediments pumped from shallow tube wells. Improved irrigation and agricultural practices can help reduce arsenic contamination, for example growing crops in raised beds instead of flooded fields. 

The Commission also agreed to develop a new code of practice that will help countries comply with the maximum level set and provide producers with good agricultural and manufacturing techniques to prevent and reduce contamination.

Veterinary drugs

Codex recommended that the use of certain veterinary drugs should be restricted in food-producing animals in order to prevent residual amounts of the drugs remaining in meat, milk, eggs or honey. 

The eight drugs (chloramphenicol, malachite green, carbadox, furazolidone, nitrofural, chlorpromazine, stilbenes and olaquinadox), including antimicrobials and growth promoters, can potentially have adverse effects on human health and may contribute to the development of drug resistance.

Other measures

Countries also agreed on maximum levels of pesticide residues and additives in foods as well as maximum levels of contaminants, including toxins called fumonisins that are produced by mould growing on maize. Other measures include new safety and quality standards for foods such as raw scallops, passion fruit, durian and okra.

Future work

Countries decided on a range of topics for future development, including establishing standards for black, white and green pepper, cumin, oregano, thyme and garlic, and setting maximum levels for cadmium in chocolate and cocoa-derived products.

The Commission also discussed the need for a Codex standard for ready-to-eat foods for malnourished children, on the proposal from UNICEF, to guarantee the safety and quality of such foods. The Commission decide to follow up on this discussion at its Committee on Nutrition and Foods for Special Dietary Uses.