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Mystery of arsenic release into groundwater solved

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New York: Stanford scientists have solved an important mystery about where the microbes responsible for releasing dangerous arsenic into groundwater in Southeast Asia get their food.

Groundwater in many countries, including India, China, Bangladesh, Myanmar and Vietnam, contains concentrations of arsenic 20 to 100 times greater than the World Health Organisation’s (WHO) recommended limit.

Arsenic is bound to iron oxide compounds in rocks from the Himalayas and gets washed down the major rivers and deposited in the lowland basins and deltas.

Scientists know that in the absence of oxygen, some bacteria living in those deposited sediments can use arsenic and iron oxide particles as an alternative means of respiration.

When they do this, however, the microbes separate the arsenic and iron oxides and transfer the toxin into underlying groundwater.

The mystery in this system, though, is an obvious source of energy that the microbes can tap to fuel the separation process.

“The question that really limits our ability to come up with predictive models of groundwater arsenic concentrations is how and why does the food they use vary across the landscape and with sediment depth,” said professor Scott Fendorf from Stanford.

In their study, Fendorf and his team found that mixing sediments collected from different depths in vials with artificial groundwater revealed that the oxygen-deprived bacteria living in the upper few feet of permanent wetlands were releasing arsenic.

However, water mixed with sediments gathered from the same shallow layers of seasonal wetlands was arsenic free.

The Stanford scientists hypothesized that bacteria residing in the shallow layers of seasonal wetlands were eating all of the digestible plant material during dry periods when sediments are exposed to air and the microbes have access to oxygen.

As a result, no food is left for the microbes when the floods returned, rendering them unable to cleave arsenic particles from iron oxides.

“The arsenic-releasing bacteria living in the shallow regions of seasonal wetlands are ‘reactive’ carbon limited – that is, they don’t release arsenic into the water because there isn’t enough carbon available in a form they can use,” Fendorf explained.

The findings have large-scale implications for projecting changes in arsenic concentrations with land development in South and Southeast Asia and for the terrestrial carbon cycle.

“If you change the hydrology of a region by building dams or levies that change the course of the water, or if you change agricultural practices and introduce oxygen or nitrate into sediments where they didn’t exist before, that will alter the release of arsenic,” Fendorf said.

The findings were published in the journal Nature Geosciences.

(IANS)

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Southeast Asian Governments ‘Celebrate’ World Press Freedom Day

According to an open letter to Facebook from 10 free expression and human rights organizations in Vietnam, the social networking behemoth has been blocking access to content on the request of the Vietnamese government.

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United Nations Special Rapporteur David Kaye speaks to the media about the situation of the right to freedom of opinion and expression in Turkey, in Ankara, Turkey, Friday, Nov. 18, 2016. " The space for critical voices, academics, journalists, lawyers and others in civil society has been under threat," Kaye said.(AP Photo/Burhan Ozbilici). RFA

Governments and state media in Southeast Asia touted improving media liberty on World Press Freedom Day Friday, but critics were swift to point out limits on expression and the jailing of many journalists across the region.

UN Special Rapporteur on Freedom of Opinion and Expression David Kaye said in a statement that celebration alone to mark the day would be an insufficient way to observe a day created by the UN General Assembly in 1993 to assess the state of press freedom worldwide, defend the media from attacks on independence and pay tribute to journalists who have died in the line of duty.

“Autocrats and demagogues too often denigrate the press, with dire consequences for safety, for democracy, and for the public’s right to know,” Kaye said in the statement.

“Today more than ever, we need not just generic celebrations, but concrete steps to improve press freedom worldwide,” he said.

The UN statement highlighted the case of two Reuters reporters in Myanmar, Wa Lone and Kyaw Soe Oo, who last month were denied their final appeals and must serve the remainder of their seven-year-sentences.

They were arrested in December 2017 while pursuing a story about the massacre of 10 Rohingya Muslims during a brutal military-led crackdown in western Myanmar’s Rakhine state. Authorities detained them shortly after two policemen with whom they had dinner in Yangon handed them state documents related to the atrocities, in what was widely viewed as a police setup.

The statement indicated that press freedom in many parts of Asia is severely lacking, including in China where “basic rights to seek, receive and impart information hardly exist.”

The theme for this year’s World Press Freedom Day is “Media for Democracy: Journalism and Elections in Times of Disinformation.”

Cambodia

UN Special Rapporteur for Human Rights in Cambodia, Rhona Smith, currently in the midst of an 11-day visit to the country, posted her thoughts about the state of press freedom under Hun Sen’s regime.

“I am concerned that Cambodia has slipped further one point to 143 over the last year, after falling 10 points from 132 the previous year in the Reporters without Borders (RSF) World Press Freedoms Index,” she wrote.

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If we need to speak out or want to know what’s going on, we use Facebook. We can’t’ rely on state TV, radio or newspapers because it’s too slow, inaccurate and restricted,” said the citizen. Pixabay

She also gave advice to Cambodia’s government on ways to improve.

“I encourage the Government to provide the space for a free media, both offline and online, including through the adoption and implementation of the draft Law on Access to Information,” she wrote.

“I also repeat my encouragement to lift the charges against the two former RFA journalists,” she added, referring to Uon Chhin and Yeang Socheameta, who were arrested in November 2017 on suspicion of continuing to provide news about Cambodia to RFA after the U.S.-funded media outlet closed its office in Cambodia that September.

Cambodia’s fall one spot in the RSF index to 143, was matched by those of neighbor Laos, Vietnam, and Myanmar, which each fell one step. In a year-on-year comparison for 2018, Laos fell one spot from 170 to 171, Vietnam fell one spot from 175 to 176, and Myanmar fell one spot from 137 to 138.

Meas Sophoan, a spokesman for the country’s Ministry of Information told RFA’s Khmer Service that Information Minister Khieu Kanharith held a press conference to mark the day where he said that press freedom is getting better each day within the kingdom.

The spokesman added that broadcast and print media are on the rise, and the country is showing how it respects human rights and press freedom, offering the press conference itself as an indication that press freedom is important to the regime.

But Long Kimmaryta, a journalist for a bilingual newspaper in Phnom Penh disagreed, saying that reporters and the press must now self-censor, after the government arrested reporters.

She said writing criticism about the government is risky in the current climate.

“If we were to write positive stories about the government, then sources within the government are happier to talk to us,” she said, adding that journalists in Cambodia can only write stories if they feel their safety isn’t threatened.

Laos

Meanwhile in neighboring Laos, the deputy editor of the government-published Vientiane Times told RFA’s Lao Service, “I think we have all kinds of freedoms because we have media laws guaranteeing those freedoms, including the freedom to write news and freedom of expression.”

“We want to improve and upgrade our reporters’ knowledge and skills and we also need to diversify the way we [source] content for our news stories,” said Deputy Editor Phonekeo Vorlakoun.

“Of course, as reporters, we want to respond to the needs of our people,” he said.

The deputy editor’s comments were contradicted by a local reporter stationed in Sanamxay district, Attapeu province who is covering the lasting damage caused by last year’s disaster at a nearby dam which claimed the lives of hundreds and has been described as Laos’ worst flooding in decades.

“All news stories, even those on technical matters, must be approved by the leadership of the district and the province before we can publish anything,” said the reporter.

An official of the Ministry of Information, Culture and Tourism agreed with the reporter saying, “The government will never force us to do anything, or order us how to do this or that, but if they say we can’t publish the story, we can’t publish it.”

A citizen of Vientiane gave insight on how the people gain access to reliable news in the country.

“If we need to speak out or want to know what’s going on, we use Facebook. We can’t’ rely on state TV, radio or newspapers because it’s too slow, inaccurate and restricted,” said the citizen.

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The letter said that Vietnam’s 64 million Facebook users use Facebook as their primary news source, citing the absence of independent media within the country. VOA

Facebook in Vietnam

But Facebook has also been the target of criticism, particularly for bowing to the whims of governments looking to restrict the public’s access to information, such as in Vietnam.

According to an open letter to Facebook from 10 free expression and human rights organizations in Vietnam, the social networking behemoth has been blocking access to content on the request of the Vietnamese government.

The letter said that Vietnam’s 64 million Facebook users use Facebook as their primary news source, citing the absence of independent media within the country.

“On January 1, a restrictive “cybersecurity” law went into effect in Vietnam but the desire of Vietnamese to stay connected and build community has not changed,” said the rights groups in the letter, signed by Reporters Without Borders, the Southeast Asian Press Alliance, Viet Tan and other groups.

“The Vietnamese government may want foreign companies to set up local data servers, censor content, and turn over private user data — but it’s up to Facebook to ultimately decide whether it will uphold human rights or not,” they said.

The letter cited Facebook as saying that blocked content was based on “local legal restrictions,” but urged the company and its CEO Mark Zuckerberg to not become “complicit in the human rights violations of authoritarian governments such as Vietnam’s.”

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Kaye, the UN Special Rapporteur,  “States must move beyond words, beyond resolutions and take immediate and sustainable action to ensure safety of journalists, the independence of the media, the plurality of voices.”

“That is the challenge of the coming year: translating celebration into action, stigmatizing and penalizing those that attack journalism, and devoting resources to the great project of media freedom.” (RFA)