(This version of the story corrects the name of the NGO in paragraph 6 to Mother Nature)
By Chris Arsenault
KOH SRALAU, Cambodia (Thomson Reuters Foundation) - Cambodian officials have promised to investigate problems in the sand mining business following complaints from fishermen that dredgers have been stealing the shore beneath their boats on an industrial scale.
"Serious actions" will be taken against anyone inappropriately exporting sand, Cambodia's Ministry of Mines and Energy said in a statement late on Wednesday.
The ministry's move came after the release of U.N. trade data compiled by campaigners this week, showing Singapore has imported more than 72 million tons of Cambodian sand since 2007.
The Cambodian government reported less than 3 million tonnes of sand exports during that period.
The discrepancy, worth more than $740 million, led a coalition of campaign groups to call on Monday for an investigation into what has happened to around 69 million tonnes of missing sand.
"The amount of illegal mining is massive," said Som Chandara, an activist with Mother Nature, one group questioning the government's accounting of sand exports.
"It's making a bad situation for the communities by polluting the water," he told the Thomson Reuters Foundation, standing on top of a pile of sand.
The Ministry of Mines and Energy pledged to investigate the cause of the difference between the U.N. data and its own.
The government maintains it has "completely eradicated lawless sand dredging" but said in a statement posted on Facebook that the industry still "faces some challenges".
As cities across Asia expand, and demand for construction materials rises, campaigners say large-scale sand mining has seriously impacted coastal ecosystems and the land itself.
"Seven beaches have already disappeared because of the mining," said Louk Pou, a fisherman on Koh Sralau, an island that is a hotspot for sand extraction 300 km (186 miles) west of Cambodia's capital Phnom Penh.
"They're just gone and the people can't enjoy them anymore," Pou told the Thomson Reuters Foundation.
Residents in the village of stilted wooden homes, narrow concrete footpaths and colorful small boats say sand dredging has plunged their once reasonably prosperous fishing community into poverty.
Large cranes and barges began appearing in the coastal region of bright green mangrove forests in 2000, Pou said.
Before dredgers - licensed to politically connected Cambodian businessmen and often operated by Vietnamese firms - began plunging into the waters to extract sand from the bottom, Pou said he earned more than $50 a day fishing for crab from his small motorboat.
Now his daily income is less than $10, and he can no longer afford to send his children to school - complaints echoed by other villagers.
"There have been big changes in fish stocks here," said fisherman's wife Neak Sopheap.
Dredging machines and sand barges dump their waste directly into the river, fishermen say. They blame "sticky oil", which now covers their nets, for decimating the crab population.
"The land has been disappearing and some of the mangrove forests have collapsed," Sopheap said during an interview on the patio of her wooden home jutting into brackish water where a river flows into the sea.
Her neighbor, Ek Sophal, nodded in agreement as she mended a plastic fishing net.
"Families are borrowing a lot of money and going into debt because there isn't enough fish," Sophal said. "The government needs to stop this dredging."
Local media reported on Thursday the government had temporarily halted sand exports by companies that hold valid permits while officials investigate campaigners' allegations.
The Ministry of Mines and Energy did not respond to requests for further comment from the Thomson Reuters Foundation. It provided no details of how its investigation into sand mining would be carried out, nor when it would be concluded.
Government officials have previously said sand dredging is sustainable and can actually help local ecosystems by preventing landslips.
Travel support for this reporting was provided by OpenLandContracts.org, an initiative of the Columbia Center on Sustainable Investment.
(Reporting By Chris Arsenault; editing by Megan Rowling; Please credit the Thomson Reuters Foundation, the charitable arm of Thomson Reuters, that covers humanitarian news, women's rights, trafficking and climate change. Visit news.trust.org)