A toxic pollution spill from a mine operated by China's top gold producer Zijin Mining Group has spread to a second province, threatening the fishing industry there, state media said Tuesday.
Poisonous waste water from the copper mine in Fujian province has contaminated the Ting river -- a major waterway in the country's southeast -- and has now flowed downstream into Guangdong province, the China Daily said.
The pollution "will pose a big challenge to local fish farming", a notice from Guangdong environmental authorities said, according to the China Daily.
The report came as Zijin, China's third-largest copper producer, issued a statement apologising for the July 3 mishap -- which killed off nearly 1,900 tonnes of fish -- and its "improper handling" of information about the spill.
Zijin said the securities regulator had launched an investigation into the company over possible violation of information disclosure rules.
"The lessons from this incident are painful and the costs are substantial," Zijin said in the statement.
During its rapid expansion, Zijin "was overconfident, had a lack of crisis awareness and did not properly handle the balance between economic efficiency, ecological benefit and public interest".
Investigators have determined that the initial leak of 9,100 cubic metres (320,000 cubic feet) of waste water from a sludge pond had flowed through an "illegally built passage" into the Ting river.
The company at first blamed heavy rains for the toxic spill, but later released preliminary findings of a government probe that found it had ignored warnings that the flow of waste water discharge at the mine was too high.
Investigators found the company had ignored a government warning in September 2009 that said repairs to an automatic water quality monitoring system were needed.
A further 500 cubic metres of waste water seeped into the Ting late Friday, but the leak was quickly contained, the China Daily said Monday, citing company sources.
Zijin has confirmed that police have detained three executives over the spill. Three local officials have been sacked, and the head of the county government has been suspended pending further investigation, state media said.
Explore further: The Salton Sea: a time-bomb amid California drought