GREEN groups urged Hong Kong authorities to help China mop up a 10-kilometre oil spill in the Pearl River yesterday, fearing the slick could spread to the territory. Green groups urged swift action to staunch the flow of oil from the Tanja Jacob tanker in the Guangzhou port of Huangpu, saying the mainland's ability to respond to the spill was unknown. The Reader in Ecology and Biodiversity at Hong Kong University, Dr John Hodgkiss, said that depending on tides and wind direction, the slick could make its way to the territory. 'We don't know how long it could take, it's difficult to predict. We just have to wait and see. Oil slicks can travel up to 1,600 km,' he said. Worldwide Fund for Nature conservation officer Ken Chu Wing-hing said Hong Kong authorities needed to get more information from China about how the spill was being handled. If the slick floated west, it would threaten the endangered Chinese white dolphins off Macau. 'If they do not restrict the flow of oil, although we are not certain about the extent, there could be serious damage here,' Mr Chu said. The tanker, carrying 28,000 tonnes of crude oil, rammed into the Guangzhou wharf while berthing on Sunday, spilling several hundred tonnes into the river. The 10-km slick of up to 300 tonnes of crude oil from Oman immediately spread downriver on the receding tide. Friends of the Earth campaigns officer Cheng Luk-ki said the Hong Kong authorities should be actively finding out what is being done about the slick, and should offer assistance if necessary. 'Under the veil of environmental protection, it's worth having co-operation,' Mr Cheng said. 'I know the Chinese authorities do have some experience in controlling slicks, but I'm not sure of the quality. 'We don't know if they are using chemicals or buoyancy to control it - we don't know which method they are using. 'There's too many other variables that could lead the slick to make its way here, such as the climate and wind,' he said. A Marine Department spokesman said the Government was monitoring the situation in Hong Kong waters, but had not been asked to help the Guangdong operation. 'They have not asked for help. We have provided them with a list of equipment - they know what resources are available,' he said.