Ghanaian authorities have arrested 168 Chinese citizens for illegal goldmining, highlighting the social and environmental challenges posed by China's growing presence on the continent.

In a six-day operation which began on Saturday and ended on Thursday morning, police and immigration officials made the arrests in the Ashanti and western regions of the country. Ghanaian authorities said it was part of a crackdown which would continue until all illegal miners had been removed from the country.

"We have arrested 168 Chinese nationals, all of whom are being detained and processed for court," said Michael Amoako-Atta, spokesman for the Ghana immigration service. He said that each of the detainees faced a fine of 2,000 Ghana cedis (around £670) for working illegally in the country and deportation.

The arrests are the latest by Ghanaian immigration, police and military authorities. Some 120 illegal miners were arrested in March. Most have been repatriated to China, while the rest are waiting for travel documents.

"Illegal mining in Ghana has assumed alarming proportions and has got to the point where it is threatening the survival of our water bodies," said Charles Wereko, spokesman for the ministry of lands and natural resources.

"Foreign nationals, especially the Chinese, have made the problem a lot worse. Unlike Ghanaians they have access to huge funds which they have been using to bring an enormous number of excavators into the country, which can destroy large areas of forest in just one day. The rate of destruction is such that, if it is not stopped, Ghana will not have any forest left.

"This operation is going to continue until all illegal miners are removed."

The arrests follow a series of pit collapses in which dozens of Ghanaian illegal miners have died, raising concern about the prevalence of the practice in Africa's second-largest gold producer after South Africa.

"Most of these illegal miners use very dangerous substances like cyanide and mercury in processing their ore, which are not biodegradable and leach into the water bodies creating serious problems for the communities who use these sources of water as drinking water," said Wereko.

"The extent of this illegality is so bad that now the state agency for processing water to provide clean drinking water for most of the communities in Ghana is not able to do their work, because the cost of cleaning up water has become too expensive."

Last month the Ghanaian president, John Dramani Mahama, established a high-level taskforce to bring "sanity" into the mining sector. "I am sending a clear signal to the offending individuals and groupings that the government will not allow their activities to cause conflict, dislocation, environmental degradation and unemployment when in fact the sector should rather benefit our communities and our country," Mahama told journalists in May.

But he has also sought to soothe relations with the Chinese – who are spending billions of dollars on construction and infrastructure projects in Ghana – and cautioned against the vilification of Chinese immigrants.

China has sent diplomats to visit the detainees, and warned

its citizens in Ghana to "strictly abide by the related laws and regulations". Yu Jie, the spokesperson for China's embassy in Ghana, urged Ghana to exercise "strong discipline" in enforcing its laws, the Chinese news agency Xinhua reported.

The South China Morning Post estimates that more than 50,000 Chinese goldminers have been to Ghana since 2005, two-thirds of them from Shanglin, an impoverished county in southern Guangxi province where news of the gold rush spread by word of mouth.

"There are about 180 households in our village and more than 100 young men are in Ghana," 24-year-old Shanglin villager Wen Daijin told the newspaper. "Many borrow money from local banks and relatives to go there. In my township, only men with physical problems don't have plans to go to Ghana."

Wen continued: "You need at least one excavator to dig sand and rocks, some trucks and two high-powered sand pumping machines to dredge for alluvial gold. The pumps are a special design, produced in our hometown."

Some Shanglin residents have returned home because of the recent crackdown, the newspaper reported.