information:filtering
Contamination due to drilling fluids

The drilling project has been opposed by some environmental groups and scientists who have argued that hot-water drilling would have a more limited environmental impact. The main concern is that the lake could become contaminated with the antifreeze that the Russians used to keep the bore hole from refreezing. Scientists of the United States National Research Council have taken the position that it should be assumed that microbial life exists in Lake Vostok and that after such a long isolation, any life forms in the lake require strict protection from contamination.

The original drilling technique employed by the Russians involved the use of Freon and kerosene to lubricate the borehole and prevent it from collapsing and freezing over; 60 short tons (54 t) of these chemicals have been used thus far on the ice above Lake Vostok. Other countries, particularly the United States and Britain, have failed to persuade the Russians not to pierce to the lake until cleaner technologies such as hot-water drilling are available. Though the Russians claim to have improved their operations, they continue to use the same borehole, which has already been contaminated with kerosene. According to the head of Russian Antarctic Expeditions, Valery Lukin, new equipment was developed by researchers at the Petersburg Nuclear Physics Institute that would ensure the lake remains uncontaminated upon intrusion. Lukin has repeatedly reassured other signatory nations to the Antarctic Treaty System that the drilling will not affect the lake, arguing that on breakthrough, water will rush up the borehole, freeze, and seal the other fluids out.

Some environmentalist groups remain unconvinced by these arguments. The Antarctic and Southern Ocean Coalition has argued that this manner of drilling is a profoundly misguided step which endangers Lake Vostok and other subglacial lakes in Antarctica (which some scientists are convinced are inter-linked with Lake Vostok). The coalition has asserted that "it would be far preferable to join with other countries to penetrate a smaller and more isolated lake before re-examining whether penetration of Lake Vostok is environmentally defensible. If we are wise, the Lake will be allowed to reveal its secrets in due course."

Lukin claims that hot-water drilling is much more dangerous for the microbiotic fauna, as it would boil the living species, and disturb the entire structure of water layers of the lake. Additionally, hot-water drilling would have required more power than the Russian expedition could have generated at their remote camp. However, the water samples obtained by the Russian team were heavily contaminated with drilling fluid, so they reported in May 2017 that it was impossible at this time to obtain reliable data on the real chemical and biological composition of the lake water.