Russian officials have downplayed the scale of the pollution in Kamchatka, while also suggesting it was not manmade. Greenpeace voiced concern last week over what it described as an ecological disaster in the region.
Russia's Natural Resources Minister said Monday that pollution in the waters off the coast of the far eastern Kamchatka peninsula was unlikely to be manmade, the RIA news agency reported.
Ecology Minister Dmitry Kobylkin said that so far research had only uncovered slightly raised levels of iron and phosphates.
He also said that the incident might have been prompted by the stormy conditions recently experienced in the region of eastern Russia.
Officials warned residents of the dangers on Saturday, urging locals to stay away from a beach in Kamchatka due to pollution that Greenpeace said was evidence of an "ecological disaster."
The incident, which saw a popular surfing beach's waters turn yellow, had caused some surfers to become nauseous, incur eye injuries and vomit. Officials later confirmed numerous surfers had suffered mild burns to their corneas.
Locals also witnessed large numbers of dead animals, including seals, octopuses and sea urchins, all washed up onto a black-sanded beach popular with tourists.
The regional governor, Vladimir Solodov, appeared to cast doubt on Kobylkin's suggestion that humans were not responsible for the situation.
He said that the sea off the remote peninsula may have been contaminated with toxic chemicals.
Testing around local bays and beaches demonstrated above-permitted levels of phenol and petroleum products while experts were investigating whether this was linked to "spills of some toxic substances," Solodov said in a statement.