Pollution levels in soil samples taken from the bed of Lake Baikal in the area near a controversial pulp and paper mill are not above the permitted level, Russia's environmental watchdog said on Wednesday.

The Baikal Pulp and Paper Mill is the only industrial enterprise that dumps waste water directly into the world's deepest freshwater lake, listed as a UNESCO World Heritage Site.

In June, the Mir-1 and Mir-2 mini-subs, involved in research in the lake, took samples of soil in the area where the mill discharges its wastewater.

"Tests showed the concentration of petrochemicals to be lower than the maximum allowable [0.05 g/m3 for waste water] and the mercury concentration to be below the detection limit," regional Rosprirodnadzor head Yevgeny Kalinin said.

Rosprirodnadzor has been regularly monitoring the area around the mill since it re-opened. he said.

In October 2008 the plant switched over to a closed water cycle, preventing the discharge of waste into the lake, but the new system proved unprofitable and the plant was forced to shut down for more than a year.

Prime Minister Vladimir Putin signed a resolution in January excluding the production of pulp, paper and cardboard from the list of operations banned in protected areas around Lake Baikal, sparking mass environmental protests.

The mill now operates at half capacity and continues to discharge toxic waste into the lake.

A probe of the mill's waste water conducted in July found the concentration of various pollutants to be above the permitted level. A total of 12 investigations were launched against the mill as a result.

However, Kalinin said the concentration of pollutants in the lake's water and soil remained "within acceptable limits" as the volume of discharged waste is below the permitted level.

The next planned inspection of the Pulp and Paper Mill's waste water is scheduled for April 2011.

IRKUTSK, August 18 (RIA Novosti)