KHABAROVSK, Russia, Dec. 25 (Xinhuanet) -- Cooperation between China and Russia in tackling the toxic slick floating down China's Songhua River was timely and has helped Russian cities effectively deal with the slick, a Russian environmental monitoring official said on Sunday.

    The two countries exchanged information on the toxic slick on time and the accurate data China provided on its track was key to the effective work by relevant Russian cities in tackling the toxic slick, Alexander Gavrilov, head of the Far Eastern Hydrometeorological Service, told Xinhua.

    The chemical spill in the Songhua River, a tributary of the Heilong River, was caused by a blast at a petrochemical plant in early November in China's northeastern Jilin province. About 100 tons of benzene, a harmful chemical, was believed to have spewed into the river.

    Last month, Russia and China signed an agreement on monitoring the water quality in the Amur River, called the Heilong River in China, and joint work outlined in the agreement is underway, Gavrilov said, adding the two countries will also sign agreements on coordinating work in monitoring water quality in border rivers.

    The most concentrated part of the toxic slick has flowed past Khabarovsk, Gavrilov said. The nitrobenzene levels in the river was 35 percent of the maximum permissible level when the slick hitthe city, he said.

    In Gavrilov's view, China's measure to open reservoirs on the Songhua River to dilute the toxic slick and its further dilution in the Amur River brought the nitrobenzene concentration level down to the safety level in Khabarovsk.

    The activated carbon China provided to Russia also helped filter out pollutants at the source of Khabarovsk's tap water in the river, the official said. Enditem