China and Russia have completed joint water sampling of the Heilongjiang river, which borders the two countries, Chinese environmental authorities said.
Environmental experts collected water samples from both sides of the river and will conduct quality analysis.
Chemical oxygen demand and contents of heavy metals are among the 40 indices to determine water quality.
Under an agreement reached in 2006, China and Russia will conduct water quality tests of for four rivers and a lake -- Heilongjiang, Wusuli, Ergune and Suifen rivers and Xingkai Lake -- to strengthen cross-border pollution control.
Monitoring of the Heilongjiang river started in June 2007, with 30 tests conducted so far.
The two countries share about 3,500 kilometers of cross-border bodies of water.
