SEOUL, Oct. 19 (UPI) -- China is concerned about the possibility of radioactive contamination after North Korea's fifth nuclear test.
In a northeastern Chinese region adjacent to the North Korea border, authorities in Yanbian are conducting pollution tests to determine the presence of radioactive material, local newspaper Yanbian Daily reported Tuesday.
China's environmental protection ministry planned the tests that are being administered in conjunction with the country's radiation safety agency and a provincial environmental agency, according to the newspaper.
The test was described as an investigation into "natural radioactive substances" but the timing of the test is inviting speculation about Beijing's concerns about Pyongyang's continued development of nuclear weapons.
The test would be conducted at 155 points across eight cities and prefectures in the area, and is to include samples of air and water, according to the report, with a special focus on groundwater samples and water that is deemed safe for drinking.
Nine different kinds of biological sampling are to take place.
The Yanbian environmental protection agency also collected air and soil samples between August and September, which were then sent to a central laboratory for analysis.
North Korea's fifth nuclear test on Sept. 9 produced a 5.3 magnitude earthquake near the Punggye-ri nuclear site.
The Tumen River separates the two sides and the nuclear site is located about 120 miles from the city of Yanji in Yanbian.
Some residents in the city with a population of about 400,000 felt their homes shake at the time of the fifth test, according to Yonhap.
In January, state-owned Chinese news network CCTV tweeted a photograph of students in Yanji after an evacuation, immediately after Pyongyang conducted what it called a "successful" hydrogen bomb test.