Density of nitrobenzene, harmful to human health, in the contaminated stretch of Songhua River, which is passing this capital city of northeast China's Heilongjiang Province and also the nation's northernmost metropolis of a 9 million population, was 30.1 times above national safety levels.
The index was measured at 6:00 a.m. on Friday at Sifangtai water intake spot of the Songhua River in Harbin, according to the municipal environmental protection authority. The nitrobenzene density, was a bit lower than the previous-day level amid sedimentation and dilution processes.
At the same time, benzene, another contaminant in the river and also a carcinogen, did not exceed national safety levels, the authority added.
China's State Environmental Protection Administration (SEPA) said in Beijing Wednesday that the Songhua River, a major water source of Harbin, suffered a major water pollution incident, which led to the four-day water supply system shutdown as of the wee hours Wednesday in Harbin.
Benzene and nitrobenzene flew into the river after the Nov. 13 blast in a petrochemical plant in Jilin Province where the river originates.
After a dashing purchase of drinking water, food and other daily necessities since Monday, local citizens became calming down.
However, anxiety hanged over some of residents. To cope with psychological pressure on some residents, counseling hotlines started on Thursday in Harbin. Meanwhile, psychiatrists with state certificates of qualification have been encouraged to provide counseling and related services free of charge.


Main body of pollutants in NE. China river flowing through Harbin
The main body of the pollutants in northeast China's Songhua River is flowing through Harbin, capital of Heilongjiang Province, China's environmental administration said in a bulletin released on Friday morning.
"At zero hour Friday, the density of nitrobenzene 16 kilometers upstream of the water sourcing spot of Harbin reached the highest level of 0.5805mg/L, 33.15 times above the safety standard," said the bulletin of State Environmental Protection Administration.
It said the density then subsided to 0.5570 mg/L at 4:00 a.m., still 31.76 times higher than the safety standard. It further dropped to 0.4943 mg/L at 7:00 a.m., 28.08 times above the safety standard.
"The density of benzene is below the safety standard in this section of the river," said the bulletin.
According to the bulletin, water quality of the Songhua River at the upstream Zhaoyuan section has met the national safety standard. The 80-km-long slick of polluted water haunted Zhaoyuan from Nov. 20 to 22.