Water cleanup a mixed bag

CHINA’S surface water quality improved in 2018, with more samples taken from rivers and lakes reaching standards fit for human use, the country’s environment ministry said last week.

Beijing has extended its campaign to tackle pollution from air to water, attempting to clean up the black and stinky streams flowing through Chinese cities and improve the water quality of its natural reserves.

But while water quality in most of China’s major waterways including the Yellow, Huai, Yangtze and Pearl rivers improved in 2018, those in northeastern China such as the Liao and Songhua were found to be even more polluted than in 2017.

China has vowed to take action to ‘‘significantly reduce’’ the volume of industrial waste water flowing into the Bohai Sea in the northern part of the country.

Among the 1940 samples from across China last year, 71% were considered grade three or better, meaning they were suitable for drinking and fishing, the Ministry of Ecology and Environment (MEE) said, up 3.1 percentage points on 2017.

Meanwhile the amount of ‘‘below grade five’’ water that cannot be used in either agriculture or industry fell by 1.6 percentage points to 6.7% in 2018.

Phosphorus and ammonium nitrate, which mainly come from industrial waste water, pesticides and organic fertilisers, were identified as the major water pollutants, the MEE said.

Chemical oxygen demand, a measure used to determine organic content in water, was also found to exceed the national level in the ‘‘below grade five’’ rivers.