Nearly half of Shenzhen's coastal waters were found to be seriously contaminated last year, and nine sewage drainage lines were found to be discharging excessive pollutants, according to a maritime study.
A professor of marine chemistry says the problem could worsen this year, as some temporary efforts to improve water quality last year for the World University Games are no longer in effect.
The 2011 study, issued on Wednesday by Shenzhen's Urban Planning and Land Resources Commission, found a total of 565 square kilometres of seriously contaminated seawater. Of the remaining waters, 145 square kilometres were lightly or moderately polluted, and 435 square kilometres were clean.
The contaminated waters were concentrated in Deep Bay and at the mouth of the Pearl River. Inorganic nitrogen and phosphates were the major pollutants.
Though the report covered only waters off Shenzhen, Professor Xu Hong , who has taught marine chemistry at Shenzhen University, said that the contaminated water could make its way to other areas, including Hong Kong.
He blamed illicit discharging of pollutants, along with a lack of oversight, for the heavy pollution. 'The government has been addressing excessive discharge through campaigns rather than regular monitoring and checks,' he said.
Xu said rapidly increasing pollution caused the high contamination levels in waters of western Shenzhen.