China's polluted lakes will never be clean unless efforts are made to eradicate land and water pollution together, a leading Chinese water resources expert said Tuesday.

"For a long time, China has not paid enough attention to land polluting sources while curing lake contamination. That's why the results were not satisfactory," Wang Hao, an academician of the Chinese Academy of Engineering, told Xinhua at the ongoing World Lake Conference held in Wuhan, capital of central China's Hubei Province.

A survey by the National Audit Office last week showed water quality in three major rivers and lakes in the country had improved only slightly despite continued pollution control efforts between 2001 to 2007 at a cost of 91 billion yuan (13.3 billion U.S. dollars).

"Lakes don't produce pollutants themselves, they receive everything left by human activities on land and drainage areas. How can we clean a lake when pollutants keep pouring in from outside?"

Lakes were vulnerable to pollution from activities such as fish breeding, the release of sediment contaminants, and the growth of invasive species in lake waters. They also faced pollution from domestic sewage and industrial wastewater discharges, agricultural fertilizers, soil erosion and over-extraction, Wang pointed out.

He proposed an integrated lake-land treatment mechanism, which combined comprehensive land pollution control measures, including higher waste discharge standards, stringent punishments by economic and administrative means, and greater public awareness through education.

The International Lake Environment Committee believes that integrated lake basins management, which are widely adopted in international practice, encompasses six key elements: institutions, policies, participation, technological possibilities, information, and sustainable financing.

He called on Chinese authorities to quickly work out systematic pollution control measures based on the situation of each lake basin while taking into consideration the factors of climate change, the emergence of new types of pollutants amid expanding human activities, and establishing effective risk assessment and prevention mechanisms.