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Check the groundwater: expert says city may be contaminated by leaked sewage and past industrial pollution

Scientist wants to build and trial a monitoring well here, but government claims the current system is adequate

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Dr John Cherry (right) demonstrates measuring groundwater levels with Professor Jimmy Jiao from the University of Hong Kong. Photo: Nora Tam

Contaminated groundwater is an ecological problem for Hong Kong and deserves more research and government monitoring, ­according to a Canadian ­hydrogeologist, who is looking to build and trial his first advanced ­monitoring well in Asia here.

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Dr John Cherry, a professor emeritus at the University of Waterloo, said nitrate pollution and overpumping of the world’s groundwater has reached “crisis proportions” and threatens to ­exacerbate “water poverty” in both rich and poor countries.

In Hong Kong, recent ­scientific studies have highlighted correlations between high discharges of nutrient-rich groundwater into Tolo Harbour and the high frequency of algal blooms or red tides in the area, which can harm marine life by depleting ­oxygen in the water.

Cherry, who received the Lee Kuan Yew Water Prize 2016 last month for his studies on groundwater in China, told the Post: “Hong Kong is not dependent on well water so some people would ask ‘why bother’?”

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“If you don’t monitor groundwater you don’t understand where the chemicals going into the ground are from ... sewage, run-off, all of the types of urban contamination that you have in a city,” Cherry explained.

He said Hong Kong’s problem was mainly contamination from leaky sewage, which is the source of nutrients such as nitrogen. But another possible source was the city’s manufacturing legacy.

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