Research Presentations

Topic 1

Interaction among men and nature

Variations of chemical pollutants and heavy metal along river

Po Leung Kuk Laws Foundation College, Hong Kong, China

Angel CHENG, Kelvin CHU, Jason LAM

Striking a balance between conservation and development has long been a controversial issue raising the awareness of people from all walks of life.  It is essential for Hong Kong as a metropolis which lacks nature conservation, to promote sustainable development.

Lam Tsuen River is one of the few remaining undistributed rivers in Hong Kong.  It is a 10.8km long river located in the northern part of the city.  There are 26 villages with more than 10,000 people living along.  The River is also an important site for the commercial farming of flowers and vegetables.  The River also carries cultural significance: The “Wish-making Tree” in the middle course attracts thousands of local and overseas tourists.  Tourists throw offerings tied with oranges onto the tree branches, making their wishes and hope to have good luck in every New Year of Chinese.

In the present study, the river water aresampled bi-weekly atthree checkpoints from November 2013 toMay 2014.  Nine water quality parameters, namely temperature, acidity, turbidity, dissolved oxygen, total dissolved solid, ammonia, nitrate, nitrite and nickel, are examined in the school laboratory through various apparatus, chemical reagents and spectrophotometer.

Through analysing these water samples, the impact of human activities along the River have been shown.  Some pollutants that are hazardous to the ecosystem like ammonia, nitrate, nitrite and nickel are found in theRiver. It is shown that, among the nine parameters examined, threehave exceeded the standard of drinking water advised by the World Health Organization.

Lam Tsuen River is a river with significant agricultural, cultural and ecological importance.  To alleviate the problem of water pollution, timely actions should be taken by the government and residents along the River, for a sustainable development of the River and the basin.

Topic 2

River Resource Conservation: A Study of E. Coli Level of Lam Tsuen River

Po Leung Kuk Laws Foundation College, Hong Kong, China

Leo CHAN, Ryan CHUNG, Kenny HAU, Cecilia YU, Sunny YU

LamTsuen River is a river located in northeast Hong Kong.  It has been documented since the Han Dynasty (BC202 – AD220).  More than 25 rural villages are still found today in the middle course, and agricultural activities, e.g. flower and vegetable farming, are common.  Unlike urban settlements, sewage systems are often absent in ruralareas.  Sewage is often discharged directly from farms and houses to the channels.

In the present study, the amount of E. Coli at three different points of the river areinvestigated.  E.coliis proven to pose health hazards to human beings. Excess number of E. Coli can cause serious digestive system upset.

River water aresampled bi-weekly atthree checkpoints along the river from November 2013 toMay 2014.  The 3M Petrifilm E. ColiCount Plate is used for the tests.  Onemillimeterof water sample is pipetted to thisgrowth platform.  The Plate is then incubated at 35^oC for 24 hours.  The indicator dye on the Plate colors the colonies and theyare being counted.

It is shown that the number of E. Coli colonies increased downstream, reflecting that there is a discharge of sewage containing E. Coli along the river course.  According to the World Health Organization, there should have no E. Coli to present in drinking water.

With complete coverage of tap water, villagers along the River are unlikely to drink the water.  Still, the impact of such contamination are in twofold, firstly, the River is a source of irrigation for the farm.  Irrigating produces with contaminated water pose health hazards to consumers; Secondly, the contamination by E. Coli implies that the aquatic ecosystem would be upset.

Lam Tsuen River is rich in historical and cultural values.  With more in-depth investigationin the future, the sources of E. Coli can be more accurately determined, and this makes the planning of remedial and recovery work easier.