Experts call for attention on coastal water pollution

Friday, June 10, 2011
Issue 1328, Page 2 – 3
Word count: 1883
Published in: Macau Daily Times

By Poyi (Natalie) Leung

Coastal water pollution in Macau is deteriorating over the years as indicated by the higher-than standard non-metal and heavy metal indices released recently by the Environmental Protection Bureau (DSPA).

The bureau has suggested a thorough investigation be launched into the source of pollutants and toxic chemicals, but the environmental experts the Macau Daily Times talked to have pointed out a number of factors and causes that may help the government discover what countermeasures should be taken to tackle the challenging issue more effectively.

According to the Macau State of Environment Report 2008-2009 which was unveiled by the DSPA at the end of last month, coastal waters were contaminated several times but three years on, the problems are still threatening the quality of water bodies in the territory.

Between 2008 and 2009, a large amount of water hyacinth floated into the Fai Chi Kei North Bay from the mainland after it opened the gates to discharge flood waters. The report said it was estimated that 3,970 tonnes and 2,145 tonnes of water hyacinth entered Macau respectively in the two years.

In addition, in February, March and June 2008 and between August and October 2009, the Maritime Administration (CP) cleaned up a total of 9.1 tonnes of dead fish in the North Bay.

The report attributed the dead fish to water pollution and adverse weather conditions.

Moreover, in October 2009 red tides were reported in Hac Sa Beach which killed marine life, and the long-existing contamination issue in the Ilha Verde Duck Canal is still causing headaches for the government and nearby residents.

Nevertheless, the samples tested by the Health Bureau (SSM) showed that water pollution in terms of non-metals in the Inner Harbour area was the most severe.

The non-metal index analyses the average pH value, dissolved oxygen, chemical oxygen demand (COD), five-day biochemical oxygen demand, nitrogen and phosphorus.

The DSPA report said the non-metal index in the Inner Harbour reached respectively 3.16 and 2.52 (the standard limit is 1.0) in 2008 and 2009, both higher than double the average value of each year.

Concerns should be paid particularly to the consistently alarming results that the non-metal index remained over 1.50 during the past 15 years, and reached beyond 2.50 in the last five years (2005-2009), the report stressed.

In Nam Van, Areia Preta and Outer Harbour the situation reportedly got worse. The indices went up or remained unchanged from 2008 (1.40, 1.43 and 1.45) to 2009 (1.54, 1.50 and 1.45).

The report also highlighted that eutrophication – a process where water bodies receive excess nutrients that stimulate a great increase of phytoplankton that consequently depletes oxygen in the water and kills specific fish and other animal populations – was the most critical in the Inner Harbour.

Analysis based on the testing in the past found that eutrophication was still “very serious” in Macau’s coastal waters.

With regard to heavy metals namely mercury, cadmium, lead, chromium, copper and zinc in the coastal waters, the DSPA described the situation as “unsatisfactory”.

Although the related indices were below the standard limit at respectively 0.17 and 0.41 in 2008 and 2009, the 2009 result surged 141.2 percent from the preceding year.

The level of lead near the Tam Kung Temple in Coloane hung between 0.9 and 1.0, while zinc near the Macau International Airport and also the Tam Kung Temple exceeded the standard limit of 1.0 in 2008.

Notable increases in heavy metal indices were reported in the following year. The levels of mercury and zinc in most of the sampling points almost reached or surpassed the standard limit (Cheok Van, Hac Sa, Taipa, Inner Harbour and Tam Kung Temple).

The lead indices in the waters near the Tam Kung Temple and the solid waste landfill also nearly reached and went beyond the standard limit respectively in 2009.

The report pointed out that the heavy metal monitoring in Macau’s coastal waters showed that the levels of lead, nickel, mercury and zinc were relatively fluctuating, but large increases were found particularly in the nickel and mercury indices.

Inner Harbour worrying 

Professor Wang Zhishi, the director of the Centre for Scientific and Technological Research at the University of Macau however stated that coastal water pollution is an “old problem” having existed in Macau since as early as 1996, as found by an environmental research group of the university.

The research group in 2002 shifted its focus to air pollution, but Wang stressed that it didn’t mean water contamination “was not there anymore”.

The academic specialised in environmental engineering told the Macau Daily Times in an interview that between 1996 and 2002, a study carried out in collaboration with Tsinghua University discovered that Escherichia coli (E. coli), a bacterium which is commonly found in the lower intestine of warm-blooded organisms, was the major problem in Inner Harbour waters due to the direct discharge of domestic sewage.

However, he said the “most troubling” problem was the sediments where at least 20 species of heavy metals and persistent organic pollutants (POPs) precipitated.

Upstream of the Inner Harbour waters – referring to the Pearl River Delta such as the mainland cities of Guangzhou, Zhuhai, Zhongshan and Shunde – was already experiencing rapid development at that time and as a result, “hazardous pollutants were transported in the river to Macau”, Wang said.

Therefore, the professor said he believed that the Inner Harbour should not only be troubled by the issue of non-metals but also organic compounds and the contamination of nitrogen and phosphorus.

“When there is no dissolved oxygen in the water body, the entire aquatic ecosystem will go wrong and fish will die. Once the system is broken it’s very hard to be restored,” Wang warned.

Despite having no scientific proof to explain the causes of high heavy metals found in the waters around Coloane, Wang told the MDTimes three factors might be playing a significant role.

First, he said it could be vehicle emissions in the form of dust blown by the wind from the ground into nearby waters; secondly, the heavy metals may come from the fly ash landfill; and lastly, the increasing construction and land dredging that eventually delivered toxic chemicals into the sea.

“While the economy is developing very fast and construction is everywhere, there must be impacts on the environment,” the professor said.

Better in 2010

The State of Environment Report 2010 is expected to be released in 2012. Wang said it is a big delay but on the other hand he predicted that the situation of water pollution would be “better” than in 2008 and 2009, when large-scale construction on the Cotai Strip was at its peak.

“In 2010 most construction projects were almost finished in Cotai and I believe pollution should improve,” Wang said.

In other words, the academic said the heavy metal problem in Coloane is “temporary”, which is different from the situation in the Macau peninsula.

“The sewage pipe system is unsound and very old and wastewater is discharged directly into the Inner Harbour,” he pointed out.

“The government needs to invest a lot to upgrade the pipes. Actions have to be taken now but it will take time, and the public also have to be patient,” he added.

The contamination in the Duck Canal and Fai Chi Kei North Bay, Wang stressed, requires regional cooperation with the mainland in order to solve the problem effectively.

Meanwhile, he also urged the government to conduct a coastal water pollution assessment on the light rail transit project. “Only assessments on air and noise were completed but an assessment on water is needed especially as some of the routes operate near the coasts.”

Treatment capacity lagging behind 

On the contrary, energy and environmental consultant Gary Chu Kar Kit said he believed the high non-metal indices found in the coastal waters of the Macau peninsula were largely a result of the “insufficient capability” of the sewage treatment plant in Areia Preta.

A view shared by chairman of the Macau Ecological Society, Ho Wai Tim. “The treatment plant has aged and therefore the amount of wastewater it has to treat every day has already exceeded its handling capacity.”

According to the DSPA report, the facility, which treats about 80 percent of the entire territory’s wastewater, is already unable to meet the demands of recent years.

Chu told the Macau Daily Times the limited amount of available land in the city is a “hidden concern” that has hindered the upgrade or expansion of the Macau Peninsula Sewage Treatment Plant, despite its current technology level being quite comprehensive.

The new reclaimed land may provide a solution but the consultant reminded that it may take at least another five to 10 years until an additional treatment plant can be built and running.

“The government must find ways to enhance the treatment capacity, for example shorten the treatment time. Europe performs very well in this area and the Macau Government can learn a lot from them,” Chu said.

On the other hand, the environmental consultant attributed the heavy metal contamination in Coloane waters to the “slow water flow” near the Tam Kung Temple.

“Land reclamation has affected the water flow significantly,” he told the MDTimes.

“This impact is brought by economic development and therefore pre-reclamation planning is very important,” he added.

Chu agreed with the DSPA report that an in-depth analysis is needed to identify the source of heavy metal pollution. He also suggested that test samples be collected inside the sewage pipes of the industrial plants or factories in Coloane to ensure they meet standards.

In response to the development on the Cotai Strip, the second phase of expansion of the Coloane Sewage Treatment Plant was already completed and became operational in 2008.

The handling capability then increased from 20,000 cubic metres to 130,000 cubic metres per day.

However, Chu said the government has the responsibility to conduct a forecast concerning whether or not the Coloane facility is still capable of meeting demands in the next couple of years, due to continued construction of large-scale properties in Cotai.

Nevertheless, he stressed that the government has its own difficulties since “there are not many other places in the world like Macau” where the economy grew so rapidly, and so too the emissions of pollutants.

Doubts over efforts 

The Ecological Society chairman told the MDTimes that he agreed it is essential for the government to find the source of pollutants and outline a long-term and systematic plan to improve the quality of coastal waters.

The organisation has been conducting water testing around the three main sewage treatment facilities, the government’s ecological reserve, the Houses Museum, Sai Van Lake and Fai Chi Kei. According to Ho Wai Tim, the trends and changes the testing uncovered coincided with those disclosed in the State of Environment Report – that coastal water pollution is “getting serious”.

Yet, he questioned which government department(s) should be responsible for the investigation.

“The Maritime Administration [CP] manages local waters, the Health Bureau [SSM] monitors water quality and the Environmental Protection Bureau [DSPA] also seems to be related,” Ho said.

“Cross-departmental tasks are always difficult but it would be even more complicated if it involves the portfolios of different policy secretaries,” he added.

The CP and DSPA are under the Secretary for Transport and Public Works whilst the SSM is under the Secretary for Social Affairs and Culture.


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