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Friday, 9 November 2012

Foodwaste and landfills in Hong Kong


Environmental Hazards and Intervention CMED 6912

 

Foodwaste and Landfills in Hong Kong

By Pauline Leong
  Helen Chan
  Grace Tsang


Introduction




Waste is inevitable in our daily activities with domestic, commercial and industrial activities. The management of solid waste (MSW) by different waste facilities which cause both environmental and health hazards is under monitored and reviewed by Environmental Protection Department (EPD) [1] and Concern Groups in Hong Kong. In this blog, the alarming increase in foodwaste which causes overwhelming burden on landfills and its hazards will be describe and discussed.


Problems of Foodwaste in Hong Kong 


In 2011, there was about 3,200 tonnes foodwaste produced daily in Hong Kong while around 2,995 tonnes of food waste (94% of foodwaste) are disposed at landfills everyday (See Figure 1) [2]and (See Figure 2) [3].


Figure 1:Where do foodwaste come from?




Figure 2: Newspaper cutting for wastefood in Hong Kong


This biodegradable waste gives great pressure to waste disposal and also leads to rapid depletion of the limited landfill void space.

Landfills in Hong Kong


Solid waste could be handled by incineration, landfills and recycling. However, there is only one incinerator commissioned now. Landfills are the major way to manage solid waste in Hong Kong (See Figure 3) [4]. There are about 13,458 tonnes of solid waste disposal at landfills in 2011, of which 8,996 tonnes (about 67%) are municipal solid waste (See Figure 4) [4]. Most of the municipal solid waste in Hong Kong is composited by putrescible (See Figure 5) [4].


Figure3: Recovery of municipal solid waste in 2011 of Hong Kong






Figure 4: Disposal of solid waste in landfills in 2011




Figure 5: Composition of Municipal Solid Waste (MSW) of Hong Kong in 2011


There were 16 landfill sites which were closed and with their current use as recreational use. Currently, there are about 3 strategic landfills and all are operated in New Terrorities namely West New Terrorities Landfill, North East New Terrorities Landfill, South East New Terrorities Landfill (See Figure 6) [5] which commenced its operation from 1993-1995. The capacity of landfills will reach its maximum capacity in 2013 (See Figure 7) [6] as projected while there is call for extension of landfills causing great protest and controversy especially on the environmental and health hazards brought to the community.



Figure 6:A Hong Kong landfill located in the northeast New Territories. (Cite CNN International)



 
Figure 7: Anticipated year of exhaustion of landfill in HK. (Cite in Travelization website)



Landfills have its pros and cons to be employed for waste disposal. Firstly, it is quite a cheap disposal method. Secondly, the waste was used to fill the quarries prior to reclamation. Thirdly, the landfill gas contributes to renewable energy supply. However, there are a number of drawbacks incurred. Firstly, the production of carbon dioxide, methane, sulphur, nitrogen as well as volatile organic compounds from anaerobic decomposition of organic matters causes air pollution. Secondly, the leachate and run off causes water pollution. Thirdly, some proven or suspected carcinogens or teratogens such as benezene, dioxins, arsenic, nickel, vinyl chloride, chromium,  polycyclic aromatic hydrocarbon etc. would emit from the sites. Last, landfill sites will attract animal vectors (seagulls, flies, rats) for some communicable disease and with problems of odour, dust, road traffic problems to the communities near-by [7].

 

Potentials Effect on Health Outcomes


Apart from the health hazards of waste management workers by occupational exposure, the health hazards of long term environmental exposure to people living next to landfill sites are under major concern. The potential health effects of landfills including air, water and soil contamination is summarized by Figure 8 [8]. It includes cancer risk, cardiovascular disease, respiratory disease, headache, gastroenteritis, nausea, fatigue, as well as skill irritation [9]. Relationship on cancer and birth defects by living near landfills are under extensive research in the UK and US in the 1980s [10,11].


Figure 8: Potentials Health Impacts of pollution by landfills




Scientific Evidence on Health Impacts


1)      Cancer



Figure 9: Potential Cancer Risks by Emission Toxin at Landfills


In 1995, Goldberg et. al conducted a study about the cancer risk of the people living in communities next to the Miron Quarry municipal solid waste landfill in Montreal, Quebec, Canada from 1981-1988 indicating a higher risk for lung, liver, stomach, prostate cancers in male, and cervical, uterine, and stomach cancer in female (See Figure 9)[8]. However, there is an absence of measurement of exposure which hampers the credibility of evidence [11]. Moreover, a detailed UK study does not indicate that the occurrence of cancer is associated with living close to the landfill sites [12,13]. Similarly, there are a lot of literature about potential negative health effects on populations living next to a landfill but there is an absence of evidence in supporting the emission of toxic substance highlighted would cause cancer at environmental levels as much of the research based on occupational or accidental exposure at high levels or the experiment of the carcinogenicity of those substance from animal studies [14]. Thus, the evidence for causal relationship between emission of toxic substance and cancer is inconclusive.

2)      Birth defect and reproductive disorders


The association of reproductive defeats and landfills has been extensively researched mainly covering the lower birth weight (< 2500 g), spontaneous abortion, fetal and infant mortality as well as the occurrence of birth defects (Figure 10) [12]. Case studies of Love Canal site (1965 to 1978) and Lipari Landfill in New Jersey (1971-75) indicated that the low birth rate is highly related with time and volume of dumping at a large waste disposal site [12]. A study conducted in California also supported the neonatal deaths and low birth weight were found to associate with time and volume of waste disposal in landfills. However, two large scale multiple site case-control studies in the USA found there was no association with birth weight and landfills [12].






Figure 10: Risk of adverse birth outcomes in populations living near landfill sites


A large geographical study of study landfill sites has further supported that the association between residence near by a landfill site and the prevalence of birth defects in Great Britain from 1982 to 1997 with large samples [13,14]. There was a small increase in the risk level of birth defects of families with newborns living within 2 km away from landfill sites. However, the study was not able to indicate whether the association are causal, or whether they might be others confounding factors that could not be addressed fully. The UK study further supports significantly heightened risk for a number of birth defects, including hypospadias, abdominal wall defects, neural tube defects, epispadias, as well as surgical correction of gastroschisis and expohalos.


Knowledge Gap on Scientific Evidence


Several studies have proven excess risk of about two to three times for certain congenital anomalies and low birth weight of families living near landfill sites. However, it is difficult to draw conclusions on the causality with the problems of small sample size, exposure misclassification, the existence of confounders and reporting bias from the participants. Most importantly, no comprehensive and long term landfill and health impact studies has been done in Hong Kong while the excess risks of congenital anomalies and low birth weight living near landfill sites was not big enough to support further policy intervention. Further research effort is essential to identify effects of potential data artefacts and confounding on the associations with landfills. Most of the research mainly focuses on the emission to air. However, more future research into other emission such as land, water and other waste management facilities could be helpful.


Local Case Study: Nuisance of Bad odors from Landfill of Tseung Kwan O


Although there is no available evidence on the health hazards from landfills in Hong Kong, people in communities near landfills are often disturbed by the bad odors and its immediate negative health impacts. For example, the residents of Lohas Park hold frequent complaints the bad odors from the landfill site of Tsuen Kwan O in Hong Kong (See Figure 11) [1]. Landfill gas odors are created by bacterial or chemical processes. The potential sources of landfill odors include sulfides, ammonia. Many people are affected by the offensive odors emitted from a landfill with the problem of nausea or headaches. Some even claimed being awakened in the midnight and disturb their sleep [9].




Figure 11: Distance between Lohas Park and Tseung Kwan O landfill site


Effects on environment


Despite the health problems, the emission of greenhouse gases from landfill such as methane and carbon dioxide, those contributing to global warming and climate change e.g. heat wave [14]. Besides, the noise pollution and traffic problem generate by the heavy-duty vehicles moving in and out in the landfill area.


Interventions to reduce the hazards


In concern of the potential hazards on human living nearby landfills, possible interventions to reduce the hazard would be mainly lying on 1) reduction of food waste and 2) promotion of waste recycling. 


1)      Reduce production of food waste


The pilot study of urban metabolism of Hong Kong shown that the per capita food, water and materials consumption have risen starting from 1970s by 20%, 40% and 149% respectively(See Figure 12)[16]. 



Figure 12: Trends in resource consumption in Hong Kong from 1971-1997


Different forms of pollution have escalated with this increasing affluence, materialism, total air emissions, carbon dioxide outputs, municipal solid wastes and sewage discharges have raised by 30%, 250%, 245% and 153% respectively (See Figure 13) [16].



Figure 12: Growth of pollution in Hong Kong from 1971-1997


Education and awareness campaigns on consumerism and environmental hazards could be promoted to help people in building more sustainable environments by reducing waste disposal on avoidable food consumption. Avoiding dissipate of food by banquets, institutes (school canteens or hostel) and domestic use could be promoted by incentives, such as requesing “Less Rice Please” in participating restaurants can enjoy $1 incentive which promoted by Greeners Action [17].  Likewise, choice for different portion size, such as BIJAS vegetarian in the Centennial Campus of The University of Hong Kong [18], which provides buffet style services and charges by weight, in order, reduces the generation of foodwaste. Moreover, the unconsumed foodwaste by markets, supermarkets and restaurants could be reused in serving dishes in feeding the deprived populations through Food Bank and Food Canteens of Non-Government Organization, such as People’s Food Bank of St. James’ Settlement [19].


2)      Promotion foodwaste recycling


As foodwaste may not be totally avoidable in both production and consumption, foodwaste recycling could be promoted to reduce the putrescible in landfills. Negative impacts of “foodwaste” can be turned into positive benefits which is useful to the environment.  Nitrogen, potassium and phosphorus fertilizers are essential to agricultural production and the prices of these materials have double increased within the past decade.  Foodwaste contains phosphorus that is a valuable resources and essential plant nutrient [20]. Other valuable resources, including energy, can be recovered from foodwaste via aerobically or anaerobically composting or incinerated energy generation [20]. 


Future Directions

 

1)      Reuse, recycling and reducing the wastes (see figure 14) [21]


The implementations of waste recycling policies in Hong Kong still have much room for improvements. Here are some recommendations which could be implemented by governments:

Ø   Implementation of high landfills charging scheme

Ø   Setting up a centralized center for recycling solid waste

Ø   Provide easily accessible drop-off recyclable material points near residential area

Ø   Promoting innovative demolition methods

Ø   Reusing the reusable waste as donations to NGOs[22]











Figure 14: Diagram of waste management direction (Cite in Agri website)

 

2)      Implementation of health assessments and nuisance caused by landfills sites


The information from the landfills study done by Environmental Protection Department of Hong Kong in 2001 was outdated for reference. Besides, the study mainly focuses on ecological impact which health impact on long term exposure has been ignored. A collaboration between the academy, Environmental Protection Department and Health Authorities is recommended in conducting large scale survey in providing local evidence on the relationship between landfills, short-term health effects including nuisance and psychological discomfort. Currently, electronic nose was installed by EPD at residential area near-by the landfills to assess the level of air pollution. However, the perception and influence of odor are quite subjective and could not be evaluated through the machine.


3)      Hazards of Long term Exposure and psychological discomfort


Current evidence could not provide convincing information to support health hazards caused by long term exposure at low risk. For example, cancer may develop after quite a long term exposure with its latency period. With the high density of population and limited living area in Hong Kong, much of the population is exposed to the hazards of landfill sites. e.g. Lohas Park near-by Tsueng Kwan O Landfill site.   Long term longitudinal studies are essential to follow up health conditions of residents living next to landfills.


Conclusion


In conclusion, the problems of foodwaste and hazards of landfills have to be resolved by a multi-prolonged approach through collaborations of government departments, NGOs, concern groups and the academy through continuous surveillance on health hazards, research, polices and education with government dedication.  The public should not overuse and misuse the natural resources especially in food to prevent the hazards to their health.


Reference:


1.      Environment protection department [homepage on the internet] Waste: problem and solutions. [Last Update 2012 April 26] Available from: http://www.epd.gov.hk/epd/english/environmentinhk/waste/prob_solutions/owt_food.html
2.      HongKong stories Fall 2011 (Backup) [homepage on the internet] From trash to treasure: Food waste in Hong Kong [Last update 2012 Oct] Available from: http://www.hkstories.net/fall2011backup/2011/11/20/food_waste_in_hong_kong/
3.   Food waste in Hong Kong.  Singtao daily. 2012 October 23.
4.      Environmental Protection Department, Monitoring of Solid Waste in Hong Kong, Waste Statistics for 2011,
6.      Travelization [homepage on the internet] Get drowned in food. [Last update 2011 Oct5] Available from: http://travelizedcarrie.wordpress.com/2011/10/05/ get-drowned-in-food/
7.      MRC institute for environmental and health, Leicester, UK, Health Hazards and waste management, British Medical Bulletin, 2003, 68, 183-197
8.      Wikipedia [homepage on the internet] File:Health effects of pollution.png. [Last Update 2012 Oct] Available from: http://en.wikipedia.org/ wiki/File:Health_ effects_of_pollution.png
9.      Rushton L. Health hazards and waste management. British Medical Bulletin. 2003; 68: 183-197.
10.      Review of Environmental and Health Effects of Waste Management: Municipal Solid Waste and Similar Wastes, Extended Summary. Department for Environment, Food and Rural Affairs. May 2004.
11.  A Review of Studies of Landfills and Human Health. Julie Goodman Gradient Corporation. October 15, 2007.
12.  Department for Environment, Food and Rural Affairs, UK, Review of Environmental and Health Effects of Waste Management, Municipal Solid Waste and Similar Wastes; Extended Summary, Queen’s Printer and Controller of HMSO, 2004
13.  Paul Elliott et al, Risk of adverse birth outcomes in populations living near landfill sites, BMJ, Volume 323. 18 August 2001.
14.  MRC institute for environmental and health, Leicester, UK, Health Hazards and waste management, British Medical Bulletin, 2003, 68, 183-197
15.  Environmental Protection Agencies [homepage on the internet] Climate Change, Methane and Other Greenhouse Gases [Last Update 2012 Oct] http://www.epa.gov/ghginfo/
16.  Warren-Rhodes K, Koenig A.  Escalating Trends in the Urban Metabolism of Hong Kong: 1971-1997.  Ambio. 2001 Nov; 30 (7): 429-38.
17.  Greener Action.  Available from: http://www.greeners-action.org/modules/AMS
18.  BIJAS Vegetarian of The University of Hong Kong. Available from: http://cedars.hku.hk/sections/campuslife/Catering/BIJASMain.php
19.  People’s Food Bank, St. James’ Settlement.  Available from: http://foodbank.sjs.org.hk/home.action
20.  Mason L, Boyle T, Fyfe J, Smith T, Cordell D.  National Food Waste Assessment: Final Report.  Institute for Sustainable Futures and University of Technology Sydney. 2011 June.
21.  Agri [homepage on the internet] Waste recycle-National collection services [Last Update 2010] Available from: http://www.agrienergy.co.uk/ other_waste_ management_services.aspx
22.  Tam WYV, Tam CM.  Evaluations of existing waste recycling methods: A Hong Kong study.  Building and Environment.
















1 comment:

  1. Great information provided, thanks for the tips on reduce, reusing, and recycling.

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