Environmental management in Singapore

From modest beginnings, Singapore rapidly developed its industrial base which today comprises high technology and high value added industries. Economic growth was accompanied by a comprehensive housing and urban development programme.The formation of the Ministry of the Environment and the Anti-Pollution Unit in the early seventies marked Singapore's commitment to protect the environment in the face of rapid developments.Together with the rapid industrialisation, housing and urban development programme, Singapore also implemented a programme to prevent pollution as well as to control pollution from those sources which cannot be prevented.The success of these programmes is evident today and we have an environment that compares well with that of any nation in the world.Plenary speaker.     

Heavy Metal Levels in Marine Sediments of Singapore

Marine environmental levels of the metals copper (Cu), zinc (Zn), lead (Pb) and cadmium (Cd) were measured from sediments collected around 20 coastal locations around Singapore, over a 2-year period. Sediment-size analysis was conducted on sediment samples, and Atomic Absorption Spectrophotometry was used in the analyses of sediment heavy metal concentrations. The levels of heavy metals in marine sediment was largely dependant on sediment particle size, as illustrated by the correlation of sediment size with Multidimensional Scaling (MDS) configurations of sediment metal concentrations. In addition, the proximity to shipping activity, and the release of anti-fouling paint from boats also influence heavy metal concentrations in marine sediments of Singapore.     

Improving the living environment of Singapore

For the past quarter century, the government of Singapore has redeveloped the city with multiple objectives. The city should be free of squatters, slums and pollutive influences. It should be clean, green and healthy for living. All necessary infrastructures are provided and function well. All the necessary building floor spaces are available to facilitate the daily needs of the people and to enhance economic growth.While all of these objectives should be kept and augmented, the city must now update its position and even give added attention to the quality of the living environment, visual and otherwise, in order to make Singapore a tropical city of excellence. This paper attempts to review the past achievements and outline the approaches envisaged for the near future.Plenary speaker.     

Proposals for the conservation of nature in urban Singapore

The benefits of conserving nature in urban environments have proved to be a significant factor in improving the quality of life for residents of major cities throughout the world. In Singapore there are still many potential areas in which conservation management techniques would support sufficient natural habitat and attract a wide diversity of wildlife.This paper attempts to establish the criteria for selecting such areas, to identify the numerous human needs to be satisfied and to describe several case study examples.     

A Value Orientation for Nature Preservation in Singapore

Over the past decade, the cause of nature preservation in Singapore had gained momentum through the efforts of the various non-governmental organisations. Tussles over disputed nature areas such as the Lower Peirce Forest, Marina South, Senoko, etc., had also garnered a great deal of publicity in the mass media. Many arguments for nature conservation were given by conservationists --- from the economic to the ecological --- without considering carefully their local relevance and impact. This paper provides an outline of a value orientation for nature preservation in Singapore --- taking into account the local context in terms of the economic, cultural, social and ecological conditions existing in this country. The major values usually associated with nature conservation are reviewed and prioritised in terms of local relevance and impact. The strategic thrust of the value orientation advocated is, in the final analysis, anthropocentric rather than non--anthropocentric in perspective.     

Characteristics of Stormwater Quality from Two Urban Watersheds in Singapore

This paper presents the results of a study on the quality of stormwater runoff from two adjacent urban watersheds in Singapore. The study involved continuous recording of rainfall and streamflow within the basins, and systematic sampling of storm runoff during rainfall events. The water samples collected were analysed for its physical and chemical constituents. The ranges and mean concentrations of common quality parameters have been established, and the flushing effects of selected parameters were studied. Correlations of event mean concentrations and pollution loads of total suspended solids and chemical oxygen demand to both antecedent dry weather period and rainfall characteristics were also carried out.     

Lichens as Bioindicators of Atmospheric Heavy Metal Pollution in Singapore

Lichens have been used as bioindicators in various atmospheric pollution assessments in several countries. This study presents the first data on levels of heavy metals (As, Cd, Cu, Ni, Pb, and Zn) in lichens at different locations in Singapore, Southeast Asia. Singapore is a fully industrialised island nation, with a prevailing tropical climate and a population of 4 million people within a confined land area of less than 700 km². The ubiquitous lichen species, Dirinaria picta was collected from six sample sites across Singapore and analysed for heavy metals using inductively coupled plasma mass spectrometry (ICPMS). No significant relationship existed between metal levels in lichen and soil, indicating that accumulated metals in lichen are primarily derived from the atmosphere. Peak concentrations of zinc (83.55 μg g⁻¹), copper (45.13 μg g⁻¹) and lead (16.59 μg g⁻¹) in lichens were found at Sembawang, Jurong and the National University of Singapore campus which are locations associated with heavy petroleum and shipping industries, and road traffic respectively. The mean heavy metal levels of lichen samples in Singapore were found to be at the upper range of values reported in the literature for temperate countries.     

Characterization and source identification of airborne trace metals in Singapore

Airborne particulate trace metals have important health implications. As a consequence, their concentrations are increasingly monitored in many urban locations worldwide. In this study, fine atmospheric particles (PM(2.5)) were collected in Singapore over a period of 83 consecutive days during 2000, and analysed to determine the concentration of trace elements using ICP-MS. Altogether, eighteen airborne trace metals were quantified: Al, Ag, Ba, Cd, Cr, Co, Cu, Fe, Ga, Li, Mn, Ni, Pb, Sr, Zn, V, Si, and Ti. While Li was the least abundant trace metal with a mean concentration of 0.2 ng m(-3), Zn showed the maximum mean concentration of 279.1 ng m(-3). Calculation of enrichment factors indicated that the elements Pb, Zn, Cd, V, Ni, Cr, and Cu were enriched by factors of 30 to 5000 relative to their natural abundance in crustal soil. The extent of metal pollution in the study area was assessed by comparing the measured concentrations to those reported in the literature for a selected number of urban sites in other parts of the world. Factor analysis was used to identify the major sources affecting particulate air pollution in Singapore. The sources that contribute to the loading of trace metal-bearing aerosols in the Singapore urban atmosphere include fuel oil-fired power plants, metal processing industry, land reclamation and construction activities, municipal solid waste incinerators, and traffic emissions.     

The distribution of polynuclear aromatic hydrocarbons in ambient air particulates in Singapore

Ambient air particulates were collected using high volume samplers at seven locations throughout Singapore. The particulates were analyzed for eleven polynuclear aromatic hydrocarbons (PAH) using high performance liquid chromatography (HPLC) with fluorescence detection. Several sample preparation techniques were used to determine which method would yield the most PAHs from the bulk sample matrix. PAH profiles (standardised against the concentration of benzo(a)pyrene) were obtained to characterise the different sampling sites chosen.     

Drainage Planning and Control in the Urban Environment the Singapore Experience

Singapore is situated 137 km north of the equator and is subject to heavy tropical rainstorms, particularly during the North-east monsoon season between November and January. Flooding was prevalent in the past as the older parts of the city were built on relatively low-lying areas and the drainage systems were not adequate to convey storm water runoff effectively. Rapid urbanisation in the 1970's and 1980's brought about drastic transformations of the hydrological characteristics of the drainage catchments in Singapore. More areas were paved up, resulting in increased storm water runoff being generated during heavy downpour. This paper deals with the strategies adopted by Singapore to keep the flood situation under control despite the vast extent of new land developments that are continuously taking place. It discusses the drainage master plan and the drainage development programmes that were implemented over the years for flood alleviation and prevention, including the drainage control policies being pursued by the Drainage Department as a land drainage authority. The paper also covers the integration of drainage projects with land developments to maximize land use and the creation of aesthetic waterways to enhance the urban environment.     

A study of the heavy metal concentrations of the Singapore River

The concentrations of lead, cadmium, copper, zinc, iron, and mercury in the water, sediment and biota of the Singapore River were determined. The concentration of the various metals in water showed significant variation at different sampling times and there was enrichment of lead content. The spatial patterns of metal distribution in the sediment could be due to the different pollution sources such as exhaust emission from boats and other environmental variables such as clay content of sediment or tide level. In the biota, higher amounts of metals were found in species inhabiting the river bed while organisms of higher trophic level such as free-swimming fishes and crabs accumulated lower amounts. In general, the flesh of fishes and crabs had the least content of metals compared to other tissues. The Concentration of various metals in bivalve, Mytilopsis sallei, which were found extensively in the river did not reflect the pollution distribution.     

Air Pollution in Singapore: Its Multielemental Aspect as Measured by Nuclear Analytical Techniques

Aerosol samples were collected in 1994 in Singapore on two occasions: once in June during the normal meteorological conditions and later in October during a long haze period caused by the heavy forest fire in Indonesia. Filtration and impaction collection methods were used simultaneously so that detailed elemental analysis of bulk as well as of different size fractions could be performed. Accelerator based nuclear analytical techniques such as Particle Induced X-Ray Emission (PIXE), Rutherford Backscattering (RBS) and Nuclear Microscopy (NM) were used for analysis. These techniques are fast, truly multielemental and perfectly suited for routine analysis of a large number of aerosol samples. Typically all samples were analysed for the following 24 elements: Na, Mg, Al, Si, P, S, Cl, K, Ca, Ti, V, Mn, Cr, Fe, Co, Ni, Cu, Zn, Ga, As, Br, Rb, Sr and Pb. Detection limits for bulk analysis were generally below ng/m3 and for single particle analysis absolute detectable mass was approximately 10-17 g. Additionally, trace elements such as Cd, Sn, Sb and Ba whose characteristic X-ray lines were normally "obscured" by the lines of other more abundant elements, were detected when analysing by nuclear microscope in single particle mode.Judging by the average concentrations of lead and sulphur which are good indicators of industrial component of air pollution the situation in Singapore is satisfactory. Pb was typically found in concentrations of 5 to 50 ng/m3 and sulphur in concentrations of 1 to 2 µg/m3. These concentrations are well below limits set by the World Health Organisation (1500 ng/m3 and 40 µg/m3, respectively). On the other hand during the haze period the average concentrations of elements like S, K, Ti, V, Mn, Ni, As and Pb were found to be 3 to 6 times higher than usual. Results are presented and discussed.     

Soil Lead and Other Metal Levels in Industrial, Residential and Nature Reserve Areas in Singapore

The use of pressure feedback microwave digestion technique has permitted rapid and efficient digestion of soil and sediment samples. The evaluation of different acid mixtures to digest soil samples were studied by mixed-level orthogonal array design. The selected acid mixture of HCl-HNO3-HF was employed in the survey of Pb, Zn, Cu, Cr and Mn in soil samples. Surface soil samples were collected from industrial, residential and nature reserve areas in Singapore. The five metal concentrations were determined by flame atomic absorption spectrometry and graphite furnace atomic absorption spectrometry. The lead and other metal contents in NBS SRM 1645, NIES CRM No. 2 and NRCC BCSS-1 sediment standard references were determined concurrently with the survey samples. Five measured metal loading on the surface soils was in the order: industrial area > residential area > nature reserve area. The trace metal concentrations in surface soil from areas of heavy traffic are higher than those from residential areas. The main sources of trace metal pollution are vehicular exhaust and industrial activities.     

Strontium/calcium ratio analysis of molluscan shells in Singapore waters using the X-ray fluorescence technique

The Sr/Ca ratios in molluscan shells in Singapore waters were measured using the X-ray fluorescence (XRF) technique. Our results show that the Sr/Ca ratio varies greatly among different species. However, within the same species, this ratio is practically the same for samples collected from sites close together but varies significantly for samples from sites far apart. Furthermore, this study shows that whole shell analysis using the XRF technique is simple and quick and that its application to environmental monitoring seems feasible.     

浅析美国和澳大利亚及新加坡道路交通噪声管理与监测

简要介绍了美国、澳大利亚及新加坡在道路交通噪声控制管理与监测技术方面的现状,分析了其经验和特点,结合我国道路交通噪声监测与评价现状提出了相应的建议。     

Design of National Groundwater Quality Monitoring Network in Egypt

In the Nile Valley and Delta the protection of groundwater resources is high priority environmental concern. Many groundwater quality problems are already dispersed and may be widespread and frequent in occurrence. Examples include problems associated with the extensive application of chemical fertilizers in agricultural specially in the new reclaimed areas, leaks in sewers, septic tanks, the aggregate effects of many different points source pollution in urban areas and natural, geologically related water quality problems. A national groundwater quality monitoring has been designed and implemented based on the stepwise procedure. The national groundwater quality monitoring network is used to quantify the quality changes in long run, either caused by pollution activities or by salt water intrusion and to describe the overall current groundwater quality status on a national scale of the main aquifers. The monitoring tools and methodologies developed in this research can be used to assure protection of public health and determine the sustainability of groundwater in various purposes. This national monitoring network plays important roles for decision makers in developing the groundwater resources management plans in different aquifers systems in Egypt.     

Evaluation of data quality in Japanese National Forest Inventory

We evaluated the quality of data being collected for the Japanese National Forest Inventory (NFI). The inventory program commenced in 1999 but has not incorporated a quality assurance (QA) program; we sought to determine what effect this was having on the quality of data being collected. Forty-eight plots in four prefectures were measured by operational field teams and then remeasured by a control team that made careful and unhurried measurements. The paired data were evaluated, including diameter, total height, tree count, species richness, and topographic condition. Compared to the control team, all field teams of each prefecture tended to significantly underestimate all of the continuous variables. Most variables had larger variability in the inventory data than has been reported in the published literature. The findings of consistent bias and large variation in the field team measurements call for urgent implementation of a quality assurance program (extensive field training and regular remeasurement) in the Japanese NFI to improve data quality, and this conclusion could be applied to the inventory system of any country that does not include a QA program.     

阿尔金山国家级自然保护区人为活动的影响简析

通过对阿尔金山国家级自然保护区生态环境现状的调查,分析了保护区内偷猎、采金以及过度放牧等人为活动对保护区生态环境退化的影响,并提出了解决问题的建议。     

Monitoring Water Quality and Quantity of National Watersheds in Turkey

National data from the hydrological network for 38 rivers out of 25 watersheds were used to detect spatial and temporal trends in water quality and quantity characteristics between 1995 and 2002. Assessment of water quality and quantity included flow rate, water temperature, pH, electrical conductivity, sodium adsorption rate, Na, K, Ca+Mg, CO₃, HCO₃, Cl, SO₄, and boron. Among the major ions assessed on a watershed basis, Turkish river waters are relatively high in Ca+Mg, Na and HCO₃, and low in K and CO₃. The watersheds in Turkey experienced a general trend of 16% decrease in flow rates between 1995 and 2002 at a mean annual rate of about 4 m³ s^?1, with a considerable spatial variation. Similarly, there appeared to be an increasing trend in river water temperature, at a mean annual rate of about 0.2°C. A substantial proportion of watersheds experienced an increase in pH, in particular, after 1997, with a maximum increase from 8.1 to 8.4 observed in Euphrates (P?R ² values in accounting for variations of pH and water temperature only. The findings of the study can provide a useful assessment of controls over water quality and quantity and assist in devising integrated and sustainable management practices for watersheds at the regional scale in Turkey.     

Pollutant monitoring in the Olympic National Park Biosphere Reserve

Interest in global contamination has been instrumental in the establishment of over 33 Biosphere Reserves in the United States. These reserves include pristine areas that have been protected from industrial development. They serve as areas in which present and future environmental pollution can be assessed.Pollutant monitoring studies are being conducted in the Olympic National Park Biosphere Reserve by the U.S. Park Service and the U.S. Environmental Protection Agency. Studies are designed to identify levels of trace element and organic contaminants in physical and biological media. Ten remote sites were selected for intensive sampling. These areas were located in the Hoh, Quinault, and Dosewallips River drainages; at Anderson and Grand Pass; near Ozette Lake and, at the northern edge of Blue Glacier. Their proximity to vehicle-traveled roads varied from 3 to 20 kilometers.Samples were taken in air, water, soil, litter and vegetation. Samples will be analyzed for organic and heavy metal contaminants. Airborne particulate size and chemical characterization is being investigated.