Central Environmental Authority Research Articles

River Gem Mining, its Impacts and Mitigation: A Case from Kumbukkan Oya, Monaragala Divisional Secretariat Area

Gem mining is one of the oldest industries and a major source of income in Sri Lanka. Both traditional and recent mechanical gem mining methods are currently being practiced. However excessive, uncontrolled and illegal gem mining activities have caused many adverse impacts. This study was carried out to analyze the environmental impacts of river gem mining and to propose suitable remedial and mitigatiory measures, with more emphasis on existing legal framework. Study was conducted along a 15 km stretch of Kumbukkan Oya in Monaragala Divisional Secretariat area, where both legal and illegal gem mining activities are taking place at a high intensity. Data were collected by spatial surveys, field surveys and interviews with mine-owners, government officials and general public. All observed mining sites were within the 60m area on both sides of riverbanks. More than 80.00% of the localities from 36 observed sites were unlicensed mines. Natural vegetation had been removed and banks were collapsed due to uncontrolled mining, destructing riverine and aquatic ecosystems. Deep pits were observed in riverbeds at 12 locations. Removed trees and debris were accumulated at the middle of the river, causing flow direction changes. Washing out of damaged banks and disturbances to the riverbed had increased river turbidity and siltation. High number of unlicensed mines, negligence of miners for license conditions, poor monitoring by relevant authorities, lack of cohesion in gem mining policies and laws and the lack of awareness have triggered these issues. Immediate cancellation of condition-violated mining licenses and initiation of legal actions against illegitimate mining activities are important in preventing unregulated mining activities. Systematic rehabilitation of damaged riverine vegetation and riverbanks shall be conducted. Issuance of mining licenses in compliance with the National Environmental (Prohibition of the use of equipment for exploration, mining and extraction of sand and gem) Regulations No.01 of 2006 in Gazette Extraordinary No.1454/4 dated 17.07.2006, demarcation of the ―Reservation Limit‖ of the river mentioned in the said Gazette Notification and obtaining Environmental Recommendations from Central Environmental Authority prior to issuing the license are important to avoid conflicts between the provisions of National Environmental Act and National Gem and Jewellary Authority Act. Issuance of licenses only subject to an acceptable rehabilitation plan submitted by the mine owners, continuous monitoring by relevant authorities and raising awareness among all the stakeholders shall be implemented. More comprehensive studies can be carried out to find the ability of implementing modern environmentally friendly mining technologies. 
 Keywords: River gem mining, Impacts, Mitigation, Kumbukkan Oya

Evaluating the Effectiveness of Speed Humps Related to Speed Profile and Noise Profile

Speed humps are an effective traffic calming measure to improve the safety of road users. On the other hand, speed humps have certain drawbacks, such as increasing emergency response time, causing damage to cars, and high noise levels due to excessive traffic. These impacts further vary with different hump profiles. Thus, the primary objective of this research is to investigate how the geometric profile of speed humps affects vehicle speed and noise level. The secondary objective is to find the Level of Service in the presence and absence of a speed hump by using VISSIM microsimulation. In this study, Lake Drive Road, Nawala, was selected with four different speed hump profiles. The Sound Meter smartphone application was used for noise monitoring. A drone camera footage was utilized to capture vehicle flows while speed trajectories of each vehicle were developed using tracking software. The developed speed profiles were used for the simulation purpose. Then, a Multiple Linear Regression (MLR) model was developed and validated to predict the hump height for the desired speed reduction and desired noise level for each selected four-vehicle category. Further, the average noise levels were found to be higher than the Central Environmental Authority's permissible noise level, and it increases with the height of the hump. It was also observed that as the height of the hump increases, vehicle speed decreases. The largest speed reduction, 42.13 %, was observed in passenger cars, while the lowest speed reduction, 23.5 %, was observed in motorcycles. Therefore, speed analysis findings reveal that passenger cars have a significant speed reduction when compared to other categories. However, the average speed reduction for all vehicles was identified as 33.85 %, and VISSIM simulations revealed that the average Level of Service (LOS) drops to LOS C from LOS A due to the presence of the speed hump. KEYWORDS: Level of Service, Speed hump profile, Speed hump, VISSIM

Design and Performance Evaluation of a Low-Cost Domestic Level Filter to Treat Kitchen Wastewater

The aspects of water security mainly govern by the availability and the quality of the water. As foreseen, use of portable fresh water for landscape irrigation can be a problem in the future. This research study was carried out with objectives of characterizing the raw kitchen wastewater (KWW), designing a domestic level filter for treating KWW and evaluating the removal efficiency of newly designed filter for reuse purpose. Four combinations of treatment systems were used namely in an order, sand and gravel layer, sand and bricks, sand and bricks with a coco peat layer and sand, bricks, coco peat and activated charcoal units for filtering. Raw kitchen wastewater samples were collected three times per day and made a composite sample by mixing equal proportion of each. Water quality parameters were measured before and after treatment of the KWW and compared with the Central Environmental Authority, Sri Lanka (CEA) standards. The average pH, Chemical Oxygen Demand (COD) and oil content in raw KWW was significantly higher than CEA standards. Based on results, raw KWW cannot be reuse for irrigation and it requires adequate treatment prior irrigation. The quality of filtrate from treatment system four resulted with the mean values of pH, electrical conductivity, temperature, total dissolved solids, COD and oil content and respectively quantitative figures were 7.2 ,0.65 mS cm-1, 29.5°C, 230.1 mg L-1, 365 mg L-1 and 2.8 g L-1 .The combination of sand, bricks, coco peat and activated charcoal filter filtrated effluent was within the CEA standards, which can be reuse for irrigation.

A social network analysis of mangrove management stakeholders in Sri Lanka's Northern Province

The sustainable management of complex social-ecological systems (SES) typically requires coordination and collaboration between various groups of stakeholders. Yet, research on collaborative stakeholder networks and their linkages with sustainable mangrove management strategies is lacking in Sri Lanka. This study presents a social network analysis (SNA) of mangrove management stakeholders and their perceptions of both existing and preferred collaborative relationships (or ties) between stakeholder groups, in the Northern Province of Sri Lanka. It further illustrates how SNA can be used to identify stakeholder collaboration and their potential role(s) in mangrove management. The perspectives of all key stakeholders have an impact on how mangroves need to be managed. Therefore, it is crucial to identify and meet with all key stakeholders in the early stages of management processes to understand their needs and constraints. Our findings indicate that the government departments mandated to conserve mangroves are not only formally appointed key stakeholders but are also perceived as central by others. Communication barriers, lack of awareness regarding the importance of mangroves, and shortages in staff and resources for conservation were major constraints to the existing mangrove management network. We highlight the potential of other stakeholders (i.e., non-mandated government stakeholders, non-governmental organizations (NGOs), and private organizations) in improving and influencing the social network in order to increase the diffusion of information. Despite existing resource extraction activities, private organizations were less represented in the mangrove management network of our study. After considering stakeholders’ expectations and requirements, we suggest the inclusion of a bridging organization such as an “Environment Network Unit” or the establishment of bridging entities in the universities and research institutes. We also recommend certain government organizations (i.e., Central Environmental Authority) to take up the role of bridging. This may help to facilitate the incorporation of relatively marginalized stakeholders in an effort to foster sustainable mangrove management in the Northern Province of Sri Lanka and beyond.

Biomedical waste management in Sri Lanka: a scientific and a legal perspective of the legislation and policies

This article reviews the Sri Lankan legal framework and policies regarding biomedical waste management (BWM). Healthcare facilities require an environmental protection license and a scheduled waste management license from the Central Environmental Authority under the National Environmental Act (main legislation on environmental management). Conditions on radioactive waste management stipulated in the licenses issued by the Sri Lanka Atomic Energy Regulatory Council of the Sri Lanka Atomic Energy Board must be fulfilled. However, there are serious loopholes in the national laws considering the World Health Organization and the International Atomic Energy Agency (for radioactive wastes) requirements. National BWM Policy is a draft and an incomplete document. Therefore, a comprehensive regulation under the main legislation or a separate law on BWM should be introduced while the policy requires a re-formulation and legitimation as a command and control policy. Compliance monitoring by relevant authorities is essential for proper enforcement of the legislation and policy decisions.

The Spatial Variation of <em>Mugil cephalus</em> in the Negombo Estuary in Relation to Physico-chemical Parameters

Analysis of physico - chemical parameters gives an insight to the spatial distribution of Mugil cephalus in Negombo estuary. The present study was carried out to the spatial distribution of Mugil cephalus that is governed by the physico - chemical parameters in bottom overlying surface water in Negombo estuary, Sri Lanka. Samplings at selected sites were done during one year study period from January 2017 to December 2017. During this study, fish (Mugil cephalus) and water samples were collected at Sea mouth, Duwa, Pitipana, Munnakkaraya, Dungalpitya, Dandugam Oya and Katunayake sites. Physico - chemical parameters such as the water temperature, salinity, pH, DO, electrical conductivity, BOD, COD and nutrients levels in the bottom overlying water were measured and analyzed using employing standards methods. The results revealed that salinity, pH, EC, BOD and nutrient levels were below the maximum permissible limits of the discharge industrial wastewater quality standards of the Central Environmental Authority (CEA), Sri Lanka. The COD levels were higher than the permissible threshold limits. The seasonality in the physico - chemical levels of water were observed with a peak period from May/June and October/November, which apparently coincided with the inter monsoonal periods of the island.

Hotspots of land use/land cover change around Bolgoda wetland, Sri Lanka

Wetlands are among the most productive ecosystems in the world. Urban wetlands are increasingly affected by population growth and developmental activities. A buffer region of 60 m from the Bolgoda lake boundary was gazetted as an Environmental Protection Area (EPA) by the Central Environmental Authority in 2009 as it is the largest freshwater wetland in Sri Lanka. This study attempts to quantify the land use changes during the period of 2001 to 2019 using GIS and to identify the ‘hot spots’ where a significant change in land use occurred. Land use/land cover (LULC) changed in the Bolgoda wetland area disproportionately. The greatest proportion of loss of natural area was observed in dense vegetation, where a 63.35 % decrease was apparent from 2000 to 2019. In contrast, the residential and commercial areas increased and in 2019 the change reached 49.62 % and 68.57 %, respectively. Hotspots were identified at Grama Niladhari divisions that belong to Kesbewa and Bandaragama DS divisions with the largest change in LULC. Thus, the results of the investigation provide vital information for the conservation and sustainable use of wetland resources in a rapidly expanding urban landscape.

EVALUATION OF ORGANIC AND RECYCLABLE WASTE SEPARATION AT GENERATION SOURCE IN RATNAPURA AND KATARAGAMA LOCAL AUTHORITIES IN SRI LANKA

The Japan International Cooperation Agency implemented a technical cooperation project from 2017 to 2019 in collaboration with Central Environmental Authority (CEA) in Sri Lanka. The project provided technical; and financial assistances in preparing solid waste management plans at selected local authorities, and consequently implemented 3R promotion programs introducing source separation at households and subsequent separate collection by local authorities. Two pilot projects were implemented based on the solid waste management plans which were aimed at reducing the amount of solid waste to be landfilled. This paper described the approaches taken and results obtained through the pilot projects in Ratnapura Municipal Council (RMC) and Kataragama Pradeshiya Sabha Town (KPS) of Sri Lanka. The pilot project in RMC consisted of distribution of household compost bins and the separate collection of five categories of waste: 1) biodegradable waste, 2) plastic and polythene, 3) paper and cardboard, 4) glass, metal and coconut shells, and 5) other residual waste; and provision of advices to households by leaflets, distribution of equipment, and implementation of an awareness program. The pilot project in KPS consisted of procurement of separation bins for biodegradable waste by cost-sharing with dischargers and the separate collection of three categories of waste: 1) biodegradable waste; 2) recyclables including paper, cardboard, plastic, polyethylene, iron and coconut shells, broken glass and glass bottles; and 3) other residual waste. The post evaluation of waste composition and final discharge amounts at disposal sites indicated that pilot projects have contributed to increase 3Rs in both pilot project areas.

Performance Comparisons on Post Combustion Flue Gas Control Systems in Locally Available Power Plants

In this study, author attempted to analyze and compare the performance of different flue gas emission control systems of selected thermal power plants in terms of standard flue gas monitoring data and proposed emission standards of stationary sources combustion systems introduced by the Central Environmental Authority (CEA) of Sri Lanka. This study, however, does not discuss any design specifications or theoretical phenomena of the selected system and focused on to present the data in more practical way. Sixty five sets of data obtained during the last 4 years (including 2017) from 3 numbers of fossil fuel fired and 5 numbers of bio fuel fired power plants were considered. Thus the numbers of data sets per plant are not equal and depend on those monitoring requirements such as annual, bi annual or quarterly and plant commissioning period. Hence some plants are having more than 10 times repeated data sets and some are having only the limited number of data sets. Data monitoring were based on the United State Environmental Protection Agency [USEPA] approved test methods. Electro Static Precipitators [ESP], Bag Filters [BF], Cyclone Separators [CS] and Wet Scrubbers [WS] are the different flue gas emission control systems incorporated in the selected bio fuel fired power plants. None of the selected fossil fuel fired power plants are incorporated in such devices for flue gas emission control system. The outcomes of this study will therefore be important and useful to compare the performance of different flue gas emission control system with respect to the type of fuel, way of combustion, types of plant and the capacity of plant etc. In addition, those information might be useful when implementing the proposed emission standard for power plants in terms of reference oxygen levels and emission limits. Finally the author tries to convince the best suitable flue gas emission control method/methods for stationary combustion systems in future development ; not only the power plants, but also the other industrial combustion systems, such as steam boilers, furnaces, kilns etc. can be modified with the suitable flue gas cleaning system.

Integrating environmental considerations in the agricultural policy process: Evidence from Nigeria

Policy processes that design, develop, and implement sectoral policies often leave environmental considerations to a central environmental authority. As a result, the environmental implications and consequences of policies and programs, even when they are explicitly recognized as a part of their mandate, are often ignored at the time of implementation. In this paper, we show how the role of individual, organizational, and system level factors in enhancing the ability of policy actors is crucial in better integration of environmental considerations in policy processes. Using data collected in Nigeria, we develop empirical evidence on such factors so that the sectoral policy process can be improved for environmental outcomes. The results indicate that explicit identification of environmental challenges, better collaboration and communication between research and policymaking, and a combination of the expertise of young analysts with the experience of senior policymakers can improve explicit consideration and follow-up of environmental issues in sectoral policy process. The lessons from this paper are also applicable to the environmental considerations of the current policy roadmap for the promotion of the agricultural sector in Nigeria, the Agriculture Promotion Policy (APP), and to other developing countries attempting implementation of such sectoral policies.

The Islandwide Ambient Air Quality Monitoring Program in Sri Lanka

In recent decades, the combination of growth of major cities across the country, increased use of vehicles, rapid industrialization, and deficiencies in both planning and environmental regulations, has led to increasing the levels of air pollution and consequent health and environmental impacts. The observed levels of criteria air pollutants (CAPs) and hazardous air pollutants (HAPs) often reach magnitudes that are considered to be a threat to human health. Ambient concentrations of gaseous pollutants and fine particles are stable or even increasing over time. Being a responsible key organization in Sri Lanka, Central Environmental Authority has been engaged with an urban air quality monitoring program across the country since 2014 under financial sponsorship of the vehicle emission trust fund of the department of motor traffic. In this program, the criteria air pollutants such as PM2.5, PM10, SO2, NOx, CO, O3 and Non methane volatile organic compounds (NMVOCs) are monitored in major cities. The 24-hour continuous monitoring for seven days in each and every city are accomplished by using fully automated mobile ambient air quality monitoring station. As observed, the recorded average concentrations of each parameter, in major cities are maintained below the National ambient air quality standards. But it was found that there is a little increasing trend of PM2.5 and PM10 in major cities compared to other pollutants. It is also notable that the average concentrations of other parameters such as SO2, NO2, CO and O3 have been recorded below the National ambient air quality standards. However, these values are defined to 24-hour continuous monitoring for 07 days and it is an instant situation on ambient air quality in the cities considered. These pollutant concentrations have been given for 24-hour consecutive 07 days for a particular city and once a year monitoring for a particular season. Hence the data is very limited and not representative for the entire year. A large set of continuous monitoring data representing all seasons in Sri Lanka is also requires in order to introduce a standard methodology at the data processing. Further an improvement of current ambient air quality monitoring program is recommended in Sri Lanka taking into account the drawbacks identified. Keywords: Ambient air quality, Criteria air pollutants, Hazardous air pollutants, National ambient air quality standards

Quality of Municipal Solid Waste Compost Produced in Sri Lanka

Rapid urbanization has made solid waste management a serious problem for local authorities in Sri Lanka. The compost production with Municipal Solid Waste (MSW) and good quality assurance of compost produced by such is crucial in utilizing these problematic wastes as an agriculturally important product. This study was focused on evaluating the overall quality of Municipal Solid Waste Compost (MSWC) in Sri Lanka. Primary and secondary data of compost physicochemical and biological characters covering 45 composting sites representing 88% of functioning Pilisaru composting sites of SL were used for the study. A large set of secondary data on MSWC quality parameters were collected from well reputed government laboratories with the approval of the Central Environmental Authority (CEA). Inadequate data were analyzed. Box plots were developed using data on color, moisture, odor, sand content, particle size, PH, conductivity, organic carbon, C:N ratio, total nitrogen, Phosphorus, Potassium, Magnesium, Calcium, Arsenic, Cadmium, Chromium, Copper, Lead, Mercury, Nickel, Zinc, Fecal coliform and Salmonella in MSWC samples. Central tendency, data distribution and deviations of each parameter were identified after eliminating outliers. The conformity percentage to Sri Lankan Standards (SLS) and Bureau of Indian Standards (BIS) were calculated. The heavy metal contents were compared with Portugal, France and Italy standards for MSWC in addition to SLS and BIS. Normal probability plots of the residual were designed in order to identify the data distribution pattern. Spatial variability of data in each individual parameter was analyzed in district basis. Mean and median value of moisture content, sand content, MgO, Hg content and fecal coli form was not conformant with SLS and BIS. Although the mean value of particle size conformant with BIS it has exceeded the levels in SLS. Cd, Cu, Zn and Ni contents showed 100% conformity with SLS, BIS, France, Italy and Portugal standards. Cr and Pb contents showed more than 90% conformity to all the standards. Colour, odour, pH, organic carbon, total N, Ca, Cd, Cr, Cu, Pb, Ni, Zn and salmonella resulted in more than 75% conformity to SLS. Sand content is the most deviated parameter from SLS. Significant special variability was reported for particular districts with regard to sand content, pH, total N, P2O5 and K2O. Thus, MSWC quality in SL could be improved via giving the emphasis on the parameters which are not conformant with the standards.Keywords: Municipal Solid Waste Compost (MSWC), Sri Lankan Standard (SLS), Bureau of Indian Standard (BIS)

Taxing the Pollution

Most firms that process rubber in Sri Lanka do not comply with national water pollution control standards. The present command and control system fails in the face of a slow enforcement process, and also because of the nature of ‘older’ production units, many of which date back to colonial times. This study seeks to estimate a pollution tax that could motivate firms to meet these standards. I use data from 62 rubber-producing firms in Sri Lanka over three years to estimate a marginal cost function for pollution abatement. I then estimate the taxes that would bring firms into compliance. The tax rate necessary for environmental compliance is 26 Sri Lankan rupees per 100 grams (in 2005 values) of Chemical Oxygen Demand (COD) per year. While the burden of this pollution tax on the average firm would be equivalent to 8.6 per cent of annual turnover, it varies with the size of the firm, which may have adverse consequences for small firms through closures or layoff of workers. I suggest that the use of this economic instrument might motivate the Central Environmental Authority (CEA) to monitor effluents more carefully and firms to make economic use of effluents.

Investigation of Illegal Encroachment and Landfilling in Bolgoda Environment Protection Area

The Bolgoda water body is the only natural lake in the Sri Lanaka situated in the westernprovince, spreading over six divisional secretaries divisions of Rathmalana, Kesbawa,Moratuwa, Panadura, Bandaragama and Kalutara. However, it is a basin estuary brackishwater body and also categorized as a semi-closed lagoon. This sort of wetland plays a vitalrole on preventing of floods by retaining of excess water in wet season and support a numberof endemic fauna and flora. Presently Bolgoda ecosystem is faced to many threats and toovercome those threats it was declared as Bolgoda is an Environmental Protection Area(EPA). However, there is no any management plan for the conservation. Therefore, this studyis focused to identify and estimate damage on Bolgoda Environmental Protection Area andalso to propose a conservation and management plan.In order to identify existing threats, field survey was conducted covering 127 locations inBolgoda EPA and with help of records available in Central Environmental Authority andDivisional Secretariats. Further, survey plans obtained from the Department of Survey wereanalysed to identify encroached area to the water body. However, illegal land filling,encroachments, spreading of invasive species, mangrove destructions and waste dumpingsites were also identified. Before preparing a conservation and management plan to addressabove threats developed a zoning map was developed according to the identified damagelevels.This study reveals that Bolgoda EPA is seriously threatened by encroachments, illegal landfilling and unauthorized constructions, discharge of industrial effluents, dumping of solidwaste including saw dust, mangrove destruction, and spreading of invasive species due towastewater discharge. The results also showed that approximate illegal land filling andencroachment in Bolgoda reservation were 0.0756 km2 and 0.0077 km2 respectively. Thedamage is severe in Moratuwa, Kesbawa, Rathmalane, and Panadura District secretariats(DSs) than Bandaragama and Kalutara DSs. However spreading of Allocacia spp wereobserved in all visited sites.

WASTEWATER TREATMENT IN DESICCATED COCONUT INDUSTRY

Coconut products are the second largest agricultural export product in Sri-Lanka after tea.Desiccated Coconut (DC) accounts for almost 40010of the total export revenues from coconutproducts. Sri Lanka is the second largest producer of desiccated coconut in the world (after thePhilippines) and the production is 3tillgrowing rapidly. Sri Lanka is estimated to produce 50,000tonnes of desiccated coconut per year accounting for 40% of the world productionMost of coconut plantations and its related industries are located in the triangle of the three citiesof Colombo, Kurunegala and Puttalam, Presently there are 64 DC mills in operation, of whicharound 50 are large-scale factories, processing over 100,000 coconuts per day. The remainingmills are medium scale; processing around 50,000 coconuts per day.mills are medium scale; processing around 50,000 coconuts per day.Some of the existing DC industries significantly contribute to the deterioration of the quality ofthe environment. According to the 1993 report of Central Environmental Authority (CEA),desiccated coconut industry is the third major water polluter in Sri Lanka after natural rubberindustry and concentrated latex industry.One coconut gives approximately 0.15 I of coconut water. Combined with wash water andsterilizing water, a factory processing 50,000 nuts/day discharges about 50m3 of wastewater perday. A characteristic waste water cocktail from a DC mill comprises COD 8000mgll, BOD4000mg/L, SS 300mg/l, Nitrogen (nitrate, nitrite and ammonia) 50mgll and PhosphorousIOmg/1.ThepH value is around 5.0.Most factories discharge their untreated or poorly treatedeffluent to general watercourses .creating significant pollution and problems for downstreamusers.In some DC mills some treatment is attempted, using physical treatment methods like screeningand oil separation. Since the strength of the waste stream is very high, physical treatment aloneis not enough. Chemical treatment methods will cerate large amounts of sludge, which also hasto be treated. Therefore the possibility of biological treatment was investigated and an aerobicbacteria mix named EM (effectivemicroorganisms) was selected.The treatment process sequence identified in this study is screening, oil separation, aeration,sedimentation, secondary aeration, secondary sedimentation and filtration. EM is added to bothaeration tanks. The optimum volumes of EM to be added to the tanks are currently underinvestigation. Batch testing with EM shows 75% COD reduction by one aerator. With twoaerators in tandem, it can reduce the COD values to comply with the Sri Lankan Standard forDischarge of Industrial Effluents in to Inland Surface Waters (1990). The treatment processdeveloped in this research overcomes the odour problem. To ensure the effluent will not havefree EM, it is chlorinated before discharge into the polishing filter for the final treatment step.

Characterization and source apportionment of particulate pollution in Colombo, Sri Lanka

Because of increasing use of vehicles and other human activities in metropolitan Colombo, Sri Lanka, a study of long– term airborne particulate monitoring at two fixed sites was initiated. The specific objectives were to measure the elemental composition of the coarse and fine air particles, to identify the trends in pollution, to identify the main pollutant sources, and to quantify the source contributions. Samples of airborne particulate matter (PM) in the < 2.5 and 2.5–10 µm size ranges (PM2.5 and PM10–2.5) were collected using “Gent” stacked filter samplers at two urban sites in Colombo. The Air Quality Monitoring Station (AQM) of the Central Environmental Authority (CEA) operated during the period of May 2000 to December 2005. The second site at Atomic Energy Authority (AEA) operated from May 2003 to December 2008. Twenty–four hour samples were collected on weekdays. The fine filter samples were analyzed for 18 elements by ED–XRF. The annual averages for PM10, PM2.5, and black carbon (BC) at the AQM station during 2000 – 2005 ranged from 50 to 100, 16 to 32, and 8 to 15 µg/m3, respectively. The fine fraction data set including BC and major elements (Na, Mg, Al, Si, Cl, Fe, Zn, Ni, Cu, V, S, Br, Pb, Cr, K, Ca and Ti) was analyzed using EPA–PMF (Positive Matrix Factorization) to explore the possible sources of the PM at the two study sites. Four factors were found at both sites. The common sources are motor vehicles, road dust, biomass and sea salt. The Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPILT) back–trajectory model was used to explore possible long range transport of pollution. Smoke and soil dust transboundary events were identified based on fine Si and K in the data base in 2003 and 2004.

Contamination Sources of Bomuruella Reservoir at Nuwara Eliya

Bomuruella Reservoir in Nuwara Eliya is an important water source in the area which indirectly contributes to the drinking water supply of the downstream people. Many agricultural lands obtain water from this reservoir and consume its water for washing and cleaning purposes. This research was focused on identifying the contamination sources of Bomuruella reservoir and to investigate the suitability of the reservoir as a drinking water source.According to the water quality analysis, BOD5 and CODMn values of most sample points did not satisfy the specified standards of Central Environmental Authority, Sri Lanka. Municipal wastewater stream and the stream from the cultivated area recorded high BOD5 levels of 7.65 mg/l and 6.55 mg/l respectively in the period of low water level of the reservoir. The stream from the cultivated area reported a high CODMn value of 595.74 mg/l during March and the stream from Kandapola plantation recorded a CODMn value of 74.44 mg/l during May. This concludes that the reservoir was contaminated with significant loads of organic wastes. Furthermore, the effluent from the leachate treatment plant recorded higher conductivity, nitrate and CODMn values which indicated that the leachate treatment plant was malfunctioning.The main cause of pollution of the reservoir is the discharge of agricultural runoff, raw sewage and wastes which include domestic, industrial and hospital waste directly into the feeder streams. It can be concluded that if the reservoir is to be used as a source of drinking water stringent measures have to be taken to control effluents.

Effect of Bio-brush medium: a coir fibre based biomass retainer on treatment efficiency of an anaerobic filter type reactor

Five Covered Activated Ditch (CAD) type test reactors set with five different specific surface areas (SSA) of Bio-brush were tested under four organic loading rates (OLR).Chemical Oxygen Demand (COD), reactor pH and suspended solids (SS) of the effluent of reactor with 200 m 2 /m 3 were monitored. The efficiency of treatment increased with increasing SSA of media. On the basis of its performance the combination of Bio-brush media with 200 m 2 /m 3 SSA under 1.0 COD kg/m 3 /d OLR was selected as the best for CAD reactors and the average COD removal achieved was about 89%. Under this OLR, correction of pH could be avoided for an efficient treatment. Reactors with higher SSA of media were able to tolerate organic shock loads comparatively. No special cycles were observed in removing biomass from the test reactor under any of the four OLRs. During maturation COD, pH and SS of treated effluent with 200 m 2 /m 3 SSA were about 100 mg/l, 6.7 - 7.2 and 26 - 43 mg/l respectively which were below the maximum desirable levels stipulated by the Central Environmental Authority. Key words : anaerobic; bio-brush; coir fibre; covered activated ditch; specific surface area; wastewater DOI: 10.4038/jrrisl.v87i0.1810 Journal of the Rubber Research Institute of Sri Lanka, (2005) 87 , 15-22

Time-Inconsistent Domestic Environmental Policies and Optimal International Environmental Arrangements

We employ the standard pollution control incorporating countries' asymmetries, not only in their consumption and environmental concerns, but also in their environmental technologies. First, we show that the absence of international collaboration makes domestic environmental policies discretionary and may result in a time-inconsistent outcome. Then, we compare two cooperative regimes: the international environmental agreement (IEA) and the central environmental authority (CEA). In certain conditions, IEAs may not be more efficient than CEAs in pollution abatement. Furthermore, although the IEA Pareto-dominates the CEA, the success of IEAs may be hampered by conflicts of interest among the signatories.

Transitions in Ancient Inland Freshwater Resource Management in Sri Lanka Affect Biota and Human Populations in and around Coastal Lagoons

The increasing anthropogenic pressure on natural environments results in impacts that affect tropical forest areas and their biodiversity. Adverse impacts on terrestrial and oceanic environments often compound in the intertidal area, where mangrove forest ecosystems thrive. In tropical coastal areas of many developing countries where people depend on wood and other mangrove forest products and services, forest degradation leads to socioeconomic problems. At the same time, increasing freshwater needs in these areas are expected to cause additional problems. On the basis of remote sensing and ground truthing complemented by colonial archival material from the Dutch East India Company (1602-1800), we report that changes to the historic system of inland freshwater management have increased dramatically in recent times. Hydrological changes, such as interbasin transfers, have resulted in a qualitative ecological and socioeconomic degradation in three coastal lagoons in southern Sri Lanka. Variations in river hydrology have caused changes in the areas suitable as mangrove habitat and, thus, have resulted in an altered distribution. However, increases in mangrove area can mask the degradation of the site in terms of floristic composition, significance of the species, and biodiversity (this effect is termed "cryptic ecological degradation"). It is important that such changes be carefully monitored to ensure biological and socioeconomic sustainability.