Carbon sequestration potential of replanted Rhizophora mucronata in Puttlam Lagoon, Kalpitiya, Sri Lanka

U.Y.I.L. Dharmasoma1, D.M.S.H.K. Ranasinghe1 and S. Wahala2
1
Department of Forestry and Environmental Science, University of Sri Jayewardenepura, Sri Lanka
2
Department of Tourism Management, Sabaragamuwa University, Sri Lanka

The potential of trees to act as carbon sinks is very important as global warming, which occurs due to increasing levels of carbon dioxide is risen over decades. Mangroves as any other tree are capable of removing carbon from atmosphere through the carbon stored in their biomass. The present study was carried in the mangrove replanted sites with 6 months, 5 and 10 years old Rhizophora mucronata in the Kalpitiya Peninsula in the Puttlam Lagoon in North West of Sri Lanka. Objectives of the present study were to assess the carbon sequestration potential of replanted R. mucronata at different ages in Puttlam Lagoon and to estimate biomass partitioning in R.mucronata in selected sites.

Transects were demarcated in each sampling site traversing from the Lagoon to inland to cover the entire width of the plantation. The width of transects were 5m and they were laid at 15m intervals within the plantation. Each transact was divided in to 5m x 5m sample plots at 5m intervals. A representative tree was selected from each diameter class in each study site for destructive sampling. The above ground parts of uprooted trees were separated in to plant components.

The belowground roots in 1m×1m area around each uprooted tree were collected by digging soil up to 30 cm depth. Fresh weight of each component was measured in the field and representative sub samples were taken to the laboratory, oven dried to constant weight at 1050C in order to calculate wet-dry weight ratio.

According to the results, average total carbon content that could be lodged in 6 months, 5 and 10 years old R. mucronata stands having survival rates of 60.67%, 83.46%, 77.33% are 0.08 t C ha-1, 1.39 t C ha-1 and 66.30 t C ha-1, respectively. Average total CO2 that could be stored as carbon without being emitted to the atmosphere in 6 months, 5 and 10 years old R. mucronata are 0.28 t C ha-1, 5.13 t C ha-1 and 243.33 t C ha-1, respectively. Carbon sequestration rate of 6 months, 5 and 10 years old R. mucronata are 0.1564 t C ha-1 yr-1, 0.3134 t C ha-1 yr-1.and 6.6302 t C ha-1 yr-1, respectively. The percentage of biomass in propagule, stem, leaves and roots of 6 months old R.mucronata are 72.95%, 9.41%, 9.64% and 8.00%, respectively. In 5 years old replanted R.mucronata the proportion of biomass in stem, leaves, branches, stilt roots and roots are 23.75%, 17.36%, 9.31%, 38.76% and 10.91%, respectively. The percentage carbon partitioning in trees are similar to percentage biomass partitioning. Root: shoot ratio of 6 months, 5 and 10 years old R.mucronata is varied with the age and the values are 1:11.5, 1:8 and 1:4.7, respectively.

Climate change mitigation: Sri Lanka’s perspective

D.M.S.H.K. Ranasinghe
Department of Forestry and Environmental Science, University of Sri Jayewardenepura, Sri Lanka

Climate Change with the associated increase in global temperature and sea level rise has become the most important global concern in the present day. A land mark event in this regard is the signing of the Climate Change Convention in 1992 in Rio, Brazil which provided targets for especially developed countries to reduce their Green House Gas (GHG) emissions by 5% of the 1990 levels by 2012.  Mitigation of global warming involves taking actions to reduce greenhouse gas emissions and to enhance sinks aimed at reducing the extent of global warming It has been found that almost 5400 million tons (Mt) of CO2 equivalents are emitted annually from various sources linked to human activities. Sri Lanka’s CO2 emission from fossil fuel combustion estimated at 2007 had been about 12,400 Gg CO2 which is only 0.04% of the global emission of 29,300 MtCO2 . The corresponding per capita CO2 emission was 648 kg in 2007 and although this is still much less than the global values, Sri Lanka has taken many policy measures that would result in mitigating GHG emissions.

In keeping with the global concern on sustainable development, the Government of Sri Lanka has taken many policy and program initiatives towards sustainable development which in turn helps to mitigate the adverse impacts of climate change.

Some of them are National Environmental Action Plan (1998-2001), establishment of National Council for Sustainable Development under the chairmanship of the President of Sri Lanka and the Haritha Lanka Action Plan having targets up to 2013.

Mitigatory measures have been taken in all the sectors including energy (power, transport, industry and household and commercial), land use, land use change and forestry, waste etc. The Energy Policy and Strategies (2006) of the country emphasizes the need to resort to sustainable energy and has a target of having  10% of the energy from renewable sources (Non-Conventional Renewable Sources) by 2015, a target which can be achieved if all the pending initiatives towards this is made operational. Further, the Government is constantly questing for clean energy. Some of the other initiatives to reduce the carbon footprint in the service sector are Leadership in Energy and Environmental Design” (LEED), ‘Greening Sri Lankan Hotels Programme’, setting up of the Sri Lanka Sustainable Energy Authority in 2007.

In the arena of industries, location of industries in industrial estates and conducting Strategic Environmental Assessments (SEA), voluntary standards like ISO 9001, ISO 14,001, Green building concepts, the Green Tax, Cleaner production initiatives, Clean Development Mechanism (CDM) benefits have provided incentives to reduce GHG in this sector. Many national initiatives are underway in reducing the GHGs in waste sector too. As a country with a high canopy forest cover of 23.5% and a forest cover of 40% in general the potential to act as a GHG sink in forestry sector is very high. While ensuring the sustainable development efforts this will help the country to obtain benefits from CDM or Reduced emissions from Deforestation and Land Degradation (REDD and REDD+) programs in the future.

Corticolous lichens as indicators of forest management regimes in the Dotalugala area of Knuckles mountain range – Sri Lanka

G. Weerakoon1, S. Somaratne2, P.A. Wolseley3 and S.C. Wijeyaratne1
1
Department of Botany, University of Sri Jayewardenepura, Sri Lanka
2
Department of Botany, The Open University of Sri Lanka
3
Department of Botany, The Natural History Museum, United Kingdom

Lichens have been widely considered as bioindicators of forest health and ecological continuity as well as atmospheric pollution. The use of lichens as bioindicators in tropical zones has been hampered by the lack of taxonomic and ecological knowledge. The purpose of the study was to assess the variation of lichen diversity in different forest management regimes under different environmental conditions on the basis that their potential uses as bioindicators of environmental alterations in different habitats in the Knuckles mountain range. The sampling sites were chosen to include pristine forest of montane and sub-montane and six different disturb vegetation types. Lichen species, their frequency and cover values were recorded together with environmental parameters in 20 sites of 100 m2 plots. Ten trees were sampled randomly in each plot. The collected data were analyzed to assess the relationship between lichen diversity and environmental conditions in different forest management regimes using one-way analysis variance, least significant difference- LSD (mean comparison) and Regression tree analysis.

There were 192 lichen species recorded from the natural vegetations, where as 148 lichen species present in the disturbed vegetation types. The results of the study have shown that there is a considerable variation in the lichen diversity along different vegetation types and their degree of disturbance. The statistical analysis revealed a significant variation in lichen diversity between the disturbed and undisturbed vegetation in the area (F = 6.213, df = 1; p ≤ 0.05). Similarly, lichen diversity in different vegetation types also indicated a remarkable variation (F =3.21, df = 7; p ≤ 0.05). The results obtained from regression tree analysis indicated that there were three important variables that determined the lichen diversity of the study area; type of vegetation, altitude and association with other cryptogamic communities.

There are distinct lichen communities associated with tree boles in disturbed forests including weedy taxa and low diversity with few forest lichen species.  The analysis of epiphytic lichen diversity showed significant difference in the natural vegetation and disturbed vegetation.

This may be due to the heterogeneity of microclimatic conditions and specialist lichen communities associated with pristine tropical forests. Thus, there is utmost importance to identify lichen communities that can be use as indicators of reflecting forest health for the purpose of sustainable management.

Invasive alien species in Indian ornamental industry

S. Rameshkumar, K. Manivannan, C.T. Sathappan and J. Padmanaban
Annamalai University, India

Quantum jump of increase in the awareness about global warming and environmental pollution made the mind set of industries, institutions, corporate and even common man to think about finding a solution to it. Establishment of ornamental gardens and green belt development in the surroundings and waste lands is becoming the best option to curtail pollution problems and it has almost been considered as mandate in urban areas. Increased green belt development and gardening activities help the industries and corporate to manage their carbon credit and in turn helps in reducing climate change.  In these green belts and corporate landscapes and even in botanical gardens many alien species are used in larger volumes.

In a survey conducted in nursery pockets and landscape industries of south India evinced the status of alien species that more than 60 per cent of the ornamental species are foreign in origin and few species are Invasive in nature. More than 50 per cent of the landscape architects opted for foreign ornamental plants to be incorporated in their present and future projects and opined it is inevitable to avoid the invasive alien ornamentals as they have preference among the clients. Though many of these plants are well accommodative and have ornamental value, there is a chance for certain highly invasive alien species to become threat for the eradication native species in the locale and may become serious weed as evident from Lantana Sp. and water hyacinth which were introduced as ornamental plants and now being a threat as major weeds in Indian sub continent. Hence it becomes necessary to have check measures to evaluate the invasiveness of the alien species when it is introduced as an ornamental plant.

Current Status of Plastic Packaging Materials in Sri Lanka

R.A. Jayasinghe, N.J.G.J. Bandaraand W.A.S.S. Dissanayake, W.M.S.K.B. Wijekoon
Department of Forestry and Environment Science, University of Sri Jayewardenepura, Sri Lanka

All the goods we purchase today require some form of packaging in order to reach their final destination in our homes or workplaces. Despite the many functions served, there is a concern about the amount of packaging that is used and readily disposed. Since it constitute a significant portion of the municipal solid waste stream which will end up in open dump sites, landfills or are burnt in open air.

This study was conducted to recognize the importance of adequate and reliable information on plastic packaging materials and to analyze the current status of the packaging materials used in the country in both qualitative and quantitative manner.

The study was carried out in the Western Province of Sri Lanka. In total, 300 households were selected for the study from the three districts, namely Colombo, Gampaha and Kalutara. Each district was again divided into three sample areas as urban, semi urban and rural according to socio-economic factors such as number of people and income level of the family. 08 groceries per sub area were selected to represent different categories of commercial establishments (Super markets, medium and small sized groceries and shops) from each district. Furthermore, 12 recycling and manufacturing plants were visited from the three districts. The respondents were selected using random sampling method and the data collection was carried out primarily through questionnaire surveys, personal interviews and field visits.

The data collected through the questionnaires were analysed qualitatively and statistically to find out the current status of plastic packaging materials in a densely populated area of the country. According to the survey results, most commonly used packaging material by households is polythene bags. 72% of the households stated that the shopping bags and grocery bags are the most common type of packaging item used in households followed by other food wrappers (59%) and lunch sheets (49%).

Most of the items in the supermarkets are packed using some kind of plastic packaging material and they are giving away bags for each and every item a customer buys. Approximately 1500-2000 bags of all sizes are sold in an average town per day. 62% of the households in urban areas stated that the most common practice of disposal is open dumping or disposing to be collected by the waste collectors of the Municipal or Urban councils. Burning is also widely practiced among many households in rural and semi urban areas as plastic materials are easily combustible. This was 68% in rural and 50% in semi urban areas consecutively.

According to the survey, only 13% of households practice proper waste separation at their homes. 60% of households do not sort by any means and 27% sort waste as organics and inorganics. Re-use capacity of plastic packaging materials are also very low. Only 20% of the households practice re-using of plastic packaging in a regular basis.

According to the data analyzed, the composition of plastic waste used for recycling are PP, PET, HDPE, LDPE, PS, PVC, PC and other polymers. The major portion of plastic waste collected for recycling consists of PP. Recyclers do not accept plastic materials which are contaminated with cement, chemicals, acids and poisons. Moreover, plastic materials found in mix waste are also not accepted due to practical difficulties in sorting them. Despite many difficulties faced by the recyclers, many stated that the industry is profitable.

Eco friendly sewerage system for low income coastal community

W.N.C. Apsara and B.C. Liyanage
Department of Civil Engineering, The Open University of Sri Lanka

The purpose of a sewerage disposal system is to carry human excreta & urine (Black water) and wastewater (Gray water) back to nature in a proper way without any harm to the environment as well as to human beings. But the implementing and operating costs of the sewerage disposal systems are normally very high which make low income communities unable to reach these techniques.

The aim of this study was to find a proper sewerage system for a low income coastal community, “Pittaniya Watta” in Moratuwa Municipal Council. The community consists of 142 families with about 710 people spreading over a 8092m2 limited area. First the real situation and the problems prevailing were found doing a questionnaire survey, which consisted 105 questions in 10 different categories that covered relevant problems in sewerage disposal according to a proper cross section.

Questionnaires were analyzed and evaluated to find daily water consumption and sewerage disposal capacities. Based on the results, Eco-sanitation and simplified sewerage system were selected as the most economical solution for the problem. The Eco-sanitation is a separate unit, which constructs above the ground level and consists of two compartments that are used only for excreta disposal and could be used alternatively for individual houses. Number of Eco-sanitation units required for the said community was 142 nos.

The simplified sewerage system is the most economical “off-site disposal system” which was designed considering both self cleansing velocity (0.5 m/s) as well as tractive tension (1 Pa). The results revealed that the best fitted minimum sewer gradient and the minimum sewer diameter were 1 in 208 and 100mm respectively. The collected sewage will be treated in primary and secondary stages in anaerobic digestion units. Three units were provided with each dimension length, width and depth of 6.2mx 3mx4m respectively and 0.2 m of free board. Using a lift station a head was added to the effluent to take it from 5m below the ground to the ground surface where the Reed bed was provided before it is released to the existing drains that are directed to the sea.  Estimated hydraulic retention time of the reed bed is 6.79 hours while dimensions are: water depth = 0.6m and surface area of the bed =78 m2.

According to the basic cost analysis on two systems Eco-san unit for each house is Rs 47925. When consider the whole community, the total cost for Eco-san was Rs 6,805,350 while the simplified sewerage system was Rs 2,886,000. However, at the operational stage of simplified sewerage system, with maintenance cost, the total cost was estimated as Rs 16,606,390.00.  Therefore, based on the cost and considering the most suitable system for the subjected community is Eco-san. But according to communicant’s desire, land scarcity, and population growth as well as future forecast on water consumption, improvement of the living standards etc. simplified sewerage system was selected as the best sewerage disposal system to implement at Pitaniya Watta low income community.

Influence of undergraduate activities on the waste composition and generation rates in a residential university: Case study

S. Wijetunga and N. Liyanaarachchi
Department of Agricultural Engineering, University of Ruhuna, Sri Lanka

The increase of waste generation and its disposal is a major problem and challenge faced by the most of the countries today.The uncontrolled disposal of different types of waste into environment is a great threat for the future of all living beings in the world. Therefore, it is essential to pay more attention for the waste management and disposal to avoid the detrimental impact on the environment. For the development of a proper treatment or disposal systems for waste management for any organization or municipality, it is essential to have the information with respect to waste composition, generation rate and its variation with time of that organization. Therefore, in this study, it was attempted to evaluate the composition and the variation of waste generation rate in the hostels of the undergraduates of University of Ruhuna with their activities.

The study was conducted in the premises and surroundings of the hostels of the undergraduates for a period of one year (September to August). The waste samples were collected from each and every hostel once in two months. The waste samples were separated into different components (such as foods, paper, plastics, etc), weighed and determined the percentages of different components.  The different types of waste generation rate per head were calculated based on the waste generation for the total study period. It was found that food remains, papers, plastics and polythene are the major components. The types of waste found in hostels of girls were less in numbers than that of boys. Leather, textiles, metals, etc could not be found in hostels of girls.

Over ~95 % of waste found in girls’ hostels were food remains and boys generate food waste about ~71%. Per capita food waste generation by girls was ~ 207 g/day while it was ~23 g/day by boys. The generation of other types of waste was higher in hostels of boys than that of girls’ hostels. It appears that the amount of waste generation varied in different months basically due to examinations and other activities of the students. During examination periods, it seems that the undergraduates may change their food habits. Based on this study, it can be concluded that major component of waste found in undergraduate hostels was food wastes and the generation rate slightly varies with the activities of undergraduates. When designing of a waste management systems for higher education institutes where students reside, higher priority should be given for the management of food waste

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Assessing the role of environment regulation on firms’ private action towards environmental quality: Case of non-adoption of solid waste management practices by food processing sector in Sri Lanka

J.M.M. Udugama and U.K. Jayasinghe-Mudalige
Department of Agribusiness Management, Wayamba University, Sri Lanka

Whether a firm takes private actions to augment environment quality, more often than not classified as a public good, in a situation where it can compensate the less significant losses in the market with relatively higher gains obtained through failures in government policy is of an economic issue of concern amongst the economists and policymakers. The specific objective of this study was to address this economic problem from an empirical point of view. It uses the special case of Sri Lankan food processing firms’ non-compliance to the recently introduced National Strategy for Solid Waste Management of the Ministry of Environment, which recommends 9 different solid waste management practices (SWMPs) for a food firm to adopt based on the production and processing activities it undertakes.

From a database containing the information with regard to different types SWMPS adopted by a firm, we have selected 160 firms which did not have even the “most economical” practices out of the 9 SWMPs recommended in place, i.e.: (1) sorting of waste based on 3R system; (2) composting and (3) good manufacturing practices (GMP). The perceptions of managers of these firms on various facets related to existing and anticipated environment regulatory framework and the legal/judiciary system were assessed by taking the scores provided by them to a series of statements (n = 14) on a multi-point bidirectional likert-scale. The Confirmatory Factor Analysis techniques, including the Scale Reliability and Unidimensionality were employed to these scores to derive an index – “Environment Regulation Responsiveness Index” (ERRI) the values of which reflects the relative strength of a firm in concern reacts to the environmental regulation (i.e. -1.0 the least to 1.0 the most responsive).

The magnitude of ERRI of a majority of the firms was relatively low (i.e. in between -0.5 to 0.5), especially for the small scale firms, indicating that firms’ did not consider the government regulation as a promising factor governing their action on environment. It also highlights that a vast majority (> 90%) of firms have “no plans” to adopt any of these practices in the near future citing the financial burden and the lack of information on SWMPs. The outcome of analysis, thus, calls attention for a critical revision and adjustments to the policy on environmental quality management at the National and Provincial level in order to promote voluntary action by firms.

Key words: compliance, environmental quality, food processing sector, regulation, solid waste management

Effects of modified artificial soils on compost worms: An approach to large scale worm production

P.M.C.S. De Silva
Department of Zoology, University of Ruhuna, Sri Lanka

Vermicomposting is a viable recycling technique. Nevertheless it has a very little popularity in soil waste management process in Sri Lanka mainly due to the lack of large scale compost worm production. Substrate is one of the major factors that determine earthworm   reproduction. Artificial soil made from fine sand (70%), kaolin clay (20%) and sphagnum peat (10%) is being used as a substrate in temperate regions and this type of artificial soils are not feasible in tropical regions due to scarcity of peat.

Therefore compost worm production was investigated in locally prepared artificial soils (AS) using paddy husk, saw dust and coco peat (composted & uncomposted). Adult earthworms of compost worms (Eisenia sp and Perionyx excavatus, n = 10, 6 replicates) were introduced into prepared AS and incubated under tropical conditions for 28 days. The moisture contents of the prepared AS was set to 50% of the respective water holding capacities. After 28 days adults were removed and containers were kept for another 28 days for hatching of the juveniles. Mortality and mean number of cocoons (28 days) and juvenile production (56 days) was determined. Temperate artificial soil was used as the control substrate.

No mortality was recorded with both species tested and in all four modified soil types, indicating their survival was not affected by the nature of modified soils.  Number of cocoons and juveniles produced by Eisenia andrei in control soil was not significantly different with AS consisted with composted coco peat and paddy husk (p> 0.05) but significantly different with AS consisted with saw dust and uncomposted coco peat (p< 0.001).  The highest mean number of juveniles of P. excavatus (168.25 and 167) and mean number of cocoons (1.47 and 1.42 cocoons/ worm/per week) were recorded in temperate AS and AS with composted coco peat respectively and lower number of juveniles were recorded in AS with saw dust and paddy husk. The results indicates that AS soils made from composted coco peat gives similar performance in juvenile production of both compost worms tested and may be used in mass scale compost worm production under tropical conditions.

Utilization of earthworms in organic waste management

P. Alagesaran and R. Deebha
Post Graduate and Research Department of Zoology, Yadava College, Madurai, India

Vermicomposting is an ecofriendly, socially sound and economically viable technology to manage the organic waste resources. It is popular particularly in India, because it is the cheapest solution to overcome the dangerous effects of modernized agriculture. Vermicomposting is the application of earthworm in producing vermifertilizer which helps in maintenance of better environment and results in sustainable agriculture. The aim of the present study was to evaluate the efficiency and the nutritional status of vermicompost processed by two earthworm species, Eisenia fetida and Eudrilus eugeniae from leaf litter and sugarcane trash.

Chemical analysis of the vermicompost obtained from leaf litter wastes showed that the quantity of organic carbon was reduced from 38.65 to 28.89 and 28.0% by E. fetida and E. eugeniae respectively. The level of nitrogen (1.30%), phosphorus (0.38%), potassium (0.57%) and calcium ((0.70%) was maximum in leaf litter vermicompost processed by E. eugeniae than E. fetida. At the end of 45 days of composting, E. eugeniae has tremendously decreased the C/N ratio from 45.47, 60.19 to 22.40 and 29.19 in the composts of leaf litter and sugarcane trash respectively. Similarly, E. eugeniae processed leaf litter compost treated with plant, Abelmoschus esculentus showed maximum height (61.4cm), number of leaves (16 per plant), leaf area (365 cm²), fruit length (15.8cm), fruit weight (17.9gm) and total chlorophyll content (3.76 mg/g.fresh wt) than those treated with sugarcane trash.

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