N. P. Ratnayake

University of Moratuwa | UoM · Department of Earth Resources Engineering

Man-made coastal structures directly affect sediment balance and sediment dynamics on the surrounding beaches. The Colombo Harbor Expansion Project has created about 5-km-long breakwater nearly perpendicular to the beach. The present study is focused on quantitatively and qualitatively analyzing the effect of the Colombo Harbor Expansion Project on...

The Mannar Basin is a Late Jurassic – Neogene rift basin located in the Gulf of Mannar between India and Sri Lanka which developed during the break-up of Gondwana. Water depths in the Gulf of Mannar are up to about 3000 m. The stratigraphy is about 4 km thick in the north of the Mannar Basin and more than 6 km thick in the south. The occurrence of...

The Kaluganga River Estuary is one of the main sources of construction sand in Sri Lanka. Salt water intrusion along this estuary due to extensive sand mining has increased over the years. Thus, the focus of the current research is to understand the relationship between river sand mining, salt water intrusion, and the resultant effects on construct...

The Lunawa Estuary has been selected as a model for studying the long-term diagnoss of tropical estuarine pollution and its impact on ecosystems. Surface and short-core sediments from the Lunawa Estuary were collected, and analyzed for total organic carbon (TOC), nitrogen, sulfur and hydrocarbon contents, hydrogen index and other related sediment p...

Phyto-mining is an environmentally sound green technique that has been employed for metal recovery from low-grade sources using hyperaccumulator plants. Due to its economic viability and wide social acceptance, this technology has been favoured over many conventional mining applications. Nickel (Ni) phyto-mining was introduced to the world with the...

Emerging clean energy transition technologies have expanded the range of nickel (Ni) applications, making it a critical metal in the metal industry. With the increasing demand, high-grade deposits are incapable of fulfilling continuous supply, and therefore, Ni recovery from low-grade deposits such as serpentine soils has gained wide attention. In...

Currently, rock phosphate is predominantly used to produce phosphorus based mineral fertilizers for agricultural purposes. However, since rock phosphate is a finite and non-renewable resource, it leads the whole world vulnerable to a future phosphorus scarcity. Therefore, prospecting of new phosphorus sources is essential to address the phosphorus...

Phytomining is an environmentally sound green technique that has been employed for metal recovery from low-grade sources using hyperaccumulator plants. Due to its economic viability and wide social acceptance, this technology has been favoured over many conventional mining applications. Nickel (Ni) phytomining was introduced to the world with the i...

The Eppawala area in Sri Lanka has an agricultural-based economy. As a result, the recent agricultural intensification could increase the risk of heavy metal contamination in lakes in the area as the main water canal in the area, i.e., Jaya Ganga, flows across these lakes. Therefore, this study focuses on the risk assessment of heavy metals in the...

The teleconnection between the Asian monsoon system and North Atlantic forcing is an enduring prospect of the Earth’s climate. During the Holocene interstadial, the Indian summer monsoon showed asynchronous weakening links to ice rafting events documented in the North Atlantic region. However, the sensitivity of the Indian Winter Monsoon in respons...

Nickel (Ni) phytomining is an emerging mining technique that uses hyperaccumulator plants to recover Ni from low-grade metal-rich soils such as serpentine. The Ginigalpelessa serpentinite deposit in Sri Lanka contains high concentrations of Ni, Cr, and Co where the phytomining potential is not well-documented. Therefore, the present study determine...

Negombo Lagoon is a vital ecological and socioeconomic resource in Sri Lanka that has become susceptible to anthropogenic heavy metal contamination. Therefore, short-core sediment samples from the Negombo Lagoon were analyzed to quantify heavy metal contaminants including both metals (Cr, Ni, Co, Cu, Cd, and Pb) and metalloid As; assess their ecolo...

The western and southwestern coastal zone of Sri Lanka is an important geographical region in terms of socioeconomic and environment contribution. However, coastal erosion has been a significant problem in this coastal zone for a long period of time due to both natural and man-made causes. As beaches become narrow or disappear, coastal communities...

The beaches of Sri Lanka, which contain a variety of sediments with varying textural properties, are more attractive destinations for tourism. The destruction of beaches by coastal erosion has intensified in some areas as a result of both natural and man-made causes. In order to plan conservation measures, it is imperative to collect baseline data...

The significant role in high-tech and green technologies, recent outstripping demand, and constrained global supply of rare earth elements (REEs) have led to the exploration of phosphate deposits worldwide as a sustainable source for the recovery of REEs as by-products. In this context, the Eppawala Phosphate Deposit (EPD) in Sri Lanka can be consi...

The world is experiencing rapid growth of nickel (Ni) demand, especially for lithium-ion batteries used in electric vehicles, while high-grade Ni deposits are being depleted due to expanding economics, growing populations, and disorganized industrialization. Therefore, a major transformation from high-grade low-bulk ores to low-grade high-bulk ores...

Phytomining is an eco-friendly mining technique which employs hyperaccumulator plants for nickel (Ni), copper, and gold recovery from low-grade ores. At present, Ni phytomining field trials have been directed to optimize the Ni accumulation levels and the overall biomass of plants using soil treatments. The Ginigalpelessa serpentinite deposit in Sr...

Sri Lanka is an island nation endowed with a wide range of coastal resources, greatly contributing to the Gross Domestic Product. Coastal erosion is a major issue related to the beaches in Sri Lanka. In this regard, Ratmalana beach is critically important as a potential tourism destination due to its proximity to the capital city and the accessibil...

A significant portion of the Coastal zone of Indian Ocean Rim Association (IORA) necessitates the implementation of coastal protection measures due to socioeconomic and environmental vulnerability brought on by coastal erosion. Depending on how well each country understands coastal systems, different approaches are taken. In Sri Lanka, where coasta...

With the recent recognition of nickel (Ni) as a critical metal due to its indispensable applications in renewable energy, the global demand for Ni has grown exponentially. Therefore, the existing high-grade ores would be inadequate to fulfill the inevitable rise in global demand for Ni in the future. As a result, recovering Ni from low-grade source...

The sustainable recovery of rare earth elements (REEs) from alternative sources is critical to secure a continuous global supply of REEs. Phosphate rocks with a low REE grade but a substantial global reserve (P2O5 = ~300 BT) are considered potential alternative sources of REEs. Despite having a promising REE potential, the Eppawala rock phosphate (...

The shoreline has emerged as a highly critical linear feature, due to its morphological shifts. Therefore, continues monitoring the changes of shoreline is a subject of great concern in recent years. Coastal erosion in western coast of Sri Lanka has endured as a long-standing issue. This research aimed to examine the shifts in shoreline positions a...

Serpentinite deposits are well known for their natural enrichments of heavy metals (Ni, Cr, Co) and depletions of macro nutrients (Ca, Mg), which have caused different ecological and health impacts in the surrounding areas. In addition, they are considered as potential sources for rare earth elements (REEs). While Ginigalpelessa, the largest serpen...

Rivers have a significant role in the coastal sediment budget as the primary sources of natural sediment. Further, it is essential to comprehend the minimum grain size threshold, also known as the littoral cutoff diameter (LCD), in order to determine the actual contribution of river sediment load to the littoral beach. This study aims to present th...

Heavy metals accumulate in the sediments of aquatic environments due to poor water solubility. Their toxic effect poses a significant threat to living organisms. Negombo Lagoon, a vital aquatic ecosystem in Sri Lanka, has become vulnerable to heavy metals mainly from urbanization-related anthropogenic activities. Previous research in this respect h...

Sri Lanka is one of the wealthiest countries in terms of gems. Therefore, gem mining is extensively carried out in many areas of Sri Lanka, including districts such as Ratnapura, Monaragala, Matale, and Kalutara. During the mining process, only valuable gemstones are collected, and the remaining gravel fraction with many heavy minerals is discarded...

Citation: Dushyantha, N.; Ilankoon, I.M.S.K.; Ratnayake, N.P.; Premasiri, H.M.R.; Dharmaratne, P.G.R.; Abeysinghe, A.M.K.B.; Rohitha, L.P.S.; Chandrajith, R.; Ratnayake, A.S.; Dissanayake, D.M.D.O.K.; et al.

Rare earth elements (REEs) are widely attracting global attention due to their crucial role in the modern lifestyle, especially in the industrial advancement towards a green economy through renewable technologies. This particular group of metals consists of the 15 lanthanides, yttrium (Y), and scandium (Sc). There are two subgroups, namely light ra...

Long-term field monitoring of shoreline changes is time-consuming, expensive, and labor-intensive. Instead, satellite images can be used as an alternative method to collect field data. The time-series satellite images are available at any location in the world that can be processed with the Google Earth Engine cloud environment. This study primaril...

Rare earth elements (REEs) are crucial to accomplish renewable energy targets throughout the world, including electrical vehicles and wind energy. Despite the extensive requirements of REEs, current supply chains are mainly fulfilled by the Chinese rare earth (RE) industry. This typically results in price volatility, supply chain uncertainties, and...

—In the recent few years, rare earth elements (REEs) were considered as critical metals with strategic importance due to their high usage in modern technology and green energy applications. Currently, with the unexpected increase of rare earth element (REE) demand and China’s market dominance, many REE processing projects are being launched or revi...

Located in the core of the Indian monsoon domain, Sri Lanka has a classic tropical monsoonal climate, thus making it an ideal platform for paleoclimatic investigations. During past decades, extensive studies have been carried out to explore the Indian Ocean monsoon variability across different time scales including in Sri Lanka. This review synthes...

Rare earth elements (REEs) are widely employed in a spectrum of high-tech applications. Since primary REE resources are limited, secondary REE sources will be crucial to reduce future supply chain gap between REE demand and supply, which is currently about 3000 t per year. In this context, lake sediments around Eppawala Phosphate Deposit (EPD) in S...

Soil contamination by heavy metals creates adverse impacts on human health, agricultural production, and ecological functions in the local ecosystem. In this context, serpentinite weathering is an event that can produce heavy metal (Cr, Ni, and Co) anomalies in the local soil profiles. Therefore, weathered rock (WR), soil, and plant samples were an...

Sri Lanka consists of only ten percent of sedimentary rocks, and high-grade metamorphic rocks underlie the rest. Most of these sedimentary terrains are post-Gondwanic and such formations help to understand the geological history of the island. We report the first record of an age diagnostic (Late Jurassic-Early Cretaceous) palynological assemblage...

Tropical wetlands are one of the major terrestrial carbon sinks during the Holocene. However, there is considerable uncertainty in the development history of tropical wetlands in different geographical regions. In this study, the main objective was to synthesize the formation history of mangrove wetlands along the southwest coast of Sri Lanka in te...

A complex coastal environment with a river outlet, a sand spit barrier and an estuary of such coastal features is controlled by wave-induced hydrodynamics and sediment dynamics. The coastal dynamics patterns can be changed by natural or anthropogenic activities. This study is mainly focused on understanding the significant changes of geomorphology,...

Global phosphorus scarcity will result in significant consequences for future food security with the depletion of current phosphate reserves. Therefore, exploration of new phosphorus sources is essential to address future phosphorus scarcity. The current study investigated the geochemical potential of lake sediment around the Eppawala Phosphate Dep...

Rare earth elements (REEs) are currently the most strategic elements in the world due to their significance in diversified technological applications. Currently, a total of 478 million tonnes of REE resources is disseminated across the world, which is dominated by carbonatite deposits. The most common REE-bearing minerals found in carbonatites are...

Sri Lanka is an island nation endowed with a wide range of coastal resources, greatly contributing to the Gross Domestic Product. Coastal erosion is a major issue related to the beaches in Sri Lanka. In this regard, Ratmalana beach is critically important as a potential tourism destination due to its proximity to the capital city and the accessibil...

Rare Earth Element (REE) quantity is a main factor that determines the wealth of a country. The main aim of this study is to discover a new REE deposit that can contribute to the Sri Lankan economy. Calido Beach is a coastal region where Kalu-river joins the sea in Kalutara, Sri Lanka. In this study, this coastal region is divided into four divisio...

Rare earth elements (REEs), a group of 17 elements comprises 15 lanthanides, scandium and yttrium, are largely attracting the world’s attention due to their importance in a wide variety of advanced technological applications. Global REEs production is mainly sourced from resources, such as carbonatites, alkaline igneous rocks, placers, laterites, a...

Abstract Global sea-level changes have been a major topic among scientists. Sea-level changes are not globally uniform. Reconstruction of paleo sea-level changes and monitoring of variations in regional sea-level are important to (i) evaluate future sea-level changes, and (ii) predict risk assessment. In this study, we examined sea-level inundation...

Rare earth elements (REEs) including fifteen lanthanides, yttrium and scandium are found in more than 250 minerals, worldwide. REEs are used in various high-tech applications across various industries, such as electrical and electronics, automotive, renewable energy, medical and defence. Therefore, the demand for REEs in the global market is increa...

The occurrence of several iron ore veins embedded in a metamorphic rock outcropping on a hill named Horakgodakanda, which is located at Pelwatta area in Uva province of Sri Lanka, was reported in 2001. The veins exposed at the top and the western slope of the hill are 30 to 100 cm in thickness and 2-3 m in length. A trench excavated along the north...

After the Indian Ocean tsunami in 2004, the possibility of the occurrence of catastrophic disasters was realized, although Sri Lanka is not close to a plate boundary. This catastrophic event has emphasized that Sri Lanka as a country may not be able to cope with these major natural disasters, in addition to localized and frequently occurring disast...

Rare Earth Elements (REEs) are a set of seventeen chemically similar elements in the periodic table, including fifteen metallic elements of the lanthanide series, Yttrium and Scandium. REEs are significantly used in numerous high-tech applications in sectors, such as metallurgy, military, petroleum and agriculture. Therefore, REEs are considered as...

Apatite mined from Eppawala (Eppawala Rock Phosphate-ERP) cannot be directly used as a fertilizer for annual crops such as paddy and vegetables because of its low water solubility. It is difficult to manufacture water soluble phosphate fertilizers from ERP due to its stable chemical formation and impurities in ERP. This study focuses on impurities...

Bacterial reactions are one of the major processes that control nutrient cycles in sediments. The aim of this study was to trace the bacterial biomarkers (hopanes) to understand early diagenetic processes in tropical mangrove dominant brackish sediments over modern timescales. Hopane homologues were examined by gas chromatography-mass spectrometry...

Holocene sea level change in the northern Indian Ocean was studied using geochemical and geophysical approaches. Molluscs were sub-sampled for radiocarbon dating from sediment cores retrieved from a south Sri Lankan coastal lagoon. They were then combined with previously published sediment core radiocarbon ages from the same lagoon. We observe a ∼2...

High-purity quartz is a major raw material in many high-tech applications. Sri Lanka is rich in quartz mineralization, with an abundance of major vein quartz deposits with purity levels exceeding 99.5% SiO2. Developing high-tech products requires considerable capital investment, expertise, and advanced processing technologies which are lacking in d...

The first beach nourishment project in Sri Lanka was carried out in 2012 over a 1.8-km stretch in the Uswetakeiyawa area by the Coast Conservation Department. About 300,000 m³ of offshore sand in the Indian Ocean was pumped using a dredging vessel for the nourishment. Three breakwaters were constructed nearly 1 year after the beach nourishment. Thi...

The variation in physicochemical properties is a notable feature to identify hydrodynamic and biogeochemical processes in coastal aquatic systems. In this study, the spatial and temporal changes of water quality parameters were measured with respect to spring and neap tides, covering both single and different monsoon periods. Bulk organic geochemic...

Beach sediments in Sri Lanka contain industrial-grade heavy mineral occurrencs. Samples of both offshore and onshore sediments were collected to examine the provenance, mineralogy and geochemical compositions of the heavy mineral occurrences. Coastal morphodynamic changes along the coastline of Sri Lanka were analyzed using the time series satellit...

Jaya-Ganga is a water canal constructed bisecting the phosphate deposit in Eppawala, Sri Lanka. It nourishes three lakes around the vicinity of the Eppawala Phosphate Deposit (EPD) where lake sediments were analyzed to prospect secondary phosphate mineralization. This study reveals that phosphate bearing materials transported through Jaya-Ganga in...

The palynological study of the Tabbowa sediments from Sri Lanka reveals predominant Jurassic gymnospermous pollen assemblage (Araucariacites australis, A. cooksonii, A. fissus and Callialasporites dampieri with spore Murospora florida) belongs to the Callovian-Kimmeridgian age. The collective palynoflora can be correlated to the Classopollis–Arauca...

Mineral exploration is a stochastic process of finding and locating commercially viable mineral resources. In this regard, lake sediment is an important material in exploration as it contains three distinct types of minerals i.e. allogenic or detrital minerals (minerals brought into the lake from outside of the lake), endogenic minerals (minerals o...

The concept of using biological process in soil improvement which is known as bio-mediated soil improvement technique has shown greater potential in engineering applications in terms of performance and environmental sustainability. In this research we performed field investigations and laboratory tests to understand the major composition of beachro...

Coral reefs are related to contemporary processes and sea-level changes over the geological time. Although corals can be dated from late Cambrian to Present, most modern reefs date approximately 5000-7000 years BP. Several Holocene inland coral reefs are preserved in the southern coastal belt of Sri Lanka as pocket deposits. These deposits can be u...