Rajith Perera

@inproceedings{Sakunthala2024,

title = {Statistical Assessment of Toxic Metal Concentrations and its Correlations in Paddy Soils: Comparing the Impact of Chemical and Organic Agricultural Practices in Sri Lanka},

author = {KADD Sakunthala and PLRA Perera and WPRT Perera and JA Liyanage and WAPJ Premaratne},

url = {https://www.researchgate.net/publication/379311099_Statistical_Assessment_of_Toxic_Metal_Concentrations_and_its_Correlations_in_Paddy_Soils_Comparing_the_Impact_of_Chemical_and_Organic_Agricultural_Practices_in_Sri_Lanka



},

year  = {2024},

date = {2024-03-01},

volume = {2},

issue = {2024},

pages = {61},

publisher = {International Research Symposium on Multidisciplinary Approaches in Indigenous Knowledge Systems - IRSIKS },

address = {Gampaha Wickramarachchi University of Indigenous Medicine, Sri Lanka},

organization = {Gampaha Wickramarachchi University of Indigenous Medicine},

abstract = {Background / Originality Evaluating the impact of chemical and organic farming practices on soil toxic metal concentrations is crucial for soil profiling in agroecosystems. Objective This study analyzed heavy metal concentrations within soil samples obtained from paddy fields in the Anamaduwa Divisional Secretariat region. Methodology Paddy soil samples were collected from a chemically fertilized field and an organically cultivated field. Employing a random stratified sampling methodology, twenty composite topsoil specimens were gathered from each paddy field. Toxic heavy metal (Cr, Ni, Pb, As, Cd) concentrations were analyzed using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). The resultant data were further analyzed using the ANOVA test followed by Tukey's pairwise comparison to determine statistically significant variations among the parameters. Furthermore, Pearson correlation analysis was applied. Findings Soil samples from chemically fertilized fields exhibited notably elevated concentrations of Cr (20.09±4.91 mg/kg), Ni (8.58±2.51 mg/kg), Pb (7.15±1.57 mg/kg), and As (0.87±0.17 mg/kg). In contrast, the soil samples from fields that were organically farmed revealed significantly lower mean concentrations of Cr (12.19±3.72 mg/kg), Ni (2.72±1.58 mg/kg), Pb (2.84±1.06 mg/kg), and As (0.49±0.18 mg/kg). The ANOVA test revealed significant differences in pH, conductivity, ammonium nitrogen, potassium, and ash content, and a notable variance in the mean concentrations of Ni, As, and Cr in organic versus chemically fertilized soils (p<0.05) while organic matter and phosphate content showed no significant differences. In the chemically fertilized field, Pearson correlations indicated a strong positive correlation between potassium and heavy metals (Pb, Cr, As, Ni) (r>0.5, p<0.05). Particularly, As showed strong correlation with Cr (r=0.912, p<0.01) and Ni (r=0.862, p<0.01), while the organic field displayed moderate correlations between As and both Cr (r=0.703, p<0.05) and Ni (r=0.779, p<0.01). Cr and Ni showed significant positive correlations (r=0.911, p<0.01) in both fields. Conclusions This suggests that organic farming practices significantly affect soil heavy metal content, leading to reduced levels of these metals. Furthermore, the positive correlations observed between potassium and heavy metals as well as among heavy metals itself emphasize a common origin among them.},

keywords = {Fertilizer, Organic Farming, paddy soil, Toxic Metals},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{Perera2024,

title = {Comparative Analysis of Physiochemical Properties and In Vitro Antioxidant Potency Among Morphotypes of Centella asiatica Grown in Sri Lanka},

author = {KGGT Perera and RAHB Ranasinghe and PLRA Perera and WPRT Perera and WAPJ Premaratne and JA Liyanage},

url = {https://www.researchgate.net/publication/377242224_Comparative_Analysis_of_Physiochemical_Properties_and_In_Vitro_Antioxidant_Potency_Among_Morphotypes_of_Centella_asiatica_Grown_in_Sri_Lanka},

doi = {https://doi.org/10.31357/fesympo.v28.7138},

year  = {2024},

date = {2024-01-06},

urldate = {2024-01-06},

volume = {28},

number = {101},

pages = {223},

publisher = {International Forestry and Environment Symposium},

address = {Department of Forestry and Environmental Science, University of Sri Jayewardenepura, Sri Lanka},

organization = {University of Sri Jayewardenepura},

abstract = {Centella asiatica commonly referred as Gotukola, is recognized for its extensive application in traditional medicine owing to its remarkable health benefits. This study investigated the differences in pH, ash content, moisture content, and in vitro antioxidant potential among three prevalent vine-type morphotypes of Centella asiatica: Wel Gotukola, Meerigima Gotukola, and Yodha Gotukola, indigenous to Sri Lanka. Centella asiatica plants of the same age (100 days) at their first harvestable matured stage, were randomly collected from domestic gardens in Gampaha District, Sri Lanka. Three replicates of each morphotype were sampled. Moisture and ash content were analyzed using the standard AOAC method, and pH was measured using the potentiometric method. DPPH (2,2-Diphenyl-1-picrylhydrazyl) radical scavenging capacity assay was used to determine the antioxidant activity. To thoroughly compare antioxidant potential among morphotypes, the ANOVA test was utilized followed by post-hoc Tukey HSD tests. Following results were obtained for the average moisture content of Wel Gotukola (83.41% ± 1.16%), Yodha Gotukola (74.33% ± 2.23%), and Meerigama Gotukola (79.46% ± 1.89%), alongside average ash content of Wel Gotukola (11.60% ± 1.02%), Yodha Gotukola (13.12% ± 2.57%), and Meerigama Gotukola (12.17% ± 2.01%). Additionally, an average pH of Wel Gotukola (6.00 ± 0.21), Yodha Gotukola (5.75 ± 0.25), and Meerigama Gotukola (5.98 ± 0.14) was observed. The antioxidant activity of Centella asiatica extracts exhibited concentration dependent increases in radical scavenging capacity. Notably, the DPPH radical scavenging potency, denoted by the minimum IC50 value, exhibited significant variations across different Gotukola varieties (p<0.05): Wel Gotukola (6.4 ± 0.54 µg/ml), Yodha Gotukola (8.56 ± 0.35 µg/ml), and Meerigama Gotukola (7.0 ± 0.75 µg/ml). Post-hoc Tukey tests showed antioxidant activity was significantly higher in Wel Gotukola compared to that of Meerigama and Yodha Gotukola morphotypes (p<0.05). Furthermore, Wel Gotukola demonstrated the highest average pH, moisture content, and the lowest mineral content. Conversely, Yodha Gotukola exhibited the lowest pH, moisture content, and the highest ash content. These findings underscore the potential of chemical parameters in elucidating the distinctive attributes of the three Gotukola varieties. Specifically, the significantly higher antioxidant potential observed in Wel Gotukola suggests its potential as an optimal candidate for herbal product development. This study imparts valuable insights into optimizing the therapeutic efficacy of formulations based on the specific Centella asiatica employed in such endeavours.},

keywords = {Antioxidant, Centella asiatica, Physiochemical Properties},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{Perera2024b,

title = {Graphene Oxide Coated Sand Composites as Molecular Sieves to Mitigate Water Contaminants},

author = {WPRT Perera and NMN Ruwanthi and PLRA Perera and AVAP Vitharama and JA Liyanage and AR Kumarasinghe},

url = {https://www.researchgate.net/publication/377242262_Graphene_Oxide_Coated_Sand_Composites_as_Molecular_Sieves_to_Mitigate_Water_Contaminants},

year  = {2024},

date = {2024-01-05},

volume = {28},

number = {166},

pages = {88},

publisher = {International Forestry and Environment Symposium},

address = {Department of Forestry and Environmental Science, University of Sri Jayewardenepura, Sri Lanka},

organization = {University of Sri Jayewardenepura},

keywords = {Adsorption, Graphene oxide, MCPA, Sand},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{Sakunthala2023,

title = {Impact of organic farming practices on toxic metal accumulation in topsoil in paddy areas: A comparative study in Sri Lanka},

author = {KADD Sakunthala and PLRA Perera and WPRT Perera and JA Liyanage and WAPJ Premaratne},

url = {https://www.researchgate.net/publication/377599811_Impact_of_organic_farming_practices_on_toxic_metal_accumulation_in_topsoil_in_paddy_areas_A_comparative_study_in_Sri_Lanka



https://conf.kln.ac.lk/iprc/media/attachments/2024/01/23/abstract-volume-2023.pdf},

year  = {2023},

date = {2023-11-24},

volume = {23},

issue = {2023},

pages = {32},

publisher = {International Postgraduate Research Conference (IPRC)},

address = {Department of Chemistry, Faculty of Science, University of Kelaniya, Sri Lanka},

organization = {University of Kelaniya, Sri Lanka},

abstract = {Given the increasing importance of sustainability in agriculture, this study investigateshow organic farming influences soil toxicity, specifically the accumulation of toxic metalsin paddy fields within the Anamaduwa Divisional Secretariat area. Collections of paddysoil samples were made both from an organically cultivated field and a chemicallyfertilized field. Twenty composite topsoil samples were collected from each paddy fieldaccording to the random sampling method. Soil quality parameters such as soil pH,conductivity, organic matter, total phosphate, potassium, ammonium nitrogen, and ashcontent were analyzed and toxic metal concentrations(Pb, Cd, As, Ni, and Cr) wereanalyzed by Inductively Coupled Plasma–Mass Spectrometry(ICP-MS). Results indicatethe soil collected from paddy areas treated with chemical fertilizers has high average pH,conductivity, total phosphate content, and potassium content. The ammonium nitrogenand ash content were enhanced in the soil collected from organic land and organiccontent fluctuated slightly between the two areas(p>0.05). Soil samples from the fieldusing chemical fertilizers displayed higher average concentrations of Pb(7.15±1.57mg/kg), As(0.87±0.17 mg/kg), Cr(20.09±4.91 mg/kg), Ni(8.58±2.51 mg/kg) compared tothe organically farmed paddy field. The mean concentrations of the Pb, As, Cr, and Ni inthe soil samples of the organically cultivated field were reported as 2.84±1.06 mg/kg,0.49±0.18 mg/kg, 12.19±3.72 mg/kg, 2.72±1.58 mg/kg respectively. Statistical analysisindicates a significant difference in mean heavy metal concentrations(As, Ni, Cr) betweenorganic and chemically fertilized soil samples(p<0.05). The concentration of Cd in thepaddy soil has not been reported in either of the selected paddy areas. In conclusion, thesustained reduction of chemical fertilizer application over a long-term period maycontribute to the decrease in toxic metal contamination observed in the paddy soil withinorganically cultivated areas. This reduction in contamination subsequently mitigates therisk of the transfer of these toxic metals to the paddy root and grain. },

keywords = {Bioaccumulation, Organic Farming, paddy soil, Sri Lanka, Toxic Metals},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{Gunathilka2023,

title = {Toxic metal contamination in food chains via paddy plant; A study in CKDu endemic area in North Western Province, Sri Lanka},

author = {VHNM Gunathilka and WPRT Perera and PLRA Perera and CC Kadigamuwa and JA Liyanage and WAPJ Premaratne},

url = {https://www.researchgate.net/publication/377600053_Toxic_metal_contamination_in_food_chains_via_paddy_plant_A_study_in_CKDu_endemic_area_in_North_Western_Province_Sri_Lanka



https://conf.kln.ac.lk/iprc/media/attachments/2024/01/23/abstract-volume-2023.pdf},

year  = {2023},

date = {2023-11-24},

volume = {23},

number = {22},

issue = {2023},

pages = {31},

publisher = {International Postgraduate Research Conference (IPRC)},

address = {Department of Chemistry, Faculty of Science, University of Kelaniya, Sri Lanka},

organization = {University of Kelaniya, Sri Lanka},

abstract = {This study addresses the urgent need for a comprehensive risk assessment of toxic metal contamination in the food chain via paddy plants in CKDu-affected areas emphasizing the health hazards associated with the transfer of toxic metals from soil to paddy grains and evaluating the health risk of consuming rice through different risk indices. Twenty composite paddy soil samples and twenty paddy plant samples with rice grains in the exact locations were collected from paddy areas in Nikawewa Grama Niladhari division during the Maha growing cycle in 2023. The analysis of Cr, Pb, As, Cd, Ni, and Cu was conducted using inductively coupled plasma-mass spectrometry (ICP-MS). Descriptive statistics revealed the average metal concentrations in rice grains as: Cr(637.42±157.44 µg/Kg), Pb(262 ±62.35 µg/Kg), As(39.29±11.97 µg/Kg), Cd(1836±192 µg/Kg), and Cu(1567 ±466 µg/Kg). Cr, As, and Cu levels in rice grains remained within WHO/FAO and codex limits. However, average Pb and Cd levels surpassed permissible limits (Pb-200 µg/Kg, Cd-50 µg/Kg; WHO). Nevertheless, the Target hazard quotient(THQ) values of Cr and Cd were greater than 1. The estimated Daily Intake(EDI) values of Cr(3.15 µg/Kg/Day) and Cd(9.15 µg/Kg/Day) are higher than Tolerable Daily Intake(TDI) values. The transfer factors(TF) for toxic metals in the soil-root system were determined as follows: Cr-0.069, Pb-0.30, As-0.67, Cd-0.49, Ni-0.10, Cu-0.23. Toxic metal transfer factors in the soil-root system were evaluated, indicating greater uptake by plant roots. When considering a metal transfer from roots to rice grains, Cd had a transfer factor greater than 1, indicating potential accumulation in grains, while Cr exhibited a notable increase in transfer factor compared to the soil-root system. The risk of toxic metal transfer from soil to paddy grains warrants concern due to potential human exposure and related health risks, including Chronic Kidney Disease, from the consumption of contaminated rice grains.},

keywords = {Contamination, Food Chain, Heavy metals, paddy soil, Risk assessment},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{Perera2023d,

title = {Advancements in multifunctional core-shell adsorbent comprising graphene oxide/ sand for adsorptive removal of water contaminants},

author = {WPRT Perera and PLRA Perera and JA Liyanage and AR Kumarasinghe},

url = {https://www.researchgate.net/publication/377600187_Advancements_in_multifunctional_core-shell_adsorbent_comprising_graphene_oxide_sand_for_adsorptive_removal_of_water_contaminants



https://conf.kln.ac.lk/iprc/media/attachments/2024/01/23/abstract-volume-2023.pdf},

year  = {2023},

date = {2023-11-24},

urldate = {2023-11-24},

volume = {23},

number = {25},

issue = {2023},

pages = {34},

publisher = {International Postgraduate Research Conference (IPRC)},

address = {Department of Chemistry, Faculty of Science, University of Kelaniya, Sri Lanka},

organization = {University of Kelaniya, Sri Lanka},

abstract = {Our study introduces a novel approach to enhance the efficiency of water treatment by developing a porous material (M-GO/S) that combines graphite oxide (GO) with river sand overcoming the limitations of conventional granular media filtration. Synthesized M-GO/S was finally characterized by X-ray Photoelectron Spectroscopy (XPS) after primary characterization via X-ray diffraction (XRD), FT-IR, Ramen, and Scanning Electron Microscopic images (SEM). The adsorptive removal efficiency of M-GO/S on selected toxic metals (Pb, Cr, Cd, and Ni), calcium, and methylene blue dye was investigated under the optimum conditions. The findings reveal the presence of a non-uniform graphene oxide coating on the surface of the sand. The incorporation of oxygenated functional moieties within the structure observed according to the comprehensive analysis of the Carbon 1s (C 1s) spectra of the M-GO/S sample in XPS spectrums and revealed the existence of four distinct carbon species exhibiting binding energies at 284.8 eV, 287.05 eV, and 288.85 eV. These carbon species were identified as C-C/C-H, CO , and COO (epoxy) functional groups, respectively. The adsorption capacities of Pb, Cr, Cd, and Ni were recorded as; 52.2 mg/g, 21.9 mg/g, 38.1 mg/g, and 21.9 mg/g respectively. Under the optimum conditions, the sand/GO nanocomposite demonstrated remarkable efficacy in removing 75% of calcium ions (elevated removal percentage than commercial coal powdered activated carbon) from simulated hard water. Apart from that, under the optimum conditions, M/GO-S was able to mitigate 95% of methylene blue which was identified as a toxic dye from the water. Therefore, based on its versatile characteristics as a multifunctional porous material, the synthesized graphene oxide-sand nanocomposite (M-GO/S) demonstrates significant potential as a viable solution for the treatment of contaminated water.},

keywords = {Adsorption, CKDu, Contamination, Estimated Daily Intake (EDI), Grains, Graphene oxide, Heavy metals, Methylene blue, Water hardness},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{Perera2023e,

title = {Exploring the toxic metal contamination and unveiling the risks in staple grains grown in a CKDu hotspot in Sri Lanka},

author = {MASN Perera and WPRT Perera and PLRA Perera and CC Kadigamuwa and JA Liyanage and WAPJ Premaratne},

url = {https://www.researchgate.net/publication/377600084_Exploring_the_toxic_metal_contamination_and_unveiling_the_risks_in_staple_grains_grown_in_a_CKDu_hotspot_in_Sri_Lanka},

year  = {2023},

date = {2023-11-24},

volume = {23},

number = {24},

issue = {2023},

pages = {33},

publisher = {International Postgraduate Research Conference (IPRC)},

address = {Department of Chemistry, Faculty of Science, University of Kelaniya, Sri Lanka},

organization = {University of Kelaniya, Sri Lanka},

abstract = {Toxic metals in dietary grains could pose health risks from direct ingestion. Thisinvestigation aims to analyze the concentrations of toxic metals in selected dietary grainsand conduct a comparative risk assessment in a region endemic to Chronic KidneyDisease of Unknown etiology(CKDu) in a non-endemic region. Six household fields in theCKDu endemic region in Nikawewa Grama Niladhari Division(GND) and three in thereference region; Wewagedara GND were selected for sampling. Inductively CoupledPlasma-Mass Spectrometry(ICP-MS) was used to determine Arsenic (As), Cadmium (Cd),Lead (Pb), Chromium (Cr), Copper (Cu), and Zinc (Zn) in composite samples collectedfrom both GND areas (pulses; [(Vigna radiata; n=20), (Vigna unguiculata; n=20), (Vignaunguiculata subsp.; n=20)] cereal; [(Oryza sativa; n=30)]. Descriptive statistics revealedaverage As concentrations in samples as follows; Oryza sativa (38.60±13.84 g/kg,) Vignaunguiculata (3.25±1.96 g/kg), As was undetectable in samples of Vigna radiate, andVigna unguiculata subsp. in CKDu endemic area. The average As concentrations of Oryzasativa in the reference area was 5.56±1.87g/kg and As was not detected in other grainspecies. All values complied with FAO/WHO & Codex permissible limits (As-100-200g/kg). The estimated Daily Intake (EDI) value of As (0.257 g/kg/day) in Oryza sativain the endemic area did not exceed the Tolerable Daily Intake (TDI) (As-0.3 g/kg/day).The average concentrations of Cd and Pb were reported in the CKDu endemic area; Oryzasativa (Cd-1276.92±234.42 g/kg, Pb-419.31±98.78 g/kg), Vigna radiata(Cd-571.31±60.71 g/kg, Pb-344.15±93.75 g/kg), Vigna unguiculata (Cd-1354.33±265.34g/kg, Pb-408.56±22.20 g/kg), and Vigna unguiculata subsp.(Cd-1546.23±355.23g/kg, Pb-408.63±115.14 g/kg) and exceeded FAO/WHO permissible limit(Cd-400g/kg, Pb-300 g/kg). But those values were within the limits in the reference areas.However, Cu, Cr, and Zn remained within FAO/WHO safe limits in both regions. A healthrisk can be generated owing to long-term consumption of staple grains grown inNikawewa GND; CKDu endemic area. 



},

keywords = {CKDu, Contamination, Estimated Daily Intake (EDI), Grains, Heavy metals},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{Perera2023,

title = {Distribution of heavy metals across different tissue types in Etroplus suratensis from Mahakanadarawa reservoir: Investigating dietary implications for CKDu in Sri Lanka},

author = {PLRA Perera and WPRT Perera and UP Liyanage and WAPJ Premaratne and JA Liyanage},

url = {https://www.researchgate.net/publication/374847754_Distribution_of_heavy_metals_across_different_tissue_types_in_Etroplus_suratensis_from_Mahakanadarawa_reservoir_Investigating_dietary_implications_for_CKDu_in_Sri_Lanka},

year  = {2023},

date = {2023-10-13},

urldate = {2023-10-13},

booktitle = {International Conference on Applied and Pure Sciences (ICAPS)},

number = {54},

pages = {54},

publisher = {University of Kelaniya, Sri Lanka},

abstract = {The escalating cases of chronic kidney disease of uncertain etiology (CKDu) in rural communities, especially in the Maradankulama-Mahakandrawa region of Sri Lanka, stipulate a critical public health investigation. Given the significant dietary reliance on Etroplus suratensis due to geographical and logistical complexities in obtaining sea fish, bioaccumulated toxic metals in this species can be a potential risk factor for CKDu. This study investigated the heavy metal content (As, Pb, Cd, Cr, Ni) in the gut, gill, and muscle tissues of E. suratensis sourced from the Mahakanadarawa Reservoir in the CKDu endemic Mihintale region. To obtain representative E. suratensis samples from across the Mahakanadarawa Reservoir, fish were collected using a randomized sampling method. Multiple random points within the reservoir were predetermined and fish were caught at each location by local fishermen using appropriate techniques. The captured fish were identified as E. suratensis and 36 samples were separated as gut, gills, and muscles for the toxic metal analysis. The heavy metal content (As, Pb, Cd, Cr, Ni) in these samples was then analysed using inductively coupled plasma mass spectrometry (ICP-MS). To thoroughly compare metal concentrations across tissue types, the non-parametric Kruskal-Wallis ANOVA test was utilized followed by post-hoc Tukey HSD tests. The non-parametric ANOVA assessed statistically significant differences in metal levels between muscle, gill, and gut tissues. Post-hoc Tukey tests then enabled pairwise comparisons between each tissue type to determine which specific metal concentrations differed. There were significant differences between tissue types for concentrations of As, Cd, Cr and Ni (p<0.001). Post-hoc Tukey tests showed As, Cr, Cd and Ni were significantly higher in gut compared to that of muscle and gill tissues (p<0.05), with the order Gut>Gill>Muscle. Pb did not deviate significantly across tissues, however, mean Pb concentrations exceeded the WHO/FAO permissible limits for dietary intake in all tissues, while Cd remained within acceptable levels. Compared to gut and gills, muscle contained relatively low concentrations of As (0.01±0.01) mg/kg, Cr (0.22±0.03) mg/kg, Pb (0.508±0.36) mg/kg, and Cd (0.015±0.13) mg/kg and Ni (0.06±0.01) Although edible muscle in some samples met regulatory limits, frequent consumption of E. suratensis from this CKDu endemic area may pose a health risk, warranting further study on geographical and seasonal variation. Ultimately, this study contributes to the growing body of evidence suggesting that bioaccumulation of toxic metals in fish poses significant CKDu risk factors.},

keywords = {Bioaccumulation, CKDu, Etroplus suratensis, Heavy metals, Inland Fish},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{Perera2023b,

title = {Development of sand/graphene composite and its application for MCPA pesticide adsorption from water},

author = {WPRT Perera and NMN Ruwanthi and PLRA Perera and Amila Kannangara and WAPJ Premaratne and JA Liyanage and AR Kumarasinghe},

url = {https://www.researchgate.net/publication/374847773_Development_of_sandgraphene_composite_and_its_application_for_MCPA_pesticide_adsorption_from_water},

year  = {2023},

date = {2023-10-13},

booktitle = {International Conference on Applied and Pure Sciences (ICAPS)},

number = {49},

pages = {113},

publisher = {University of Kelaniya, Sri Lanka},

abstract = {This research endeavours to synthesize a novel adsorbent, sand/graphene oxide composite (M-GO/S), achieved through the iterative deposition of graphene oxide layers on river sand employing a thermal annealing process. Scanning electron microscopic (SEM) and Fourier-transform infrared spectroscopy (FT-IR) characterization studies revealed the presence of a non-uniform graphene oxide coating on the surface of the sand and the incorporation of oxygenated functional moieties within the structure. Comparative evaluations show the heightened adsorption capacity of this new composite entity with alternative sorbent materials, such as activated carbon, graphene oxide, and sand to adsorb neutral 2-methyl-4-chlorophenoxyacetic acid (MCPA) pesticide molecule. To analyse the MCPA adsorption parameters, High-performance liquid chromatography (HPLC)was used (Solvent mixture-Acetonitrile: Distilled water (1:1); Flow rate-1.5µLmin-1; Wave length-275nm). The retention time for the MCPA was reported as 1.538s. The optimization studies and adsorption modelling were carried out, focusing on the adsorption of MCPA onto the M-GO/S. Accordingly, the optimum concentration, dosage, and contact time were 75 mg/L, 0.05 g, and 105 minutes respectively, at neutral pH values. The investigation of adsorption equilibrium isotherms has highlighted the Freundlich model's (multilayer adsorption) superior explanatory capacity in characterizing the adsorption phenomenon. Concurrently, the analysis of adsorption kinetics has demonstrated a favourable fit with the pseudo-second-order model (with a correlation coefficient denoted as 0.9754), implying a prevailing chemical sorption mechanism underlying the adsorption process. Although MCPA possesses either neutral or negatively charged (upon dissolution) surfaces, the M-GO/S composite exhibits significant adsorption capability towards MCPA. Consequently, the synthesized composite emerges as a viable candidate for effectively mitigating MCPA pesticide contamination from water.},

keywords = {Adsorption, Graphene oxide, Kinetic, Pesticide, Sand},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{Perera2023c,

title = {Assessment of contaminant levels of hazardous toxic metals and subsequent risk analysis in agricultural soil and selected comestibles within a region afflicted by CKDu in Sri Lanka},

author = {MASN Perera and CC Kadigamuwa and VHNM Gunathilka and GA Samaraweera and WPRT Perera and PLRA Perera and JA Liyanage and WAPJ Premaratne},

url = {https://www.researchgate.net/publication/374847819_Assessment_of_contaminant_levels_of_hazardous_toxic_metals_and_subsequent_risk_analysis_in_agricultural_soil_and_selected_comestibles_within_a_region_afflicted_by_CKDu_in_Sri_Lanka},

year  = {2023},

date = {2023-10-13},

booktitle = {International Conference on Applied and Pure Sciences (ICAPS)},

number = {55},

pages = {55},

publisher = {University of Kelaniya, Sri Lanka},

abstract = {Agricultural commodities constitute a pivotal component of the human daily sustenance, yet they are susceptible to contamination by pernicious heavy metals, notably Hg, Cd, Pb, and As. Consequently, agricultural products represent a substantive source of apprehension for human well-being and health. This study aims to evaluate related risk indices of agricultural soils (n=25) and selected comestible grains, namely Oryza sativa (n=25), Vigna radiata (n=25), Vigna unguiculata (n=25), and Vigna unguiculata subsp. (n=25), within the endemic region of Nikawewa Grama Niladhari Division (GND) in North Western Province (NWP) and the reference region, Wewagedara GND in NWP where no evidence for Chronic Kidney Disease of unknown etiology (CKDu). The concentrations of metals in the collected samples were determined by using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and based on that risk indices were calculated. The mean geo-accumulation index (Igeo) for four metals in soil was As-0.82, Cd-1.47, Cu-0.91, and Pb 1.31. That indicates no anthropogenic activities related to As, Cd and Cu while Pb is responsible for moderate pollution in endemic area. Estimated Daily Intake (EDI) values for these heavy metals were calculated with respect to the all grains. EDI means of As and Pb in the endemic and the reference areas for all grain samples were within the Tolerable Daily Intake (TDI) set by United States Environmental Protection Agency (USEPA) (As-0.300 g/kg/day) and World Health Organization (WHO) (Pb-3.600 g/kg/day) while Cd (EDI in endemic area; Oryza sativa-6.385 g/kg/day, Vigna unguiculata-3.386 g/kg/day and Vigna unguiculata subsp.-3.866 g/kg/day) highly exceeded the tolerable weekly intake (TWI) of European Food Safety Authority (EFSA) (Cd-2.5 g/kg/week) in both areas. EDI of Cr in rice samples (1.138 g/kg/day) in endemic area exceeded the TDI set by EFSA (1.0 g/kg/day) and all other values of Cr were below the TDI in both areas. According to the USEPA (intolerable cancer risk (CR)-> 1 x 10-4) cancer risk exist for all these staple grains. Igeo of Pb in the soil, raising concerns about their bioavailability and uptake by the food crops and EDI were indicated the long-term consumption of these foods especially Oryza sativa poses a serious threat to human health. Implementing proper soil management practices, monitoring heavy metal levels in crops, and raising public awareness about safe consumption practices are crucial steps towards mitigating the risk of CKDu.},

keywords = {CKDu, Heavy metals, Parbolic Rice, Risk assessment},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{wprt2023core,

title = {Core-Shell Adsorbent Granules Fabricated from Sand/Graphene Oxide Nanocomposite for Adsorptive Removal of Pb (II)},

author = {WPRT Perera and PLRA Perera and AR Kumarasinghe and JA Liyanage},

url = {https://www.researchgate.net/publication/367653776_Environmental_Engineering_and_Green_Technology_Core-Shell_Adsorbent_Granules_Fabricated_from_SandGraphene_Oxide_Nano-Composite_for_Adsorptive_Removal_of_Pb_II},

year  = {2023},

date = {2023-01-01},

urldate = {2023-01-01},

booktitle = {International Forestry and Environment Symposium},

volume = {27},

number = {55},

pages = {129},

address = {Sri Lanka},

organization = {University of Sri Jayewardenepura},

series = {Environmental Engineering and Green Technology},

abstract = {Core-shell absorbent granules are produced by coating commercial sand gravels with graphite oxide (few-layer oxidized graphene sheets). Graphite oxide (GO) is synthesized chemically from vein graphite, a rare form of high-purity natural graphite. Repeated coatings of graphite oxide on the sand followed by low temperature (120 0 C) thermal pyrolysis produce core-shell granules with a hierarchical structure in which sand gravels are covered by graphite oxide layers. The intention of this study is to assess the feasibility of the mitigation of Pb (II) from the water by sand/graphene oxide nano-composite and study the dynamic behavior of the adsorption mechanism using mathematical modeling. Individual materials and the resulting nanocomposite are characterized using a range of spectroscopic (FTIR, XRD, XPS) and microscopic (SEM/EDXA) techniques to elucidate the process of transforming individual materials into nanocomposite and to assess its suitability for removing Pb (II) from water. Stable sand/graphite oxide nanocomposites were obtained upon five times coating of GO on the sand surface and characterization shows that functionalized and a porous coating developed on the sand. The Pb (II) removal efficiency increases from high-acidic to neutral pH and decreases after basic (pH-8). The adsorption process takes 150 minutes to reach the equilibrium. After 150 minutes, the Pb (II) ion adsorption rate was constant. The maximum dosage of the nanocomposite needed to reach the equilibrium was 0.06g. Under the optimum conditions, 96.3% of Pb (II) removal efficiency was recorded from simulated Pb (II) containing water. According to the mathematical modeling, adsorption follows the Langmuir isotherm and fits well with the pseudo 2 nd order kinetics model, indicating a homogeneous adsorption process via a monolayer process and Pb adsorbed onto the surface of the sand/GO nanocomposite by chemisorption. Sand/GO nanocomposite is an excellent candidate for removing Pb (II) from contaminated water.},

keywords = {Adsorption, Graphene oxide, Sand, Water treatment},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{perera2022adsorptive,

title = {Adsorptive removal of Cd (II) from aqueous solutions by sand/graphite oxide nano-composites: characterization, isotherm, and kinetic studies},

author = {WPRT Perera and PLRA Perera and AR Kumarasingha and JA Liyanage},

url = {https://www.researchgate.net/publication/367161154_Adsorptive_removal_of_Cd_II_from_aqueous_solutions_by_sandgraphite_oxide_nano-composites_characterization_isotherm_and_kinetic_studies},

year  = {2022},

date = {2022-12-01},

urldate = {2022-12-01},

booktitle = {International Postgraduate Research Conference (IPRC) },

volume = {2022},

pages = {93},

publisher = {Faculty of Graduate Studies, University of Kelaniya Sri Lanka},

abstract = {Core-shell absorbent granules were developed by coating commercial sand gravels with graphite oxide (few-layer oxidized graphene sheets). Graphite oxide (GO) is synthesized chemically from vein graphite, a rare form of high-purity natural graphite (NVG). Modified Hammer's method was followed in order to synthesize graphene oxide from the NVG. Repeated coatings of graphite oxide on the sand followed by low temperature (120 0 C) thermal pyrolysis resulted in core-shell granules with a hierarchical structure in which sand gravels are covered by graphite oxide layers. Five times GO coated water stable sand/graphite oxide nano-composites (M-S/GO) were developed for further adsorption studies. The adsorption performance and mechanism of Cd (II) removal were investigated and FT-IR, SEM, EDX, and XPS were used to characterize the (M-S/GO) as spectroscopic and microscopic characterization methods. Optimization studies were carried out to find the effective pH of the media, dosage, initial concentration of Cd (II), and contact time that reached the equilibrium. Apart from that, the models of kinetics (pseudo-first order and pseudo-second order), and isotherms (Langmuir and Freundlich) were introduced. Characterization findings indicated that un-uniform graphene oxide coatings had been constructed on the sand surface and the surface of the nano-composite comprised of oxygen-based functional groups. Under optimum conditions (0.08 g/L of dosage, 65 mg/L initial Cd concentration, 120 min of contact time), the M-S/GO removed 93.8% of Cd (II) from simulated water at pH 8.0 (30 ± 2 ℃) and the process reached equilibrium after 120 minutes. The adsorption capacity of Cd (II) was augmented when increasing the pH of the medium up to pH=8, and then it tended to reduce. Further, the experimental data have been fitted with the Langmuir isotherm model indicating that monolayer adsorption of Cd (II) occurs on the surface of M-S/GO. Apart from that, M-S/GO had a maximum adsorption capacity (mg/g) (Qmax) value for Cd (II) adsorption (16.12 mg/g) than sand and GO, the equilibrium parameter (RL) value in this study was 0.071, which indicates that Cd (II) adsorption onto the surface of the M-S/GO is favorable. The experiment kinetic data were best fitted to a pseudo-second-order kinetic model indicating that Cd (II) has adsorbed onto the surface of the M-S/GO by a chemical sorption mechanism. These findings imply that M-S/GO could be used as an effective adsorbent for removing Cd (II) from contaminated water sources. More research is required to determine the reusability of M-S/GO in the adsorptive removal process.},

keywords = {Adsorption, Cadmium, Graphene oxide, Isotherm, Kinetic, Sand},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{kumari2022investigation,

title = {Investigation of toxic metals contamination status in red raw rice (Bg 350) grown in North Central province in Sri Lanka},

author = {MKJK Kumari and WAPJ Premaratne and PLRA Perera and WPRT Perera and JA Liyanage},

url = {https://www.researchgate.net/publication/367091781_Investigation_of_toxic_metals_contamination_status_in_red_raw_rice_Bg_350_grown_in_North_Central_Province_in_Sri_Lanka},

year  = {2022},

date = {2022-12-01},

urldate = {2022-01-01},

booktitle = { International Postgraduate Research Conference (IPRC)},

pages = {87},

publisher = {Faculty of Graduate Studies, University of Kelaniya Sri Lanka},

abstract = {Red raw rice consumption is high due to its nutritional properties. The chemical components of food

are correlated with their ability to sustain better human health. Rice is the staple food of Sri Lanka.

Although it is a good source of nutrients in a diet, its consumption can also lead to exposure to toxic

metals due to environmental pollution. Rice is grown extensively in the North Central Province (NCP)

where the prevalence of chronic kidney disease of unknown origin (CKDu) is high. This study was

aimed to determine the toxic metal content such as Arsenic (As), Cadmium (Cd), and Lead (Pb) in

domestically grown red raw rice in NCP and assess the risk of these values to human health. A total of

35 samples Of red raw rice were obtained from farmers in NCP during Yala growing cycle in 2021 based

on the eight sampling sites. As, Cd and Pb levels were analyzed by Inductively Coupled Plasma-Mass

Spectrometry (l •Ille potential health risk was estimated by Estimated Daily Intake (EDI). The mean Pb levels

in red raw rice were higher than the FAO/WHO allowable limits (Pb-200 gg/kg) in all the selected areas

except the Rambewa area. The highest mean pb concentration was recorded in the Horowpathana area

as 429.93±100.93 pg/kg. As and Cd values were within FAO/WHO allowable limits (As-200 pg/kg, Cd-

400 gg/kg). The highest mean value of as was recorded in the Medirigiriya area, and it was 97.72±18.19

gg/kg. The highest Cd level was recorded in the Horowpathana area as 60.70±24.39 gg/kg The

estimated daily intake (EDI) values are also significantly lower than the Tolerable Daily Intake (TDI)

(Pb-250 gg/day, Cd-62 gg/day. As-3 gg/day). Dietary exposure is the most common route through

which these toxic metals enter the human body. Long term consumption of red raw rice causes to

accumulate the toxic metals in body tissues and generates adverse health effects of residents in selected

CKDu prevalent areas in NCP. It is suggested that further studies are needed to get a more

comprehensive idea on the public health concerns of toxic metals due to red raw rice consumption in

Sri Lanka.},

keywords = {CKDu, Contamination, Toxic Metals},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{perera2022comparison,

title = {A comparison of food contamination by heavy metals/metalloids in CKDu prevalent areas and a reference area; A study in Sri Lanka},

author = {PLRA Perera and WPRT Perera and JA Liyanage and WAPJ Premaratne},

url = {https://www.researchgate.net/publication/367091378_A_comparison_of_food_contamination_by_heavy_metalsmetalloids_in_CKDu_prevalent_areas_and_a_reference_area_A_study_in_Sri_Lanka},

year  = {2022},

date = {2022-12-01},

urldate = {2022-12-01},

booktitle = {International Postgraduate Research Conference},

volume = {2022},

pages = {99},

publisher = {Faculty of Graduate Studies, University of Kelaniya Sri Lanka},

abstract = {During the past two decades, so many studies have been involved in exploring the relationship between the prevalence of chronic kidney disease of unknown etiology (CKDu) and exposure to toxic metals. These studies revealed signs of chronic low levels of toxic metal exposure in Sri Lanka. To assess the risk of negative health effects and propose appropriate public health interventions, novel research studies will be very beneficial. This assessment was performed to study the toxic metal contamination status in domestic rice, leafy vegetables, legumes, and citrus fruits in the CKDu prevalence area in north central province in Sri Lanka and to compare those levels with a reference area in the Eastern province in Sri Lanka where CKDu is not prevalent. CKDu hot spots areas Maradankulama-Mahakanadarawa in the Anuradhapura district, Sri Lanka was selected for sampling and Buddhangala Grama Niladhari area in Ampara district was selected as a reference site. Food samples, including (Oryza sativa; n=25, Centella asiatica; n=25, Citrus crenatiflora; n=18, Vigna radiata; n=10) were collected from the stratified sampling method in both areas and the collected food samples were digested by microwave digestion according to the standard procedures and the concentrations of metal ions in food samples, including Cadmium, Nickel, Chromium, Copper, Iron, Manganese, Lead, Zinc, Arsenic, and Calcium, were measured using Inductive Coupled Plasma technique (ICP). As a results of the study, mean As and Pb concentrations of Oryza sativa (As-0.15 mg/kg, Pb-3.10 mg/kg) and Citrus crenatiflora (As-0.15 mg/kg, Pb-0.47 mg/kg), Pb (0.65 mg/kg) and Cd (0.05 mg/kg) content in Centella asiatica, and mean concentrations of As (0.14 mg/kg), Pb (9.25 mg/kg) and Cu (57.8 mg/kg) in Vigna radiata have exceeded the permissible limits given by the FAO and WHO, 2011: As-0.1 mg/kg, Pb-0.1 mg/kg, Cd-0.05 mg/kg, Cr-2.3 mg/kg, Cu-40 mg/kg. However, none of the food samples collected from the reference areas has exceeded the permissible limits of analyzed heavy metals/metalloids. THQ (Target Hazard Quotient) values of Cr have exceeded the threshold values for all food species. Furthermore, Pb is also regarded as a toxic element and THQ values of Pb in Oryza sativa and Vigna radiate are noticeably high. Meanwhile, THQ values of the food samples in the reference areas have not exceeded the threshold values. According to the outcome of the study, there is a noticeable difference reported in toxic metals contamination status between the CKDu-prone areas and the reference area. Therefore, the consumption of analyzed rice, leafy vegetables, and legumes was estimated to be risky, and their regular consumption may boost the likelihood of CKDu prevalence in those areas. Further studies are required to monitor and assess heavy metals and metalloids in soil, and fertilizers to find the pathways of contamination of food by toxic metals.},

keywords = {Arsenic, Cadmium, chronic kidney disease, CKDu, Food Safety, Heavy metals, Lead, Nephropathy},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{Kumari2022,

title = {Investigation of Toxic Metals in Parboiled Rice Grown in Anuradhapura District},

author = {MKJK Kumari and WAPJ Premaratne and PLRA Perera and WPRT Perera and JA Liyanage},

url = {https://www.researchgate.net/publication/366701095_Investigation_of_Toxic_Metals_in_Parboiled_Rice_Grown_in_Anuradhapura_District},

year  = {2022},

date = {2022-11-10},

urldate = {2022-11-10},

booktitle = {International Conference on Innovation and Emerging Technologies (ICIET)},

volume = {2022},

pages = {122},

address = {Sri Lanka},

organization = {University of Sri Jayewardenepura},

abstract = {Parboiling is the most common processing method used in the rice industry, which affects on quality of rice. This study was designed to determine the levels of toxic metals such as arsenic (As), cadmium (Cd), and lead (Pb) in rice grown in Anuradhapura district (AD) which was identified as one of the high chronic kidney diseases of unknown etiology (CKDu) prevalent areas in North Central province, Sri Lanka. A total of 70 parboiled rice samples were obtained from six areas in AD. The levels of As, Cd, and Pb were determined using inductively coupled plasma-mass spectrometry (ICP-MS) followed by microwave acid digestion. Except for Pb, levels of As, and Cd in all rice samples were lower than the maximum permissible limits (As-200 µg/kg and Cd-400 µg/kg) given by the FAO/WHO. The mean Pb level of rice samples collected from some areas exceeded the FAO/WHO allowable limits (Pb-200 µg/kg). Rambewa area has reported 1122 µg/kg mean Pb content in the rice samples. The highest mean value for As was recorded as 95 µg/kg in Kahatagasdigiliya area. The highest Cd level was recorded in Rambewa area as 65 µg/kg. The highest estimated weekly Pb intake was recorded as 39 µg/kg body weight. The highest estimated weekly As and Cd intakes were recorded as 3 µg/kg body weight and 2 µg/kg body weight. The estimated weekly metal intake values are also significantly lower than the provisional tolerable weekly intake (PTWI) (Pb-5 µg/kg body weight, Cd-7 µg/kg body weight, and As-15µg/kg body weight) except for Pb in Rambewa area. Contamination of the Pb, As, and Cd in rice grains may occur via transfer from the paddy soil. Therefore, the parboiled rice may contribute to generating adverse health risks via metal toxicity of the residents in selected CKDu prevalent areas.},

keywords = {CKDu, Parbolic Rice, Toxic Metals},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{P2023,

title = {Toxic metal contamination of Inland Fish (Etroplus suratensis) in Mahakanadarawa reservoir: A study in a CKDu prevalent area, Sri Lanka},

author = {Lahiru P and WPRT Perera and PLRA Perera and JA Liyanage and WAPJ Premaratne},

url = {https://www.researchgate.net/publication/365029106_TOXIC_METAL_CONTAMINATION_OF_INLAND_FISH_Etroplus_suratensis_IN_MAHAKANADARAWA_RESERVOIR_A_STUDY_IN_A_CKDu_PREVALENT_AREA_SRI_LANKA},

year  = {2022},

date = {2022-10-10},

urldate = {2023-10-10},

booktitle = {PGIS Research Congress, 2022 (RESCON)},

volume = {2022},

number = {64},

pages = {14},

address = {Sri Lanka},

organization = {University of Peradeniya},

abstract = {Fish is a great source of protein, polyunsaturated fatty acids (PUFA), lipo-soluble vitamins, and essential minerals. Meanwhile, people who live in the dry zone of Sri Lanka consume inland fish species collected from irrigation reservoirs. Toxic metals tend to accumulate in fish; thus, it is important to investigate the safety of the consumption of inland fish. This study evaluated the toxic metal contamination status of the edible fish (Etroplus suratensis) in the Mahakanadarawa tank and assessed the risk of fish consumption. Mihintale Divisional Secretariat Division was identified as a major CKDu-prone area in the Anuradhapura District. Mahakanadarawa tank is a major fishing source in the area. Fifteen E. suratensis samples were collected from the Mahakanadarawa tank in April 2022. The fish muscle parts, gut, and gills were removed, stored in sterile polyethylene bags, and kept at 4°C during transport. The concentration of metal elements, including Mn, Co, As, Cd, Cr, Pb, Cu, Zn, Al, Fe, and Ni, was determined in an acid-digested sample using inductively coupled plasma mass spectrometry. The average contents of the nephrotoxic heavy metals/metalloids such as As, Cd, Pb, and Cr in the gut tissues of E. suratensis had reported elevated values compared to other tissue parts (gills and muscle). The average Pb content in the tissues of the gills, muscles, and gut of E. suratensis exceeded the permissible limits given by WHO/FAO. Average Cd contents did not exceed the permissible level in all analyzed tissue types, while average Zn and Cu levels have also complied with the WHO/FAO standard limits. The edible part of the fish consisted of an average of As = 0.01(±0.01) mg/kg, Cr = 0.22 (±0.03) mg/kg, Mn = 1.19 (± 0.36) mg/kg, and Al = 180.8 (±137.0) mg/kg. Even small amounts of toxic metals are reported in edible tissues of the E. suratensis; long-term consumption of fish may generate a negative health effect on consumers. Further risk assessment of toxic metals in E. suratensis in different reservoirs, including reference areas (CKDu-non-endemic areas), needs to be investigated in future studies.},

keywords = {CKDu, Contamination, E. suratensis;, Heavy metals, Inland Fish},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{ranasinghe2022risk,

title = {Risk assessment of toxic metal contamination in groundwater and paddy soil; A study in CKDu affected Maradankulama area in Anuradhapura, Sri Lanka},

author = {RAHB Ranasinghe and WAPJ Premaratne and PLRA Perera and WPRT Perera and JA Liyanage},

url = {https://www.researchgate.net/publication/364716756_Risk_assessment_of_toxic_metal_contamination_in_groundwater_and_paddy_soil_A_study_in_CKDu_affected_Maradankulama_area_in_Anuradhapura_Sri_Lanka},

year  = {2022},

date = {2022-10-01},

urldate = {2022-01-01},

booktitle = {International Conference on Applied and Pure Sciences},

publisher = {Faculty of Science, University of Kelaniya Sri Lanka},

organization = {Faculty of Science, University of Kelaniya, Sri Lanka},

abstract = {Chronic Kidney Disease of Unknown Etiology (CKDu) has emerged as a serious public health concern in Sri Lanka. The North Central Region (NCR) has the highest CKDu prevalence in the country, and the disease is more prevalent among farming communities and people who rely on groundwater as their primary source of drinking water. Meanwhile, heavy metal/metalloids exposure and accumulation are recognized as the causative agent of many acute and chronic diseases in certain vulnerable human tissues, including the kidneys. This study assesses the level of contamination of heavy metals/metalloids in drinking water and agricultural soil in a CKDu endemic area in NCR, Sri Lanka. Fifteen groundwater samples collected from wells were analyzed for pH, EC, hardness, heavy metals, and anion concentration using potentiometric, conductometric, titrimetric, inductively coupled plasma mass spectrometric, and ion chromatographic methods, respectively. From six sampling sites in a paddy field, composite soil samples were collected from the surface, and two depths (30 cm and 60 cm). Soil samples were analyzed for pH, EC, organic matter, potassium, phosphate, and heavy metals using potentiometric, conductometric, titrimetric, flame photometric, colorimetric, and inductively coupled plasma mass spectrometric methods respectively. Accordingly, the mean pH of groundwater is 7.25 and this lies within the guideline values. Mean EC is 662.4 µS/cm and mean hardness is 287.0 mg CaCO3/L. Among fifteen samples, four and five water samples have exceeded the health guideline values for EC and hardness, respectively. Metal content varies in the following order, Cd < As < Cr < Cu < Co < Fe < Ni < Mn < Zn. Pb was not detected in any of the water samples and other metals were found in concentrations well below the standard guideline values. Only one sample and three samples exceeded the guideline value for fluoride and nitrite, respectively. Mean pH, EC, organic matter, potassium, and phosphate in paddy soil is 7.57, 101.8 µS/cm, 1.34%, 148.9 mg/kg, and 24.05 mg/kg respectively. Heavy metal content in soil varies in the following order, Cd < As < Pb < Co < Ni < Cu < Zn < Cr < Mn < Fe. Paddy soil from the very bottom showed the highest pH, Pb, Cd, As, Zn, Ni, Mn, Cr, and Fe content while the highest EC, organic matter and potassium content was detected in topsoil. EC, organic matter, and potassium content decreased with the depth of the soil, and the concentration of Pb, As, Zn, Mn, and Fe increased with the depth. This study reveals the dependence of some soil quality parameters on the depth of the soil profile. Monitoring the soil quality is important to minimize the possibility of heavy metal uptake by rice plants. Low heavy metal concentration in groundwater may not have an acute health effect on humans. But long-term chronic exposure to toxic heavy metals together with high EC, hardness, and fluoride would be a reason to trigger the prevalence of CKDu in Maradankulama area.},

keywords = {CKDu, Drinking water, paddy soil, Toxic Metals},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{perera2022health,

title = {Health risk analysis of toxic metals via consumption of rice and other food species grown in Mahakanadarawa-Maradankulama areas in Anuradhapura district; A study in Sri Lanka},

author = {PLRA Perera and WPRT Perera and JA Liyanage and WAPJ Premaratne},

url = {https://www.researchgate.net/publication/364622134_Health_risk_analysis_of_toxic_metals_via_consumption_of_rice_and_other_food_species_grown_in_Mahakanadarawa_-Maradankulama_areas_in_Anuradhapura_district_A_study_in_Sri_Lanka},

year  = {2022},

date = {2022-10-01},

urldate = {2022-10-01},

booktitle = {International Conference on Applied and Pure Sciences (ICAPS)},

pages = {76},

publisher = {Faculty of Science, University of Kelaniya Sri Lanka},

abstract = {Chronic Kidney Disease of unknown etiology (CKDu) is a heterogeneous disorder that impairs kidney functions and structure. Even though a number of studies were conducted on this issue, a specific reason has not yet been discovered. Unexpected contaminants have harmed crop quality in recent decades, threatening food security and human health. This study was designed to assess the status of toxic metal contamination of frequently consuming food species in selected Maradankulama-Mahakanadarawa Grama Niladari (GN) divisions to evaluate the link between CKDu prevalence and food safety in the selected areas. Maradankulama-Mahakanadarawa GN divisions in Anuradhapura district, Sri Lanka, were selected as the sampling areas. The sampling procedure was conducted in April (2022). Food samples, including (rice grains of Oryza sativa; n=25, leaves of Centella asiatica; n=25, fruits of Citrus crenatiflora; n=18, grains of Vigna radiate; n=10) were according to the random stratified sampling method and the collected food samples were digested by microwave digestion. (added 8.0 mL of conc. Nitric acid to 0.2 g of food sample and digested) The concentrations of metal ions in food samples, including Cadmium, Nickel, Chromium, Copper, Iron, Manganese, Lead, Zinc, Arsenic, and Calcium, were measured using the Inductive Coupled Plasma technique (ICP). Statistical analysis was done using SPSS Statistics Software. Accordingly, mean As and Pb concentrations of Oryza sativa (As-0.15 mg/kg, Pb-3.10 mg/kg) and Citrus crenatiflora (As-0.15 mg/kg, Pb-0.47 mg/kg), Pb (0.65 mg/kg) and Cd (0.05 mg/kg content in Centella asiatica, and mean concentrations of As (0.14 mg/kg), Pb (9.25 mg/kg) and Cu (57.8 mg/kg) in Vigna radiate exceeded the permissible limits given by the FAO and WHO, 2011 (As-0.1 mg/kg, Pb-0.1 mg/kg, Cd-0.05 mg/kg, Cr-2.3 mg/kg, Cu-40 mg/kg). In addition to Pb, Cd, As, Cr and Cu, other detected metals have not exceeded the permissible limits in all samples. According to the Target Hazard Quotient (THQ) values of Cr exceeded the threshold value of 1 for all food species. In addition to that, Pb is also considered a toxic element, and THQ values of Pb in Oryza sativa and Vigna radiate reported noticeably high values. The total EDIs (Estimated Daily Intake) of Cr, Ni, Cd, As, Cu and Pb for all selected food samples studied have not exceeded the maximum tolerable daily intake consumption of analyzed rice, leafy vegetables, and legumes was deemed unsafe, and their regular consumption may cause a risk for the prevalence of CKDu in selected areas.},

keywords = {CKDu, Food Safety, Health Risk, Heavy metals, Nephropathy},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{sampath2022evaluation,

title = {Evaluation of toxic metal contamination in surface sediments and water in Mahakanadarawa tank; Anuradhapura, Sri Lanka},

author = {M Sampath and RT Perera and PLRA Perera and JA Liyanage and WAPJ Premaratne},

url = {https://www.researchgate.net/publication/364716334_Evaluation_of_toxic_metal_contamination_in_surface_sediments_and_water_in_Mahakanadarawa_tank_Anuradhapura_Sri_Lanka},

year  = {2022},

date = {2022-10-01},

urldate = {2022-01-01},

booktitle = {International Conference on Applied and Pure Sciences},

pages = {9},

publisher = {Faculty of Science, University of Kelaniya Sri Lanka},

abstract = {Toxic elements, including heavy metals/metalloids, readily contaminate water reservoirs via natural mechanisms such as surface runoff, precipitation, and atmospheric deposition. As a result, some toxic metals can be accumulated in surface sediments in the reservoirs and be incorporated into the food chains. It has become a major issue because various trace elements contaminate water, soil, and sediments, which can have serious health consequences due to their toxicity, persistence, and carcinogenic nature. This study was carried out with the aim of analysing the sediment quality in a major irrigation tank called Mahakanadarawa tank in Anuradhapura district, which is located in a high prevalence of chronic kidney disease of unknown etiology (CKDu) in Sri Lanka. Fifteen composite sediment samples (five samples in each of fifteen different locations) were randomly collected around the Mahakanadarawa tank in April (2022). Twenty surface water samples (Triplicated) were collected from the Mahakanadarawa lake using twenty different locations. Concentrations of metal elements including Mn, Co, As, Cd, Pb, Cu, Zn, Na, K, Al, Ca, Mg, Fe, and Ni were determined using inductively coupled plasma mass spectrometry (ICP-MS) and multi-element standards were used for the instrumental calibration. Statistical analysis was done using SPSS Statistics Software. According to the analysis of the sediment samples, none of the analysed toxic metals have exceeded the severe effect level as well as the lowest effect level. Abundancy of the metals in the sediments samples is varied as Fe> Mn > Cr> Zn > Cu >Pb > Ni >Co> As> Cd. The Igeo (Geo Accumulation value) values obtained, and the index values exhibit that the sediment samples have a tendency to transfer to an unpolluted to moderately polluted stage with analysed toxic metals except for Zn and Cd. Owing to the long-term intense applications of the crop fertilisers and pesticides in the area, toxic metals may be transferred and concentrated in the tanks from the agricultural fields. Apart from that, average concentrations values of analysed metals, including toxic metals such as Pb, As, and Cd in surface water, were far below the irrigation standards. Contamination of food chains and worsening the hazardous conditions for aquatic life can occur due to the toxic metal accumulations in the surface sediments. In order to conduct a health risk assessment for the consumption of tank fish from Mahakanadarawa tank, further studies should be performed by conducting several sampling cycles of sediment and water as well as toxic metal contamination status of inland fish in Mahakanadarawa tank also need to be evaluated.},

keywords = {ckd, CKDu, Contamination, Heavy metals, Sediment, Surface Water},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{mkjk2022bioaccumulation,

title = {Bioaccumulation of toxic metals in Oryza sativa grown in North Central Province in Sri Lanka},

author = {MKJK Kumari and WAPJ Premaratne and PLRA Perera and WPRT Perera and JA Liyanage},

url = {https://www.researchgate.net/publication/361999369_Bioaccumulation_of_toxic_metals_in_Oryza_sativa_grown_in_North_Central_Province_in_Sri_Lanka},

year  = {2022},

date = {2022-06-01},

urldate = {2022-01-01},

booktitle = {International Symposium on Agriculture and Environment(ISAE)},

volume = {2022},

pages = {32},

publisher = {University of Ruhuna, Sri Lanka},

abstract = {This study was carried out to assess the levels of heavy metals such as Arsenic (As), Cadmium (Cd), and Lead (Pb) in domestically grown rice sold in North Central Province (NCP) which is identified as a high CKDu prevalent area in Sri Lanka. Based on eight paddy areas, thirty Oryza sativa composite samples were collected in each selected Divisional Secretariat (DS) area in NCP. Samples were subjected to microwave digestion process and As, Cd and Pb analysis were carried out by the ICP-MS. The mean Pb levels in domestically grown rice were significantly higher than the FAO/WHO allowable limits (Pb-200 µg/kg) in most of the DS areas. Among selected DS areas, the Padaviya DS area has highlighted reporting 2815 µg/kg mean Pb content in the rice samples. However, none of the mean values of As and Cd in rice samples in selected areas have exceeded the FAO/WHO allowable limits (As-200 µg/kg, Cd-400 µg/kg). The Highest Cd contamination was reported in Higurakgoda and Padaviya DS areas and the values were 106.69 µg/kg, 105.69 µg/kg, respectively. The highest mean value of as was reported in the Kebithigollewa DS area and it was 49.75 µg/kg. The values of estimated daily intake (EDI) of the analyzed metals were also very far below than the Tolerable Daily Intake (TDI) (Pb-250 µg/day, Cd-62 µg/day, As-3 µg/day). Owing to high Pb content in domestically grown rice samples in selected areas, long term consumption of rice causes to accumulate the Pb in body tissues and generates a health risk of residents in selected CKDu affected areas in NCP.},

keywords = {CKDu, Contamination, Parbolic Rice, Toxic Metals},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{perera2021risk,

title = {Risk Assessment of Bioaccumulation of Toxic Metals in Rice Grains (Oryza sativa) in a CKDu Endemic Area; A Study in Mihintale Division, Sri Lanka},

author = {PLRA Perera and WPRT Perera and JA Liyanage},

url = {https://www.researchgate.net/publication/354193460_Risk_assessment_of_bioaccumulation_of_toxic_metals_in_rice_grains_Oryza_sativa_in_a_CKDu_endemic_area_A_study_in_Mihintale_division_Sri_Lanka},

year  = {2021},

date = {2021-08-01},

urldate = {2021-01-01},

booktitle = {Research Symposium of the Faculty of Allied Health Sciences - RuFARS},

publisher = {Faculty of Allied Health Sciences, University of Ruhuna, Galle, Sri Lanka},

abstract = {Background: Chronic Kidney Disease of unknown etiology (CKDu) is a heterogeneous disorder affecting kidney structure and its functions. CKDu has rapidly spread throughout Sri Lanka in the past two decades and has become predominant in the North Central Region. Food or water borne diseases are one of the key issues in food safety assurance in Sri Lanka. Pesticides and heavy metals play an important role in modern agriculture and food safety. Objective: To evaluate the toxic metal contamination status in the polished rice samples (BG 300) grown in the Maradankulama area. Methods: Maradankulama GN Division was selected based on the available information on medical/hospital records, which has the highest number of CKDu patients in the Mihintale Division as the sampling area. A survey protocol was also developed. Thirty polished rice samples (BG 300) were collected from the households subject to three paddy areas in the Maradankulama GN area according to the random stratified sampling method and heavy metal concentrations of rice samples (Chromium, Lead, Arsenic and Cadmium) were analyzed by ICP-MS. Results: The male CKDu patients were higher than females (Male, 57.15%; Female, 42.85%). All the CKDu patients subjected to the survey in the area belong to the farming community within the age group of 60-70 years. In Maradankulama Cr(7.268±0.046), Pb(1.923±0.209), As(0.064±0.009) and Cd(0.026±0.003) were detected in mg/kg levels. Among the analyzed metals in the rice samples, mean Cr and Pb contents have exceeded the maximum permissible level (MPL) according to the Codex Alimentarius commission guidelines. Conclusion: Arsenic and Cadmium contents in the rice samples were well below the Codex standard. However, rice samples have been contaminated with some nephrotoxic metals such as Chromium and Lead. Hence, long term exposure to the toxic metals may generate a risk for kidney damage in people.},

keywords = {CKDu, CODEX, Contamination, Oryza sativa, Toxic Metals},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{perera2019preparationb,

title = {Preparation, Characterization and Evaluation of Lead Adsorption Efficiency of Chitosan Coated Activated Carbon},

author = {PLRA Perera and CSK Rajapakse},

url = {https://www.researchgate.net/publication/339133101_Preparation_Characterization_and_Evaluation_of_Lead_Adsorption_Efficiency_of_Chitosan_Coated_Activated_Carbon},

doi = {http://dx.doi.org/10.6084/m9.figshare.11827962.v1},

year  = {2019},

date = {2019-12-01},

urldate = {2019-01-01},

booktitle = {International Postgraduate Research Conference(IPRC)},

publisher = {University of Kelaniya, Sri Lanka},

abstract = {Heavy metal contamination in various water resources is of great concern because of the toxic effect on human beings and other animals and plants in the environment. Lead is a major element which is released to the environment including water bodies by many industries and it is well known that the presence of Pb(II) in water, even at very low concentrations, is extremely harmful to the human. Therefore, the aim of the present study was to investigate the Pb adsorption potential of chitosan coated activated carbon derived from rice husk (CCAC) in aqueous media. First, chitin was extracted from shrimp shell wastes by following a standard procedure and it was deacetylated to obtain chitosan (deacetylation percentage = 82%). In the preparation of activated carbon from rice husk, HCl acid (5 % v/v) was used as the activating agent. The adsorbent of the study, CCAC was then prepared by coating activated carbon derived from rice husk (20.00 g) with chitosan (3.00 g dissolved in 1% v/v acetic acid) to improve the stability and mechanical strength of chitosan. The surface morphology and the elemental composition of CCAC was examined by Scanning Electron Microscopy & Energy Dispersive Spectroscopy (SEM/EDAX). The novel adsorbent was further characterized by Fourier Transform Infrared Spectroscopy (FT-IR). In order to determine the Pb adsorption potential of CCAC, batch adsorption studies were conducted at room temperature at pH 7. The effects of various experimental parameters such as initial Pb (II) concentration, dose of adsorbent and shaking time on Pb adsorption to CCAC were evaluated. According to the results, the maximum lead removal percentage (89%) was observed at initial Pb (II) concentration of 2 ppm, adsorbent dosage of 1 g/L and 120 minutes of shaking time. Further, the equilibrium adsorption data were analyzed by the Langmuir isotherm model and the Freundlich isotherm model for Pb adsorption onto CCAC. Among the two models, Langmuir isotherm best fitted with the equilibrium data (R2= 0.9916) with a maximum adsorption capacity (q0) of 24.39 mg/g. Based on the results, it can be concluded that CCAC can be considered as an efficient and cost-effective adsorbent for the removal of heavy metals such as Pb from industrial wastewater.},

keywords = {Activated carbon, Chitosan, Pb removal, wastewater},

pubstate = {published},

tppubtype = {inproceedings}

}

@inproceedings{perera2019preparation,

title = {Preparation, characterization and properties of activated carbon derived from rice husk},

author = {PLRA Perera and C. S. K. Rajapakse},

url = {https://www.researchgate.net/publication/336823780_Preparation_characterization_and_properties_of_activated_carbon_derived_from_rice_husk},

doi = {http://dx.doi.org/10.6084/m9.figshare.10052615.v1},

year  = {2019},

date = {2019-10-01},

urldate = {2019-01-01},

booktitle = {The International Research Symposium on Pure and Applied Sciences (IRSPAS) 2019},

pages = {145},

abstract = {Rice, the staple food of the Sri Lankans is one of the important crops occupying 34% of the total cultivated area in the country. Thus, rice processing generates a large quantity of rice husk, as waste material. Therefore, the main objective of the present work was to investigate the potential of using this agricultural waste, rice husk as a precursor for the production of low-cost activated carbon (AC) as an adsorbent for the removal of heavy metals (Pb (II), Cd (II) etc.). Therefore, the present study was carried out to evaluate the effect of carbonization time and activating agent on AC production from rice husk and its Pb (II) removal capacity. Cleaned and dried rice husks samples (12.00 g) were separately carbonized at 400 °C under constant nitrogen flow for 60 minutes -150 minutes (60 min, 90 min, 120 min, 150 min) and chemically activated by HCl. The AC yield was calculated in each sample and duplicate using standard equations. In order to determine the lead removal percentages (Pb%) of AC derived from rice husk at different carbonized temperatures, first AC samples were added (1.00 g) separately to a Pb(II) standard solution (5.00 mg L-1), stirred for 1 hour at pH 7 at room temperature. The solutions were filtered and the residual Pb was determined by Atomic Absorption Spectrophotometry (AAS). Further, the AC with the highest Pb removal capacity was characterized by Scanning Electron Microscopy & Energy Dispersive Spectroscopy (SEM/EDAX), and Fourier Transform Infrared Spectroscopy (FT-IR), Proximate analysis, of the AC were also studied. The percent yield of AC prepared from rice husk with HCl activation, and its corresponding %Pb removal potential were fluctuated with increasing carbonization time. The highest AC yield (20.50%), the highest %Pb removal (93.31%) was observed for the AC prepared by carbonization of rice husk at 400 °C for 120 minutes with HCl activation. The results of the proximate analysis revealed that the ash content, moisture content volatile matter content and fixed carbon content of the AC were 32.47%, 34.94%, 24.20%, and 8.39% respectively. Based on the results, it can be concluded that AC derived from rice husk can be considered as an efficient and cost-effective adsorbent for the removal Pb from wastewater},

keywords = {Activated carbon, Pb removal, Rice Husk, wastewater},

pubstate = {published},

tppubtype = {inproceedings}

}