Browsing by Author "Deeyamulla, M. P."

Now showing 1 - 14 of 14

Assessment of Heavy Metal Contamination in Negombo Lagoon and Achchankulam Estuary in Mannar District.
(In: Proceedings of the International Postgraduate Research Conference 2017 (IPRC – 2017), Faculty of Graduate Studies, University of Kelaniya, Sri Lanka., 2017) Handagiripathira, H. M. N. L.; Deeyamulla, M. P.; Chandrajith, R. L. R.
Coastal water bodies such as lagoons and estuaries receive various types of pollutants due to anthropogenic influences resulted from rapid economic growth and urbanization. During the last decays, heavy metal contamination in aquatic systems has become one of the major problems due to its toxicity, durability and special depositional properties. Therefore, main objective was to study the concentrations of heavy metals to understand the levels of contamination in the water bodies of lagoon and estuaries situated in urbanized and industrialized areas of Sri Lanka. As such selected study sites were Negombo lagoon situated in Gampaha district and Achchankulam estuary situated in Mannar district. Water samples were collected in the wet season of 2015. The elemental concentrations of V, Mn, Fe, Cr, Co, Ni, Cu, Zn, As, Cd and Pb were measured in the 32 samples collected from Negombo lagoon and 10 samples from Achchankulam estuary using ICP-MS technique. In-situ measurements for the physico-chemical parameters of pH, conductivity, salinity and TDS were measured using a portable meter. The averaged metal concentrations obtained for 2 study sites were compared. All most all were remarkably high in the Achchankulam estuary except the V, Mn and Cu. The averaged Co, Ni and Zn showed 50% higher concentrations in Achchankulam than the Negombo. The As and Pb averaged concentrations were 75% higher and averaged Cd concentration was significantly higher as 216% in the estuary than the lagoon. The assessed Cr concentrations in both sites have exceeded the threshold level, 50.00 ppb; according to the proposed Ambient water quality standards for inland waters (Central Environmental Authority, 2001). Furthermore, this assessment showed that the averaged Cd concentration in the Achchankulam estuary extremely exceeded the threshold level, 5.00 ppb. The fresh water inputs of the lagoon is received from Attanagalu Oya and industrial zone in Ekala while estuary is receiving that from the second longest Malwathu Oya, which passes through 164 km of the agricultural farming lands to reach the coast of Mannar from Anuradhapura. So it may be possible that high Cd, As and Pb levels in the estuary may be a consequence of the higher utilization of fertilizer and agrochemicals which contain heavy metals as impurities, than other areas in Sri Lanka.
Assessment of polycyclic aromatic hydrocarbons and heavy metals in the vicinity of an oil refinery in Sri Lanka using moss as a bioindicator.
(International Research Symposium on Pure and Applied Sciences, 2017 Faculty of Science, University of Kelaniya, Sri Lanka., 2017) Nirmani, L. P. T.; Deeyamulla, M. P.
Polyaromatic hydrocarbons (PAHs) and heavy metals are toxic compounds emitted from various anthropogenic sources and have a great effect on the human health as well as on the environment. Population living closer to the vicinity of an oil refinery may be at a greater risk of exposure to PAHs through inhalation, ingestion, and direct contact with the contaminated media. Atmospheric deposition of pollutants occur through both wet and dry deposition. Biomonitoring agent and passive monitoring technique were used in this study to evaluate heavy metal and PAH content in moss (Hyophila Involuta) collected from 30 sampling sites around the Sapugaskanda oil refinery with a 5 km radii. Sample collection was carried out in two separate days in September 2016. This study aimed to obtain a possible correlation between the atmospheric deposition of heavy metals and radial distribution pattern using epiphyte mosses collected from each sites. 16 PAHs were identified and quantified using High Performance Liquid Chromatography (HPLC). Bioaccumulation ability of seven heavy metals (Cr, Ni, Cd, Cu, Pb, Fe and Zn) were evaluated by Ion coupled plasma mass spectroscopy (ICP – MS). Contamination factor (CF) and Pollution loading index (PLI) were determined with reference to the background heavy metal concentration values. Maximum heavy metal accumulation was observed in a 2 km radii from the oil refinery. All the sampling sites showed CF>1 except for heavy metals Cr and Cd in few sampling sites. Pollution loading index for each radius showed a higher value with reference to the background levels. Low molecular weight (LMW) PAHs move away from the source (Sapugaskanda refinery) and high molecular weight (HMW) PAHs deposit near the emission source. Total concentration of carcinogenic PAHs varied from 0.25 to 13.75 ng/g. According to the study, total PAHs deposition observed around the vicinity of the oil refinery was in the range of 20 – 4398 ng/g. Due to the similar pollution sources, PAHs have often been found to coexist with environmental pollutants including heavy metals. Correlation studies were carried out statistically. There was a positive correlation between the Fe with Low molecular weight Polyaromatic hydrocarbons (LMW PAH) and High molecular weight polyaromatic hydrocarbons (HMW PAH) (p< 0.05). There were few correlations among several metals. Fe showed a positive correlation with metals such as Ni, Cu and Cd whereas Ni showed positive correlation with Cu and Cd. There was no significant correlation among other metals and PAHs. (p> 0.05).
Atmospheric chemical composition of bulk precipitation in different regions of Gampaha District
(Faculty of Science, University of Kelaniya Sri Lanka, 2022) Edirisinghe, E. A. C. P; Deeyamulla, M. P.
Wet and dry deposition, both referred to as bulk precipitation, are the two methods of removing gases and particulates from the atmosphere. This research primarily focuses on bulk precipitation analysis to evaluate the pollution sources and the extent of seasonal characteristics of precipitation for air quality monitoring in the vicinity of Kerawalapitiya-Yughadhanavi Power Plant, the largest oil-fired power plant, and Sapugaskanda Oil Refinery, the single largest oil refinery in Sri Lanka. During the northeast and first intermonsoon seasons, 30 rainwater samples were collected over a five-month period from November 2021 to March 2022, in Kerawalapitiya (site A), Sapugaskanda (site B), and Kadawatha (site C), all densely populated and heavily industrialized areas, and Keragala (background site D), a rural area in Gampaha district where anthropogenic influence is minimal. Based on volume weighted mean (VWM) pH variation, Kadawatha area showed acidic precipitation (5.21±0.3) during the study period, while sites A (6.81±0.3), B (5.75±0.8) and D (6.12±0.2) had alkaline pH values. The neutralization factors (NFs) for the major cations (Na+, K+, Mg2+,Ca2+, and NH4+) in the precipitation indicated that higher levels of Na+ and NH4+ contributed to the neutralization of the acidic components at sites A and D, respectively. The VWM concentrations of ionic species were determined by ion chromatography followed the order of Na+> Ca2+>SO42-> Mg2+>NO3->Cl->NH4+>K+>Br-> F- in Kerawalapitiya, NO3->SO42->Ca2+>Na+> Cl-> K+> NH4+>Mg2+> Br->F- in Sapugaskanda and SO42->NO3->Na+> K+>Cl->Ca2+>Mg2+>Br->F- in Kadawatha. Nevertheless, Keragala showed a relatively low ionic composition, and it was in the order of NO3->NH4+>Na+>Cl->Ca2+>K+> SO42->Mg2+>Br->F-. There was a reduction in the VWM SO42- concentration in the Sapugaskanda site compared to a previous study done in this area in 2021. This may be due to the time-to-time shutdown of the Sapugaskanda oil refinery during the study period for the first time since 1969. Enrichment factors (EFs) associated with the sea (EFsea)and crust (EFcrust) confirmed that the Cl- ions at all four sites were marine in origin, although Ca2+, K+, and SO42- were not from marine sources. In addition, the values of EFsea and EFcrust for SO42- and NO3- showed greater than 1 in all four sites. This may be due to human activities in the study area. Also, Mg2+ has a significant contribution from both marine and soil at sites B, C, and D, while it is of anthropogenic origin at site-A. VWM metal concentrations determined by ICP-MS revealed that all sites had higher values for Al, Mg, K, and Zn, but lower concentrations of Cd, As, Co, and Cr. The results of this study further confirmed that rainwater analysis is an indirect indicator of air quality in a given area.
Atmospheric chemical composition of bulk precipitation of selected areas of Galle District.
(Faculty of Science, University of Kelaniya Sri Lanka, 2023) Amunugama, H. M. L. V.; Deeyamulla, M. P.
The quality of the atmosphere refers to its composition and the presence of pollutants, while precipitation can have direct effects on the quality of the atmosphere. Both wet and dry deposition contribute to the removal of pollutants and particles from the atmosphere. Therefore, it is very important to collect data on the chemical composition of the atmosphere to identify air pollution and its causes and to control air pollution. This study focuses on the chemical composition of precipitation in selected areas of Galle district, one of the most urbanized districts in the southern province. Wet precipitation samples were collected from three industrial sites, Unawatuna, Bataduwa, Koggala and the Sinharaja rainforest area of Lankagama, the country's last viable area of primary tropical rainforest. Wet precipitation samples were collected from September 2022 to February 2023, which covers the South-West monsoon, Second inter-monsoon, and North-East monsoon seasons and a total of 40 samples were analysed for pH, conductivity, Na+, K+, Mg2+, Ca2+, NH4 +, Cl-, F-, Br-, SO4 2-, NO3 -, Cu, Pb, Ni, Cd, Fe, Al, Zn, C, and Mn. Based on VWM (Volume Weighted Mean) pH values Unawatuna (6.95±0.6), Bataduwa (6.69±0.8) and Koggala (6.8±0.3) sites had slightly alkaline pH values, while the control site Lankagama-Sinharaja (5.73±0.02) had slightly acidic pH. The volume-weighted average concentrations of major ionic species in the precipitation samples from the industrial sites were in the order Na+ > Cl- > SO4 2- > Ca2+ > NO3 - > NH4 + > K+ > Mg2+ > Br- > F-, while the control site followed the order of Na+ > Cl- > SO4 2- > Ca2+ > NH4 + > K+ > NO3 - > Mg2+ > F- > Br-. The neutralization factor (NF) for Na+ ions indicates that higher Na+ concentrations contribute to the neutralization of acidic components at the Unawatuna, Koggala and Lankagama sites. When considering the marine contribution, The Enrichment Factors (EF) calculated for SO4 2-/Na+, Ca2+/Na+ and Mg2+/Na+ ratios were higher than the reference value, suggesting that several anthropogenic sources other than marine may be contributing. Among metallic constituents, Zn and Al concentration were higher at all sites except the Koggala site, which had higher Fe content. Pb and Ni concentrations were below the detection limit of ICP-MS at all sampling sites. This study confirmed the relationship between atmospheric chemical composition and nearby anthropogenic and natural sources, as well as the indirect relationship between rainwater analysis and air quality in a given region. Furthermore, the precipitation data from Sinharaja demonstrates the absence of pollution, further solidifying its reliability as a backdrop.
Atmospheric chemical composition of bulk precipitation of the vicinity of oil refinery in Sapugaskanda, Sri Lanka
(Faculty of Science, University of Kelaniya, Sri Lanka, 2021) Karunarathna, M. M. S. T.; Deeyamulla, M. P.; Kannangara, A. T.
Rainwater quality is critical because it can be used to forecast air quality. The aim of the current study was to investigate the chemical characteristics of bulk precipitation in Kelaniya, Sapugaskanda, and Siyambalape, an area close to an oil refinery in Gampaha District, one of Sri Lanka's most densely populated and urbanized districts. Wet precipitation samples were analyzed for pH, conductivity, Na+, K+, Mg2+, Ca2+, F-, Cl-, NO3-, SO42-, Pb, Cu, Mn, Al, Zn, Ni, Cr, Cd, and Fe for a total of 18 samples between 2020 July and 2020 October. The results obtained were compared with 6 samples taken from a background area situated in Kidelpitiya, Meegoda where the anthropogenic influence is minimum. Volume-weighted average concentrations of the major ionic species present in precipitation samples were in the order of F−< K+< NO3−< Mg2+< Cl−< SO42−< Ca2+< Na+. Neutralization of the acidic species would take place due to the presence of MgCO3 and CaCO3. Other than the anthropogenic sources natural sources were also considered. When considering a marine contribution, SO42−/Na+, Ca2+/Na+, and Mg2+/Na+ ratios are higher than the reference value suggesting that contribution of sources be possible other than marine. When considering a soil contribution, SO42−/Ca2+, NO3−/Ca2+, Na+/Ca2+, and Cl- /Ca2+ ratios are higher than the reference value suggesting that contribution of sources be possible other than soil. It was also found that Al is the most predominant trace element in the area while Fe is the least (All are in metallic forms not in the ionic forms). Investigation of correlation between major ionic species and elements (Ca2+, SO42-, Al, Cu, Zn, and NO3-) in the wet precipitation samples identified probable anthropogenic sources such as heavy traffic, biomass burning, large-scale constructions, and waste incineration. The highest correlation between Na+ and Cl- is probably due to marine contribution. A comparison between the background and the study area was carried out to identify the difference between the chemical compositions of the atmosphere during the given period suggesting that the area has a higher chemical composition of the species interested rather than the background. Also, this study reveals the effect of the Covid-19 pandemic on the reduction of the chemical composition of such species of the atmosphere in the area of interest. This study reveals that the chemical composition in the atmosphere is strongly dependent on both anthropogenic and natural phenomena around the area of study.
Atmospheric heavy metal analysis in Chronic Kidney Diseases of unknown aetiology (CKDu) affected areas using moss bio-monitoring
(Research Symposium on Pure and Applied Sciences, 2018 Faculty of Science, University of Kelaniya, Sri Lanka, 2018) De Silva, K. M. T.; Deeyamulla, M. P.
Air pollution is a common issue faced by both urban and rural areas due to many factors. Heavy metals are one of the major types of air pollutants that can cause different health issues in humans including kidney diseases. Although only a handful of studies have been conducted so far to link air pollution with kidney disease, correlations have been found between atmospheric particulate matters with kidney diseases. These particulate matter are capable of absorbing heavy metals. Cr, Pb and Cd are three such heavy metals identified with a direct link towards kidney diseases. Therefore, in this study, the atmospheric levels of these three heavy metals were investigated in areas with high occurrence of Chronic Kidney Diseases. The study was carried out using moss biomonitoring as the method of atmospheric monitoring. Two variations of this method which are native moss analysis and moss bag technique were used. In native moss technique, moss samples (Hyophila involuta) of the selected species were collected from different locations of the study area and were analysed. In the moss bag method, nylon bags containing the selected moss species were placed in different locations of the study area, keeping undisturbed for 100 days, collected and analysed. In this study Medawachchiya was selected as the study area due to the high records of CKDu in the area. Levels of Cr, Cd and Pb in 4 different geographic locations within Medawachchiya were compared and the accumulation of heavy metal during 100 day period was analysed using moss bag technique. All the analysis was done using Flame Atomic Absorption Spectrophotometry (GBC 5000). According to the native moss analysis, highest amount of heavy metal detected was Cr (22.29 ± 3.15 μg/gmoss), followed by Pb (16.48 ± 1.80 μg/gmoss) and Cd (1.21 ± 0.06 μg/gmoss). According to the Native moss analysis, the highest levels of Cr, Pb and Cd were recorded at Kirigollewa Gramaniladhari division. There were no significant difference between Cd, and Pb amounts between Kirigollewa and other areas (P=0.357), but there was a significantly higher amount of Cr in this area compared to other areas (P=0.033). Considering the CKDu patient data, Kirigollewa can be recognized as a high prevalent area of the disease. Moss bag analysis revealed an increase of Pb and Cr levels during the given period but a decrease of Cd level in all areas. However, to establish a possible correlation with CKDu, more analysis is required.
Characterization of airborne microplastics in different indoor environments in University of Kelaniya, Sri Lanka-A preliminary study
(Faculty of Science, University of Kelaniya Sri Lanka, 2024) Saumya, R. L. K.; Deeyamulla, M. P.; De Silva, D. S. M.; Athukorala, A.; Bakir, A.; McGoran, A. R.
Airborne microplastic (MP) contamination in indoor environments is an increasing concern due to potential health risks from inhalation. This study examined the distribution, polymer composition, and morphology of airborne MPs in five indoor settings at the University of Kelaniya, Sri Lanka. Passive sampling was conducted over 14 days in one office, two laboratories, and two lecture halls. A diverse array of MP forms and colors were identified using stereomicroscopy and advanced micro imaging. Further analyses were carried out using laser direct infrared spectrometer (LDIR) to identify the constituent polymer types of MPs. Fibers dominated the fallout samples in the office (100%), lecture hall 2 (60%), laboratory 1(56.25%), lecture hall1 (25%), whereas no fibers were found in the sample taken from laboratory 2. However, fragments were identified only in the sample collected from laboratory 2. Films were present at all locations except the office, but their number was relatively lower compared to fibers. The deposition rates of fibers were 3.7 × 102 fibers/m2/day in the laboratory 1, 0.82× 102 fibers/m2/day in the lecture hall 1, 1.23 × 102 fibers/m2/day in the lecture hall 2, and 1.64 × 102 fibers/m2/day in the office. The deposition rates of films in laboratory 1 and the lecture hall 2 were close to each other, corresponding to 1.64 × 102 films/m2/day. Among the selected indoor environments examined in this study, laboratory 1 exhibited the highest deposition rate of MPs on both fibers and films. The increased accumulation is likely due to the proximity of an active construction site, which could facilitate the transport of MPs into the laboratory. Furthermore, the laboratory's heavy use by approximately 60 students daily may have contributed to higher MPs levels. Conversely, laboratory 2 displayed the lowest deposition rate of MPs. This difference can be linked to several factors, including its relatively lower student occupancy, the shorter durations students spend within the laboratory environment and the air-conditioned nature. In all selected indoor environment settings, the prevalent color among MPs is transparent. Laboratory 1 exhibits a relatively balanced representation of transparent (35.29%), green (35.29%) and red (17.69%) MPs, while laboratory 2 predominantly comprises blue (50%) MPs. Lecture hall 1 shows a significant presence of blue MPs (50%), while lecture hall 2 primarily consists of transparent MPs (60%). The office environment exclusively contains transparent MPs. Laboratory 1 and laboratory 2 predominantly have MPs in the 100–250 μm range, while lecture hall 1 and lecture hall 2 show more varied sizes with larger particles being more prevalent, and the office environment mainly contains particles in the 250–500 μm. LDIR spectroscopy was revealed that the MPs were composed of polyamide (17%), polyethylene (10%), polyurethane (7%), polyester (6%), polypropylene (4%), and acrylonitrile butadiene styrene (2%). This study highlights the prevalence of MPs in various indoor environments, emphasizing the importance of evaluating health risks associated with long term exposure.
Comparison of the tolerance of cadmium (Cd2+), lead (Pb2+) and their mixtures by Staphylococcus sp. isolated from a water body receiving textile effluent
(4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Aththanayake, A. M. K. C. B.; Rathnayake, I. V. N.; Deeyamulla, M. P.
Cd2+ and Pb2+ are widely used heavy metals in industries such as electroplating, battery, plastic and pigment production etc. These heavy metals are considered as highly threatening substances to human body, which can cause carcinogenic effects and organ dysfunctions. The isolated Staphylococcus sp. from waste effluent was exposed to a range of single and mixed metal concentrations of Cd2+ and Pb2+ in modified Tris-minimal medium. The growth patterns of Staphylococcus sp. during 24-hour intervals were monitored spectrophotometrically at 600 nm. The effective concentrations (EC50) of Staphylococcus sp. were calculated up to 72 hours. Staphylococcus sp. showed a gradually increasing growth in Pb2+ containing medium, where as a decreasing growth in Cd2+ containing medium was observed after 48 hours. It showed an increasing growth when grown in the presence of both metals. EC50 values at 24, 48 and 72 hours with Cd2+ and their mixture showed a gradual decrease while EC50 values of Pb2+ showed a gradual increase. Results of the study indicated that Staphylococcus sp. has comparatively high tolerance to Pb2+ than Cd2+ and their mixtures
Determination of enhancement of atmospheric heavy metal concentration and total nitrogen content in moss from traffic exposure
(Research Symposium on Pure and Applied Sciences, 2018 Faculty of Science, University of Kelaniya, Sri Lanka, 2018) Perera, L. E. H.; Deeyamulla, M. P.
Heavy metal concentration and total nitrogen content were surveyed using moss as a bioindicator. The effect of NOX emissions from traffic on moss tissue nitrogen and tissue concentrations of Pb, Cu, Cd and Cr were determined. Moss species, Barbula unguiculata (70 samples) growing next to roads that were exposed to different traffic densities as high, medium and low were collected from different sites in the Western province of Sri Lanka. Selection of the sampling sites were based on google map online traffic application. Results were compared with background level concentrations of heavy metals and total nitrogen content obtained from Sinharaja rain forest where the anthropogenic influence is minimum. Bioaccumulation of heavy metals were determined by Atomic Absorption Spectrophotometer (AAS). Colorimetric method and the conventional Kjeldhal method were compared for the determination of total nitrogen content and the total nitrogen amount was determined using the rapid colorimetric method. Background levels of Pb, Cu, Cd and Cr were 7.23 ± 2.11 µg/g, 5.53 ± 1.75 µg/g, 0.17 ± 0.06 µg/g and 6.61 ± 2.58 µg/g respectively. Background sites showed a total nitrogen content of 3.25 ± 0.05 mg/g. Mosses collected from sites that were exposed to high traffic had a total nitrogen content ranging between 7.19 - 13.16 mg/g. The Pb, Cu, Cd and Cr contents had ranges between 30.87 - 45.98 µg/g, 63.73 - 95.24 µg/g, 3.22 - 3.76 µg/g and 41.98 - 64.12 µg/g respectively. Sites that were exposed to medium traffic showed a total nitrogen content ranging between 6.62 - 8.67 mg/g. The Pb, Cu, Cd and Cr contents had ranges between 21.17 - 28.39 µg/g, 44.38 - 56.09 µg/g, 1.59 - 2.94 µg/g and 24.60 - 41.41 µg/g respectively. Sites that were exposed to low traffic showed a total nitrogen content ranging between 6.84 - 10.63 mg/g. The Pb, Cu, Cd and Cr contents had ranges between 10.40 - 13.62 µg/g, 26.36 - 39.83 µg/g, 1.06 - 1.62 µg/g and 16.71 - 19.54 µg/g respectively. This work indicates that the heavy metal contents have a positive correlation with the traffic exposure with Cu being greater than other heavy metals (Pb, Cr, Cd) and that the total nitrogen content does not show a clear correlation with the traffic exposure. Therefore, in order to obtain a positive correlation, the traffic exposure should be compared with the stable isotope ratio (δ 15N).
Monitoring heavy metal air pollution using moss as a biomonitor and developing a mathematical relationship based on surrogate approach, to determine heavy metal loads in moss
(4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Yohani, A. A. R .; Deeyamulla, M. P.
Atmospheric pollution is one of the major problems that mankind is dealing with. Under air pollutants, heavy metals are toxic and persist in the environment. Monitoring heavy metal loads in the atmosphere is therefore of immense importance for environmental studies. As direct monitoring instruments are expensive and difficult to handle in extreme conditions, the biomonitors can be used as an alternative, cost effective method to monitor heavy metal air pollution. In this study, Barbula unguiculata moss species was used as the biomonitor to determine atmospheric heavy metal content since it was readily available in all selected areas. Sampling areas were divided into 4 major categories i.e. Pettah and Borella under the heavy traffic areas, University of Kelaniya under the moderate traffic area, Kegalle (Nelumdeniya) under the less traffic area and Sapugaskanda as the model area for industrial pollution where number of major industries are present. In each study area, five sub sampling sites were chosen and those selected sites were triplicated. Five heavy metals (Cu, Cr, Zn, Pb and Ni) were analyzed using Flame Atomic Absorption Spectrophotometry. Sinharaja rainforest was treated as the background area where anthropogenic activities and industrial emissions were minimum. According to the native moss analysis, two heavy traffic areas, industrial area and moderate traffic area were in contaminated levels with all five selected heavy metals. Based on the calculated pollution load index values, atmospheric heavy metal pollution in selected areas follows the order, Pettah > Borella ~ Sapugaskanda > University of Kelaniya > Kegalle. Besides the atmospheric heavy metal loads, same heavy metal loads in soil samples from the same five areas were analyzed. The correlation analysis was performed and there was no any clear correlation among heavy metal loads in the atmosphere and the soil of the selected five areas as the soil heavy metal loads depend on several other external factors. It was found from the study that surrogate approach was an effective methodology for the determination of heavy metal contents by using only two surrogate heavy metals per each site. By using Pearson Correlation Analysis and Multiple Linear Regression Analysis, mathematical relationships were developed to estimate heavy metal loads and those were validated and the reliability was assessed.
Plant and Plant Associated Microflora: Potential Bioremediation Option of Indoor Air Pollutants.
(Nepal Journal of Biotechnology, 2021, 2021) Gunasinghe, Y. H. K. I. S.; Rathnayake, I.V.N.; Deeyamulla, M. P.
Indoor air pollution is a significant problem today because the release of various contaminants into the indoor air has created a major health threat for humans occupying indoors. Volatile Organic Compounds (VOCs) are ...
Staphylococcus edaphicus KCB02A11 incorporated with natural adsorbents: first report on its tolerance and removal of hexavalent chromium [Cr(VI)]
(Springer Link, 2024) Aththanayake, A. M. K. C. B.; Rathnayake., I. V. N.; Deeyamulla, M. P.; Megharaj, Mallavarapu
Deteriorating the quality of different parts of the ecosystem due to toxic metals is a serious global issue. Hexavalent chromium is a metal that can cause adverse effects on all living beings, including plants, animals, and microorganisms, on exposure to high concentrations for prolonged periods. Removing hexavalent chromium from various types of wastes is challenging; hence the present study investigated the use of bacteria incorporated with selected natural substrates in removing hexavalent chromium from water. Isolated Staphylococcus edaphicus KCB02A11 has shown higher removal efficiency with a wide hexavalent chromium range (0.025-8.5 mg/L) within 96 h. Incorporating the isolated strain with natural substrates commonly found in the environment (hay and wood husk) showed high removal potential [100% removal with 8.5 mg/L of Cr(VI)], even within less than 72 h, with the formation of biofilms on the used substrates applied for metal removal on a large scale for prolonged periods. This study is the first report investigating hexavalent chromium tolerance and removal by Staphylococcus edaphicus KCB02A11.
Staphylococcus edaphicus KCB02A11 incorporated with natural adsorbents: first report on its tolerance and removal of hexavalent chromium [Cr(VI)]
(2023) Aththanayake, A. M. K. C. B.; Rathnayake, I. V. N.; Deeyamulla, M. P.; Megharaj, Mallavarapu
Deteriorating the quality of different parts of the ecosystem due to toxic metals is a serious global issue. Hexavalent chromium is a metal that can cause adverse effects on all living beings, including plants, animals, and microorganisms, on exposure to high concentrations for prolonged periods. Removing hexavalent chromium from various types of wastes is challenging; hence the present study investigated the use of bacteria incorporated with selected natural substrates in removing hexavalent chromium from water. Isolated Staphylococcus edaphicus KCB02A11 has shown higher removal efficiency with a wide hexavalent chromium range (0.025-8.5 mg/L) within 96 h. Incorporating the isolated strain with natural substrates commonly found in the environment (hay and wood husk) showed high removal potential [100% removal with 8.5 mg/L of Cr(VI)], even within less than 72 h, with the formation of biofilms on the used substrates applied for metal removal on a large scale for prolonged periods. This study is the first report investigating hexavalent chromium tolerance and removal by Staphylococcus edaphicus KCB02A11.
Study of chemical composition and microbial content of bulk depositions of selected sites in Gampaha district
(Faculty of Science, University of Kelaniya Sri Lanka, 2022) Navarathne, W. R. M. H. P.; Deeyamulla, M. P.; Rathnayake, I. V. N.
Wet atmospheric deposition, a natural primary scavenging process, removes organic and inorganic pollutants from the atmosphere. Significant variations in this process are observed depending on geographic conditions and anthropogenic factors. There is considerable research interest in the composition of atmospheric depositions, as it is important to decide the extent of atmospheric pollution and to predict the atmospheric quality of a selected area. However, in Sri Lanka, fewer previous studies have been reported on the chemical composition and microbial content of rainwater. In this study, three sites; Kerawalapitiya (Site A), University of Kelaniya (site B), and Keragala (Site C-control site), were selected from Gampaha district to investigate the chemical and microbial parameters of rainwater from November 2021 to March 2022. The bulk precipitation was analyzed for pH, conductivity, cations (Na+, Ca2+, NH4+, K+, Mg2+), anions (NO3-, SO42-, Cl-, Br-, F-) using ion chromatography and trace metal elements (Mg, Al, Zn, As Fe, Ni, Pb, Cu, Mn, Cr, Co, Cd) using Inductively coupled plasma-mass spectrophotometer. The pH range of all considered events was 5.98-7.31(±0.4). Volume Weighted Average (VWA) conductivity was 120, 72 and 55, respectively in sites A, B, and C. The highest VWA conductivity was observed in Kerawalapitiya. Although there were differences in the order of ions, Na+ and Ca2+ can be mentioned as the dominant cations in all the sites except in Keragala, where NH4+ was the dominant cation. Further, SO42-, Cl-, and NO3- can be mentioned as dominant anions in the selected sites. VWA of trace metal elements showed that the most abundant metal in all the sites was Mg, followed by Al and Zn. Co and Cr metal concentrations were comparatively the lowest in all three sites. The highest neutralization potential was associated with Na+, Ca2+ and NH4+ in sites A, B, and C, where the neutralization factors were 1.396, 0.655 and 0.310, respectively. Furthermore, the One -way ANOVA test revealed that there were significant differences in bacterial and fungal contents between all three sites (pbacteria= 0.000, pfungi = 0.027, ɑ=0.05).