Browsing by Author "Bandara, K. R. V."

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Imposex in the gastropod, Thais clavigera as a sensitive biomarker for tibutyltin (TBT) pollution
(Faculty of Science, University of Kelaniya Sri Lanka, 2023) Bandara, K. R. V.; Manage, P. M.
Imposex occurs when certain invertebrates are exposed to organotin antifouling paints, resulting in the formation of morphological traits such as the penis and vas deferens in female gastropod mollusks or the superimposition of male morphological features onto females. Imposex is a morphological biomarker that can be used to detect organotin contamination in marine habitats. Among the various butyltin compounds, TBT accumulates the most and is the most common cause of imposex. TBT-induced imposex may be responsible for a significant amount of the loss of certain coastal marine invertebrates. The gastropod, Thais clavigera was used for imposex studies considering its high TBT sensitivity. T. clavigera species were collected from both commercial and fishery harbors in Western and Southern coastal stretches (n=30). Imposex response in the populations was evaluated by using the Relative Percentage Penis Length Index (RPLI) and Vas Deferens Length Index (VDLI), and Imposex development was assessed by calculating the indices of imposex incidence or Frequency (I %) given as a percentage of imposexaffected females in the sample. Statistical analyses were done by using Anova, 2016. Results revealed that the highest imposex frequency and TBT concentration were detected in Colombo harbor (TBT= 303± 7.4 ng/L; I= 38%), where the highest TBT concentration was recorded in Sri Lanka. Dikkowita (97± 4.3 ng/L; I= 36%), Galle (110± 4.1 ng/L; I=8%), Mirissa (54± 3.6 ng/L; I= 5%) and Kirinda (2. 2± 0.3 ng/L; I= 2%) followed with varying TBT concentrations and I%. No imposex frequency was recorded in samples collected from Dewundara and Hambanthota harbors, showing the relationship between contamination levels of TBT and imposex development in mollusks. RPLI in T. clavigera was found from 14.63% to 24.77%. Further, it was found that the imposex severity was high in females of T. clavigera collected from the Colombo and Dikkowita harbors. A positive correlation between the frequency of imposex incidence and TBT concentrations found at different locations (p<0.05 & r2= 0.64) suggests that imposex-affected females in the population of T. clavigera augment with increasing TBT concentrations in the marine environment. It could be concluded that TBT is a potential xenobiotic chemical that acts as an environmental hormone that adversely affects mollusks causing reproductive impairment and leading to imposex incidences.
Levels of Naphthalene and Phenanthrene in seawater along the coastal belt from Colombo to Mirissa in Sri Lanka
(Faculty of Science, University of Kelaniya Sri Lanka, 2023) Mallikarachchi, K. E. P.; Bandara, K. R. V.; Manage, P. M.
Polycyclic Aromatic Hydrocarbons (PAHs) are pervasive pollutants in marine and coastal settings. Naphthalene (NAP) and Phenanthrene (PHE) are among the sixteen PAHs recognized as priority pollutants by the United States Environmental Protection Agency. Due to their persistence, bioaccumulative capacity, and probable carcinogenicity, PAHs pose a serious threat to the health and wellbeing of humans when ingested. The present study was carried out to evaluate the levels of NAP and PHE in seawater along the coastal belt from Colombo to Mirissa, where coastal water pollution is considered to be high. Seawater samples collected from 19 distinct locations (n=3 each) along the selected area underwent HPLC analysis, followed by organic solvent extraction. Each of these locations provided three replicates, facilitating a reliable evaluation of the concentrations of NAP and PHE. The NAP concentration along the coastal belt was from 1.70 to 15.05 mg/L. The highest NAP concentration was recorded in Mirissa (15.05 ± 0.14 mg/L), followed by Galle Face, Bentota, Rathgama, Wellawatta, Gintota, Galle, Ambalangoda, Weligama, Kalutara, Unawatuna, Ratmalana, Moratuwa, Koggala, Hikkaduwa, Mount Lavinia, Panadura, and Wadduwa. In comparison, the lowest NAP concentration was detected in Dehiwala (1.70 ± 0.00 mg/L). The highest PHE concentration was recorded in Ambalangoda (5.36 ± 0.55 mg/L) followed by Mirissa, Galleface, Weligama, Rathgama, Gintota, Bentota, Galle, Koggala, Unawatuna, Hikkaduwa, Wellawatta, Dehiwala, Ratmalana, Wadduwa, Mount Lavinia, Panadura, and Moratuwa. However, PHE was not detected in Kalutara. Mirissa was heavily polluted, having the highest NAP concentration and the second highest concentration of PHE (5.25 ± 0.03 mg/L). The concentrations of NAP and PHE in all coastal water samples except Kalutara exceeded the maximum permissible concentration (􀂦PAHs = 0.030 μg/L) stated by the Environmental Quality Criteria for the United States. The high concentrations of PAHs might be due to high oil and grease content caused by engine oil leaks from fishing boats and boat repair stations, infrequent oil and sludge spills from nearby industries, unintentional oil spills when refueling, and tributary inflows. Since NAP has a higher solubility in water, the concentration of NAP in seawater is higher than that of PHE. This study provides valuable information for EIA programs and contributes to developing effective strategies to mitigate PAH pollution in coastal waters. Broader studies are recommended to pinpoint the sources of PAHs and explore strategies for reducing environmental emissions.
Novel solid phase micro extraction (SPME) Method for GC-MS analysis of Tributyltin.
(4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Bandara, K. R. V.; Chinthaka, S. D. M.; Manage, P.M.
Tributyltin (TBT) is an organotin compound belongs to the group of Persistent Organic Pollutants (POPs) and one of the active ingredients in biocides used to control a broad spectrum of organisms. Antifouling paints which are used for boat hulls, docks, fishnets contain tributyltin to prevent the growth of aquatic fouling organisms. Increasing concentration of TBT in the environment, due to anthropogenic activities cause toxicological impact on target and non-target organisms having sexual disorders like sex changes at ultra-trace level called imposex. According to WHO, the No Observed Effective Level (NOEL) of TBT is below 1 ng L-1, thus a highly specific and sensitive analytical methods are needed to detect TBT in parts per trillion (ppt) level. In the present study, a new ultra-trace quantification method to detect TBT using Solid Phase Micro Extraction (SPME) followed by Gas Chromatography-Mass Spectrometry (GCMS) was optimized. TBT derivatization to tributyltinhydride was carried out using potassium borohydride (KBH4). Medium polar PDMS/DVB, fused silica (65 μm, 24 Ga) SPME fiber were found to be the most appropriate conditions for extraction and pre-concentration of derivatized TBT hydride compound. The best conditions for the extraction were optimized and analyses were done by using GC-MS under 270 ºC desorption temperature and 1 mL min-1 of helium gas flow rate. Field samples were collected from highly polluted and heavy boat traffic area along the coastal belt from Dikkovita to Mirissa, Sri Lanka. The optimal extraction conditions were found to be 10 minutes extraction time, pH 4.9 and the ambient temperature 30 ºC. The highest TBT concentration was detected in Colombo port (303±4.7 ng L-1) following the TBT was recorded in the fishery harbors at Beruwala (124±4.1 ng L-1), Galle (110±4.1 ng L-1), Dikkovita (97±4.3 ng L-1), Hikkaduwa (77±5.3 ng L-1) and Ambalangoda (57±5.2 ng L-1). TBT concentrations in Dehiwala, Wellawatta, Madu, Benthota and Gin ganga river mouths were recorded as 268±4.1 ng L-1, 240±3.4 ng L-1, 214±3.3 ng L-1, 145±2.7 ng L-1 and 50± 2.1 ng L-1 respectively. The recovery of the TBT extraction was 87±2.1 % for the artificial sea water while the Minimum Quantification Level (MQL) was 1 ng L-1. The Minimum Detection Level (MDL) of the method was calculated as0.3 ng L-1. The optimized method is a solvent free and the use of SPME is highly sensitive method to detect TBT in parts per trillion (ppt) levels.